import Database from 'better-sqlite3';
import { mkdirSync } from 'fs';

mkdirSync('data', { recursive: true });

const db = new Database('data/fiddles.db');
db.pragma('journal_mode = WAL');
db.pragma('foreign_keys = ON');

db.exec(`
  CREATE TABLE IF NOT EXISTS fiddles (
    id TEXT PRIMARY KEY,
    title TEXT NOT NULL DEFAULT 'Untitled',
    html TEXT NOT NULL DEFAULT '',
    css TEXT NOT NULL DEFAULT '',
    css_type TEXT NOT NULL DEFAULT 'css',
    js TEXT NOT NULL DEFAULT '',
    js_type TEXT NOT NULL DEFAULT 'javascript',
    created_at TEXT NOT NULL DEFAULT (datetime('now')),
    updated_at TEXT NOT NULL DEFAULT (datetime('now'))
  )
`);

// Migration: add js_type column for existing databases
try {
  db.exec(`ALTER TABLE fiddles ADD COLUMN js_type TEXT NOT NULL DEFAULT 'javascript'`);
} catch (_) { /* column already exists */ }

// Migration: add listed column
try {
  db.exec(`ALTER TABLE fiddles ADD COLUMN listed INTEGER NOT NULL DEFAULT 1`);
} catch (_) { /* column already exists */ }

// Migration: add options column (JSON string for per-fiddle settings like tailwind)
try {
  db.exec(`ALTER TABLE fiddles ADD COLUMN options TEXT NOT NULL DEFAULT '{}'`);
} catch (_) { /* column already exists */ }

// Tags tables
db.exec(`
  CREATE TABLE IF NOT EXISTS tags (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL UNIQUE COLLATE NOCASE
  )
`);

db.exec(`
  CREATE TABLE IF NOT EXISTS fiddle_tags (
    fiddle_id TEXT NOT NULL REFERENCES fiddles(id) ON DELETE CASCADE,
    tag_id INTEGER NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
    PRIMARY KEY (fiddle_id, tag_id)
  )
`);

db.exec(`CREATE INDEX IF NOT EXISTS idx_fiddles_listed_updated ON fiddles(listed, updated_at DESC)`);

export const stmts = {
  insert: db.prepare(`
    INSERT INTO fiddles (id, title, html, css, css_type, js, js_type, listed, options)
    VALUES (@id, @title, @html, @css, @css_type, @js, @js_type, @listed, @options)
  `),
  get: db.prepare('SELECT * FROM fiddles WHERE id = ?'),
  update: db.prepare(`
    UPDATE fiddles SET title = @title, html = @html, css = @css,
      css_type = @css_type, js = @js, js_type = @js_type, listed = @listed,
      options = @options, updated_at = datetime('now')
    WHERE id = @id
  `),
  list: db.prepare('SELECT id, title, css_type, js_type, created_at, updated_at FROM fiddles ORDER BY updated_at DESC LIMIT 50'),

  // Tags
  getTagsForFiddle: db.prepare(`
    SELECT t.id, t.name FROM tags t
    JOIN fiddle_tags ft ON ft.tag_id = t.id
    WHERE ft.fiddle_id = ?
  `),
  insertTag: db.prepare('INSERT OR IGNORE INTO tags (name) VALUES (?)'),
  getTagByName: db.prepare('SELECT id, name FROM tags WHERE name = ? COLLATE NOCASE'),
  insertFiddleTag: db.prepare('INSERT OR IGNORE INTO fiddle_tags (fiddle_id, tag_id) VALUES (?, ?)'),
  deleteFiddleTags: db.prepare('DELETE FROM fiddle_tags WHERE fiddle_id = ?'),
  listTags: db.prepare(`
    SELECT t.id, t.name, COUNT(ft.fiddle_id) as count
    FROM tags t
    LEFT JOIN fiddle_tags ft ON ft.tag_id = t.id
    GROUP BY t.id
    HAVING count > 0
    ORDER BY count DESC
  `),
};

/**
 * Upsert tags for a fiddle. Accepts an array of tag name strings.
 */
export function setFiddleTags(fiddleId, tagNames) {
  stmts.deleteFiddleTags.run(fiddleId);
  for (const name of tagNames) {
    const trimmed = name.trim();
    if (!trimmed) continue;
    stmts.insertTag.run(trimmed);
    const tag = stmts.getTagByName.get(trimmed);
    if (tag) stmts.insertFiddleTag.run(fiddleId, tag.id);
  }
}

export default db;