import os
import pandas as pd
import gspread
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
import json
import gradio as gr
import time
from datetime import datetime, timedelta
import threading
from dotenv import load_dotenv

# Load environment variables
load_dotenv()

# Scopes (read-only)
SCOPES = ["https://www.googleapis.com/auth/spreadsheets.readonly"]

def authorize():
    creds = None
    
    # Get JSON content from environment variables
    token_json_content = os.getenv('TOKEN_JSON')
    credentials_json_content = os.getenv('CREDENTIALS_JSON')
    
    # Load token from environment variable if exists
    if token_json_content:
        try:
            token_info = json.loads(token_json_content)
            creds = Credentials.from_authorized_user_info(token_info, SCOPES)
        except json.JSONDecodeError:
            print("⚠️ Invalid TOKEN_JSON format in environment variable")
    
    # If no valid credentials, start OAuth flow
    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            creds.refresh(Request())
        else:
            if not credentials_json_content:
                raise ValueError("CREDENTIALS_JSON environment variable is required for OAuth flow")
            
            try:
                credentials_info = json.loads(credentials_json_content)
                flow = InstalledAppFlow.from_client_config(credentials_info, SCOPES)
                creds = flow.run_local_server(port=0)
            except json.JSONDecodeError:
                raise ValueError("Invalid CREDENTIALS_JSON format in environment variable")
        
        # Save token back to environment (for this session only)
        # Note: You may want to update your .env file manually with the new token
        print("🔄 New token generated. Consider updating TOKEN_JSON in your .env file with:")
        print(f"TOKEN_JSON={creds.to_json()}")
    
    return gspread.authorize(creds)

# Function to get data from a specific sheet
def get_sheet_data(spreadsheet, gid, sheet_name):
    try:
        sheet = spreadsheet.get_worksheet_by_id(gid)
        all_values = sheet.get_all_values()
        
        if not all_values or len(all_values) <= 4:
            print(f"⚠️ {sheet_name} sheet doesn't have enough data")
            return pd.DataFrame()
        
        # Use row 4 as headers (the actual column names)
        headers = all_values[4]
        clean_headers = []
        seen_headers = {}
        
        for i, header in enumerate(headers):
            if header.strip():  # Non-empty header
                base_header = header.strip()
                # Handle duplicate headers by adding a counter
                if base_header in seen_headers:
                    seen_headers[base_header] += 1
                    clean_header = f"{base_header}_{seen_headers[base_header]}"
                else:
                    seen_headers[base_header] = 0
                    clean_header = base_header
                clean_headers.append(clean_header)
            else:  # Empty header
                clean_headers.append(f"Empty_Col_{i}")

        # Create DataFrame starting from row 5 (after headers)
        data_rows = all_values[5:]
        if data_rows:
            df = pd.DataFrame(data_rows, columns=clean_headers)
            # Remove completely empty columns
            df = df.loc[:, (df != '').any(axis=0)]
            print(f"✅ Loaded {len(df)} rows from {sheet_name}")
            return df
        else:
            print(f"⚠️ No data rows found in {sheet_name}")
            return pd.DataFrame()
            
    except Exception as e:
        print(f"❌ Error loading {sheet_name}: {str(e)}")
        return pd.DataFrame()

# Function to get details sheet information
def get_details_info(spreadsheet):
    try:
        details_sheet = spreadsheet.get_worksheet_by_id(847680829)
        all_values = details_sheet.get_all_values()
        
        if not all_values:
            return None
        
        # Use row 4 as headers
        headers = all_values[4]
        clean_headers = []
        for i, header in enumerate(headers):
            if header.strip():
                clean_headers.append(header.strip())
            else:
                clean_headers.append(f"Empty_Col_{i}")
        
        # Get data rows after header
        data_rows = all_values[5:]
        
        if data_rows:
            df = pd.DataFrame(data_rows, columns=clean_headers)
            df = df.loc[:, (df != '').any(axis=0)]
            
            details_info = {}
            
            # Extract specific information
            for idx in range(len(df)):
                student_data = df.iloc[idx]
                year_value = str(student_data.get('YEAR', '')).strip()
                
