from flask import Blueprint, render_template, request, redirect, url_for, flash
from flask_login import login_required, current_user
from extensions import db, environment, htmx
from jinja2_fragments import render_block
import secrets
import json

settings = Blueprint('settings', __name__)

@settings.route("/", methods=["GET"])
@login_required
def index():
    return redirect(url_for('settings.api_keys'))

@settings.route("/export", methods=["GET"])
@login_required
def export():
    """Display data export page or download data export"""
    # Check if this is a download request
    if request.args.get('download') == 'true':
        from flask import make_response
        from datetime import datetime
        
        user_id = current_user.id
        
        # Get all user data
        export_data = db.export_user_data(user_id)
        
        # Add export metadata
        export_data['_export_metadata'] = {
            'exported_at': datetime.now().isoformat(),
            'export_version': '1.0',
            'application': 'Functions Platform'
        }
        
        # Create JSON response
        response = make_response(json.dumps(export_data, indent=2, default=str))
        response.headers['Content-Type'] = 'application/json'
        
        # Generate filename with username and timestamp
        username = current_user.username
        timestamp = datetime.now().strftime('%Y%m%d_%H%M%S')
        filename = f'user_data_export_{username}_{timestamp}.json'
        response.headers['Content-Disposition'] = f'attachment; filename={filename}'
        
        return response
    
    # Otherwise show the export page
    if htmx:
        return render_block(
            environment,
            "dashboard/settings/export.html",
            "page"
        )
    return render_template("dashboard/settings/export.html")

@settings.route("/api-keys", methods=["GET"])
@login_required
def api_keys():
    user_id = current_user.id
    api_keys = db.list_api_keys(user_id)
    
    # Parse scopes for display
    for key in api_keys:
        if isinstance(key['scopes'], str):
            key['scopes'] = json.loads(key['scopes'])
            
    # Fetch user's functions for scoping
    functions = db.get_http_functions_for_user(user_id)

    if htmx:
        return render_block(
            environment, 
            "dashboard/settings/api_keys.html", 
            "page", 
            api_keys=api_keys,
            functions=functions
        )
    return render_template("dashboard/settings/api_keys.html", api_keys=api_keys, functions=functions)

@settings.route("/api-keys", methods=["POST"])
@login_required
def create_api_key():
    user_id = current_user.id
    name = request.form.get("name", "My API Key")
    scopes_list = request.form.getlist("scopes")
    
    if not scopes_list:
        scopes = ["*"]
    else:
        scopes = scopes_list

    # Generate a secure random key
    key = f"sk_{secrets.token_urlsafe(24)}"
    
    db.create_api_key(user_id, name, key, scopes)
    
    flash(f"API Key created: {key} - Save it now, you won't see it again!", "success")
    return redirect(url_for("settings.api_keys"))

@settings.route("/api-keys/<int:key_id>", methods=["DELETE"])
@login_required
def delete_api_key(key_id):
    user_id = current_user.id
    db.delete_api_key(user_id, key_id)
    return "", 200

@settings.route("/theme", methods=["POST"])
@login_required
def toggle_theme():
    user_id = current_user.id
    theme = request.form.get("theme")
    if theme in ['light', 'dark']:
        db.update_user_theme_preference(user_id, theme)
        # Return empty string as we'll handle the UI update via client-side JS or just let the class toggle persist
        # Actually, for HTMX we might want to return something or just 200 OK.
        return "", 200
    return "Invalid theme", 400

@settings.route("/database_schema", methods=["GET"])
@login_required
def database_schema():
    """Display database schema with ERD visualization"""
    # Fetch database schema information
    schema_info = get_database_schema()
    
    if htmx:
        return render_block(
            environment,
            "dashboard/settings/database_schema.html",
            "page",
            schema_info=schema_info
        )
    return render_template("dashboard/settings/database_schema.html", schema_info=schema_info)

def get_database_schema():
    """Fetch database schema information for ERD generation"""
    # Get all tables
    tables = db.execute("""
        SELECT 
            table_name,
            COALESCE(obj_description((quote_ident(table_schema)||'.'||quote_ident(table_name))::regclass), '') as table_comment
        FROM information_schema.tables
        WHERE table_schema = 'public'
        AND table_type = 'BASE TABLE'
        ORDER BY table_name
    """)
    
    schema_data = []
    
    for table in tables or []:
        table_name = table['table_name']
        
