import { mkdir } from "node:fs/promises";
import { dirname } from "node:path";
import { drizzle } from "drizzle-orm/libsql";
import { createClient } from "@libsql/client";
import * as schema from "./skill-registry-schema.js";
import { resolveSkillRegistryDbPath } from "../home-paths.js";

export type SkillRegistryDb = ReturnType<typeof drizzle<typeof schema>>;

let _db: SkillRegistryDb | null = null;

const CREATE_SKILLS_TABLE = `
CREATE TABLE IF NOT EXISTS skills (
  id TEXT PRIMARY KEY,
  source_id TEXT NOT NULL,
  name TEXT NOT NULL,
  description TEXT,
  source_url TEXT,
  active_version_id TEXT,
  removed_at INTEGER,
  created_at INTEGER NOT NULL,
  updated_at INTEGER NOT NULL
)`;

const CREATE_SKILL_VERSIONS_TABLE = `
CREATE TABLE IF NOT EXISTS skill_versions (
  id TEXT PRIMARY KEY,
  skill_id TEXT NOT NULL,
  version TEXT NOT NULL,
  fetched_at INTEGER NOT NULL,
  cache_dir TEXT
)`;

const CREATE_SKILL_FILES_TABLE = `
CREATE TABLE IF NOT EXISTS skill_files (
  id TEXT PRIMARY KEY,
  version_id TEXT NOT NULL,
  path TEXT NOT NULL,
  kind TEXT NOT NULL,
  size_bytes INTEGER
)`;

const CREATE_COMMUNITY_RATINGS_TABLE = `
CREATE TABLE IF NOT EXISTS community_ratings (
  id TEXT PRIMARY KEY,
  skill_id TEXT NOT NULL,
  fetched_at INTEGER NOT NULL,
  average_rating REAL,
  rating_count INTEGER,
  source TEXT
)`;

export async function getSkillRegistryDb(): Promise<SkillRegistryDb> {
  if (_db !== null) return _db;

  const dbPath = resolveSkillRegistryDbPath();
  await mkdir(dirname(dbPath), { recursive: true });

  const client = createClient({ url: `file:${dbPath}` });
  _db = drizzle({ client, schema });

  await client.execute(CREATE_SKILLS_TABLE);
  await client.execute(CREATE_SKILL_VERSIONS_TABLE);
  await client.execute(CREATE_SKILL_FILES_TABLE);
  await client.execute(CREATE_COMMUNITY_RATINGS_TABLE);

  return _db;
}

/** Reset the singleton — used for test cleanup */
export function resetSkillRegistryDb(): void {
  _db = null;
}