import sqlite3
import uuid
from pathlib import Path

from loguru import logger
from sqlalchemy import inspect, text, create_engine

from ..services.settings_manager import SettingsManager
from .models import (
    Base,
    ResearchStrategy,
    RateLimitAttempt,
    RateLimitEstimate,
)
from ...utilities.db_utils import DB_PATH, get_db_session


def import_default_settings_file(db_session):
    """
    Imports all settings from the default settings file to the DB.
    """
    settings_mgr = SettingsManager(db_session)
    if settings_mgr.db_version_matches_package():
        # We probably shouldn't bother loading settings if the version didn't
        # change.
        return
    logger.info("Detected a new version of default settings, upgrading DB.")

    # Create settings manager and import settings
    try:
        # This will not overwrite existing settings, but will delete
        # extraneous ones. This should be enough to update anyone with
        # old versions of the settings.
        settings_mgr.load_from_defaults_file(overwrite=False, delete_extra=True)
        logger.info("Successfully imported settings from files")

        # Update the saved version.
        settings_mgr.update_db_version()
    except Exception:
        logger.exception("Error importing settings from files")


def remove_research_log_table(engine):
    """
    Remove the redundant research_log table if it exists

    Args:
        engine: SQLAlchemy engine

    Returns:
        bool: True if operation was successful, False otherwise
    """
    try:
        inspector = inspect(engine)

        # Check if table exists
        if inspector.has_table("research_log"):
            # For SQLite, we need to use raw SQL for DROP TABLE
            with engine.connect() as conn:
                conn.execute("DROP TABLE research_log")
                conn.commit()
            logger.info("Successfully removed redundant 'research_log' table")
            return True
        else:
            logger.info("Table 'research_log' does not exist, no action needed")
            return True
    except Exception:
        logger.exception("Error removing research_log table")
        return False


def create_research_strategy_table(engine):
    """
    Create the research_strategies table if it doesn't exist

    Args:
        engine: SQLAlchemy engine

    Returns:
        bool: True if operation was successful, False otherwise
    """
    try:
        inspector = inspect(engine)

        # Check if table exists
        if not inspector.has_table("research_strategies"):
            # Create the table using ORM
            Base.metadata.create_all(
                engine, tables=[ResearchStrategy.__table__]
            )
            logger.info("Successfully created 'research_strategies' table")
            return True
        else:
            logger.info(
                "Table 'research_strategies' already exists, no action needed"
            )
            return True
    except Exception:
        logger.exception("Error creating research_strategies table")
        return False


def create_rate_limiting_tables(engine):
    """
    Create rate limiting tables if they don't exist

    Args:
        engine: SQLAlchemy engine

    Returns:
        bool: True if operation was successful, False otherwise
    """
    try:
        inspector = inspect(engine)

        tables_to_create = []

        # Check if rate_limit_attempts table exists
        if not inspector.has_table("rate_limit_attempts"):
            tables_to_create.append(RateLimitAttempt.__table__)
            logger.info("Need to create 'rate_limit_attempts' table")

        # Check if rate_limit_estimates table exists
        if not inspector.has_table("rate_limit_estimates"):
            tables_to_create.append(RateLimitEstimate.__table__)
            logger.info("Need to create 'rate_limit_estimates' table")

        if tables_to_create:
            # Create the tables using ORM
            Base.metadata.create_all(engine, tables=tables_to_create)
            logger.info(
                f"Successfully created {len(tables_to_create)} rate limiting tables"
            )
        else:
            logger.info("Rate limiting tables already exist, no action needed")

        return True
    except Exception:
        logger.exception("Error creating rate limiting tables")
        return False


def add_research_id_to_benchmark_results(engine):
    """
    Add research_id column to benchmark_results table if it doesn't exist.
    """
    try:
        import sqlite3

        # Get database path from engine
        db_path = engine.url.database

        logger.info("Checking if benchmark_results needs research_id column...")

        conn = sqlite3.connect(db_path)

        try:
            cursor = conn.cursor()

