import { drizzle } from 'drizzle-orm/bun-sqlite';
import { Database } from 'bun:sqlite';
import { migrate } from 'drizzle-orm/bun-sqlite/migrator';
import * as schema from './schema';
import { config } from '../config';
import { mkdirSync, existsSync } from 'fs';
import { dirname, resolve } from 'path';

// Ensure data directory exists
const dbDir = dirname(config.DATABASE_PATH);
if (!existsSync(dbDir)) {
  mkdirSync(dbDir, { recursive: true });
}

const sqlite = new Database(config.DATABASE_PATH, { create: true });
sqlite.exec('PRAGMA journal_mode = WAL');
sqlite.exec('PRAGMA foreign_keys = ON');

export const db = drizzle(sqlite, { schema });
export { sqlite };

/**
 * Run database migrations automatically on startup.
 * Uses CREATE TABLE IF NOT EXISTS semantics (via drizzle migrate)
 * so it is safe to call on every boot -- already-applied migrations
 * are tracked in the drizzle __drizzle_migrations journal table.
 *
 * The migrationsFolder path is resolved relative to the project root
 * (where package.json lives) so it works regardless of cwd.
 */
function autoMigrate() {
  try {
    // Resolve the drizzle folder relative to this file's location:
    // src/db/index.ts  ->  ../../drizzle
    const migrationsFolder = resolve(import.meta.dir, '../../drizzle');
    migrate(db, { migrationsFolder });
    console.info('[DB] Auto-migration completed successfully.');
  } catch (err) {
    console.error('[DB] Auto-migration failed:', err);
    // Do not crash the process -- tables may already exist from a prior run.
    // Fallback: create core tables with raw SQL if drizzle migrations folder is missing.
    try {
      createTablesIfNotExist();
      console.info('[DB] Fallback table creation completed.');
    } catch (fallbackErr) {
      console.error('[DB] Fallback table creation also failed:', fallbackErr);
    }
  }
}

/**
 * Fallback: create all required tables using raw SQL CREATE TABLE IF NOT EXISTS.
 * This is only used when the drizzle migrations folder cannot be found.
 */
function createTablesIfNotExist() {
  sqlite.exec(`
    CREATE TABLE IF NOT EXISTS users (
      id TEXT PRIMARY KEY NOT NULL,
      plane_user_id TEXT,
      display_name TEXT NOT NULL,
      email TEXT NOT NULL UNIQUE,
      git_username TEXT,
      role TEXT NOT NULL,
      password_hash TEXT NOT NULL,
      login_attempts INTEGER DEFAULT 0,
      locked_until INTEGER,
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS projects (
      id TEXT PRIMARY KEY NOT NULL,
      plane_project_id TEXT NOT NULL UNIQUE,
      name TEXT NOT NULL,
      identifier TEXT,
      last_synced_at INTEGER,
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS sprint_snapshots (
      id TEXT PRIMARY KEY NOT NULL,
      project_id TEXT REFERENCES projects(id),
      plane_cycle_id TEXT NOT NULL,
      name TEXT NOT NULL,
      start_date TEXT,
      end_date TEXT,
      total_points INTEGER DEFAULT 0,
      completed_points INTEGER DEFAULT 0,
      total_issues INTEGER DEFAULT 0,
      completed_issues INTEGER DEFAULT 0,
      burndown_data TEXT,
      status TEXT,
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS task_snapshots (
      id TEXT PRIMARY KEY NOT NULL,
      plane_issue_id TEXT NOT NULL,
      project_id TEXT REFERENCES projects(id),
      sprint_id TEXT REFERENCES sprint_snapshots(id),
      title TEXT NOT NULL,
      status TEXT,
      priority TEXT,
      assignee_id TEXT REFERENCES users(id),
      story_points INTEGER,
      created_at INTEGER,
      completed_at INTEGER,
      due_date TEXT,
      labels TEXT,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS milestones (
      id TEXT PRIMARY KEY NOT NULL,
      plane_module_id TEXT NOT NULL,
      project_id TEXT REFERENCES projects(id),
      name TEXT NOT NULL,
      status TEXT,
      target_date TEXT,
      total_issues INTEGER DEFAULT 0,
      completed_issues INTEGER DEFAULT 0,
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS git_commits (
      id TEXT PRIMARY KEY NOT NULL,
      repo_name TEXT NOT NULL,
      sha TEXT NOT NULL UNIQUE,
      author_email TEXT,
      author_name TEXT,
      user_id TEXT REFERENCES users(id),
      message TEXT,
      additions INTEGER DEFAULT 0,
      deletions INTEGER DEFAULT 0,
      committed_at INTEGER NOT NULL,
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS git_prs (
      id TEXT PRIMARY KEY NOT NULL,
      repo_name TEXT NOT NULL,
      external_id INTEGER NOT NULL,
      title TEXT,
      user_id TEXT REFERENCES users(id),
      author_username TEXT,
      state TEXT,
      additions INTEGER DEFAULT 0,
      deletions INTEGER DEFAULT 0,
      review_comments INTEGER DEFAULT 0,
      created_at INTEGER,
      merged_at INTEGER,
      merge_time_hours REAL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS objectives (
      id TEXT PRIMARY KEY NOT NULL,
      title TEXT NOT NULL,
      owner_id TEXT REFERENCES users(id),
      project_id TEXT REFERENCES projects(id),
      period TEXT NOT NULL,
      progress REAL DEFAULT 0,
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS key_results (
      id TEXT PRIMARY KEY NOT NULL,
      objective_id TEXT NOT NULL REFERENCES objectives(id),
      title TEXT NOT NULL,
      target_value REAL NOT NULL,
      current_value REAL DEFAULT 0,
      unit TEXT,
      weight REAL DEFAULT 1,
      linked_plane_cycle_id TEXT,
      linked_plane_module_id TEXT,
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS author_mappings (
      id TEXT PRIMARY KEY NOT NULL,
      git_email TEXT,
      git_username TEXT,
      user_id TEXT REFERENCES users(id),
      created_at INTEGER NOT NULL,
      updated_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS project_repos (
      id TEXT PRIMARY KEY NOT NULL,
      project_id TEXT NOT NULL REFERENCES projects(id),
      repo_name TEXT NOT NULL,
      created_at INTEGER NOT NULL
    );

    CREATE TABLE IF NOT EXISTS sync_logs (
      id TEXT PRIMARY KEY NOT NULL,
      source TEXT NOT NULL,
      status TEXT NOT NULL,
      message TEXT,
      records_processed INTEGER DEFAULT 0,
      synced_at INTEGER NOT NULL
    );
  `);
}

// Run auto-migration on module load (i.e. on server startup)
autoMigrate();