import { webcrypto } from 'node:crypto';
import { readFileSync, readdirSync } from 'node:fs';
import { DatabaseSync } from 'node:sqlite';
import { runInNewContext } from 'node:vm';
import ts from 'typescript';
import * as engine from '../game/engine';
import * as bots from '../game/bots';
import * as seatAiDelegation from '../lib/seat-ai-delegation';
import type * as Rooms from '../db/rooms';

/** Execute the production room module and SQL, with a hook immediately before its CAS. */
export function unitStore(runBots = bots.runBots, migrationThrough?: string) {
  const sqlite = new DatabaseSync(':memory:');
  const hooks: {
    beforeWrite?: () => Promise<void>;
    beforeStatement?: (sql: string) => Promise<void>;
    afterStatement?: (sql: string) => Promise<void>;
    beforeBatch?: () => Promise<void>;
  } = {};
  const writes: { expected: number; changes: number }[] = [];
  for (const file of readdirSync(new URL('../drizzle/', import.meta.url))
    .filter((f) => f.endsWith('.sql'))
    .filter((f) => !migrationThrough || f <= migrationThrough)
    .sort())
    sqlite.exec(
      readFileSync(new URL('../drizzle/' + file, import.meta.url), 'utf8'),
    );
  class Statement {
    values: (string | number | null)[] = [];
    constructor(readonly sql: string) {}
    bind(...values: (string | number | null)[]) {
      this.values = values;
      return this;
    }
    async first() {
      return sqlite.prepare(this.sql).get(...this.values) ?? null;
    }
    async run() {
      await hooks.beforeStatement?.(this.sql);
      const continuation = this.sql.startsWith('UPDATE rooms SET state');
      if (continuation) await hooks.beforeWrite?.();
      const changes = Number(
        sqlite.prepare(this.sql).run(...this.values).changes,
      );
      if (continuation)
        writes.push({ expected: Number(this.values[3]), changes });
      await hooks.afterStatement?.(this.sql);
      return { meta: { changes } };
    }
  }
  const database = {
    prepare: (sql: string) => new Statement(sql),
    batch: async (statements: Statement[]) => {
      await hooks.beforeBatch?.();
      sqlite.exec('BEGIN');
      try {
        const results = [];
        for (const statement of statements) results.push(await statement.run());
        sqlite.exec('COMMIT');
        return results;
      } catch (error) {
        sqlite.exec('ROLLBACK');
        throw error;
      }
    },
  };
  function loadRooms() {
    const exports = {};
    runInNewContext(
      ts.transpileModule(
        readFileSync(new URL('../db/rooms.ts', import.meta.url), 'utf8'),
        {
          compilerOptions: {
            module: ts.ModuleKind.CommonJS,
            target: ts.ScriptTarget.ES2022,
          },
        },
      ).outputText,
      {
        exports,
        crypto: webcrypto,
        TextEncoder,
        structuredClone,
        // Keep persisted JSON values in the test realm for strict structural assertions.
        JSON,
        require: (name: string) => {
          if (name === 'cloudflare:workers') return { env: { DB: database } };
          if (name === '@/game/engine') return engine;
          if (name === '@/game/bots') return { ...bots, runBots };
          if (name === '@/lib/seat-ai-delegation') return seatAiDelegation;
          throw new Error('Unexpected module ' + name);
        },
      },
    );
    return exports as typeof Rooms;
  }
  return {
    rooms: loadRooms(),
    restart: loadRooms,
    sqlite,
    hooks,
    writes,
    database,
  };
}