            # Check if table exists
            cursor.execute(
                "SELECT name FROM sqlite_master WHERE type='table' AND name='benchmark_results'"
            )
            if not cursor.fetchone():
                logger.info("benchmark_results table does not exist, skipping")
                return True

            # Check if research_id column already exists
            cursor.execute("PRAGMA table_info(benchmark_results)")
            columns = cursor.fetchall()
            has_research_id = any(col[1] == "research_id" for col in columns)

            if has_research_id:
                logger.info("benchmark_results already has research_id column")
                return True

            # Add research_id column
            logger.info("Adding research_id column to benchmark_results table")
            cursor.execute(
                "ALTER TABLE benchmark_results ADD COLUMN research_id TEXT"
            )

            conn.commit()
            logger.info(
                "Successfully added research_id column to benchmark_results"
            )
            return True

        finally:
            conn.close()

    except Exception:
        logger.exception("Error adding research_id column to benchmark_results")
        return False


def add_uuid_id_column_to_research_history(engine):
    """
    Adds a new `uuid_id` string column to the `research_history` table if it
    does not exist already.
    """
    try:
        import sqlite3

        # Get database path from engine
        db_path = engine.url.database

        logger.info("Checking if research_history needs uuid_id column...")

        conn = sqlite3.connect(db_path)

        try:
            cursor = conn.cursor()

            # Check if table exists
            cursor.execute(
                "SELECT name FROM sqlite_master WHERE type='table' AND name='research_history'"
            )
            if not cursor.fetchone():
                logger.info("research_history table does not exist, skipping")
                return True

            # Check if uuid_id column already exists
            cursor.execute("PRAGMA table_info(research_history)")
            columns = cursor.fetchall()
            has_uuid_id = any(col[1] == "uuid_id" for col in columns)

            if has_uuid_id:
                logger.info("research_history already has uuid_id column")
                return True

            # Add uuid_id column
            logger.info("Adding uuid_id column to research_history table")
            cursor.execute(
                "ALTER TABLE research_history ADD COLUMN uuid_id CHAR(36)"
            )

            conn.commit()
            logger.info("Successfully added uuid_id column to research_history")
            return True

        finally:
            conn.close()

    except Exception:
        logger.exception("Error adding uuid_id column to research_history")
        return False


def convert_research_id_to_string_if_needed(engine):
    """
    Convert research_id columns from Integer to String in all tables.
    Preserves existing data by converting integer IDs to string format.
    Only runs if integer research_id columns are detected.
    """
    try:
        import sqlite3

        # Get database path from engine
        db_path = engine.url.database

        logger.info(
            "Checking if research_id columns need conversion to string..."
        )

        conn = sqlite3.connect(db_path)
        conn.execute("PRAGMA foreign_keys = OFF")

        try:
            cursor = conn.cursor()

            # List of tables that might have research_id columns
            tables_to_check = [
                "token_usage",
                "model_usage",
                "search_calls",
                "benchmark_results",
            ]

            tables_needing_conversion = []

            # Check which tables need conversion
            for table_name in tables_to_check:
                # Check if table exists
                cursor.execute(
                    "SELECT name FROM sqlite_master WHERE type='table' AND name=?",
                    (table_name,),
                )
                if not cursor.fetchone():
                    continue

                # Check if research_id column exists and is integer type
                cursor.execute(f"PRAGMA table_info({table_name})")
                columns = cursor.fetchall()

                for col in columns:
                    col_name, col_type = col[1], col[2]
                    if col_name == "research_id" and (
                        "INTEGER" in col_type.upper()
                        or "INT" in col_type.upper()
                    ):
                        tables_needing_conversion.append(table_name)
                        break

            if not tables_needing_conversion:
                logger.info(
                    "All research_id columns are already string type, no conversion needed"
                )
                return True

            logger.info(
                f"Converting research_id to string in tables: {tables_needing_conversion}"
            )

            # Convert each table
            for table_name in tables_needing_conversion:
                logger.info(f"Converting {table_name} table...")

