import sqlite3 from 'node-sqlite3-wasm';

type Database = sqlite3.Database;

/**
 * SQLite schema based on the MySQL erit_main_db schema
 * All tables use snake_case naming to match the server database
 * Data is encrypted before storage and decrypted on retrieval
 */

export const SCHEMA_VERSION = 2;

/**
 * Initialize the local SQLite database with all required tables
 * @param db - SQLite database instance
 */
export function initializeSchema(db: Database): void {
    // Enable foreign keys
    db.exec('PRAGMA foreign_keys = ON');

    // AI Conversations
    db.exec(`
        CREATE TABLE IF NOT EXISTS ai_conversations (
            conversation_id TEXT PRIMARY KEY,
            book_id TEXT NOT NULL,
            mode TEXT NOT NULL,
            title TEXT NOT NULL,
            start_date INTEGER NOT NULL,
            status INTEGER NOT NULL,
            user_id TEXT NOT NULL,
            summary TEXT,
            convo_meta TEXT NOT NULL,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // AI Messages History
    db.exec(`
        CREATE TABLE IF NOT EXISTS ai_messages_history (
            message_id TEXT PRIMARY KEY,
            conversation_id TEXT NOT NULL,
            role TEXT NOT NULL,
            message TEXT NOT NULL,
            message_date INTEGER NOT NULL,
            FOREIGN KEY (conversation_id) REFERENCES ai_conversations(conversation_id) ON DELETE CASCADE
        );
    `);

    // Book Acts
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_acts (
            act_id INTEGER PRIMARY KEY,
            title TEXT NOT NULL,
            last_update INTEGER DEFAULT 0
        );
    `);

    // Book Act Summaries
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_act_summaries (
            act_sum_id TEXT PRIMARY KEY,
            book_id TEXT NOT NULL,
            user_id TEXT NOT NULL,
            act_index INTEGER NOT NULL,
            summary TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book AI Guide Line
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_ai_guide_line (
            user_id TEXT NOT NULL,
            book_id TEXT NOT NULL,
            global_resume TEXT,
            themes TEXT,
            verbe_tense INTEGER,
            narrative_type INTEGER,
            langue INTEGER,
            dialogue_type INTEGER,
            tone TEXT,
            atmosphere TEXT,
            current_resume TEXT,
            last_update INTEGER DEFAULT 0,
            PRIMARY KEY (user_id, book_id),
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book Chapters
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_chapters (
            chapter_id TEXT PRIMARY KEY,
            book_id TEXT NOT NULL,
            author_id TEXT NOT NULL,
            title TEXT NOT NULL,
            hashed_title TEXT,
            words_count INTEGER,
            chapter_order INTEGER,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book Chapter Content
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_chapter_content (
            content_id TEXT PRIMARY KEY,
            chapter_id TEXT NOT NULL,
            author_id TEXT NOT NULL,
            version INTEGER NOT NULL DEFAULT 2,
            content TEXT,
            words_count INTEGER NOT NULL,
            time_on_it INTEGER NOT NULL DEFAULT 0,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (chapter_id) REFERENCES book_chapters(chapter_id) ON DELETE CASCADE
        );
    `);

    // Book Chapter Infos
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_chapter_infos (
            chapter_info_id TEXT PRIMARY KEY,
            chapter_id TEXT,
            act_id INTEGER,
            incident_id TEXT,
            plot_point_id TEXT,
            book_id TEXT,
            author_id TEXT,
            summary TEXT,
            goal TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (chapter_id) REFERENCES book_chapters(chapter_id) ON DELETE CASCADE,
            FOREIGN KEY (incident_id) REFERENCES book_incidents(incident_id) ON DELETE CASCADE,
            FOREIGN KEY (plot_point_id) REFERENCES book_plot_points(plot_point_id) ON DELETE CASCADE
        );
    `);

    // Book Characters
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_characters (
            character_id TEXT PRIMARY KEY,
            book_id TEXT NOT NULL,
            user_id TEXT NOT NULL,
            first_name TEXT NOT NULL,
            last_name TEXT,
            category TEXT NOT NULL,
            title TEXT,
            image TEXT,
            role TEXT,
            biography TEXT,
            history TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book Character Attributes
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_characters_attributes (
            attr_id TEXT PRIMARY KEY,
            character_id TEXT NOT NULL,
            user_id TEXT NOT NULL,
            attribute_name TEXT NOT NULL,
            attribute_value TEXT NOT NULL,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (character_id) REFERENCES book_characters(character_id) ON DELETE CASCADE
        );
    `);

