From 8436cfa46e1544bd2582c1907e30478180093918 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 01/13] Revert "docs(#33): update readme"

This reverts commit 0b5a038aa62a1e3f6c1575065fe19d5cd3eaeac7.
---
 README.md | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/README.md b/README.md
index 607f0d0..8f3304c 100644
--- a/README.md
+++ b/README.md
@@ -13,13 +13,12 @@ ARGUS is a Python-based market analytics project evolving from a small FX conver
 
 ARGUS is currently focused on building a clean local foundation:
 
-- currency conversion using live ExchangeRate API data
-- historical market-data retrieval using yfinance
+- currency conversion using live exchange-rate data
 - calculator and conversion logic
 - input validation and error handling
 - Tkinter GUI prototype
 - legacy CLI/debug interface
-- pandas/matplotlib-based analytics prototype
+- first pandas/matplotlib-based analytics prototype
 - tests and documentation
 
 > [!IMPORTANT]
@@ -67,16 +66,19 @@ Each roadmap phase is treated as a separate development sprint. The roadmap desc
 ## Current Features
 
 - Calculator
-- Currency conversion using live ExchangeRate API data
-- Historical market-data retrieval using yfinance
+- Currency conversion using live exchange rates
 - Input validation and error handling
 - Tkinter GUI prototype
 - Legacy CLI/debug interface
 - Basic pandas-based trend metrics
 - Matplotlib-based trend visualization
-- Basic client, service and analytics pipeline
+- Mock time-series data for early analytics development
 - Basic test suite
 
+> [!CAUTION]
+> Historical market data support is still limited.  
+> The current live exchange-rate client is useful for simple conversion, but future analytics work will require additional data sources such as Frankfurter or yfinance.
+
 ---
 
 ## Project Structure
@@ -113,7 +115,6 @@ README.md
 
 - requests
 - python-dotenv
-- yfinance
 - pandas
 - NumPy
 - matplotlib
@@ -123,7 +124,6 @@ README.md
 ### Current data source
 
 - ExchangeRate API for live currency conversion
-- yfinance for historical market-data retrieval and analytics
 
 ---
 
@@ -136,6 +136,7 @@ Planned or likely future technologies include:
 ### Data sources
 
 - Frankfurter API for historical FX data
+- yfinance for broader market data
 - possible additional market-data APIs later
 
 ### Data processing
@@ -192,7 +193,7 @@ Before running ARGUS locally, make sure you have:
 - Python 3.11 or newer
 - Git
 - pip
-- an ExchangeRate API key for live currency conversion. Historical analytics currently use yfinance and do not require an additional API key.
+- an ExchangeRate API key for live currency conversion
 
 Recommended for development:
 
@@ -341,9 +342,9 @@ The project now has a runnable local Python application, a Tkinter GUI prototype
 
 Current focus:
 
-- continue Sprint 2 — Market Analytics & Data Source Expansion
-- extend historical market-data support beyond the first yfinance client
+- start Sprint 2 — Market Analytics & Data Source Expansion
+- improve historical exchange-rate data support
 - add stronger market metrics
 - expand pandas-based analytics workflows
 - improve dashboard usefulness without adding unnecessary chart noise
-- document metric definitions, assumptions and data-source behavior
\ No newline at end of file
+- document metric definitions, assumptions and data-source behavior

From 01e9ac6088a506e5cc6436638be691909226c2d9 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 02/13] Revert "docs(#33): add docstrings"

This reverts commit 5d26c6a41e86e3f4e5a02db2f1790a72e289f96e.
---
 src/argus/clients/yfinance_client.py     | 19 +++----------------
 src/argus/services/timeseries_service.py | 24 +++++++-----------------
 2 files changed, 10 insertions(+), 33 deletions(-)

diff --git a/src/argus/clients/yfinance_client.py b/src/argus/clients/yfinance_client.py
index de86041..88f1527 100644
--- a/src/argus/clients/yfinance_client.py
+++ b/src/argus/clients/yfinance_client.py
@@ -3,22 +3,6 @@
 
 
 def get_timeseries(curr_symbol, start, end, interval):
-    """
-    Fetch historical exchange-rate time series data from Yahoo Finance.
-
-    Args:
-        curr_symbol (str): Currency symbol used by Yahoo Finance, for example
-            "EURUSD=X".
-        start (str): Start date of the requested time range in YYYY-MM-DD format.
-        end (str): End date of the requested time range in YYYY-MM-DD format.
-        interval (str): Data interval supported by Yahoo Finance, for example
-            "1d", "1h", or "15m".
-
-    Returns:
-        pandas.DataFrame | None: A DataFrame containing the columns ``date`` and
-        ``rate`` if data was successfully fetched. Returns ``None`` if the
-        request fails, returns no data, or an exception occurs.
-    """
     try:
         yf_logger = logging.getLogger("yfinance")
         yf_logger.disabled = True
@@ -41,3 +25,6 @@ def get_timeseries(curr_symbol, start, end, interval):
         return data
     except Exception:
         return None
+
+
+get_timeseries("EURUSD=X", "2024-01-01", "2024-01-02", "1m")
diff --git a/src/argus/services/timeseries_service.py b/src/argus/services/timeseries_service.py
index b6251bb..9fe7796 100644
--- a/src/argus/services/timeseries_service.py
+++ b/src/argus/services/timeseries_service.py
@@ -11,25 +11,15 @@ def prepare_trend_analysis(
     curr_symbol: str, start: str, end: str, intervall: str
 ) -> tuple[pd.DataFrame, dict] | None:
     """
-    Prepare time-series data for trend analysis.
+    Prepares the data for trend analysis by adding conversion rates, daily percentage change, and rolling average.
 
-    Fetches historical exchange-rate data for the given currency symbol and
-    enriches it with daily percentage changes and a rolling average. It also
-    calculates the minimum and maximum exchange rates for the resulting time
-    series.
+    Arg1: mock_curr: str - the currency code for which the trend analysis is to
+    be performed
+    Arg2: df: pd.DataFrame - the DataFrame containing the dates for which the
+    conversion rates are to be added
 
-    Args:
-        curr_symbol (str): Currency symbol used by Yahoo Finance, for example
-            "EURUSD=X".
-        start (str): Start date of the requested time range in YYYY-MM-DD format.
-        end (str): End date of the requested time range in YYYY-MM-DD format.
-        intervall (str): Data interval supported by Yahoo Finance, for example
-            "1d", "1h", or "15m".
-
-    Returns:
-        tuple[pd.DataFrame, dict] | None: A tuple containing the prepared
-        DataFrame and a dictionary with minimum and maximum rates. Returns
-        ``None`` if no time-series data could be fetched.
+    Return: tuple[pd.DataFrame, dict] - a tuple containing the updated DataFrame with conversion rates,
+    daily percentage change, and rolling average, and a dictionary with the minimum and maximum rates
     """
 
     df = get_timeseries(curr_symbol, start, end, intervall)

