-- Retrieval schema for external knowledge ingestion
CREATE EXTENSION IF NOT EXISTS vector;
CREATE EXTENSION IF NOT EXISTS pg_trgm;

CREATE SCHEMA IF NOT EXISTS retrieval;

CREATE TABLE IF NOT EXISTS retrieval.items (
  id           BIGSERIAL PRIMARY KEY,
  external_id  TEXT UNIQUE,
  kind         TEXT CHECK (kind IN ('api_doc','code_symbol','snippet','note')) NOT NULL,
  lang         TEXT,
  framework    TEXT,
  version      TEXT,
  meta         JSONB DEFAULT '{}'::jsonb,
  created_at   TIMESTAMPTZ NOT NULL DEFAULT now(),
  updated_at   TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE IF NOT EXISTS retrieval.chunks (
  id           BIGSERIAL PRIMARY KEY,
  item_id      BIGINT REFERENCES retrieval.items(id) ON DELETE CASCADE,
  content      TEXT NOT NULL,
  token_count  INT,
  symbol       TEXT,
  section_path TEXT,
  modality     TEXT DEFAULT 'text',
  hash         TEXT,
  created_at   TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE IF NOT EXISTS retrieval.embeddings (
  chunk_id     BIGINT PRIMARY KEY REFERENCES retrieval.chunks(id) ON DELETE CASCADE,
  embedding    VECTOR(1024),
  created_at   TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE UNIQUE INDEX IF NOT EXISTS retrieval_chunks_hash_idx
  ON retrieval.chunks(hash)
  WHERE hash IS NOT NULL;

CREATE INDEX IF NOT EXISTS retrieval_embeddings_ivf
  ON retrieval.embeddings USING ivfflat (embedding vector_cosine_ops)
  WITH (lists = 2048);

CREATE INDEX IF NOT EXISTS retrieval_chunks_content_trgm
  ON retrieval.chunks USING gin (content gin_trgm_ops);