-- name: CreateRequest :one
INSERT INTO requests (
    user_id, kind,
    artist_mbid, album_mbid, track_mbid,
    artist_name, album_title, track_title
) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
RETURNING *;

-- name: GetRequestByID :one
SELECT * FROM requests WHERE id = $1;

-- name: ListRequestsForUser :many
SELECT * FROM requests
WHERE user_id = $1
ORDER BY requested_at DESC
LIMIT $2;

-- name: ListRequestsByStatus :many
SELECT * FROM requests
WHERE status = $1
ORDER BY requested_at DESC
LIMIT $2;

-- name: ListApprovedRequestsForReconcile :many
SELECT * FROM requests
WHERE status = 'approved'
ORDER BY decided_at ASC
LIMIT $1;

-- name: ApproveRequest :one
UPDATE requests
   SET status     = 'approved',
       decided_at = now(),
       decided_by = $2,
       updated_at = now()
 WHERE id = $1 AND status = 'pending'
 RETURNING *;

-- name: RejectRequest :one
UPDATE requests
   SET status     = 'rejected',
       notes      = $2,
       decided_at = now(),
       decided_by = $3,
       updated_at = now()
 WHERE id = $1 AND status = 'pending'
 RETURNING *;

-- name: CancelRequest :one
-- $2 serves as both the ownership guard (user_id = $2) and the
-- decided_by audit field. The generated parameter struct names it
-- DecidedBy — callers must pass the cancelling user's UUID, and
-- a wrong UUID will silently no-op (zero rows updated) rather than
-- erroring at the SQL layer.
UPDATE requests
   SET status     = 'rejected',
       notes      = 'cancelled by user',
       decided_at = now(),
       decided_by = $2,
       updated_at = now()
 WHERE id = $1 AND user_id = $2 AND status = 'pending'
 RETURNING *;

-- name: CompleteRequest :one
-- Reconciler transitions an approved request to completed when its
-- target track/album/artist has appeared in the library. Callers
-- should set ONLY the matched_*_id corresponding to the request's
-- kind and pass pgtype.UUID{} (Valid: false) for the others —
-- per-kind one-of-three is the contract, NULL for the others
-- preserves auditability if the matched row is later evicted.
UPDATE requests
   SET status            = 'completed',
       matched_track_id  = $2,
       matched_album_id  = $3,
       matched_artist_id = $4,
       completed_at      = now(),
       updated_at        = now()
 WHERE id = $1 AND status = 'approved'
 RETURNING *;

-- name: HasNonTerminalRequestForMBID :one
-- Whether something is already on its way: a pending, approved or completed
-- request at the given level, an open want for the release group, or a
-- follow of the artist. Sets the `requested` flag on catalogue search.
-- Terminal-status (rejected, failed) requests do not count. MBIDs are unique
-- per entity type, so checking one id against every column cannot
-- false-match.
SELECT (EXISTS (
    SELECT 1 FROM requests r
    WHERE r.status IN ('pending', 'approved', 'completed')
      AND ((r.kind = 'artist' AND r.artist_mbid = @mbid)
        OR (r.kind = 'album'  AND r.album_mbid  = @mbid)
        OR (r.kind = 'track'  AND r.track_mbid  = @mbid))
) OR EXISTS (
    SELECT 1 FROM wants w WHERE w.release_group_mbid = @mbid AND w.fulfilled_at IS NULL
) OR EXISTS (
    SELECT 1 FROM follows f WHERE f.artist_mbid = @mbid
))::bool AS requested;

-- name: GetNonTerminalRequestForMBID :one
-- Returns the oldest non-terminal (pending/approved/completed) request
-- whose own-kind MBID matches @mbid, or pgx.ErrNoRows when none. Create()
-- uses this to dedupe: a re-request for something already in flight
-- returns the existing row instead of inserting a duplicate.
SELECT * FROM requests
 WHERE status IN ('pending', 'approved', 'completed')
   AND ((kind = 'artist' AND artist_mbid = @mbid)
     OR (kind = 'album'  AND album_mbid  = @mbid)
     OR (kind = 'track'  AND track_mbid  = @mbid))
 ORDER BY requested_at ASC
 LIMIT 1;

-- name: RepointRequestsAlbumMbid :exec
-- A want moved from a release id to its group (#5241) takes the requests
-- that name it along, so the reconciler finds it.
UPDATE requests
   SET album_mbid = sqlc.arg(new_mbid),
       updated_at = now()
 WHERE album_mbid = sqlc.arg(old_mbid);