From c8fb004a684dc00a532c64f27c13081335b75d3e Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 03/13] Revert "style(#33): reformat with ruff"

This reverts commit e78c8aba2c1ce5ca562c91e07a15cffd80600dce.
---
 src/argus/clients/yfinance_client.py |  4 +--
 tests/test_yfinance_client.py        | 46 ++++++++++++----------------
 2 files changed, 21 insertions(+), 29 deletions(-)

diff --git a/src/argus/clients/yfinance_client.py b/src/argus/clients/yfinance_client.py
index 88f1527..f25b66b 100644
--- a/src/argus/clients/yfinance_client.py
+++ b/src/argus/clients/yfinance_client.py
@@ -26,5 +26,5 @@ def get_timeseries(curr_symbol, start, end, interval):
     except Exception:
         return None
 
-
-get_timeseries("EURUSD=X", "2024-01-01", "2024-01-02", "1m")
+    
+get_timeseries("EURUSD=X","2024-01-01","2024-01-02","1m")
\ No newline at end of file
diff --git a/tests/test_yfinance_client.py b/tests/test_yfinance_client.py
index faf15fc..7e46c48 100644
--- a/tests/test_yfinance_client.py
+++ b/tests/test_yfinance_client.py
@@ -2,11 +2,10 @@
 import pandas as pd
 import pandas.testing as pdt
 
-
 def test_get_dataframe(monkeypatch):
     test_resp = pd.DataFrame(
         {
-            "Close": [1.105583, 1.103875, 1.094176],
+        "Close": [1.105583, 1.103875, 1.094176],
         },
         index=pd.to_datetime(["2024-01-01", "2024-01-02", "2024-01-03"]),
     )
@@ -16,22 +15,19 @@ def test_get_dataframe(monkeypatch):
     test_end = "2024-01-04"
     test_interval = "1d"
 
+    
     def fake_yfinance_download(*args, **kwargs):
         return test_resp
-
+    
     monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-
-    result = get_timeseries(test_curr, test_start, test_end, test_interval)
-    expected = pd.DataFrame(
-        {
-            "date": pd.to_datetime(["2024-01-01", "2024-01-02", "2024-01-03"]),
-            "rate": [1.105583, 1.103875, 1.094176],
-        }
-    )
+    
+    result = get_timeseries(test_curr,test_start,test_end,test_interval)
+    expected = pd.DataFrame({
+        "date": pd.to_datetime(["2024-01-01", "2024-01-02", "2024-01-03"]),
+        "rate": [1.105583, 1.103875, 1.094176]})
     assert result is not None
     pdt.assert_frame_equal(result, expected)
 
-
 def test_get_none(monkeypatch):
     test_curr = "EURUSD=X"
     test_start = "2024-01-01"
@@ -40,13 +36,12 @@ def test_get_none(monkeypatch):
 
     def fake_yfinance_download(*args, **kwargs):
         return None
-
+    
     monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-
-    result = get_timeseries(test_curr, test_start, test_end, test_interval)
+    
+    result = get_timeseries(test_curr,test_start,test_end,test_interval)
     assert result is None
 
-
 def test_get_empty_frame(monkeypatch):
     test_curr = "EURUSD=X"
     test_start = "2024-01-01"
@@ -55,13 +50,12 @@ def test_get_empty_frame(monkeypatch):
 
     def fake_yfinance_download(*args, **kwargs):
         return pd.DataFrame()
-
+    
     monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-
-    result = get_timeseries(test_curr, test_start, test_end, test_interval)
+    
+    result = get_timeseries(test_curr,test_start,test_end,test_interval)
     assert result is None
 
-
 def test_error_raise(monkeypatch):
     test_curr = "EURUSD=X"
     # start date is inclusiv and end date is exclusiv - the range 2024-01-01-2024-01-01 is not possible
@@ -69,12 +63,10 @@ def test_error_raise(monkeypatch):
     test_end = "2024-01-02"
     test_interval = "1d"
 
-    def fake_yfinance_download(
-        tickers=test_curr, start=test_start, end=test_end, interval=test_interval
-    ):
+    def fake_yfinance_download(tickers=test_curr,start=test_start,end=test_end,interval=test_interval):
         return Exception("fake yfinance error")
-
+    
     monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-
-    result = get_timeseries(test_curr, test_start, test_end, test_interval)
-    assert result is None
+    
+    result = get_timeseries(test_curr,test_start,test_end,test_interval)
+    assert result is None
\ No newline at end of file

From be2262a9480a35e690b13c434d5931afe737ea1d Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 04/13] Revert "test(#33): add tests for client"

This reverts commit b38e77c267caa037372aa3b5dc941c8da1081ff0.
---
 src/argus/clients/yfinance_client.py     | 30 ----------
 src/argus/clients/yfinancy_client.py     | 19 +++++++
 src/argus/services/timeseries_service.py |  2 +-
 tests/test_yfinance_client.py            | 72 ------------------------
 4 files changed, 20 insertions(+), 103 deletions(-)
 delete mode 100644 src/argus/clients/yfinance_client.py
 create mode 100644 src/argus/clients/yfinancy_client.py
 delete mode 100644 tests/test_yfinance_client.py

