import streamlit as st
import pandas as pd
from src.data_loader import (
    load_sdg_data,
    get_country_list,
    filter_data,
    get_latest_data,
    get_country_metrics,
    get_data_summary,
)
from src.viz_engine import (
    create_world_map,
    create_radar_chart,
    create_trend_chart,
    create_detailed_trend_chart,
)
from src.ai_engine import SDG_AI_Report_Engine
import os
import re

# Define SCRIPT_DIR early
SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))

from src.config_manager import get_config
from datetime import datetime

# Initialize configuration
config = get_config()

# Force data path to prefer SDR2025 if available
default_sdr2025 = os.path.join(SCRIPT_DIR, 'data', 'SDR2025-data.xlsx')
DATA_PATH = config.get('data_sources.primary_data_path') or default_sdr2025
if not DATA_PATH or not os.path.exists(DATA_PATH):
    if os.path.exists(default_sdr2025):
        DATA_PATH = default_sdr2025

# Load AI configuration and engine
config_valid = config.get('ai_engine.enabled', True) and (config.get('ai_engine.api_key') or config.get('ai_engine.base_url'))
ai_engine = SDG_AI_Report_Engine(config.get('ai_engine.base_url'), config.get('ai_engine.api_key')) if config_valid else None

# Use a fixed model as requested
SELECTED_MODEL_KEY = 'azure-gpt-4.1'

@st.cache_data(ttl=config.get('data_sources.cache_ttl_seconds', 3600))
def get_data():
    df = load_sdg_data(DATA_PATH)
    summary = get_data_summary(df)
    return df, summary

df, data_summary = get_data()

# Page Config
st.set_page_config(
    page_title=config.get('ui.page_title', 'Global SDG Tracker AI'),
    page_icon=config.get('ui.page_icon', '🌍'),
    layout=config.get('ui.layout', 'wide'),
)

# Load CSS
css_path = os.path.join(SCRIPT_DIR, 'assets', 'style.css')
if os.path.exists(css_path):
    with open(css_path) as f:
        st.markdown(f"<style>{f.read()}</style>", unsafe_allow_html=True)

# Sidebar
with st.sidebar:
    st.markdown('### 🌍 Global Settings')

    # Country list now returns only countries in the latest year (SDR 2025)
    country_list = get_country_list(df)
    if not country_list:
        st.warning('No countries available in the data source. Please check your data configuration.')
        selected_country = st.selectbox('Select Country', [], key='country_select')
    else:
        selected_country = st.selectbox('Select Country', country_list, index=0, key='country_select')

    # Year range dynamic from data summary
    if data_summary and data_summary.get('year_range'):
        min_year, max_year = data_summary['year_range']
    else:
        min_year, max_year = 2000, 2025

    # Handle case where min_year == max_year (single year data)
    if min_year == max_year:
        # For single year data, allow selection of that year only
        year_range = (min_year, max_year)
        st.info(f'📅 Data available for year: {min_year} (single year dataset)')
    else:
        # For multi-year data, use the full range with 10-year window
        default_start = max(min_year, max_year - 10)
        year_range = st.slider('Year Range', min_year, max_year, (default_start, max_year), key='year_slider')

    st.divider()
    st.markdown('### 📊 Project Info')
    st.info('Global SDG Tracker AI v2025.1\nData: SDR 2025 (SDSN)')

# Top-level navigation
tab_names = ['Global Overview', 'Country Analysis', 'AI Report']
if 'active_tab' not in st.session_state:
    st.session_state['active_tab'] = tab_names[0]

st.session_state['active_tab'] = st.radio('Navigation', tab_names, index=tab_names.index(st.session_state['active_tab']), horizontal=True, label_visibility='collapsed')
active_tab = st.session_state['active_tab']

if active_tab == 'Global Overview':
    st.header('Global SDG Progress (SDR 2025)')
    latest_df = get_latest_data(df)
    fig_map = create_world_map(latest_df)
    st.plotly_chart(fig_map, use_container_width=True)

    st.subheader('Top Performers (Latest Year, SDR 2025)')
    top_10 = latest_df.sort_values('sdg_index_score', ascending=False).head(10)[['country', 'sdg_index_score']]
    st.table(top_10)

elif active_tab == 'Country Analysis':
    st.header(f'Projected Performance: {selected_country} (SDR 2025)')

    latest_year = year_range[1]
    metrics = get_country_metrics(df, selected_country, latest_year)

    if not metrics:
        st.warning(f"⚠️ Data for '{selected_country}' in {latest_year} is not available or incomplete.")
    else:
        col1, col2, col3, col4 = st.columns(4)

        prev_year = latest_year - 1
        prev_metrics = get_country_metrics(df, selected_country, prev_year)
        score_delta = (metrics.get('score', 0) - prev_metrics.get('score', 0)) if prev_metrics else 0

        col1.metric('Latest SDG Score', f"{metrics.get('score', 0):.1f}", delta=f"{score_delta:+.1f}")
        col2.metric('Global Rank', f"{metrics.get('rank', 'N/A')} / {metrics.get('country_count', 'N/A')}")
        col3.metric('Global Average', f"{metrics.get('global_avg', 0):.1f}")
        diff = metrics.get('score', 0) - metrics.get('global_avg', 0)
        col4.metric('Performance vs Avg', f"{diff:+.1f}", delta_color='normal')