                # Get Average Reward Points
                if 'AVERAGE REWARD POINT' in year_value:
                    details_info['average_points'] = {
                        'I': student_data.get('I', ''),
                        'II': student_data.get('II', ''),
                        'II L': student_data.get('II L', ''),
                        'III': student_data.get('III', ''),
                        'IV': student_data.get('IV', '')
                    }
                
                # Get IP 2 Redemption Dates
                elif 'Last Day for IP 2 Redemption Duration' in str(student_data.get('Redemption Dates', '')):
                    details_info['ip2_redemption'] = {
                        'S1': student_data.get('S1', ''),
                        'S2': student_data.get('S2', ''),
                        'S3': student_data.get('S3', ''),
                        'S4': student_data.get('S4', ''),
                        'S5': student_data.get('S5', ''),
                        'S6': student_data.get('S6', ''),
                        'S7': student_data.get('S7', ''),
                        'S8': student_data.get('S8', '')
                    }
                
                # Get IP 1 Redemption Dates
                elif 'Last Day for IP 1 Redemption Duration' in str(student_data.get('Redemption Dates', '')):
                    details_info['ip1_redemption'] = {
                        'S1': student_data.get('S1', ''),
                        'S2': student_data.get('S2', ''),
                        'S3': student_data.get('S3', ''),
                        'S4': student_data.get('S4', ''),
                        'S5': student_data.get('S5', ''),
                        'S6': student_data.get('S6', ''),
                        'S7': student_data.get('S7', ''),
                        'S8': student_data.get('S8', '')
                    }
                
                # Get Last Updated Information
                elif 'POINTS LAST UPDATED' in year_value:
                    details_info['last_updated'] = year_value
            
            return details_info
            
    except Exception as e:
        print(f"❌ Error loading Details Sheet: {str(e)}")
        return None

# Initialize global variables
print("🚀 Initializing application...")
client = authorize()
SHEET_ID = os.getenv('GOOGLE_SHEET_ID')
spreadsheet = client.open_by_key(SHEET_ID)

# Load data from all sheets (Original 3 + New 17 = 20 sheets total)
sheet_configs = [
    # Original sheets
    {"gid": 688907204, "name": "AIML"},
    {"gid": 451167295, "name": "AIDS"}, 
    {"gid": 1955995189, "name": "Sheet_3"},
    {"gid": 821473193, "name": "Sheet_4"},
    {"gid": 1798819643, "name": "Sheet_5"},
    {"gid": 1057532042, "name": "Sheet_6"},
    {"gid": 1848020834, "name": "Sheet_7"},
    {"gid": 48570283, "name": "Sheet_8"},
    {"gid": 559332743, "name": "Sheet_9"},
    {"gid": 1481375682, "name": "Sheet_10"},
    {"gid": 1136877763, "name": "Sheet_11"},
    {"gid": 510521423, "name": "Sheet_12"},
    {"gid": 1936618, "name": "Sheet_13"},
    {"gid": 91989289, "name": "Sheet_14"},
    {"gid": 30073516, "name": "Sheet_15"},
    {"gid": 857542309, "name": "Sheet_16"},
    {"gid": 790318539, "name": "Sheet_17"},
    {"gid": 587090068, "name": "Sheet_18"},
    {"gid": 260192612, "name": "Sheet_19"},
    {"gid": 400900059, "name": "Sheet_20"}
]

# 🕒 GLOBAL DATA CACHE WITH 12-HOUR AUTO-REFRESH
data_cache = {
    "combined_df": None,
    "details_info": None,
    "last_update": None,
    "cache_duration_hours": 12,  # 12 hours cache
    "is_loading": False
}

def load_all_data():
    """Load and cache all data from Google Sheets"""
    global data_cache
    
    if data_cache["is_loading"]:
        print("⏳ Data loading already in progress...")
        return data_cache["combined_df"], data_cache["details_info"]
    
    data_cache["is_loading"] = True
    print(f"🔄 Loading fresh data from {len(sheet_configs)} Google Sheets...")
    start_time = time.time()
    
    try:
        # Load all sheet data
        all_dataframes = []
        for config in sheet_configs:
            df = get_sheet_data(spreadsheet, config["gid"], config["name"])
            if not df.empty:
                df['Source_Sheet'] = config["name"]
                all_dataframes.append(df)
                print(f"   📋 {config['name']}: {len(df)} rows")

        # Combine dataframes
        if all_dataframes:
            try:
                combined_df = pd.concat(all_dataframes, ignore_index=True, sort=False)
                print(f"✅ Successfully combined {len(combined_df)} records from {len(all_dataframes)} sheets")
            except Exception as e:
                print(f"❌ Error combining dataframes: {str(e)}")
                print("🔄 Trying alternative approach...")
                