diff --git a/src/argus/clients/yfinance_client.py b/src/argus/clients/yfinance_client.py
deleted file mode 100644
index f25b66b..0000000
--- a/src/argus/clients/yfinance_client.py
+++ /dev/null
@@ -1,30 +0,0 @@
-import yfinance as yf
-import logging
-
-
-def get_timeseries(curr_symbol, start, end, interval):
-    try:
-        yf_logger = logging.getLogger("yfinance")
-        yf_logger.disabled = True
-        data = yf.download(
-            tickers=curr_symbol,
-            start=start,
-            end=end,
-            interval=interval,
-            multi_level_index=False,
-            progress=False,
-        )
-        yf_logger.disabled = False
-        if data is None:
-            return None
-        if data.empty:
-            return None
-        data = data.reset_index()
-        data = data[["Date", "Close"]]
-        data = data.rename(columns={"Date": "date", "Close": "rate"})
-        return data
-    except Exception:
-        return None
-
-    
-get_timeseries("EURUSD=X","2024-01-01","2024-01-02","1m")
\ No newline at end of file
diff --git a/src/argus/clients/yfinancy_client.py b/src/argus/clients/yfinancy_client.py
new file mode 100644
index 0000000..9d903ed
--- /dev/null
+++ b/src/argus/clients/yfinancy_client.py
@@ -0,0 +1,19 @@
+import yfinance as yf
+
+
+def get_timeseries(curr_symbol, start, end, interval):
+    data = yf.download(
+        tickers=curr_symbol,
+        start=start,
+        end=end,
+        interval=interval,
+        multi_level_index=False,
+        progress=False,
+    )
+    if data is None:
+        return None
+    data = data.reset_index()
+    data = data[["Date", "Close"]]
+    data = data.rename(columns={"Date": "date", "Close": "rate"})
+    result = data.copy()
+    return result
diff --git a/src/argus/services/timeseries_service.py b/src/argus/services/timeseries_service.py
index 9fe7796..82f1a97 100644
--- a/src/argus/services/timeseries_service.py
+++ b/src/argus/services/timeseries_service.py
@@ -1,5 +1,5 @@
 import pandas as pd
-from argus.clients.yfinance_client import get_timeseries
+from argus.clients.yfinancy_client import get_timeseries
 from argus.analytics.metrics.trend_metrics import (
     add_rolling_average,
     add_daily_percentage_change,
diff --git a/tests/test_yfinance_client.py b/tests/test_yfinance_client.py
deleted file mode 100644
index 7e46c48..0000000
--- a/tests/test_yfinance_client.py
+++ /dev/null
@@ -1,72 +0,0 @@
-from argus.clients.yfinance_client import get_timeseries
-import pandas as pd
-import pandas.testing as pdt
-
-def test_get_dataframe(monkeypatch):
-    test_resp = pd.DataFrame(
-        {
-        "Close": [1.105583, 1.103875, 1.094176],
-        },
-        index=pd.to_datetime(["2024-01-01", "2024-01-02", "2024-01-03"]),
-    )
-    test_resp.index.name = "Date"
-    test_curr = "EURUSD=X"
-    test_start = "2024-01-01"
-    test_end = "2024-01-04"
-    test_interval = "1d"
-
-    
-    def fake_yfinance_download(*args, **kwargs):
-        return test_resp
-    
-    monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-    
-    result = get_timeseries(test_curr,test_start,test_end,test_interval)
-    expected = pd.DataFrame({
-        "date": pd.to_datetime(["2024-01-01", "2024-01-02", "2024-01-03"]),
-        "rate": [1.105583, 1.103875, 1.094176]})
-    assert result is not None
-    pdt.assert_frame_equal(result, expected)
-
-def test_get_none(monkeypatch):
-    test_curr = "EURUSD=X"
-    test_start = "2024-01-01"
-    test_end = "2024-01-04"
-    test_interval = "1d"
-
-    def fake_yfinance_download(*args, **kwargs):
-        return None
-    
-    monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-    
-    result = get_timeseries(test_curr,test_start,test_end,test_interval)
-    assert result is None
-
-def test_get_empty_frame(monkeypatch):
-    test_curr = "EURUSD=X"
-    test_start = "2024-01-01"
-    test_end = "2024-01-01"
-    test_interval = "1d"
-
-    def fake_yfinance_download(*args, **kwargs):
-        return pd.DataFrame()
-    
-    monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-    
-    result = get_timeseries(test_curr,test_start,test_end,test_interval)
-    assert result is None
-
-def test_error_raise(monkeypatch):
-    test_curr = "EURUSD=X"
-    # start date is inclusiv and end date is exclusiv - the range 2024-01-01-2024-01-01 is not possible
-    test_start = "2024-01-04"
-    test_end = "2024-01-02"
-    test_interval = "1d"
-
-    def fake_yfinance_download(tickers=test_curr,start=test_start,end=test_end,interval=test_interval):
-        return Exception("fake yfinance error")
-    
-    monkeypatch.setattr("yfinance.download", fake_yfinance_download)
-    
-    result = get_timeseries(test_curr,test_start,test_end,test_interval)
-    assert result is None
\ No newline at end of file

From c66b6e7fdf85265277175eca529dfa79b1836858 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 05/13] Revert "style(#33): remove unused lib"

This reverts commit d26c290f65cd9c8883ffee420741f81e67a77f88.
---
 src/argus/gui/app.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/argus/gui/app.py b/src/argus/gui/app.py
index 9a19523..3801998 100644
--- a/src/argus/gui/app.py
+++ b/src/argus/gui/app.py
@@ -1,4 +1,5 @@
 import tkinter as tk
+import pandas as pd
 from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
 from argus.analytics.charts.trend_chart import create_trendchart
 from argus.services.calculator_service import calc, check_op

From 080c411889e5f829b3a2b6c3dc6bbc786cc59261 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 06/13] Revert "style(#33): unused lib remove"

This reverts commit 9eb6dc5ce4c164d53e6d4b4e1549364947182f9b.
---
 src/argus/analytics/charts/trend_chart.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/argus/analytics/charts/trend_chart.py b/src/argus/analytics/charts/trend_chart.py
index 1293361..462cffc 100644
--- a/src/argus/analytics/charts/trend_chart.py
+++ b/src/argus/analytics/charts/trend_chart.py
@@ -1,4 +1,5 @@
 import matplotlib.pyplot as plt
+import pandas as pd
 from argus.services.timeseries_service import prepare_trend_analysis
 
 

From 2994aa57930ec0865dca60dae2c1ae467d4da0d5 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 07/13] Revert "style(#33): ruff reformat"

This reverts commit 555e5cc91d0c9a5ad4a7a3ea8eb34dd185e796da.
---
 src/argus/analytics/charts/trend_chart.py |  4 ++--
 src/argus/clients/yfinancy_client.py      | 18 ++++++------------
 src/argus/gui/app.py                      |  8 ++++----
 src/argus/services/timeseries_service.py  |  8 +++-----
 src/legacy/gui/app.py                     |  1 -
 tests/test_timeseries_service.py          |  2 +-
 6 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/src/argus/analytics/charts/trend_chart.py b/src/argus/analytics/charts/trend_chart.py
index 462cffc..f889b83 100644
--- a/src/argus/analytics/charts/trend_chart.py
+++ b/src/argus/analytics/charts/trend_chart.py
@@ -3,7 +3,7 @@
 from argus.services.timeseries_service import prepare_trend_analysis
 
 
-def create_trendchart(curr_symbol: str, start: str, end: str, interval: str):
+def create_trendchart(curr_symbol: str, start:str,end:str,interval:str):
     """
     Create a trend chart for exchange-rate analysis.
 
