-- 007_attachments.sql
-- File attachments for chat messages (v0.12.0)
--
-- Blobs live in object storage (PVC / S3). This table holds metadata.
-- Access control: always join through channels — attachments inherit
-- channel membership as their access boundary.

CREATE TABLE IF NOT EXISTS attachments (
    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    channel_id      UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
    user_id         UUID NOT NULL REFERENCES users(id),
    message_id      UUID REFERENCES messages(id) ON DELETE SET NULL,
    filename        VARCHAR(255) NOT NULL,
    content_type    VARCHAR(127) NOT NULL,
    size_bytes      BIGINT NOT NULL,
    storage_key     TEXT NOT NULL,
    extracted_text  TEXT,
    metadata        JSONB DEFAULT '{}'::jsonb,
    created_at      TIMESTAMPTZ DEFAULT NOW()
);

-- Primary access pattern: find attachments for a channel (auth check joins here)
CREATE INDEX IF NOT EXISTS idx_attachments_channel ON attachments(channel_id);

-- Quota calculation: SUM(size_bytes) WHERE user_id = $1
CREATE INDEX IF NOT EXISTS idx_attachments_user_size ON attachments(user_id);

-- Find attachments for a specific message
CREATE INDEX IF NOT EXISTS idx_attachments_message ON attachments(message_id) WHERE message_id IS NOT NULL;

-- Orphan cleanup: find unlinked attachments older than threshold
CREATE INDEX IF NOT EXISTS idx_attachments_orphan ON attachments(created_at) WHERE message_id IS NULL;