                # Get the current table schema
                cursor.execute(
                    f"SELECT sql FROM sqlite_master WHERE type='table' AND name='{table_name}'"
                )
                create_sql = cursor.fetchone()[0]

                # Create new table name
                new_table_name = f"{table_name}_new"

                # Modify the CREATE TABLE statement to change research_id to TEXT
                new_create_sql = create_sql.replace(
                    f"CREATE TABLE {table_name}",
                    f"CREATE TABLE {new_table_name}",
                )
                new_create_sql = new_create_sql.replace(
                    "research_id INTEGER", "research_id TEXT"
                )
                new_create_sql = new_create_sql.replace(
                    "research_id INT", "research_id TEXT"
                )

                # Create the new table
                cursor.execute(new_create_sql)

                # Copy data from old table to new table, converting research_id to string
                cursor.execute(f"SELECT * FROM {table_name}")
                old_rows = cursor.fetchall()

                if old_rows:
                    # Get column names
                    cursor.execute(f"PRAGMA table_info({table_name})")
                    columns = cursor.fetchall()
                    column_names = [col[1] for col in columns]
                    research_id_index = (
                        column_names.index("research_id")
                        if "research_id" in column_names
                        else -1
                    )

                    # Prepare insert statement
                    placeholders = ",".join(["?" for _ in column_names])
                    insert_sql = f"INSERT INTO {new_table_name} ({','.join(column_names)}) VALUES ({placeholders})"

                    # Convert rows and insert
                    converted_rows = []
                    for row in old_rows:
                        row_list = list(row)
                        # Convert research_id to string if it's not None
                        if (
                            research_id_index >= 0
                            and row_list[research_id_index] is not None
                        ):
                            row_list[research_id_index] = str(
                                row_list[research_id_index]
                            )
                        converted_rows.append(tuple(row_list))

                    cursor.executemany(insert_sql, converted_rows)
                    logger.info(
                        f"Converted {len(converted_rows)} rows in {table_name}"
                    )

                # Drop old table and rename new table
                cursor.execute(f"DROP TABLE {table_name}")
                cursor.execute(
                    f"ALTER TABLE {new_table_name} RENAME TO {table_name}"
                )

                logger.info(
                    f"Successfully converted {table_name} research_id to string"
                )

            # Commit all changes
            conn.commit()
            logger.info(
                "All research_id columns converted to string successfully!"
            )
            return True

        finally:
            conn.execute("PRAGMA foreign_keys = ON")
            conn.close()

    except Exception:
        logger.exception("Error converting research_id columns to string")
        return False


def create_provider_models_table(engine):
    """Create provider_models table for caching available models"""
    with engine.connect() as conn:
        result = conn.execute(
            text(
                "SELECT name FROM sqlite_master WHERE type='table' AND name='provider_models'"
            )
        )
        if result.fetchone():
            logger.info(
                "Table 'provider_models' already exists, no action needed"
            )
            return

        logger.info("Creating 'provider_models' table...")

        # Create the table
        conn.execute(
            text(
                """
            CREATE TABLE provider_models (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                provider VARCHAR(50) NOT NULL,
                model_key VARCHAR(255) NOT NULL,
                model_label VARCHAR(255) NOT NULL,
                model_metadata JSON,
                last_updated DATETIME DEFAULT CURRENT_TIMESTAMP NOT NULL,
                UNIQUE(provider, model_key)
            )
            """
            )
        )

        # Create index on provider
        conn.execute(
            text(
                "CREATE INDEX ix_provider_models_provider ON provider_models (provider)"
            )
        )

        conn.commit()
        logger.info("Table 'provider_models' created successfully")


def migrate_to_uuid():
    """
    Migrate all research_id fields from integers to UUIDs.

