import type { Knex } from 'knex';

import { DatabaseDriver } from '../database';
import type { CreateDriverResult, DatabaseAdapter, KnexConfig } from '../../../types/main';


/**
 * Knex adapter for the DatabaseDriver
 */
export class KnexAdapter implements DatabaseAdapter {
  #connection: Knex;
  #tableName!: string;

  constructor(config: KnexConfig) {
    this.#connection = config.connection;
  }

  setTableName(tableName: string): void {
    this.#tableName = tableName;
  }

  async get(key: string): Promise<{ value: string; expiresAt: number | null } | undefined> {
    const result = await this.#connection
      .from(this.#tableName)
      .select(['value', 'expires_at'])
      .where('key', key)
      .first();

    if (!result) return;

    return { value: result.value, expiresAt: result.expires_at };
  }

  async delete(key: string): Promise<boolean> {
    const result = await this.#connection.from(this.#tableName).where('key', key).delete();
    return result > 0;
  }

  async deleteMany(keys: string[]): Promise<number> {
    return await this.#connection.from(this.#tableName).whereIn('key', keys).delete();
  }

  async disconnect(): Promise<void> {
    await this.#connection.destroy();
  }

  async createTableIfNotExists(): Promise<void> {
    const hasTable = await this.#connection.schema.hasTable(this.#tableName);
    if (hasTable) return;

    await this.#connection.schema.createTable(this.#tableName, (table) => {
      table.string('key', 255).notNullable().primary();
      table.text('value', 'longtext');
      table.timestamp('expires_at').nullable();
    });
  }

  async pruneExpiredEntries(): Promise<void> {
    await this.#connection.from(this.#tableName).where('expires_at', '<', new Date()).delete();
  }

  async clear(prefix: string): Promise<void> {
    await this.#connection.from(this.#tableName).where('key', 'like', `${prefix}%`).delete();
  }

  async set(row: { key: string; value: any; expiresAt: Date | null }): Promise<void> {
    await this.#connection
      .from(this.#tableName)
      .insert({ key: row.key, value: row.value, expires_at: row.expiresAt })
      .onConflict('key')
      .merge(['value', 'expires_at']);
  }
}

/**
 * Create a knex driver
 * You will need to install the underlying database package (mysql2, pg, sqlite3, etc)
 */
export function knexDriver(options: KnexConfig): CreateDriverResult<DatabaseDriver> {
  return {
    options,
    factory: (config: KnexConfig) => {
      const adapter = new KnexAdapter(config);
      return new DatabaseDriver(adapter, config);
    },
  };
}