                # Alternative approach: standardize columns first
                standard_columns = ['SL. NO.', 'YEAR', 'ROLL NO.', 'STUDENT NAME', 'COURSE CODE', 
                                   'DEPARTMENT', 'MENTOR NAME', 'CUMULATIVE REWARD POINTS', 
                                   'REEDEMED POINTS', 'BALANCE POINTS', 'Source_Sheet']
                
                standardized_dfs = []
                for df in all_dataframes:
                    new_df = pd.DataFrame()
                    for col in standard_columns:
                        if col == 'Source_Sheet':
                            new_df[col] = df.get('Source_Sheet', '')
                        else:
                            # Try to find matching column
                            found_col = None
                            for df_col in df.columns:
                                if col.upper() in df_col.upper() or df_col.upper() in col.upper():
                                    found_col = df_col
                                    break
                            
                            if found_col:
                                new_df[col] = df[found_col]
                            else:
                                new_df[col] = ''
                    
                    standardized_dfs.append(new_df)
                
                combined_df = pd.concat(standardized_dfs, ignore_index=True, sort=False)
                print(f"✅ Alternative approach successful: {len(combined_df)} records combined")
        else:
            combined_df = pd.DataFrame()
            print("❌ No data found in any sheets")

        # Load details info
        details_info = get_details_info(spreadsheet)
        
        # Update cache
        data_cache["combined_df"] = combined_df
        data_cache["details_info"] = details_info
        data_cache["last_update"] = datetime.now()
        
        load_time = time.time() - start_time
        print(f"⏱️ Data loaded and cached in {load_time:.2f} seconds")
        print(f"📊 Next auto-refresh in {data_cache['cache_duration_hours']} hours")
        
        return combined_df, details_info
        
    except Exception as e:
        print(f"❌ Error loading data: {str(e)}")
        return data_cache.get("combined_df", pd.DataFrame()), data_cache.get("details_info", None)
    
    finally:
        data_cache["is_loading"] = False

def get_cached_data():
    """Get data from cache or refresh if 12 hours have passed"""
    now = datetime.now()
    
    # Check if cache is empty or expired (12 hours)
    if (data_cache["last_update"] is None or 
        data_cache["combined_df"] is None or
        (now - data_cache["last_update"]).total_seconds() > (data_cache["cache_duration_hours"] * 3600)):
        
        print("🔄 Cache expired or empty, loading fresh data...")
        return load_all_data()
    else:
        cache_age_hours = (now - data_cache["last_update"]).total_seconds() / 3600
        print(f"🚀 Using cached data (age: {cache_age_hours:.1f} hours)")
        return data_cache["combined_df"], data_cache["details_info"]

def auto_refresh_worker():
    """Background worker to auto-refresh data every 12 hours"""
    while True:
        try:
            # Sleep for 12 hours (43200 seconds)
            time.sleep(43200)
            print("⏰ 12-hour auto-refresh triggered...")
            load_all_data()
        except Exception as e:
            print(f"❌ Auto-refresh error: {str(e)}")
            # If error, wait 1 hour before trying again
            time.sleep(3600)

# Load initial data
print("📊 Loading initial data...")
load_all_data()

# Start background auto-refresh thread
refresh_thread = threading.Thread(target=auto_refresh_worker, daemon=True)
refresh_thread.start()
print("🕒 Auto-refresh thread started (updates every 12 hours)")

# Function to search student with cached data
def search_student(roll_no):
    if not roll_no.strip():
        return "❌ Please enter a roll number"
    