    Strategy:
    1. Add new UUID columns alongside existing integer columns
    2. Generate UUIDs for existing data (or keep as string versions of integers)
    3. Update foreign key relationships
    4. Drop old integer columns and rename UUID columns
    """
    db_path = Path(DB_PATH)
    if not db_path.exists():
        logger.info("Database doesn't exist yet, migration not needed")
        return

    logger.info(f"Starting UUID migration on {db_path}")

    conn = sqlite3.connect(db_path)
    conn.execute(
        "PRAGMA foreign_keys = OFF"
    )  # Disable FK constraints during migration

    try:
        cursor = conn.cursor()

        # 1. Migrate research_history table (main research IDs)
        logger.info("Migrating research_history table...")

        # Check if the table exists and has the old structure
        cursor.execute("PRAGMA table_info(research_history)")
        columns = cursor.fetchall()
        has_uuid_id = any(col[1] == "uuid_id" for col in columns)

        if not has_uuid_id:
            # Add UUID column
            cursor.execute(
                "ALTER TABLE research_history ADD COLUMN uuid_id TEXT"
            )

            # Generate UUIDs for existing records (convert integer ID to UUID format)
            cursor.execute("SELECT id FROM research_history")
            existing_ids = cursor.fetchall()

            for (old_id,) in existing_ids:
                # Generate a deterministic UUID based on the old ID
                new_uuid = str(
                    uuid.uuid5(uuid.NAMESPACE_OID, f"research_{old_id}")
                )
                cursor.execute(
                    "UPDATE research_history SET uuid_id = ? WHERE id = ?",
                    (new_uuid, old_id),
                )

            logger.info(
                f"Generated UUIDs for {len(existing_ids)} research records"
            )

        # 2. Migrate metrics tables
        logger.info("Migrating metrics tables...")

        # Token usage table
        cursor.execute("PRAGMA table_info(token_usage)")
        columns = cursor.fetchall()
        has_uuid_research_id = any(
            col[1] == "uuid_research_id" for col in columns
        )

        if not has_uuid_research_id:
            cursor.execute(
                "ALTER TABLE token_usage ADD COLUMN uuid_research_id TEXT"
            )

            # Convert existing research_ids to UUIDs (deterministic conversion)
            cursor.execute(
                "SELECT DISTINCT research_id FROM token_usage WHERE research_id IS NOT NULL"
            )
            research_ids = cursor.fetchall()

            for (research_id,) in research_ids:
                if research_id:
                    new_uuid = str(
                        uuid.uuid5(
                            uuid.NAMESPACE_OID, f"research_{research_id}"
                        )
                    )
                    cursor.execute(
                        "UPDATE token_usage SET uuid_research_id = ? WHERE research_id = ?",
                        (new_uuid, research_id),
                    )

            logger.info(
                f"Migrated {len(research_ids)} research IDs in token_usage"
            )

        # Model usage table
        cursor.execute("PRAGMA table_info(model_usage)")
        columns = cursor.fetchall()
        has_uuid_research_id = any(
            col[1] == "uuid_research_id" for col in columns
        )

        if not has_uuid_research_id:
            cursor.execute(
                "ALTER TABLE model_usage ADD COLUMN uuid_research_id TEXT"
            )

            cursor.execute(
                "SELECT DISTINCT research_id FROM model_usage WHERE research_id IS NOT NULL"
            )
            research_ids = cursor.fetchall()

            for (research_id,) in research_ids:
                if research_id:
                    new_uuid = str(
                        uuid.uuid5(
                            uuid.NAMESPACE_OID, f"research_{research_id}"
                        )
                    )
                    cursor.execute(
                        "UPDATE model_usage SET uuid_research_id = ? WHERE research_id = ?",
                        (new_uuid, research_id),
                    )

            logger.info(
                f"Migrated {len(research_ids)} research IDs in model_usage"
            )

        # Search calls table
        cursor.execute("PRAGMA table_info(search_calls)")
        columns = cursor.fetchall()
        has_uuid_research_id = any(
            col[1] == "uuid_research_id" for col in columns
        )

        if not has_uuid_research_id:
            cursor.execute(
                "ALTER TABLE search_calls ADD COLUMN uuid_research_id TEXT"
            )

            cursor.execute(
                "SELECT DISTINCT research_id FROM search_calls WHERE research_id IS NOT NULL"
            )
            research_ids = cursor.fetchall()

            for (research_id,) in research_ids:
                if research_id:
                    new_uuid = str(
                        uuid.uuid5(
                            uuid.NAMESPACE_OID, f"research_{research_id}"
                        )
                    )
                    cursor.execute(
                        "UPDATE search_calls SET uuid_research_id = ? WHERE research_id = ?",
                        (new_uuid, research_id),
                    )

            logger.info(
                f"Migrated {len(research_ids)} research IDs in search_calls"
            )