@@ -31,7 +31,7 @@ def create_trendchart(curr_symbol: str, start: str, end: str, interval: str):
         Minimum and maximum exchange-rate values are marked with scatter
         points and annotations.
     """
-    result = prepare_trend_analysis(curr_symbol, start, end, interval)
+    result = prepare_trend_analysis(curr_symbol,start,end,interval)
     if result is None:
         return None
     df, min_max_rates = result
diff --git a/src/argus/clients/yfinancy_client.py b/src/argus/clients/yfinancy_client.py
index 9d903ed..68b505e 100644
--- a/src/argus/clients/yfinancy_client.py
+++ b/src/argus/clients/yfinancy_client.py
@@ -1,19 +1,13 @@
 import yfinance as yf
 
-
-def get_timeseries(curr_symbol, start, end, interval):
-    data = yf.download(
-        tickers=curr_symbol,
-        start=start,
-        end=end,
-        interval=interval,
-        multi_level_index=False,
-        progress=False,
-    )
+def get_timeseries(curr_symbol,start,end,interval):
+    data = yf.download(tickers=curr_symbol,
+        start=start,end=end,interval=interval,multi_level_index=False,progress=False
+    ) 
     if data is None:
         return None
     data = data.reset_index()
-    data = data[["Date", "Close"]]
+    data = data[["Date","Close"]]
     data = data.rename(columns={"Date": "date", "Close": "rate"})
     result = data.copy()
-    return result
+    return result
\ No newline at end of file
diff --git a/src/argus/gui/app.py b/src/argus/gui/app.py
index 3801998..cb70fca 100644
--- a/src/argus/gui/app.py
+++ b/src/argus/gui/app.py
@@ -78,9 +78,9 @@ def show_trend() -> None:
     global trend_chart_widget
 
     curr_symbol = "EURUSD=X"
-    start = "2024-01-01"
-    end = "2025-01-01"
-    interval = "1d"
+    start="2024-01-01"
+    end="2025-01-01"
+    interval="1d"
 
     calc_frame.pack_forget()
     conv_frame.pack_forget()
@@ -91,7 +91,7 @@ def show_trend() -> None:
     content.pack(side="top", fill=tk.BOTH, expand=True)
 
     if trend_canvas is None:
-        fig = create_trendchart(curr_symbol, start, end, interval)
+        fig = create_trendchart(curr_symbol,start,end,interval)
         if fig is None:
             return None
         fig.set_size_inches(7, 4)
diff --git a/src/argus/services/timeseries_service.py b/src/argus/services/timeseries_service.py
index 82f1a97..b506162 100644
--- a/src/argus/services/timeseries_service.py
+++ b/src/argus/services/timeseries_service.py
@@ -7,9 +7,7 @@
 )
 
 
-def prepare_trend_analysis(
-    curr_symbol: str, start: str, end: str, intervall: str
-) -> tuple[pd.DataFrame, dict] | None:
+def prepare_trend_analysis(curr_symbol: str, start:str,end:str,intervall:str) -> tuple[pd.DataFrame, dict] | None:
     """
     Prepares the data for trend analysis by adding conversion rates, daily percentage change, and rolling average.
 
@@ -21,8 +19,8 @@ def prepare_trend_analysis(
     Return: tuple[pd.DataFrame, dict] - a tuple containing the updated DataFrame with conversion rates,
     daily percentage change, and rolling average, and a dictionary with the minimum and maximum rates
     """
-
-    df = get_timeseries(curr_symbol, start, end, intervall)
+    
+    df = get_timeseries(curr_symbol, start,end,intervall)
     if df is None:
         return None
     df = add_daily_percentage_change(df)
diff --git a/src/legacy/gui/app.py b/src/legacy/gui/app.py
index ff9d790..cf52257 100644
--- a/src/legacy/gui/app.py
+++ b/src/legacy/gui/app.py
@@ -33,7 +33,6 @@ def show_menu() -> None:
 
     menu_frame.pack(side="right", fill=tk.BOTH, expand=True)
 
-
 def show_trend() -> None:
     """
     Displays the trend chart in the application. It prepares the data for trend analysis,
diff --git a/tests/test_timeseries_service.py b/tests/test_timeseries_service.py
index 7dd3c9f..4b7ac40 100644
--- a/tests/test_timeseries_service.py
+++ b/tests/test_timeseries_service.py
@@ -22,7 +22,7 @@ def test_get_a_full_timeseries():
         "max_date": ["2024-01-01 00:00:00"],
         "max_rate": [1.1055831909179688],
     }
-    result = prepare_trend_analysis(test_curr, test_start, test_end, test_interval)
+    result = prepare_trend_analysis(test_curr, test_start,test_end,test_interval)
     if result is None:
         return False
     result_df, result_dict = result

From aaf5920c585b0f241b94912dcc0993cfea31d2bf Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 08/13] Revert "test(#33): add a test service"

This reverts commit 92d774baf5d68610f5a45b841855ebf85f5ef1ec.
---
 tests/test_timeseries_service.py | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/tests/test_timeseries_service.py b/tests/test_timeseries_service.py
index 4b7ac40..83b6e1c 100644
--- a/tests/test_timeseries_service.py
+++ b/tests/test_timeseries_service.py
@@ -4,31 +4,28 @@
 from argus.services.timeseries_service import prepare_trend_analysis
 
 
-def test_get_a_full_timeseries():
+def test_is_pct_change_added():
     test_curr = "EURUSD=X"
-    test_start = "2024-01-01"
-    test_end = "2024-01-04"
+    test_start = ""
+    test_end = ""
     test_interval = "1d"
 
     expect_result = {
-        "date": ["2024-01-01", "2024-01-02", "2024-01-03"],
-        "rate": [1.1055831909179688, 1.1038745641708374, 1.0941756963729858],
-        "daily_pct_change": [np.nan, -0.1545452898675692, -0.8786204622023064],
-        "roll_avg": [1.1055831909179688, 1.104728877544403, 1.101211150487264],
+        "date": ["2026-06-01", "2026-06-02", "2026-06-03"],
+        "rate": [1.08, 1.1, 1.14],
+        "daily_pct_change": [np.nan, 1.85185185185186, 3.6363636363636154],
+        "roll_avg": [1.08, 1.09, 1.1066666666666667],
     }
     expect_dict = {
-        "min_date": ["2024-01-03 00:00:00"],
-        "min_rate": [1.0941756963729858],
-        "max_date": ["2024-01-01 00:00:00"],
-        "max_rate": [1.1055831909179688],
+        "min_date": ["2026-06-01"],
+        "min_rate": [1.08],
+        "max_date": ["2026-06-03"],
+        "max_rate": [1.14],
     }
     result = prepare_trend_analysis(test_curr, test_start,test_end,test_interval)
     if result is None:
-        return False
+        return None
     result_df, result_dict = result
-    result_df["date"] = result_df["date"].astype("str")
-    result_dict["min_date"] = [str(result_dict["min_date"][0])]
-    result_dict["max_date"] = [str(result_dict["max_date"][0])]
     expect_df = pd.DataFrame(expect_result)
 
     pdt.assert_frame_equal(result_df, expect_df)

From a5d1ebefe3a7e4885afa9532593c2c34a40cd9f9 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 09/13] Revert "refactor(#33): mock client is legacy"

