from flask import Flask, render_template, request, redirect, url_for, send_file, flash
import io
import base64
import matplotlib.pyplot as plt
import preprocessor, helper
import pandas as pd

app = Flask(__name__)
app.secret_key = "change-this-secret"


def figure_to_png_base64(fig):
    buf = io.BytesIO()
    fig.savefig(buf, format='png', bbox_inches='tight')
    plt.close(fig)
    buf.seek(0)
    return base64.b64encode(buf.read()).decode('utf-8')


@app.route('/', methods=['GET'])
def index():
    return render_template('index.html')


@app.route('/analyze', methods=['POST'])
def analyze():
    file = request.files.get('chat_file')
    if not file or file.filename == '':
        flash('Please upload a WhatsApp chat .txt file')
        return redirect(url_for('index'))

    try:
        data = file.read().decode('utf-8')
    except Exception:
        file.stream.seek(0)
        data = file.read().decode('latin-1', errors='ignore')

    df = preprocessor.preprocess(data)

    users = df['user'].unique().tolist()
    if 'group_notification' in users:
        users.remove('group_notification')
    users.sort()
    users.insert(0, 'overall')

    selected_user = request.form.get('user') or 'overall'
    if selected_user not in users:
        selected_user = 'overall'

    num_messages, num_words, num_media_messages = helper.fetch_stats(selected_user, df)

    charts = {}

    if selected_user == 'overall':
        x, new_df = helper.most_busy_user(df)
        fig, ax = plt.subplots()
        ax.bar(x.index, x.values, color=['#ef4444','#10b981','#3b82f6','#f59e0b','#8b5cf6'])
        plt.xticks(rotation=45, ha='right')
        charts['busy_users'] = figure_to_png_base64(fig)
        busy_table = new_df.to_html(classes='table table-striped table-sm', index=False)
    else:
        busy_table = None

    wc_image = helper.create_wordcloud(selected_user, df)
    wc_b64 = None
    if wc_image is not None:
        fig_wc, ax_wc = plt.subplots(figsize=(10, 5))
        ax_wc.imshow(wc_image, interpolation='bilinear')
        ax_wc.axis('off')
        wc_b64 = figure_to_png_base64(fig_wc)

    most_common_df = helper.most_common_words(selected_user, df)
    common_b64 = None
    if not most_common_df.empty:
        fig_mc, ax_mc = plt.subplots()
        ax_mc.barh(most_common_df[0], most_common_df[1])
        plt.xticks(rotation=45)
        common_b64 = figure_to_png_base64(fig_mc)

    emojis_df = helper.emoji_helper(selected_user, df)
    emoji_table = emojis_df.to_html(classes='table table-striped table-sm', index=False)
    emoji_pie_b64 = None
    if not emojis_df.empty:
        top_emojis = emojis_df.head(4)
        fig_em, ax_em = plt.subplots()
        ax_em.pie(top_emojis[1], labels=top_emojis[0], autopct='%0.2f%%')
        emoji_pie_b64 = figure_to_png_base64(fig_em)

    timeline = helper.monthly_timeline(selected_user, df)
    timeline_b64 = None
    if not timeline.empty:
        fig_tl, ax_tl = plt.subplots()
        ax_tl.plot(timeline['time'], timeline['message'], color='#10b981')
        plt.xticks(rotation=45, ha='right')
        timeline_b64 = figure_to_png_base64(fig_tl)

    deltas, rstats = helper.response_time_stats(selected_user, df)
    resp_hist_b64 = None
    if rstats['count'] > 0:
        fig_rt, ax_rt = plt.subplots()
        ax_rt.hist(deltas, bins=30, color='#93c5fd', edgecolor='#1f2937')
        ax_rt.set_xlabel('Reply time (minutes)')
        ax_rt.set_ylabel('Frequency')
        ax_rt.set_title('Reply Time Distribution')
        resp_hist_b64 = figure_to_png_base64(fig_rt)

    request.environ['analysis_df'] = df
    request.environ['analysis_selected_user'] = selected_user

    return render_template(
        'results.html',
        users=users,
        selected_user=selected_user,
        stats={
            'messages': num_messages,
            'words': num_words,
            'media': num_media_messages
        },
        busy_chart=charts.get('busy_users'),
        busy_table=busy_table,
        wc_b64=wc_b64,
        common_b64=common_b64,
        emoji_table=emoji_table,
        emoji_pie_b64=emoji_pie_b64,
        timeline_b64=timeline_b64,
        resp_hist_b64=resp_hist_b64
    )


@app.route('/download', methods=['POST'])
def download():
    file = request.files.get('chat_file')
    selected_user = request.form.get('user') or 'overall'
    if not file or file.filename == '':
        flash('Please upload a chat file to generate report')
        return redirect(url_for('index'))

    try:
        data = file.read().decode('utf-8')
    except Exception:
        file.stream.seek(0)
        data = file.read().decode('latin-1', errors='ignore')

    df = preprocessor.preprocess(data)
    pdf_buffer = helper.generate_pdf_report(selected_user, df)
    return send_file(
        pdf_buffer,
        as_attachment=True,
        download_name=f"whatsapp_analysis_{'overall' if selected_user=='overall' else selected_user}.pdf",
        mimetype='application/pdf'
    )


if __name__ == '__main__':
    app.run(host='0.0.0.0', port=7860, debug=False)