    # Convert roll number to uppercase for consistent searching
    roll_no = roll_no.strip().upper()
    
    # Get cached data (fast response, auto-refreshes every 12 hours)
    combined_df, details_info = get_cached_data()
    
    if combined_df.empty:
        return "❌ No data available from Google Sheets"
    
    # Look for 'ROLL NO.' column
    roll_column = None
    for col in combined_df.columns:
        if 'roll' in col.lower() and 'no' in col.lower():
            roll_column = col
            break
    
    if roll_column is None:
        return f"❌ Roll number column not found. Available columns: {list(combined_df.columns)}"
    
    # Convert the roll numbers in DataFrame to uppercase for comparison
    student = combined_df[combined_df[roll_column].astype(str).str.strip().str.upper() == roll_no]
    if student.empty:
        return f"❌ Roll No '{roll_no}' not found in any sheet"
    
    # Log to see which roll number is asked by user
    print("Roll No Searched:", roll_no) 
    
    record = student.iloc[0].to_dict()
    student_year = str(record.get('YEAR', '')).strip()
    
    # Format output - Simplified version
    output = []
    output.append("=" * 80)
    output.append("STUDENT DETAILS")
    output.append("=" * 80)
    
    # Main student details
    main_fields = ['ROLL NO.', 'STUDENT NAME', 'YEAR', 'DEPARTMENT', 'MENTOR NAME', 
                   'CUMULATIVE REWARD POINTS', 'REEDEMED POINTS', 'BALANCE POINTS']
    
    for field in main_fields:
        value = record.get(field, '')
        if str(value).strip():
            output.append(f"{field:<25}: {value}")
    
    # Get student's current points (clean numeric value)
    try:
        student_points_str = str(record.get('BALANCE POINTS', '')).replace(',', '').strip()
        student_points = float(student_points_str) if student_points_str else 0
    except:
        student_points = 0
    
    # Add year-specific average points and analysis
    if details_info and 'average_points' in details_info:
        output.append("\n" + "=" * 80)
        output.append(f"AVERAGE REWARD POINTS FOR YEAR {student_year}")
        output.append("=" * 80)
        
        if student_year in details_info['average_points']:
            avg_points_str = details_info['average_points'][student_year]
            try:
                avg_points = float(avg_points_str) if avg_points_str else 0
            except:
                avg_points = 0
            
            if avg_points > 0:
                output.append(f"Average Points for Year {student_year:<8}: {avg_points_str}")
                
                # Calculate difference and provide guidance
                points_difference = avg_points - student_points
                
                if points_difference > 0:
                    # Student is below average
                    output.append(f"\n🎯 POINTS NEEDED TO REACH AVERAGE: {points_difference:.0f} points")
                    output.append("\n💡 WAYS TO EARN POINTS:")
                    output.append("   • PS Activities")
                    output.append("   • TAC")
                    output.append("   • Hackathons / Technical Events")
                    output.append("   • Project Competitions")
                else:
                    # Student is at or above average
                    output.append(f"\n🎉 EXCELLENT! You are {abs(points_difference):.0f} points ABOVE the average!")
                    output.append("   Keep up the great work! 🌟")
    
    # Add last updated info
    if details_info and 'last_updated' in details_info:
        output.append("\n" + "-" * 60)
        output.append("LAST UPDATE INFO")
        output.append("-" * 60)
        output.append(details_info['last_updated'])
    
    output.append("\n" + "=" * 80)
    
    return "\n".join(output)

# Function to get system information
def get_system_info():
    combined_df, details_info = get_cached_data()
    
    if not details_info:
        return "❌ No system information available"
    
    output = []
    output.append("=" * 80)
    output.append("SYSTEM INFORMATION")
    output.append("=" * 80)
    
    # Average Points
    if 'average_points' in details_info:
        output.append("\nAVERAGE REWARD POINTS BY YEAR:")
        output.append("-" * 40)
        for year, points in details_info['average_points'].items():
            if points:
                output.append(f"Year {year:<10}: {points}")
    
