"""
Migration script to update FundTable schema:
- Change fund_size from VARCHAR to INTEGER
- Remove estimated_investment_size column
- Add check_size_lower INTEGER column
- Add check_size_upper INTEGER column
"""

import sys
from pathlib import Path

# Add preprocessor to path
sys.path.insert(0, str(Path(__file__).parent))

from models import engine
from sqlalchemy import text


def migrate_fund_table():
    """
    Migrate the funds table to add check_size fields and update fund_size type.

    SQLite doesn't support ALTER COLUMN directly, so we need to:
    1. Create new table with correct schema
    2. Copy data from old table
    3. Drop old table
    4. Rename new table
    """

    print("🔄 Starting fund table migration...")

    with engine.connect() as conn:
        # Start transaction
        trans = conn.begin()

        try:
            # Check if migration is needed
            result = conn.execute(text("PRAGMA table_info(funds)"))
            columns = {row[1]: row[2] for row in result}

            if "check_size_lower" in columns and "check_size_upper" in columns:
                print("✅ Migration already applied - check_size columns exist")
                return

            print("📊 Current columns:", list(columns.keys()))

            # Create new table with updated schema
            print("\n1️⃣ Creating new funds table with updated schema...")
            conn.execute(
                text("""
                CREATE TABLE IF NOT EXISTS funds_new (
                    id INTEGER PRIMARY KEY,
                    investor_id INTEGER NOT NULL,
                    fund_name VARCHAR,
                    fund_size INTEGER,
                    fund_size_source_url VARCHAR,
                    check_size_lower INTEGER,
                    check_size_upper INTEGER,
                    source_url VARCHAR,
                    source_provider VARCHAR,
                    geographic_focus JSON,
                    investment_stage_focus JSON,
                    sector_focus JSON,
                    created_at DATETIME DEFAULT CURRENT_TIMESTAMP NOT NULL,
                    updated_at DATETIME,
                    FOREIGN KEY (investor_id) REFERENCES investors(id)
                )
            """)
            )

            # Copy data from old table to new table
            print("2️⃣ Copying data from old table...")

            # Check if old estimated_investment_size column exists
            if "estimated_investment_size" in columns:
                # We have estimated_investment_size but it's a string
                # We'll set check_size fields to NULL for now - they'll be repopulated when re-parsing
                conn.execute(
                    text("""
                    INSERT INTO funds_new (
                        id, investor_id, fund_name, fund_size, fund_size_source_url,
                        check_size_lower, check_size_upper,
                        source_url, source_provider, 
                        geographic_focus, investment_stage_focus, sector_focus,
                        created_at, updated_at
                    )
                    SELECT 
                        id, investor_id, fund_name, 
                        CAST(fund_size AS INTEGER) as fund_size,
                        fund_size_source_url,
                        NULL as check_size_lower,
                        NULL as check_size_upper,
                        source_url, source_provider,
                        geographic_focus, investment_stage_focus, sector_focus,
                        created_at, updated_at
                    FROM funds
                """)
                )
            else:
                # No estimated_investment_size column (fresh install or already migrated partially)
                conn.execute(
                    text("""
                    INSERT INTO funds_new (
                        id, investor_id, fund_name, fund_size, fund_size_source_url,
                        check_size_lower, check_size_upper,
                        source_url, source_provider,
                        geographic_focus, investment_stage_focus, sector_focus,
                        created_at, updated_at
                    )
                    SELECT 
                        id, investor_id, fund_name,
                        CAST(fund_size AS INTEGER) as fund_size,
                        fund_size_source_url,
                        NULL as check_size_lower,
                        NULL as check_size_upper,
                        source_url, source_provider,
                        geographic_focus, investment_stage_focus, sector_focus,
                        created_at, updated_at
                    FROM funds
                """)
                )

            rows_copied = conn.execute(
                text("SELECT COUNT(*) FROM funds_new")
            ).fetchone()[0]
            print(f"   ✅ Copied {rows_copied} rows")

            # Drop old table
            print("3️⃣ Dropping old funds table...")
            conn.execute(text("DROP TABLE funds"))

            # Rename new table
            print("4️⃣ Renaming funds_new to funds...")
            conn.execute(text("ALTER TABLE funds_new RENAME TO funds"))

            # Commit transaction
            trans.commit()

            print("\n✅ Migration completed successfully!")
            print("\n📝 Summary:")
            print("   - fund_size: VARCHAR → INTEGER")
            print("   - estimated_investment_size: REMOVED")
            print("   - check_size_lower: ADDED (INTEGER)")
            print("   - check_size_upper: ADDED (INTEGER)")
            print(f"   - {rows_copied} fund records migrated")

            print(
                "\n⚠️  Note: check_size_lower and check_size_upper are NULL for existing records."
            )
            print("   Run the investor CSV parser again to populate these fields.")

        except Exception as e:
            trans.rollback()
            print(f"\n❌ Migration failed: {e}")
            raise


if __name__ == "__main__":
    migrate_fund_table()