// Convert videos.id and slides.id (plus every FK that references them) from
// serial integers to UUID (gen_random_uuid).
//
// Safe for dev: truncates all video data first. Re-run the push script after
// migrating to re-ingest videos. shared_assets (asset library) is unchanged.
//
// This is a one-way migration. There is no meaningful down path.

const CHILD_TABLES = [
  // table                  FK constraint name                         UNIQUE constraint name                     UNIQUE expression
  ['narration_segments', 'narration_segments_project_id_fkey', 'narration_segments_project_key_unique', '(project_id, segment_key)'],
  ['cutouts',            'cutouts_project_id_fkey',            'cutouts_project_name_unique',            '(project_id, name)'],
  ['filter_chains',      'filter_chains_project_id_fkey',       null,                                     null],
  ['video_assets',       'video_assets_project_id_fkey',        'video_assets_project_key_unique',        '(project_id, asset_key)'],
  ['audio_tracks',       'audio_tracks_project_id_fkey',        'audio_tracks_project_key_unique',        '(project_id, track_key)'],
  ['citations',          'citations_project_id_fkey',            null,                                     null],
  ['project_sync',       'project_sync_project_id_fkey',        'project_sync_project_id_key',            '(project_id)'],
  ['transcripts',        'transcripts_project_id_fkey',          'transcripts_project_source_unique',      '(project_id, source_name)'],
];

exports.up = (pgm) => {
  // ── Clear all video data ─────────────────────────────────────────────────
  pgm.sql('TRUNCATE videos CASCADE');

  // ── 1. Drop all FKs pointing at videos.id BEFORE touching the PK ────────
  // slides
  pgm.sql('ALTER TABLE slides DROP CONSTRAINT IF EXISTS slides_video_id_fkey');
  pgm.sql('ALTER TABLE slides DROP CONSTRAINT IF EXISTS slides_video_id_gnommo_slide_id_unique');
  // all other child tables
  for (const [table, fkName, uniqueName] of CHILD_TABLES) {
    pgm.sql(`ALTER TABLE ${table} DROP CONSTRAINT IF EXISTS ${fkName}`);
    if (uniqueName) pgm.sql(`ALTER TABLE ${table} DROP CONSTRAINT IF EXISTS ${uniqueName}`);
  }

  // ── 2. videos.id: serial → uuid ─────────────────────────────────────────
  pgm.sql('ALTER TABLE videos ALTER COLUMN id DROP DEFAULT');
  pgm.sql('ALTER TABLE videos DROP CONSTRAINT videos_pkey');
  pgm.sql('ALTER TABLE videos ALTER COLUMN id TYPE uuid USING gen_random_uuid()');
  pgm.sql('ALTER TABLE videos ALTER COLUMN id SET DEFAULT gen_random_uuid()');
  pgm.sql('ALTER TABLE videos ADD PRIMARY KEY (id)');

  // ── 3. slides: video_id FK column, then id PK ───────────────────────────
  pgm.sql('ALTER TABLE slides ALTER COLUMN video_id TYPE uuid USING gen_random_uuid()');
  pgm.sql('ALTER TABLE slides ADD CONSTRAINT slides_video_id_gnommo_slide_id_unique UNIQUE (video_id, gnommo_slide_id)');
  pgm.sql('ALTER TABLE slides ADD CONSTRAINT slides_video_id_fkey FOREIGN KEY (video_id) REFERENCES videos(id) ON DELETE CASCADE');

  pgm.sql('ALTER TABLE slides ALTER COLUMN id DROP DEFAULT');
  pgm.sql('ALTER TABLE slides DROP CONSTRAINT slides_pkey');
  pgm.sql('ALTER TABLE slides ALTER COLUMN id TYPE uuid USING gen_random_uuid()');
  pgm.sql('ALTER TABLE slides ALTER COLUMN id SET DEFAULT gen_random_uuid()');
  pgm.sql('ALTER TABLE slides ADD PRIMARY KEY (id)');

  // ── 4. All other child tables: project_id integer → uuid ────────────────
  for (const [table, fkName, uniqueName, uniqueExpr] of CHILD_TABLES) {
    pgm.sql(`ALTER TABLE ${table} ALTER COLUMN project_id TYPE uuid USING gen_random_uuid()`);
    if (uniqueName && uniqueExpr) {
      pgm.sql(`ALTER TABLE ${table} ADD CONSTRAINT ${uniqueName} UNIQUE ${uniqueExpr}`);
    }
    pgm.sql(`ALTER TABLE ${table} ADD CONSTRAINT ${fkName} FOREIGN KEY (project_id) REFERENCES videos(id) ON DELETE CASCADE`);
  }
};

exports.down = () => {
  // Intentionally empty — reversing uuid → serial would require re-sequencing
  // all IDs and is not worth implementing for a dev-only migration.
};