    # Redemption Dates
    if 'ip1_redemption' in details_info:
        output.append("\nIP 1 REDEMPTION DATES:")
        output.append("-" * 40)
        for semester, date in details_info['ip1_redemption'].items():
            if date and date != '-':
                output.append(f"{semester:<10}: {date}")
    
    if 'ip2_redemption' in details_info:
        output.append("\nIP 2 REDEMPTION DATES:")
        output.append("-" * 40)
        for semester, date in details_info['ip2_redemption'].items():
            if date and date != '-':
                output.append(f"{semester:<10}: {date}")
    
    if 'last_updated' in details_info:
        output.append(f"\nLAST UPDATED:")
        output.append("-" * 40)
        output.append(details_info['last_updated'])
    
    # Cache info
    if data_cache["last_update"]:
        cache_age = datetime.now() - data_cache["last_update"]
        hours = cache_age.total_seconds() / 3600
        next_refresh_hours = 12 - hours
        output.append(f"\n📊 Data age: {hours:.1f} hours")
        if next_refresh_hours > 0:
            output.append(f"⏰ Next auto-refresh in: {next_refresh_hours:.1f} hours")
        else:
            output.append("⏰ Auto-refresh due now")
    
    output.append("\n" + "=" * 80)
    
    return "\n".join(output)

# Create Gradio interface
with gr.Blocks(title="Student Reward Points Check", theme=gr.themes.Soft()) as app:
    gr.Markdown("# 🎓 Student Reward Points Check")
    gr.Markdown("### Search for student details including reward points and redemption dates")
    gr.Markdown("🕒 **Auto-Updates**: Data automatically refreshes every 12 hours")
    
    with gr.Tabs():
        with gr.TabItem("🔍 Student Search"):
            with gr.Row():
                with gr.Column(scale=3):
                    roll_input = gr.Textbox(
                        label="Enter Roll Number",
                        placeholder="e.g., 7376222AL181",
                        value=""
                    )
                with gr.Column(scale=1):
                    search_btn = gr.Button("🔍 Search Student", variant="primary")
            
            result_output = gr.Textbox(
                label="Student Details",
                lines=25,
                max_lines=30,
                show_copy_button=True,
                autoscroll=False
            )
            
        with gr.TabItem("ℹ️ System Information"):
            system_btn = gr.Button("📊 Get System Information", variant="secondary")
            system_output = gr.Textbox(
                label="System Information",
                lines=30,
                max_lines=50,
                show_copy_button=True,
                autoscroll=False,
                interactive=False,
                show_label=True
            )
    
    # Event handlers
    search_btn.click(fn=search_student, inputs=roll_input, outputs=result_output)
    roll_input.submit(fn=search_student, inputs=roll_input, outputs=result_output)
    system_btn.click(fn=get_system_info, outputs=system_output)
    
    # Load system info on startup
    app.load(fn=get_system_info, outputs=system_output)
    
    # 🌟 FOOTER SECTION
    gr.Markdown("---")
    with gr.Row():
        with gr.Column():
            gr.Markdown(
                """
                <div style="text-align: center; margin-top: 20px; padding: 20px; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); border-radius: 10px; color: white;">
                    <h3 style="margin: 0; color: white;">💻 Developed with ❤️ by</h3>
                    <h2 style="margin: 5px 0; color: #ffd700;">PRANESH S</h2>
                    <div style="margin: 15px 0;">
                        <a href="https://github.com/Pranesh-2005" target="_blank" style="color: #ffd700; text-decoration: none; margin: 0 10px; font-size: 16px;">
                            🐱 GitHub
                        </a>
                        <span style="color: #ffd700;">|</span>
                        <a href="https://www.linkedin.com/in/pranesh5264/" target="_blank" style="color: #ffd700; text-decoration: none; margin: 0 10px; font-size: 16px;">
                            💼 LinkedIn
                        </a>
                    </div>
                    <p style="margin: 10px 0; font-style: italic; color: #e0e0e0;">Made with 💝 Love and Support</p>
                    <p style="margin: 5px 0; font-size: 14px; color: #b0b0b0;">🚀 Empowering students with instant reward points tracking</p>
                </div>
                """,
                elem_id="footer"
            )

# Launch the app
if __name__ == "__main__":
    print("🚀 Launching Gradio interface...")
    app.launch(share=False, debug=True, server_name="0.0.0.0", server_port=7860, pwa=True)