        # 3. Migrate benchmark tables
        logger.info("Migrating benchmark tables...")

        # Check if benchmark_results table exists
        cursor.execute(
            "SELECT name FROM sqlite_master WHERE type='table' AND name='benchmark_results'"
        )
        if cursor.fetchone():
            cursor.execute("PRAGMA table_info(benchmark_results)")
            columns = cursor.fetchall()
            has_uuid_research_id = any(
                col[1] == "uuid_research_id" for col in columns
            )

            if not has_uuid_research_id:
                cursor.execute(
                    "ALTER TABLE benchmark_results ADD COLUMN uuid_research_id TEXT"
                )

                cursor.execute(
                    "SELECT DISTINCT research_id FROM benchmark_results WHERE research_id IS NOT NULL"
                )
                research_ids = cursor.fetchall()

                for (research_id,) in research_ids:
                    if research_id:
                        new_uuid = str(
                            uuid.uuid5(
                                uuid.NAMESPACE_OID, f"research_{research_id}"
                            )
                        )
                        cursor.execute(
                            "UPDATE benchmark_results SET uuid_research_id = ? WHERE research_id = ?",
                            (new_uuid, research_id),
                        )

                logger.info(
                    f"Migrated {len(research_ids)} research IDs in benchmark_results"
                )

        # Commit all changes
        conn.commit()
        logger.info("UUID migration completed successfully!")

        # Note: We're keeping both old and new columns for now
        # The application will use the new UUID columns
        # Old columns can be dropped in a future migration once everything is stable

    except Exception as e:
        logger.error(f"Error during UUID migration: {e}")
        conn.rollback()
        raise
    finally:
        conn.execute("PRAGMA foreign_keys = ON")  # Re-enable FK constraints
        conn.close()


def cleanup_old_columns():
    """
    Cleanup migration - drops old integer columns after UUID migration is stable.
    Run this only after confirming the UUID migration is working correctly.
    """
    logger.warning(
        "This will permanently remove old integer research_id columns!"
    )
    logger.warning("Make sure to backup your database before running this!")

    conn = sqlite3.connect(DB_PATH)
    conn.execute("PRAGMA foreign_keys = OFF")

    try:
        # For SQLite, we need to recreate tables to drop columns
        # This is complex, so we'll leave old columns for now
        # They can be cleaned up manually if needed

        logger.info("Cleanup deferred - old columns remain for safety")

    finally:
        conn.execute("PRAGMA foreign_keys = ON")
        conn.close()


def ensure_database_initialized(engine=None, db_session=None):
    """
    Initialize the database and run any necessary database migrations

    Args:
        engine: SQLAlchemy engine
        db_session: Optional SQLAlchemy session
    """
    logger.info("Initializing database at {}.", DB_PATH)

    if engine is None:
        # Create SQLAlchemy engine
        engine = create_engine(f"sqlite:///{DB_PATH}")
    if db_session is None:
        db_session = get_db_session()

    # Create all tables if they don't exist
    Base.metadata.create_all(engine)

    # Import existing settings from files
    import_default_settings_file(db_session)

    try:
        # 1. Remove the redundant research_log table
        remove_research_log_table(engine)

        # 2. Create research_strategies table
        create_research_strategy_table(engine)

        # 4. Create rate limiting tables
        create_rate_limiting_tables(engine)

        # 5. Add research_id column to benchmark_results if missing
        add_research_id_to_benchmark_results(engine)

        # 6. Convert research_id columns from integer to string
        convert_research_id_to_string_if_needed(engine)

        # 7. Add uuid_id column to research_history if missing
        add_uuid_id_column_to_research_history(engine)

        # 8. Create provider_models table for caching
        create_provider_models_table(engine)

        logger.info("Schema upgrades completed successfully")
        return True
    except Exception:
        logger.exception("Error during schema upgrades")
        return False
    finally:
        db_session.close()