        # Get columns for this table
        columns = db.execute("""
            SELECT 
                column_name,
                data_type,
                is_nullable,
                column_default,
                character_maximum_length
            FROM information_schema.columns
            WHERE table_schema = 'public'
            AND table_name = %s
            ORDER BY ordinal_position
        """, [table_name])
        
        # Get foreign keys for this table
        foreign_keys = db.execute("""
            SELECT
                kcu.column_name,
                ccu.table_name AS foreign_table_name,
                ccu.column_name AS foreign_column_name
            FROM information_schema.table_constraints AS tc
            JOIN information_schema.key_column_usage AS kcu
                ON tc.constraint_name = kcu.constraint_name
                AND tc.table_schema = kcu.table_schema
            JOIN information_schema.constraint_column_usage AS ccu
                ON ccu.constraint_name = tc.constraint_name
                AND ccu.table_schema = tc.table_schema
            WHERE tc.constraint_type = 'FOREIGN KEY'
            AND tc.table_name = %s
            AND tc.table_schema = 'public'
        """, [table_name])
        
        # Get primary keys
        primary_keys = db.execute("""
            SELECT kcu.column_name
            FROM information_schema.table_constraints tc
            JOIN information_schema.key_column_usage kcu
                ON tc.constraint_name = kcu.constraint_name
                AND tc.table_schema = kcu.table_schema
            WHERE tc.constraint_type = 'PRIMARY KEY'
            AND tc.table_name = %s
            AND tc.table_schema = 'public'
        """, [table_name])
        
        pk_columns = [pk['column_name'] for pk in (primary_keys or [])]
        
        schema_data.append({
            'table_name': table_name,
            'columns': columns or [],
            'foreign_keys': foreign_keys or [],
            'primary_keys': pk_columns
        })
    
    return schema_data

@settings.route("/execute_query", methods=["POST"])
@login_required
def execute_query():
    """Execute a user-scoped SQL query"""
    query = request.json.get('query', '').strip()
    
    if not query:
        return {"error": "No query provided"}, 400
    
    # Basic validation - must be SELECT only
    query_upper = query.upper()
    if not query_upper.startswith('SELECT'):
        return {"error": "Only SELECT queries are allowed"}, 400
    
    # Check for dangerous keywords
    dangerous_keywords = ['DROP', 'DELETE', 'INSERT', 'UPDATE', 'ALTER', 'CREATE', 'TRUNCATE', 'GRANT', 'REVOKE']
    for keyword in dangerous_keywords:
        if keyword in query_upper:
            return {"error": f"Keyword '{keyword}' is not allowed"}, 400
    
    user_id = current_user.id
    
    # List of tables that have user_id column
    user_scoped_tables = [
        'http_functions', 'timer_functions', 'shared_environments', 
        'api_keys', 'http_function_invocations', 'timer_function_invocations'
    ]
    
    # Automatically add user_id filter if querying user-scoped tables
    modified_query = query
    for table in user_scoped_tables:
        if table in query.lower():
            # Add WHERE clause if not present
            if 'WHERE' not in query_upper:
                modified_query = f"{query} WHERE {table}.user_id = {user_id}"
            # Append to existing WHERE clause
            elif f'{table}.user_id' not in query.lower() and 'user_id' not in query.lower():
                modified_query = f"{query} AND {table}.user_id = {user_id}"
            break
    
    # Limit results to prevent massive queries
    if 'LIMIT' not in query_upper:
        modified_query = f"{modified_query} LIMIT 100"
    
    try:
        results = db.execute(modified_query)
        
        if not results:
            return {
                "columns": [],
                "rows": [],
                "row_count": 0,
                "message": "Query executed successfully, but returned no results."
            }
        
        # Convert results to JSON-serializable format
        columns = list(results[0].keys()) if results else []
        rows = []
        
        for row in results:
            row_data = []
            for col in columns:
                value = row[col]
                # Convert datetime to string
                if hasattr(value, 'isoformat'):
                    value = value.isoformat()
                row_data.append(value)
            rows.append(row_data)
        
        return {
            "columns": columns,
            "rows": rows,
            "row_count": len(rows),
            "message": f"Query executed successfully. {len(rows)} row(s) returned.",
            "query_executed": modified_query
        }
        
    except Exception as e:
        return {"error": f"Query execution failed: {str(e)}"}, 500