# File: frequency.py
# Copyright (C) 2026 Erick Ahmed
# SPDX-License-Identifier: AGPL-3.0-or-later

import argparse
from pathlib import Path
import pandas as pd
import plotly.express as px
import plotly.graph_objects as go
from utils.extractor import load_data

def calc_freq(df: pd.DataFrame) -> pd.DataFrame:
    """Calculates frequency counts and percentages for identifiers."""
    freq_df = df['Identifier'].value_counts().reset_index()
    freq_df.columns = ['Identifier', 'Count']
    total = freq_df['Count'].sum()
    freq_df['Percentage'] = (freq_df['Count'] / total * 100).round(2)
    return freq_df.sort_values('Count', ascending=True)

def plot_freq(stats_df: pd.DataFrame, title: str) -> go.Figure:
    """Generates interactive horizontal bar chart with log x-axis."""
    fig = px.bar(
        stats_df, y='Identifier', x='Count', orientation='h', title=title, log_x=True,
        labels={'Identifier': 'PGN / CAN ID', 'Count': 'Message Count'},
        color='Count', color_continuous_scale='Turbo',
        hover_data={'Percentage': ':.2f', 'Count': True, 'Identifier': True}
    )
    fig.update_layout(
        height=max(600, len(stats_df) * 18), width=1000,
        xaxis_title='Total Message Count (Log Scale)', yaxis_title='PGN or CAN ID',
        yaxis={'categoryorder': 'total ascending'},
        plot_bgcolor='rgba(0,0,0,0)', paper_bgcolor='white',
        font=dict(family="Segoe UI, Arial, sans-serif", size=12),
        hoverlabel=dict(bgcolor="white", font_size=13, font_family="Segoe UI"),
        margin=dict(l=250, r=50, t=80, b=50),
        title=dict(font=dict(size=20), x=0.5)
    )
    fig.update_traces(hovertemplate="<b>%{y}</b><br>Count: %{x:,}<br>Share: %{customdata[0]}%<extra></extra>")
    return fig

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Analyze CAN bus frequency.")
    parser.add_argument("-i", "--input", type=Path, required=True)
    parser.add_argument("-o", "--output", type=Path, default=Path("freq_report.html"))
    parser.add_argument("-t", "--title", type=str, default="CAN Bus Message Frequency")
    args = parser.parse_args()

    df = load_data(args.input)
    stats = calc_freq(df)
    fig = plot_freq(stats, title=args.title)
    fig.write_html(str(args.output), include_plotlyjs='cdn')