-- Migration 024: Add 'note' source_type to documents and dirty_sources
-- SQLite does not support ALTER CONSTRAINT, so we use the table-rebuild pattern.

-- ============================================================
-- 1. Rebuild dirty_sources with updated CHECK constraint
-- ============================================================

CREATE TABLE dirty_sources_new (
  source_type TEXT NOT NULL CHECK (source_type IN ('issue','merge_request','discussion','note')),
  source_id INTEGER NOT NULL,
  queued_at INTEGER NOT NULL,
  attempt_count INTEGER NOT NULL DEFAULT 0,
  last_attempt_at INTEGER,
  last_error TEXT,
  next_attempt_at INTEGER,
  PRIMARY KEY(source_type, source_id)
);

INSERT INTO dirty_sources_new SELECT * FROM dirty_sources;
DROP TABLE dirty_sources;
ALTER TABLE dirty_sources_new RENAME TO dirty_sources;
CREATE INDEX idx_dirty_sources_next_attempt ON dirty_sources(next_attempt_at);

-- ============================================================
-- 2. Rebuild documents with updated CHECK constraint
-- ============================================================

-- 2a. Backup junction table data
CREATE TEMP TABLE _doc_labels_backup AS SELECT * FROM document_labels;
CREATE TEMP TABLE _doc_paths_backup AS SELECT * FROM document_paths;

-- 2b. Drop all triggers that reference documents
DROP TRIGGER IF EXISTS documents_ai;
DROP TRIGGER IF EXISTS documents_ad;
DROP TRIGGER IF EXISTS documents_au;
DROP TRIGGER IF EXISTS documents_embeddings_ad;

-- 2c. Drop junction tables (they have FK references to documents)
DROP TABLE IF EXISTS document_labels;
DROP TABLE IF EXISTS document_paths;

-- 2d. Create new documents table with 'note' in CHECK constraint
CREATE TABLE documents_new (
  id INTEGER PRIMARY KEY,
  source_type TEXT NOT NULL CHECK (source_type IN ('issue','merge_request','discussion','note')),
  source_id INTEGER NOT NULL,
  project_id INTEGER NOT NULL REFERENCES projects(id),
  author_username TEXT,
  label_names TEXT,
  created_at INTEGER,
  updated_at INTEGER,
  url TEXT,
  title TEXT,
  content_text TEXT NOT NULL,
  content_hash TEXT NOT NULL,
  labels_hash TEXT NOT NULL DEFAULT '',
  paths_hash TEXT NOT NULL DEFAULT '',
  is_truncated INTEGER NOT NULL DEFAULT 0,
  truncated_reason TEXT CHECK (
    truncated_reason IN (
      'token_limit_middle_drop','single_note_oversized','first_last_oversized',
      'hard_cap_oversized'
    )
    OR truncated_reason IS NULL
  ),
  UNIQUE(source_type, source_id)
);

-- 2e. Copy all existing data
INSERT INTO documents_new SELECT * FROM documents;

-- 2f. Swap tables
DROP TABLE documents;
ALTER TABLE documents_new RENAME TO documents;

-- 2g. Recreate all indexes on documents
CREATE INDEX idx_documents_project_updated ON documents(project_id, updated_at);
CREATE INDEX idx_documents_author ON documents(author_username);
CREATE INDEX idx_documents_source ON documents(source_type, source_id);
CREATE INDEX idx_documents_hash ON documents(content_hash);

-- 2h. Recreate junction tables
CREATE TABLE document_labels (
  document_id INTEGER NOT NULL REFERENCES documents(id) ON DELETE CASCADE,
  label_name TEXT NOT NULL,
  PRIMARY KEY(document_id, label_name)
) WITHOUT ROWID;
CREATE INDEX idx_document_labels_label ON document_labels(label_name);

CREATE TABLE document_paths (
  document_id INTEGER NOT NULL REFERENCES documents(id) ON DELETE CASCADE,
  path TEXT NOT NULL,
  PRIMARY KEY(document_id, path)
) WITHOUT ROWID;
CREATE INDEX idx_document_paths_path ON document_paths(path);

-- 2i. Restore junction table data from backups
INSERT INTO document_labels SELECT * FROM _doc_labels_backup;
INSERT INTO document_paths SELECT * FROM _doc_paths_backup;

-- 2j. Recreate FTS triggers (from migration 008)
CREATE TRIGGER documents_ai AFTER INSERT ON documents BEGIN
  INSERT INTO documents_fts(rowid, title, content_text)
  VALUES (new.id, COALESCE(new.title, ''), new.content_text);
END;

CREATE TRIGGER documents_ad AFTER DELETE ON documents BEGIN
  INSERT INTO documents_fts(documents_fts, rowid, title, content_text)
  VALUES('delete', old.id, COALESCE(old.title, ''), old.content_text);
END;

CREATE TRIGGER documents_au AFTER UPDATE ON documents
WHEN old.title IS NOT new.title OR old.content_text != new.content_text
BEGIN
  INSERT INTO documents_fts(documents_fts, rowid, title, content_text)
  VALUES('delete', old.id, COALESCE(old.title, ''), old.content_text);
  INSERT INTO documents_fts(rowid, title, content_text)
  VALUES (new.id, COALESCE(new.title, ''), new.content_text);
END;

-- 2k. Recreate embeddings cleanup trigger (from migration 009)
CREATE TRIGGER documents_embeddings_ad AFTER DELETE ON documents BEGIN
  DELETE FROM embeddings
    WHERE rowid >= old.id * 1000
      AND rowid < (old.id + 1) * 1000;
END;

-- 2l. Rebuild FTS index to ensure consistency after table swap
INSERT INTO documents_fts(documents_fts) VALUES('rebuild');

-- ============================================================
-- 3. Defense triggers: clean up documents when notes are
--    deleted or flipped to system notes
-- ============================================================

CREATE TRIGGER notes_ad_cleanup AFTER DELETE ON notes
WHEN old.is_system = 0
BEGIN
  DELETE FROM documents WHERE source_type = 'note' AND source_id = old.id;
END;

CREATE TRIGGER notes_au_system_cleanup AFTER UPDATE OF is_system ON notes
WHEN NEW.is_system = 1 AND OLD.is_system = 0
BEGIN
  DELETE FROM documents WHERE source_type = 'note' AND source_id = OLD.id;
END;

-- ============================================================
-- 4. Drop temp backup tables
-- ============================================================

DROP TABLE IF EXISTS _doc_labels_backup;
DROP TABLE IF EXISTS _doc_paths_backup;

INSERT INTO schema_version (version, applied_at, description)
VALUES (24, strftime('%s', 'now') * 1000, '024_note_documents');