This reverts commit ec28aa8a3a4a8a31bcabc82bd9ee7a72d9552c35.
---
 pyproject.toml                                |   1 -
 src/{legacy => argus}/clients/mock_client.py  |   0
 src/argus/clients/yfinancy_client.py          |   4 +
 src/legacy/analytics/__init__.py              |   0
 src/legacy/analytics/charts/__init__.py       |   0
 src/legacy/analytics/charts/trend_chart.py    |  72 ----------
 src/legacy/analytics/metrics/__init__.py      |   0
 src/legacy/analytics/metrics/trend_metrics.py |  75 -----------
 src/legacy/clients/__init__.py                |   0
 src/legacy/gui/app.py                         | 125 ------------------
 src/legacy/services/timeseries_service.py     |  32 -----
 tests/test_timeseries_service.py              |  14 +-
 12 files changed, 10 insertions(+), 313 deletions(-)
 rename src/{legacy => argus}/clients/mock_client.py (100%)
 delete mode 100644 src/legacy/analytics/__init__.py
 delete mode 100644 src/legacy/analytics/charts/__init__.py
 delete mode 100644 src/legacy/analytics/charts/trend_chart.py
 delete mode 100644 src/legacy/analytics/metrics/__init__.py
 delete mode 100644 src/legacy/analytics/metrics/trend_metrics.py
 delete mode 100644 src/legacy/clients/__init__.py
 delete mode 100644 src/legacy/gui/app.py
 delete mode 100644 src/legacy/services/timeseries_service.py

diff --git a/pyproject.toml b/pyproject.toml
index e2dc784..665f963 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,6 @@ dependencies = [
     "pandas",
     "numpy",
     "matplotlib",
-    "yfinance",
 ]
 