    // Book Character Relations
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_characters_relations (
            rel_id INTEGER PRIMARY KEY,
            character_id INTEGER NOT NULL,
            char_name TEXT NOT NULL,
            type TEXT NOT NULL,
            description TEXT NOT NULL,
            history TEXT NOT NULL,
            last_update INTEGER DEFAULT 0
        );
    `);

    // Book Guide Line
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_guide_line (
            user_id TEXT NOT NULL,
            book_id TEXT NOT NULL,
            tone TEXT,
            atmosphere TEXT,
            writing_style TEXT,
            themes TEXT,
            symbolism TEXT,
            motifs TEXT,
            narrative_voice TEXT,
            pacing TEXT,
            intended_audience TEXT,
            key_messages TEXT,
            last_update INTEGER DEFAULT 0,
            PRIMARY KEY (user_id, book_id),
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book Incidents
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_incidents (
            incident_id TEXT PRIMARY KEY,
            author_id TEXT NOT NULL,
            book_id TEXT NOT NULL,
            title TEXT NOT NULL,
            hashed_title TEXT NOT NULL,
            summary TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book Issues
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_issues (
            issue_id TEXT PRIMARY KEY,
            author_id TEXT NOT NULL,
            book_id TEXT NOT NULL,
            name TEXT NOT NULL,
            hashed_issue_name TEXT NOT NULL,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book Location
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_location (
            loc_id TEXT PRIMARY KEY,
            book_id TEXT NOT NULL,
            user_id TEXT NOT NULL,
            loc_name TEXT NOT NULL,
            loc_original_name TEXT NOT NULL,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book Plot Points
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_plot_points (
            plot_point_id TEXT PRIMARY KEY,
            title TEXT NOT NULL,
            hashed_title TEXT NOT NULL,
            summary TEXT,
            linked_incident_id TEXT,
            author_id TEXT NOT NULL,
            book_id TEXT NOT NULL,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book World
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_world (
            world_id TEXT PRIMARY KEY,
            name TEXT NOT NULL,
            hashed_name TEXT NOT NULL,
            author_id TEXT NOT NULL,
            book_id TEXT NOT NULL,
            history TEXT,
            politics TEXT,
            economy TEXT,
            religion TEXT,
            languages TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE
        );
    `);

    // Book World Elements
    db.exec(`
        CREATE TABLE IF NOT EXISTS book_world_elements (
            element_id TEXT PRIMARY KEY,
            world_id TEXT NOT NULL,
            user_id TEXT NOT NULL,
            element_type INTEGER NOT NULL,
            name TEXT NOT NULL,
            original_name TEXT NOT NULL,
            description TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (world_id) REFERENCES book_world(world_id) ON DELETE CASCADE
        );
    `);

    // Erit Books
    db.exec(`
        CREATE TABLE IF NOT EXISTS erit_books (
            book_id TEXT PRIMARY KEY,
            type TEXT NOT NULL,
            author_id TEXT NOT NULL,
            title TEXT NOT NULL,
            hashed_title TEXT NOT NULL,
            sub_title TEXT,
            hashed_sub_title TEXT,
            summary TEXT,
            serie_id INTEGER,
            desired_release_date TEXT,
            desired_word_count INTEGER,
            words_count INTEGER,
            cover_image TEXT,
            last_update INTEGER DEFAULT 0
        );
    `);

    // Erit Book Series
    db.exec(`
        CREATE TABLE IF NOT EXISTS erit_book_series (
            serie_id INTEGER PRIMARY KEY,
            name TEXT NOT NULL,
            author_id INTEGER NOT NULL
        );
    `);

    // Erit Editor Settings
    db.exec(`
        CREATE TABLE IF NOT EXISTS erit_editor (
            user_id TEXT,
            type TEXT NOT NULL,
            text_size INTEGER NOT NULL,
            text_intent INTEGER NOT NULL,
            interline TEXT NOT NULL,
            paper_width INTEGER NOT NULL,
            theme TEXT NOT NULL,
            focus INTEGER NOT NULL
        );
    `);

    // Erit Users
    db.exec(`
        CREATE TABLE IF NOT EXISTS erit_users (
            user_id TEXT PRIMARY KEY,
            first_name TEXT NOT NULL,
            last_name TEXT NOT NULL,
            username TEXT NOT NULL,
            email TEXT NOT NULL,
            origin_email TEXT NOT NULL,
            origin_username TEXT NOT NULL,
            author_name TEXT,
            origin_author_name TEXT,
            plateform TEXT NOT NULL,
            social_id TEXT,
            user_group INTEGER NOT NULL DEFAULT 4,
            password TEXT,
            term_accepted INTEGER NOT NULL DEFAULT 0,
            verify_code TEXT,
            reg_date INTEGER NOT NULL,
            account_verified INTEGER NOT NULL DEFAULT 0,
            erite_points INTEGER NOT NULL DEFAULT 100,
            stripe_customer_id TEXT,
            credits_balance REAL DEFAULT 0
        );
    `);

