-- +goose Up
-- pending_uploads tracks short-lived presigned-URL upload sessions for direct
-- client-to-B2 uploads. A row is created when the client requests a presigned
-- POST policy, and either claimed (linked to a task_completion_image or
-- document_image) or reaped by the cleanup worker after expiry.
CREATE TABLE pending_uploads (
    id              BIGSERIAL PRIMARY KEY,
    user_id         BIGINT NOT NULL REFERENCES auth_user(id) ON DELETE CASCADE,
    category        VARCHAR(32) NOT NULL,
    b2_key          VARCHAR(255) NOT NULL UNIQUE,
    content_type    VARCHAR(127) NOT NULL,
    expected_bytes  BIGINT NOT NULL,
    actual_bytes    BIGINT,
    claimed_at      TIMESTAMPTZ,
    created_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    expires_at      TIMESTAMPTZ NOT NULL
);

-- Quota lookups: SUM/COUNT by user, ordered by recency.
CREATE INDEX idx_pending_uploads_user_created
    ON pending_uploads (user_id, created_at DESC);

-- Cleanup worker scan: only unclaimed expired rows. Partial index keeps it tiny.
CREATE INDEX idx_pending_uploads_cleanup
    ON pending_uploads (expires_at) WHERE claimed_at IS NULL;

-- task_completion_image and document_image gain an optional FK to the
-- pending_uploads row that produced them. Nullable so legacy rows (uploaded
-- through the multipart path) keep working.
ALTER TABLE task_taskcompletionimage
    ADD COLUMN pending_upload_id BIGINT REFERENCES pending_uploads(id) ON DELETE SET NULL;

ALTER TABLE task_documentimage
    ADD COLUMN pending_upload_id BIGINT REFERENCES pending_uploads(id) ON DELETE SET NULL;

-- +goose Down
ALTER TABLE task_documentimage DROP COLUMN IF EXISTS pending_upload_id;
ALTER TABLE task_taskcompletionimage DROP COLUMN IF EXISTS pending_upload_id;
DROP TABLE IF EXISTS pending_uploads;