 [project.optional-dependencies]
diff --git a/src/legacy/clients/mock_client.py b/src/argus/clients/mock_client.py
similarity index 100%
rename from src/legacy/clients/mock_client.py
rename to src/argus/clients/mock_client.py
diff --git a/src/argus/clients/yfinancy_client.py b/src/argus/clients/yfinancy_client.py
index 68b505e..170289e 100644
--- a/src/argus/clients/yfinancy_client.py
+++ b/src/argus/clients/yfinancy_client.py
@@ -9,5 +9,9 @@ def get_timeseries(curr_symbol,start,end,interval):
     data = data.reset_index()
     data = data[["Date","Close"]]
     data = data.rename(columns={"Date": "date", "Close": "rate"})
+    # Need to figure out, how to normalize the dataframe
+    #result = data.reset_index(level=2,col_level=2,drop=True)
+    #result = result[["Date", "Close"]]
+    #result = result.rename(columns={"Date": "date", "Close": "rate"})
     result = data.copy()
     return result
\ No newline at end of file
diff --git a/src/legacy/analytics/__init__.py b/src/legacy/analytics/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/legacy/analytics/charts/__init__.py b/src/legacy/analytics/charts/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/legacy/analytics/charts/trend_chart.py b/src/legacy/analytics/charts/trend_chart.py
deleted file mode 100644
index e18aeb1..0000000
--- a/src/legacy/analytics/charts/trend_chart.py
+++ /dev/null
@@ -1,72 +0,0 @@
-import matplotlib.pyplot as plt
-import pandas as pd
-from legacy.services.timeseries_service import prepare_trend_analysis
-
-
-def create_trendchart(curr: str, dates: pd.DataFrame):
-    """
-    Create a trend chart for exchange-rate analysis.
-
-    Builds a Matplotlib figure showing the exchange rate, its rolling
-    average, and the daily percentage change for a selected currency.
-    The minimum and maximum exchange-rate values are highlighted in the
-    chart.
-
-    Args:
-        curr (str): Currency code or currency pair identifier used for
-            the trend analysis.
-        dates (pd.DataFrame): DataFrame containing the date information
-            used to prepare the time-series analysis.
-
-    Returns:
-        matplotlib.figure.Figure: Matplotlib figure containing the trend
-        chart.
-
-    Notes:
-        The chart uses two y-axes:
-
-            - The left y-axis displays the exchange rate and rolling average.
-            - The right y-axis displays the daily percentage change.
-
-        Minimum and maximum exchange-rate values are marked with scatter
-        points and annotations.
-    """
-    df = pd.DataFrame()
-    df, min_max_rates = prepare_trend_analysis(curr, dates)
-    min_date = min_max_rates["min_date"][0]
-    min_rate = min_max_rates["min_rate"][0]
-    max_date = min_max_rates["max_date"][0]
-    max_rate = min_max_rates["max_rate"][0]
-
-    # Rate and Rolling Average needs seperat x-Achse von Daily Percentage Chnage erhalten
-    fig, ax1 = plt.subplots(figsize=(5, 3.5), dpi=100)
-
-    # Subplot 1
-    ax1.plot(df["date"], df["rate"], color="black", label="Exchange Rate")
-    ax1.plot(df["date"], df["roll_avg"], color="blue", label="Rolling Average")
-
-    # Scatter and Annote Min/Max Rate
-    ax1.scatter(min_date, min_rate, color="red")
-    ax1.scatter(max_date, max_rate, color="green")
-    ax1.annotate("Min", (min_date, min_rate))
-    ax1.annotate("Max", (max_date, max_rate))
-
-    # Rotate date values for better visibillity
-    ax1.tick_params(axis="x", rotation=45)
-
-    # Subplot 2
-    ax2 = ax1.twinx()
-    bar_colors = ["green" if x >= 0 else "red" for x in df["daily_pct_change"]]
-    ax2.bar(
-        df["date"],
-        df["daily_pct_change"],
-        color=bar_colors,
-        alpha=0.4,
-        label="Daily Change",
-    )
-    ax2.legend(loc="upper left")
-    ax2.set_ylabel("Percentage Scale")
-
-    # Adjust the layout
-    fig.tight_layout()
-    return fig
diff --git a/src/legacy/analytics/metrics/__init__.py b/src/legacy/analytics/metrics/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/legacy/analytics/metrics/trend_metrics.py b/src/legacy/analytics/metrics/trend_metrics.py
deleted file mode 100644
index 5622acb..0000000
--- a/src/legacy/analytics/metrics/trend_metrics.py
+++ /dev/null
@@ -1,75 +0,0 @@
-import pandas as pd
-
-
-def add_daily_percentage_change(df: pd.DataFrame) -> pd.DataFrame:
-    """
-        Add the daily percentage change of the exchange rate.
-
-    Calculates the percentage change between each rate value and the
-    previous rate value. The result is added as a new column named
-    ``daily_pct_change``.
-
-    Args:
-        df (pd.DataFrame): DataFrame containing at least a ``rate`` column.
-
-    Returns:
-        pd.DataFrame: A copy of the input DataFrame with an added
-        ``daily_pct_change`` column.
-
-    Notes:
-        The first row will contain ``NaN`` because there is no previous
-        rate value to compare against.
-    """
-    result = df.copy()
-    result["daily_pct_change"] = result["rate"].pct_change() * 100
-    return result
-
-
-def add_rolling_average(df: pd.DataFrame) -> pd.DataFrame:
-    """
-    Add a rolling average of the exchange rate.
-
-    Calculates a rolling mean over the ``rate`` column using a fixed
-    window size of 3 rows. The result is added as a new column named
-    ``roll_avg``.
-
-    Args:
-        df (pd.DataFrame): DataFrame containing at least a ``rate`` column.
-
-    Returns:
-        pd.DataFrame: A copy of the input DataFrame with an added
-        ``roll_avg`` column.
-    """
-    result = df.copy()
-    result["roll_avg"] = result["rate"].rolling(window=3, min_periods=1).mean()
-    return result
-
-
-def get_min_max_rates(df: pd.DataFrame) -> dict:
-    """
-    Get the minimum and maximum exchange-rate values.
-
-    Finds the rows with the lowest and highest values in the ``rate``
-    column and returns their dates and rates in a dictionary.
-
-    Args:
-        df (pd.DataFrame): DataFrame containing at least ``date`` and
-            ``rate`` columns.
-
-    Returns:
-        dict: Dictionary containing the minimum and maximum rate data with
-        the following keys:
-
-            - ``min_date``: Date of the lowest exchange rate.
-            - ``min_rate``: Lowest exchange-rate value.
-            - ``max_date``: Date of the highest exchange rate.
-            - ``max_rate``: Highest exchange-rate value.
-    """
-    min_max = {"min_date": [], "min_rate": [], "max_date": [], "max_rate": []}
-    min_id = df["rate"].idxmin()
-    max_id = df["rate"].idxmax()
-    min_max["min_date"].append(df.loc[min_id, "date"])
-    min_max["min_rate"].append(df.loc[min_id, "rate"])
-    min_max["max_date"].append(df.loc[max_id, "date"])
-    min_max["max_rate"].append(df.loc[max_id, "rate"])
-    return min_max
diff --git a/src/legacy/clients/__init__.py b/src/legacy/clients/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/src/legacy/gui/app.py b/src/legacy/gui/app.py
deleted file mode 100644
index cf52257..0000000
--- a/src/legacy/gui/app.py
+++ /dev/null
@@ -1,125 +0,0 @@
-import tkinter as tk
-import pandas as pd
-from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
-from legacy.analytics.charts.trend_chart import create_trendchart
-
-
-def on_close() -> None:
-    """
-    Handles the closing of the application window. It ensures that any open trend chart is destroyed and
-    the application is properly closed.
-    """
-    if trend_chart_widget is not None:
-        trend_chart_widget.destroy()
-
-    root.quit()
-    root.destroy()
-
-
-def hide_trend_chart() -> None:
-    """
-    Hides the trend chart from the GUI if it is currently displayed.
-    """
-    if trend_chart_widget is not None:
-        trend_chart_widget.pack_forget()
-
-
-def show_menu() -> None:
-    """
-    Displays the main menu in the application. It updates the GUI to show the menu interface.
-    """
-    app_frame.pack_forget()
-    hide_trend_chart()
-
-    menu_frame.pack(side="right", fill=tk.BOTH, expand=True)
-
-def show_trend() -> None:
-    """
-    Displays the trend chart in the application. It prepares the data for trend analysis,
-    creates the trend chart, and updates the GUI to show the chart.
-    """
-    global trend_canvas
-    global trend_chart_widget
-
-    mock_dates = {
-        "date": [
-            "2026-06-01",
-            "2026-06-02",
-            "2026-06-03",
-            "2026-06-04",
-            "2026-06-05",
-            "2026-06-06",
-            "2026-06-07",
-            "2026-06-08",
-            "2026-06-09",
-            "2026-06-10",
-            "2026-06-11",
-            "2026-06-12",
-            "2026-06-13",
-            "2026-06-14",
-            "2026-06-15",
-        ]
-    }
-    mock_dates = pd.DataFrame(mock_dates)
-    mock_curr = "USD"
-
-    menu_frame.pack_forget()
-
-    app_frame.pack(fill=tk.BOTH, expand=True)
-    sidebar.pack(side="top", fill="x")
-    content.pack(side="top", fill=tk.BOTH, expand=True)
-
-    if trend_canvas is None:
-        fig = create_trendchart(mock_curr, mock_dates)
-        fig.set_size_inches(7, 4)
-
-        trend_canvas = FigureCanvasTkAgg(fig, master=content)
-        trend_chart_widget = trend_canvas.get_tk_widget()
-
-    if trend_chart_widget is None:
-        return
-    trend_canvas.draw()
-    trend_chart_widget.pack(fill=tk.BOTH, expand=True)
-
-
-def app() -> None:
-    """
-    The main function that initializes and starts the GUI application. It sets up the main window, frames, labels, entries, and buttons, and defines the layout of the application.
-    """
-    root.mainloop()
-
-
-# Window
-root = tk.Tk()
-root.title("FX-Converter Lab")
-root.geometry("800x600")  # Width x Length
-root.protocol("WM_DELETE_WINDOW", on_close)
-
-# Frames
-menu_frame = tk.Frame(root)
-app_frame = tk.Frame(root)
-sidebar = tk.Frame(app_frame)
-content = tk.Frame(app_frame)
-
-# Trend chart is loaded lazily
-trend_canvas = None
-trend_chart_widget = None
-
-# Labels
-menu_label = tk.Label(menu_frame, text="Menu", font=("Arial", 20))
-menu_label.pack(pady=20)
-
-
-# Buttons
-from_menu_trend_chart = tk.Button(menu_frame, text="Trend Chart", command=show_trend)
-from_sidebar_trend_chart = tk.Button(sidebar, text="Trend Chart", command=show_trend)
-return_menu = tk.Button(sidebar, text="Back to menu", command=show_menu)
-
-from_menu_trend_chart.pack(fill="x", padx=50, pady=15)
-from_sidebar_trend_chart.pack(side="left")
-return_menu.pack(side="left")
-
-show_menu()
-
-if __name__ == "__main__":
-    app()
diff --git a/src/legacy/services/timeseries_service.py b/src/legacy/services/timeseries_service.py
deleted file mode 100644
index d79d599..0000000
--- a/src/legacy/services/timeseries_service.py
+++ /dev/null
@@ -1,32 +0,0 @@
-import pandas as pd
-from legacy.clients.mock_client import get_mock_timeseries
-from legacy.analytics.metrics.trend_metrics import (
-    add_rolling_average,
-    add_daily_percentage_change,
-    get_min_max_rates,
-)
-
-
-def prepare_trend_analysis(
-    mock_curr: str, df: pd.DataFrame
-) -> tuple[pd.DataFrame, dict]:
-    """
-    Prepares the data for trend analysis by adding conversion rates, daily percentage change, and rolling average.
-
-    Arg1: mock_curr: str - the currency code for which the trend analysis is to
-    be performed
-    Arg2: df: pd.DataFrame - the DataFrame containing the dates for which the
-    conversion rates are to be added
-
-    Return: tuple[pd.DataFrame, dict] - a tuple containing the updated DataFrame with conversion rates,
-    daily percentage change, and rolling average, and a dictionary with the minimum and maximum rates
-    """
-    df["rate"] = 0.0
-    # For each date one API call to get the rate
-    for i in range(len(df)):
-        date = str(df.loc[i, "date"])
-        df.loc[i, "rate"] = get_mock_timeseries(mock_curr, date)
-    df = add_daily_percentage_change(df)
-    df = add_rolling_average(df)
-    min_max_rates = get_min_max_rates(df)
-    return df, min_max_rates
diff --git a/tests/test_timeseries_service.py b/tests/test_timeseries_service.py
index 83b6e1c..dbc5675 100644
--- a/tests/test_timeseries_service.py
+++ b/tests/test_timeseries_service.py
@@ -5,10 +5,11 @@
 