    // Location Element
    db.exec(`
        CREATE TABLE IF NOT EXISTS location_element (
            element_id TEXT PRIMARY KEY,
            location TEXT NOT NULL,
            user_id TEXT NOT NULL,
            element_name TEXT NOT NULL,
            original_name TEXT NOT NULL,
            element_description TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (location) REFERENCES book_location(loc_id) ON DELETE CASCADE
        );
    `);

    // Location Sub Element
    db.exec(`
        CREATE TABLE IF NOT EXISTS location_sub_element (
            sub_element_id TEXT PRIMARY KEY,
            element_id TEXT NOT NULL,
            user_id TEXT NOT NULL,
            sub_elem_name TEXT NOT NULL,
            original_name TEXT NOT NULL,
            sub_elem_description TEXT,
            last_update INTEGER DEFAULT 0,
            FOREIGN KEY (element_id) REFERENCES location_element(element_id) ON DELETE CASCADE
        );
    `);

    // User Keys
    db.exec(`
        CREATE TABLE IF NOT EXISTS user_keys (
            user_id TEXT NOT NULL,
            brand TEXT NOT NULL,
            key TEXT NOT NULL,
            actif INTEGER NOT NULL DEFAULT 1,
            FOREIGN KEY (user_id) REFERENCES erit_users(user_id) ON DELETE CASCADE
        );
    `);

    // User Last Chapter
    db.exec(`
        CREATE TABLE IF NOT EXISTS user_last_chapter (
            user_id TEXT NOT NULL,
            book_id TEXT NOT NULL,
            chapter_id TEXT NOT NULL,
            version INTEGER NOT NULL,
            PRIMARY KEY (user_id, book_id),
            FOREIGN KEY (book_id) REFERENCES erit_books(book_id) ON DELETE CASCADE,
            FOREIGN KEY (chapter_id) REFERENCES book_chapters(chapter_id) ON DELETE CASCADE
        );
    `);

    // Create indexes for better performance
    createIndexes(db);

    // Set schema version for new databases (prevents unnecessary migrations)
    initializeSchemaVersion(db);
}

/**
 * Create indexes for frequently queried columns
 */
function createIndexes(db: Database): void {
    db.exec(`
        CREATE INDEX IF NOT EXISTS idx_ai_conversations_book ON ai_conversations(book_id);
        CREATE INDEX IF NOT EXISTS idx_ai_conversations_user ON ai_conversations(user_id);
        CREATE INDEX IF NOT EXISTS idx_ai_messages_conversation ON ai_messages_history(conversation_id);
        CREATE INDEX IF NOT EXISTS idx_chapters_book ON book_chapters(book_id);
        CREATE INDEX IF NOT EXISTS idx_chapter_content_chapter ON book_chapter_content(chapter_id);
        CREATE INDEX IF NOT EXISTS idx_characters_book ON book_characters(book_id);
        CREATE INDEX IF NOT EXISTS idx_character_attrs_character ON book_characters_attributes(character_id);
        CREATE INDEX IF NOT EXISTS idx_world_book ON book_world(book_id);
        CREATE INDEX IF NOT EXISTS idx_world_elements_world ON book_world_elements(world_id);
    `);
}

/**
 * Get current schema version from database
 */
function getDbSchemaVersion(db: Database): number {
    try {
        const result = db.get('SELECT version FROM _schema_version LIMIT 1') as { version: number } | undefined;
        return result?.version ?? 0;
    } catch {
        return 0;
    }
}

/**
 * Set schema version in database
 */
function setDbSchemaVersion(db: Database, version: number): void {
    db.exec('CREATE TABLE IF NOT EXISTS _schema_version (version INTEGER PRIMARY KEY)');
    db.run('DELETE FROM _schema_version');
    db.run('INSERT INTO _schema_version (version) VALUES (?)', [version]);
}

/**
 * Initialize schema version for new databases
 * Only sets version if table doesn't exist yet (new DB)
 */
function initializeSchemaVersion(db: Database): void {
    const currentVersion = getDbSchemaVersion(db);
    if (currentVersion === 0) {
        setDbSchemaVersion(db, SCHEMA_VERSION);
    }
}