    filtered_df = filter_data(df, selected_country, year_range)

    col_left, col_right = st.columns([1, 1])
    with col_left:
        st.subheader('SDG Goal Multi-dimensional Analysis')
        fig_radar = create_radar_chart(df, selected_country, latest_year)
        if fig_radar:
            st.plotly_chart(fig_radar, use_container_width=True)

    with col_right:
        st.subheader('Historical Trend')
        fig_trend = create_trend_chart(filtered_df)
        st.plotly_chart(fig_trend, use_container_width=True)

    st.subheader('Detailed Goals Trends')
    fig_det_trend = create_detailed_trend_chart(filtered_df)
    st.plotly_chart(fig_det_trend, use_container_width=True)

    # Export CSV
    st.divider()
    csv = filtered_df.to_csv(index=False).encode('utf-8') if not filtered_df.empty else b''
    st.download_button(label='📥 Export Country Data to CSV', data=csv, file_name=f'SDG_Data_{selected_country}_{latest_year}.csv', mime='text/csv')

elif active_tab == 'AI Report':
    st.header('🤖 AI-Powered Strategic Analysis (SDR 2025)')

    # Recompute metrics and filtered_df to avoid stale variables
    latest_year = year_range[1]
    metrics = get_country_metrics(df, selected_country, latest_year)
    filtered_df = filter_data(df, selected_country, year_range)

    # Defensive checks: if no metrics or no filtered data, stop and inform user
    if metrics is None or filtered_df.empty:
        st.error(f"⚠️ 國家 '{selected_country}' 在 {latest_year} 年 SDG 數據中不存在或無完整資料，請選擇其他國家（例如 Finland、Sweden、China 等）。")
        st.stop()

    if not config_valid:
        st.warning('⚠️ AI report functionality is not configured. Set environment variables to enable it.')
    else:
        # AI Settings Layout
        col_lang, col_depth = st.columns(2)
        with col_lang:
            report_lang = st.selectbox('Language / 報告語言', ['Chinese', 'English', 'Japanese'], key='lang_select')
        with col_depth:
            report_depth = st.selectbox('Report Depth / 報告深度', ['Short', 'Standard', 'Detailed'], index=0, key='depth_select')
            depth_map = {'Short': 300, 'Standard': 800, 'Detailed': 1500}
            selected_length = depth_map[report_depth]

        # Automatically determine Report Type based on Depth
        if selected_length == 1500:
            selected_type = 'professional'  # Detailed -> Professional Report
        elif selected_length == 800:
            selected_type = 'policy'  # Standard -> Policy Brief
        else:
            selected_type = 'summary'  # Short -> Executive Summary

        if st.button('🤖 Generate Professional Report / 生成專業報告', help='點擊生成基於AI的專業SDG分析報告'):
            try:
                with st.spinner('AI is analyzing SDG data and generating strategic insights...'):
                    meta = {
                        'country': selected_country,
                        'start_year': year_range[0],
                        'end_year': year_range[1],
                        'report_type': selected_type,  # Auto-selected based on depth
                        'latest_score': f"{metrics.get('score', 'N/A'):.1f}" if isinstance(metrics.get('score'), (int, float)) else metrics.get('score', 'N/A'),
                        'rank': metrics.get('rank', 'N/A'),
                        'total_countries': metrics.get('country_count', 'N/A'),
                        'global_avg': f"{metrics.get('global_avg', 'N/A'):.1f}" if isinstance(metrics.get('global_avg'), (int, float)) else metrics.get('global_avg', 'N/A'),
                        'length': selected_length if 'selected_length' in locals() else 800
                    }

                    report = ai_engine.generate_report(filtered_df, meta, language=report_lang)

                    if isinstance(report, str):
                        # Remove all HTML comments (like <!-- thought blocks -->) instead of splitting
                        report = re.sub(r'<!--.*?-->', '', report, flags=re.DOTALL).strip()
                    
                    st.session_state['current_report'] = report
            except Exception as e:
                st.error(f"❌ AI報告生成失敗：{str(e)}")

    if 'current_report' in st.session_state:
        st.divider()
        st.subheader(f"📝 策略分析報告: {selected_country}")
        
        # Display the report in a container
        with st.container(border=True):
            st.markdown(st.session_state['current_report'])
        
        # Add download button
        report_text = st.session_state['current_report']
        st.download_button(
            label="📥 下載完整報告 (Markdown)",
            data=report_text,
            file_name=f"SDG_Report_{selected_country}_{datetime.now().strftime('%Y%V%d')}.md",
            mime="text/markdown"
        )

# Footer
st.divider()
st.markdown(
    """
<div class="footer">
    <p><b>Global SDG Tracker AI v2025.1</b></p>
    <p>Developed by Senior AI & Environmental Systems Engineer</p>
    <p>Data Source: <b>Sustainable Development Report 2025 (SDSN & Dublin University Press)</b> | Released: June 2025</p>
    <p><i>Note: The 2025 data follows the latest UN SDG indicator framework and official SDSN computations.</i></p>
</div>
""",
    unsafe_allow_html=True,
)