 
 def test_is_pct_change_added():
-    test_curr = "EURUSD=X"
-    test_start = ""
-    test_end = ""
-    test_interval = "1d"
+    test_curr = "USD"
+    test_dates = {
+        "date": ["2026-06-01", "2026-06-02", "2026-06-03"],
+    }
+    test_dates = pd.DataFrame(test_dates)
 
     expect_result = {
         "date": ["2026-06-01", "2026-06-02", "2026-06-03"],
@@ -22,10 +23,7 @@ def test_is_pct_change_added():
         "max_date": ["2026-06-03"],
         "max_rate": [1.14],
     }
-    result = prepare_trend_analysis(test_curr, test_start,test_end,test_interval)
-    if result is None:
-        return None
-    result_df, result_dict = result
+    result_df, result_dict = prepare_trend_analysis(test_curr, test_dates)
     expect_df = pd.DataFrame(expect_result)
 
     pdt.assert_frame_equal(result_df, expect_df)

From b0d845e864ad8866d9745c5167a1909784d9bf91 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 10/13] Revert "feat(#33): remove debug prints"

This reverts commit b5273d5f927b1faeaa09eafae522e181881d75ce.
---
 src/argus/analytics/charts/trend_chart.py |  6 ++----
 src/argus/clients/yfinancy_client.py      |  3 +++
 src/argus/gui/app.py                      | 10 ++++------
 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/argus/analytics/charts/trend_chart.py b/src/argus/analytics/charts/trend_chart.py
index f889b83..27dd211 100644
--- a/src/argus/analytics/charts/trend_chart.py
+++ b/src/argus/analytics/charts/trend_chart.py
@@ -31,10 +31,8 @@ def create_trendchart(curr_symbol: str, start:str,end:str,interval:str):
         Minimum and maximum exchange-rate values are marked with scatter
         points and annotations.
     """
-    result = prepare_trend_analysis(curr_symbol,start,end,interval)
-    if result is None:
-        return None
-    df, min_max_rates = result
+
+    df, min_max_rates = prepare_trend_analysis(curr_symbol,start,end,interval)
     min_date = min_max_rates["min_date"][0]
     min_rate = min_max_rates["min_rate"][0]
     max_date = min_max_rates["max_date"][0]
diff --git a/src/argus/clients/yfinancy_client.py b/src/argus/clients/yfinancy_client.py
index 170289e..31877ca 100644
--- a/src/argus/clients/yfinancy_client.py
+++ b/src/argus/clients/yfinancy_client.py
@@ -9,6 +9,9 @@ def get_timeseries(curr_symbol,start,end,interval):
     data = data.reset_index()
     data = data[["Date","Close"]]
     data = data.rename(columns={"Date": "date", "Close": "rate"})
+    print(data.head())
+    print(data.index)
+    print(data.columns)
     # Need to figure out, how to normalize the dataframe
     #result = data.reset_index(level=2,col_level=2,drop=True)
     #result = result[["Date", "Close"]]
diff --git a/src/argus/gui/app.py b/src/argus/gui/app.py
index cb70fca..c656154 100644
--- a/src/argus/gui/app.py
+++ b/src/argus/gui/app.py
@@ -77,9 +77,9 @@ def show_trend() -> None:
     global trend_canvas
     global trend_chart_widget
 
-    curr_symbol = "EURUSD=X"
-    start="2024-01-01"
-    end="2025-01-01"
+    curr_symbol = "EURUSD=X",
+    start="2024-01-01",
+    end="2024-02-01",
     interval="1d"
 
     calc_frame.pack_forget()
@@ -92,15 +92,13 @@ def show_trend() -> None:
 
     if trend_canvas is None:
         fig = create_trendchart(curr_symbol,start,end,interval)
-        if fig is None:
-            return None
         fig.set_size_inches(7, 4)
 
         trend_canvas = FigureCanvasTkAgg(fig, master=content)
         trend_chart_widget = trend_canvas.get_tk_widget()
 
     if trend_chart_widget is None:
-        return None
+        return
     trend_canvas.draw()
     trend_chart_widget.pack(fill=tk.BOTH, expand=True)
 

From d36e90c4cbbb913e90b87e72e613f9463bf4c0e7 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 11/13] Revert "feat(#33): replace mock-client"

This reverts commit 53329924a28f4c927005e7312b1886bc7a3b8c6e.
---
 src/argus/analytics/charts/trend_chart.py |  6 ++---
 src/argus/clients/yfinancy_client.py      | 19 +++++-----------
 src/argus/gui/app.py                      | 27 ++++++++++++++++++-----
 src/argus/services/timeseries_service.py  | 15 ++++++++-----
 4 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/src/argus/analytics/charts/trend_chart.py b/src/argus/analytics/charts/trend_chart.py
index 27dd211..d475bc7 100644
--- a/src/argus/analytics/charts/trend_chart.py
+++ b/src/argus/analytics/charts/trend_chart.py
@@ -3,7 +3,7 @@
 from argus.services.timeseries_service import prepare_trend_analysis
 
 
-def create_trendchart(curr_symbol: str, start:str,end:str,interval:str):
+def create_trendchart(curr: str, dates: pd.DataFrame):
     """
     Create a trend chart for exchange-rate analysis.
 