/**
 * Check if a column exists in a table
 */
function columnExists(db: Database, tableName: string, columnName: string): boolean {
    const columns = db.all(`PRAGMA table_info(${tableName})`) as { name: string }[];
    return columns.some(col => col.name === columnName);
}

/**
 * Safely drop a column if it exists
 */
function dropColumnIfExists(db: Database, tableName: string, columnName: string): void {
    if (columnExists(db, tableName, columnName)) {
        try {
            db.exec(`ALTER TABLE ${tableName} DROP COLUMN ${columnName}`);
        } catch (e) {
            console.error(`[Migration] Failed to drop column ${columnName} from ${tableName}:`, e);
        }
    }
}

/**
 * Recreate a table with a new schema while preserving data
 */
function recreateTable(db: Database, tableName: string, newSchema: string, columnsToKeep: string): void {
    try {
        db.exec('PRAGMA foreign_keys = OFF');
        db.exec(`CREATE TABLE ${tableName}_backup AS SELECT ${columnsToKeep} FROM ${tableName}`);
        db.exec(`DROP TABLE ${tableName}`);
        db.exec(newSchema);
        db.exec(`INSERT INTO ${tableName} (${columnsToKeep}) SELECT ${columnsToKeep} FROM ${tableName}_backup`);
        db.exec(`DROP TABLE ${tableName}_backup`);
        db.exec('PRAGMA foreign_keys = ON');
    } catch (e) {
        console.error(`[Migration] Failed to recreate table ${tableName}:`, e);
        db.exec('PRAGMA foreign_keys = ON');
    }
}

/**
 * Run migrations to update schema from one version to another
 */
export function runMigrations(db: Database): void {
    const currentVersion = getDbSchemaVersion(db);

    if (currentVersion >= SCHEMA_VERSION) {
        return;
    }

    // Migration v2: Remove NOT NULL constraints to allow null values from server sync
    if (currentVersion < 2) {
        // Recreate erit_books with nullable hashed_sub_title and summary
        recreateTable(db, 'erit_books', `
            CREATE TABLE erit_books (
                book_id TEXT PRIMARY KEY,
                type TEXT NOT NULL,
                author_id TEXT NOT NULL,
                title TEXT NOT NULL,
                hashed_title TEXT NOT NULL,
                sub_title TEXT,
                hashed_sub_title TEXT,
                summary TEXT,
                serie_id INTEGER,
                desired_release_date TEXT,
                desired_word_count INTEGER,
                words_count INTEGER,
                cover_image TEXT,
                last_update INTEGER DEFAULT 0
            )
        `, 'book_id, type, author_id, title, hashed_title, sub_title, hashed_sub_title, summary, serie_id, desired_release_date, desired_word_count, words_count, cover_image, last_update');

        // Recreate book_chapter_content with nullable content
        recreateTable(db, 'book_chapter_content', `
            CREATE TABLE book_chapter_content (
                content_id TEXT PRIMARY KEY,
                chapter_id TEXT NOT NULL,
                author_id TEXT NOT NULL,
                version INTEGER NOT NULL DEFAULT 2,
                content TEXT,
                words_count INTEGER NOT NULL,
                time_on_it INTEGER NOT NULL DEFAULT 0,
                last_update INTEGER DEFAULT 0,
                FOREIGN KEY (chapter_id) REFERENCES book_chapters(chapter_id) ON DELETE CASCADE
            )
        `, 'content_id, chapter_id, author_id, version, content, words_count, time_on_it, last_update');

        // Recreate book_chapter_infos with nullable summary and goal
        recreateTable(db, 'book_chapter_infos', `
            CREATE TABLE book_chapter_infos (
                chapter_info_id TEXT PRIMARY KEY,
                chapter_id TEXT,
                act_id INTEGER,
                incident_id TEXT,
                plot_point_id TEXT,
                book_id TEXT,
                author_id TEXT,
                summary TEXT,
                goal TEXT,
                last_update INTEGER DEFAULT 0,
                FOREIGN KEY (chapter_id) REFERENCES book_chapters(chapter_id) ON DELETE CASCADE,
                FOREIGN KEY (incident_id) REFERENCES book_incidents(incident_id) ON DELETE CASCADE,
                FOREIGN KEY (plot_point_id) REFERENCES book_plot_points(plot_point_id) ON DELETE CASCADE
            )
        `, 'chapter_info_id, chapter_id, act_id, incident_id, plot_point_id, book_id, author_id, summary, goal, last_update');
    }

    // Update schema version
    setDbSchemaVersion(db, SCHEMA_VERSION);
}