-- Semantic search: embeddings tracking and queue
-- Note: actual vectors are stored in the HNSW index file on disk.
-- This table tracks which messages have been embedded and by which provider.

CREATE TABLE IF NOT EXISTS embeddings (
    message_id INTEGER PRIMARY KEY REFERENCES messages(id) ON DELETE CASCADE,
    provider TEXT NOT NULL,
    model TEXT NOT NULL,
    dimensions INTEGER NOT NULL,
    embedded_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS embedding_queue (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    message_id INTEGER NOT NULL REFERENCES messages(id) ON DELETE CASCADE,
    status TEXT NOT NULL DEFAULT 'pending' CHECK (status IN ('pending', 'processing', 'completed', 'failed')),
    attempts INTEGER NOT NULL DEFAULT 0,
    last_error TEXT,
    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
    completed_at TIMESTAMP
);

CREATE UNIQUE INDEX IF NOT EXISTS idx_embedding_queue_message ON embedding_queue(message_id);
CREATE INDEX IF NOT EXISTS idx_embedding_queue_status ON embedding_queue(status);

INSERT INTO schema_migrations (version) VALUES (5);