@@ -31,8 +31,8 @@ def create_trendchart(curr_symbol: str, start:str,end:str,interval:str):
         Minimum and maximum exchange-rate values are marked with scatter
         points and annotations.
     """
-
-    df, min_max_rates = prepare_trend_analysis(curr_symbol,start,end,interval)
+    df = pd.DataFrame()
+    df, min_max_rates = prepare_trend_analysis(curr, dates)
     min_date = min_max_rates["min_date"][0]
     min_rate = min_max_rates["min_rate"][0]
     max_date = min_max_rates["max_date"][0]
diff --git a/src/argus/clients/yfinancy_client.py b/src/argus/clients/yfinancy_client.py
index 31877ca..206a5e3 100644
--- a/src/argus/clients/yfinancy_client.py
+++ b/src/argus/clients/yfinancy_client.py
@@ -2,19 +2,10 @@
 
 def get_timeseries(curr_symbol,start,end,interval):
     data = yf.download(tickers=curr_symbol,
-        start=start,end=end,interval=interval,multi_level_index=False,progress=False
-    ) 
-    if data is None:
-        return None
-    data = data.reset_index()
-    data = data[["Date","Close"]]
-    data = data.rename(columns={"Date": "date", "Close": "rate"})
-    print(data.head())
-    print(data.index)
-    print(data.columns)
+        start=start,end=end,interval=interval
+    )
     # Need to figure out, how to normalize the dataframe
-    #result = data.reset_index(level=2,col_level=2,drop=True)
-    #result = result[["Date", "Close"]]
-    #result = result.rename(columns={"Date": "date", "Close": "rate"})
-    result = data.copy()
+    result = data.reset_index(level=2,col_level=2,drop=True)
+    result = result[["Date", "Close"]]
+    result = result.rename(columns={"Date": "date", "Close": "rate"})
     return result
\ No newline at end of file
diff --git a/src/argus/gui/app.py b/src/argus/gui/app.py
index c656154..829a905 100644
--- a/src/argus/gui/app.py
+++ b/src/argus/gui/app.py
@@ -77,10 +77,27 @@ def show_trend() -> None:
     global trend_canvas
     global trend_chart_widget
 
-    curr_symbol = "EURUSD=X",
-    start="2024-01-01",
-    end="2024-02-01",
-    interval="1d"
+    mock_dates = {
+        "date": [
+            "2026-06-01",
+            "2026-06-02",
+            "2026-06-03",
+            "2026-06-04",
+            "2026-06-05",
+            "2026-06-06",
+            "2026-06-07",
+            "2026-06-08",
+            "2026-06-09",
+            "2026-06-10",
+            "2026-06-11",
+            "2026-06-12",
+            "2026-06-13",
+            "2026-06-14",
+            "2026-06-15",
+        ]
+    }
+    mock_dates = pd.DataFrame(mock_dates)
+    mock_curr = "USD"
 
     calc_frame.pack_forget()
     conv_frame.pack_forget()
@@ -91,7 +108,7 @@ def show_trend() -> None:
     content.pack(side="top", fill=tk.BOTH, expand=True)
 
     if trend_canvas is None:
-        fig = create_trendchart(curr_symbol,start,end,interval)
+        fig = create_trendchart(mock_curr, mock_dates)
         fig.set_size_inches(7, 4)
 
         trend_canvas = FigureCanvasTkAgg(fig, master=content)
diff --git a/src/argus/services/timeseries_service.py b/src/argus/services/timeseries_service.py
index b506162..3646200 100644
--- a/src/argus/services/timeseries_service.py
+++ b/src/argus/services/timeseries_service.py
@@ -1,5 +1,5 @@
 import pandas as pd
-from argus.clients.yfinancy_client import get_timeseries
+from argus.clients.mock_client import get_mock_timeseries
 from argus.analytics.metrics.trend_metrics import (
     add_rolling_average,
     add_daily_percentage_change,
@@ -7,7 +7,9 @@
 )
 
 
-def prepare_trend_analysis(curr_symbol: str, start:str,end:str,intervall:str) -> tuple[pd.DataFrame, dict] | None:
+def prepare_trend_analysis(
+    mock_curr: str, df: pd.DataFrame
+) -> tuple[pd.DataFrame, dict]:
     """
     Prepares the data for trend analysis by adding conversion rates, daily percentage change, and rolling average.
 
@@ -19,10 +21,11 @@ def prepare_trend_analysis(curr_symbol: str, start:str,end:str,intervall:str) ->
     Return: tuple[pd.DataFrame, dict] - a tuple containing the updated DataFrame with conversion rates,
     daily percentage change, and rolling average, and a dictionary with the minimum and maximum rates
     """
-    
-    df = get_timeseries(curr_symbol, start,end,intervall)
-    if df is None:
-        return None
+    df["rate"] = 0.0
+    # For each date one API call to get the rate
+    for i in range(len(df)):
+        date = str(df.loc[i, "date"])
+        df.loc[i, "rate"] = get_mock_timeseries(mock_curr, date)
     df = add_daily_percentage_change(df)
     df = add_rolling_average(df)
     min_max_rates = get_min_max_rates(df)

From 7712c1309cf1d3e795a977f0f0b30e9aaf07ff67 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 12/13] Revert "feat(#33): normalize the dataframe from
 yfinance"

This reverts commit 962354bd58e08d42446907a66a8ec5a190277c4d.
---
 src/argus/clients/yfinancy_client.py | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/src/argus/clients/yfinancy_client.py b/src/argus/clients/yfinancy_client.py
index 206a5e3..e69de29 100644
--- a/src/argus/clients/yfinancy_client.py
+++ b/src/argus/clients/yfinancy_client.py
@@ -1,11 +0,0 @@
-import yfinance as yf
-
-def get_timeseries(curr_symbol,start,end,interval):
-    data = yf.download(tickers=curr_symbol,
-        start=start,end=end,interval=interval
-    )
-    # Need to figure out, how to normalize the dataframe
-    result = data.reset_index(level=2,col_level=2,drop=True)
-    result = result[["Date", "Close"]]
-    result = result.rename(columns={"Date": "date", "Close": "rate"})
-    return result
\ No newline at end of file

From 756f2716d404db2f891f510f4b5d9af1ab617e13 Mon Sep 17 00:00:00 2001
From: Lev Gusiev <89646710+BytecodeBrewer@users.noreply.github.com>
Date: Sat, 20 Jun 2026 17:21:03 +0200
Subject: [PATCH 13/13] Revert "feat(#33): add func to get data from yfinance"

This reverts commit 2563f3d36a63610f2a23b35a601826c2d52e9be7.
---
 src/argus/clients/yfinancy_client.py | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 delete mode 100644 src/argus/clients/yfinancy_client.py

diff --git a/src/argus/clients/yfinancy_client.py b/src/argus/clients/yfinancy_client.py
deleted file mode 100644
index e69de29..0000000