import { mkdirSync, readFileSync } from 'node:fs';
import { dirname, join } from 'node:path';
import { Database } from 'bun:sqlite';
import { drizzle } from 'drizzle-orm/bun-sqlite';
import { schema } from './schema';

type AppDrizzleDb = ReturnType<typeof createDb>;

declare global {
  // eslint-disable-next-line no-var
  var __fiscalSqliteClient: Database | undefined;
  // eslint-disable-next-line no-var
  var __fiscalDrizzleDb: AppDrizzleDb | undefined;
}

function getDatabasePath() {
  const raw = process.env.DATABASE_URL?.trim() || 'file:data/fiscal.sqlite';
  let databasePath = raw.startsWith('file:') ? raw.slice(5) : raw;

  if (databasePath.startsWith('///')) {
    databasePath = databasePath.slice(2);
  }

  if (!databasePath) {
    throw new Error('DATABASE_URL must point to a SQLite file path.');
  }

  return databasePath;
}

function hasTable(client: Database, tableName: string) {
  const row = client
    .query('SELECT name FROM sqlite_master WHERE type = ? AND name = ? LIMIT 1')
    .get('table', tableName) as { name: string } | null;

  return row !== null;
}

function hasColumn(client: Database, tableName: string, columnName: string) {
  if (!hasTable(client, tableName)) {
    return false;
  }

  const rows = client.query(`PRAGMA table_info(${tableName})`).all() as Array<{ name: string }>;
  return rows.some((row) => row.name === columnName);
}

function applySqlFile(client: Database, fileName: string) {
  const sql = readFileSync(join(process.cwd(), 'drizzle', fileName), 'utf8');
  client.exec(sql);
}

function ensureLocalSqliteSchema(client: Database) {
  if (!hasTable(client, 'filing_statement_snapshot')) {
    applySqlFile(client, '0001_glossy_statement_snapshots.sql');
  }

  if (hasTable(client, 'task_run')) {
    const missingTaskColumns: Array<{ name: string; sql: string }> = [
      { name: 'stage', sql: "ALTER TABLE `task_run` ADD `stage` text NOT NULL DEFAULT 'queued';" },
      { name: 'stage_detail', sql: 'ALTER TABLE `task_run` ADD `stage_detail` text;' },
      { name: 'resource_key', sql: 'ALTER TABLE `task_run` ADD `resource_key` text;' },
      { name: 'notification_read_at', sql: 'ALTER TABLE `task_run` ADD `notification_read_at` text;' },
      { name: 'notification_silenced_at', sql: 'ALTER TABLE `task_run` ADD `notification_silenced_at` text;' }
    ];

    for (const column of missingTaskColumns) {
      if (!hasColumn(client, 'task_run', column.name)) {
        client.exec(column.sql);
      }
    }
  }

  if (!hasTable(client, 'task_stage_event')) {
    applySqlFile(client, '0003_task_stage_event_timeline.sql');
  }

  if (hasTable(client, 'watchlist_item')) {
    const missingWatchlistColumns: Array<{ name: string; sql: string }> = [
      { name: 'category', sql: 'ALTER TABLE `watchlist_item` ADD `category` text;' },
      { name: 'tags', sql: 'ALTER TABLE `watchlist_item` ADD `tags` text;' }
    ];

    for (const column of missingWatchlistColumns) {
      if (!hasColumn(client, 'watchlist_item', column.name)) {
        client.exec(column.sql);
      }
    }
  }

  if (!hasTable(client, 'filing_taxonomy_snapshot')) {
    applySqlFile(client, '0005_financial_taxonomy_v3.sql');
  }
}

export function getSqliteClient() {
  if (!globalThis.__fiscalSqliteClient) {
    const databasePath = getDatabasePath();

    if (databasePath !== ':memory:') {
      mkdirSync(dirname(databasePath), { recursive: true });
    }

    const client = new Database(databasePath, { create: true });
    client.exec('PRAGMA foreign_keys = ON;');
    client.exec('PRAGMA journal_mode = WAL;');
    client.exec('PRAGMA busy_timeout = 5000;');
    ensureLocalSqliteSchema(client);

    globalThis.__fiscalSqliteClient = client;
  }

  return globalThis.__fiscalSqliteClient;
}

function createDb() {
  return drizzle(getSqliteClient(), { schema });
}

export const db = globalThis.__fiscalDrizzleDb ?? createDb();

if (!globalThis.__fiscalDrizzleDb) {
  globalThis.__fiscalDrizzleDb = db;
}

export const __dbInternals = {
  ensureLocalSqliteSchema,
  getDatabasePath,
  hasColumn,
  hasTable
};