Constant MIGRATION_005 

const MIGRATION_005: &str = r#"
-- Recreate downloads table without foreign key constraint on item_id
-- This allows downloading items that haven't been synced locally yet

CREATE TABLE IF NOT EXISTS downloads_new (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    item_id TEXT NOT NULL,  -- No foreign key constraint - item may not be synced yet
    user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,

    -- File info
    file_path TEXT NOT NULL,
    file_size INTEGER,
    mime_type TEXT,

    -- Download state
    status TEXT DEFAULT 'pending',  -- pending, downloading, completed, failed, paused
    progress REAL DEFAULT 0,        -- 0.0 to 1.0

    -- Transcoding options used
    bitrate INTEGER,
    container TEXT,

    -- Timestamps
    queued_at TEXT DEFAULT CURRENT_TIMESTAMP,
    started_at TEXT,
    completed_at TEXT,

    -- Error tracking
    error_message TEXT,
    retry_count INTEGER DEFAULT 0,

    -- Priority and progress tracking (from migration 004)
    priority INTEGER DEFAULT 0,
    bytes_downloaded INTEGER DEFAULT 0,

    UNIQUE(item_id, user_id)
);

-- Copy existing data
INSERT OR IGNORE INTO downloads_new (
    id, item_id, user_id, file_path, file_size, mime_type, status, progress,
    bitrate, container, queued_at, started_at, completed_at, error_message,
    retry_count, priority, bytes_downloaded
)
SELECT
    id, item_id, user_id, file_path, file_size, mime_type, status, progress,
    bitrate, container, queued_at, started_at, completed_at, error_message,
    retry_count, priority, bytes_downloaded
FROM downloads;

-- Drop old table and rename new one
DROP TABLE IF EXISTS downloads;
ALTER TABLE downloads_new RENAME TO downloads;

-- Recreate indexes
CREATE INDEX IF NOT EXISTS idx_downloads_status ON downloads(status);
CREATE INDEX IF NOT EXISTS idx_downloads_queue
  ON downloads(status, priority DESC, queued_at ASC)
  WHERE status IN ('pending', 'downloading');
"#;

Migration to relax foreign key constraint on downloads.item_id Allows downloading items that haven’t been synced to local database yet