-- ==========================================
-- Chat Switchboard — 006 Knowledge Bases
-- ==========================================
-- Knowledge bases, documents, chunks, and bindings to channels/personas.
-- ICD §5 (Knowledge Bases)
-- ==========================================

-- =========================================
-- KNOWLEDGE BASES
-- =========================================

CREATE TABLE IF NOT EXISTS knowledge_bases (
    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name            TEXT NOT NULL,
    description     TEXT NOT NULL DEFAULT '',
    scope           TEXT NOT NULL DEFAULT 'global',
    owner_id        UUID REFERENCES users(id) ON DELETE CASCADE,
    team_id         UUID REFERENCES teams(id) ON DELETE CASCADE,
    embedding_config JSONB NOT NULL DEFAULT '{}',
    document_count  INT NOT NULL DEFAULT 0,
    chunk_count     INT NOT NULL DEFAULT 0,
    total_bytes     BIGINT NOT NULL DEFAULT 0,
    status          TEXT NOT NULL DEFAULT 'active',
    discoverable    BOOLEAN NOT NULL DEFAULT true,
    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at      TIMESTAMPTZ NOT NULL DEFAULT now(),

    CONSTRAINT kb_scope_check CHECK (
        (scope = 'global'   AND owner_id IS NULL) OR
        (scope = 'team'     AND team_id IS NOT NULL) OR
        (scope = 'personal' AND owner_id IS NOT NULL)
    )
);

CREATE INDEX IF NOT EXISTS idx_kb_scope ON knowledge_bases(scope);
CREATE INDEX IF NOT EXISTS idx_kb_owner ON knowledge_bases(owner_id) WHERE owner_id IS NOT NULL;
CREATE INDEX IF NOT EXISTS idx_kb_team  ON knowledge_bases(team_id)  WHERE team_id IS NOT NULL;

COMMENT ON COLUMN knowledge_bases.discoverable IS 'false = hidden from user KB lists, only accessible through persona binding';


-- =========================================
-- KB DOCUMENTS
-- =========================================

CREATE TABLE IF NOT EXISTS kb_documents (
    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
    filename        TEXT NOT NULL,
    content_type    TEXT NOT NULL,
    size_bytes      BIGINT NOT NULL,
    storage_key     TEXT NOT NULL,
    extracted_text  TEXT,
    chunk_count     INT NOT NULL DEFAULT 0,
    status          TEXT NOT NULL DEFAULT 'pending',
    error           TEXT,
    uploaded_by     UUID NOT NULL REFERENCES users(id),
    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at      TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS idx_kbdoc_kb ON kb_documents(kb_id);


-- =========================================
-- KB CHUNKS
-- =========================================

CREATE TABLE IF NOT EXISTS kb_chunks (
    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
    document_id     UUID NOT NULL REFERENCES kb_documents(id) ON DELETE CASCADE,
    chunk_index     INT NOT NULL,
    content         TEXT NOT NULL,
    token_count     INT NOT NULL DEFAULT 0,
    embedding       VECTOR(3072),
    metadata        JSONB NOT NULL DEFAULT '{}',
    created_at      TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE INDEX IF NOT EXISTS idx_kbchunk_kb  ON kb_chunks(kb_id);
CREATE INDEX IF NOT EXISTS idx_kbchunk_doc ON kb_chunks(document_id);


-- =========================================
-- CHANNEL ↔ KB BINDING
-- =========================================

CREATE TABLE IF NOT EXISTS channel_knowledge_bases (
    channel_id      UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
    kb_id           UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
    enabled         BOOLEAN NOT NULL DEFAULT true,
    added_at        TIMESTAMPTZ NOT NULL DEFAULT now(),
    PRIMARY KEY (channel_id, kb_id)
);


-- =========================================
-- PERSONA ↔ KB BINDING (v0.17.0)
-- =========================================

CREATE TABLE IF NOT EXISTS persona_knowledge_bases (
    persona_id  UUID NOT NULL REFERENCES personas(id) ON DELETE CASCADE,
    kb_id       UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
    auto_search BOOLEAN NOT NULL DEFAULT false,
    added_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
    PRIMARY KEY (persona_id, kb_id)
);

CREATE INDEX IF NOT EXISTS idx_persona_kb_persona ON persona_knowledge_bases(persona_id);
CREATE INDEX IF NOT EXISTS idx_persona_kb_kb      ON persona_knowledge_bases(kb_id);

COMMENT ON TABLE persona_knowledge_bases IS 'Binds KBs to personas — the persona becomes a gateway to its KBs';
COMMENT ON COLUMN persona_knowledge_bases.auto_search IS 'true = auto-prepend top-K results to context; false = kb_search tool only';