feat: keep each member's listening history and move a guest's history into the account on login

db/migrations/00005_listens.sql

@@ -0,0 +1,21 @@
+-- +goose Up
+-- 关闭之后不再记录新的播放历史，已有的保留。
+ALTER TABLE members ADD COLUMN record_listens boolean NOT NULL DEFAULT true;
+
+-- 成员在房间里听到过的歌，每首只留最近一次。元数据存一份快照，不关联 tracks：管理员删除已存储的媒体时会连带删掉 tracks 中对应的行。
+CREATE TABLE listens (
+    member_id uuid NOT NULL REFERENCES members ON DELETE CASCADE,
+    source text NOT NULL,
+    track_id text NOT NULL,
+    title text NOT NULL,
+    artist text,
+    album text,
+    cover_url text,
+    cover_key text,
+    duration_ms bigint NOT NULL,
+    page_url text NOT NULL,
+    heard_at timestamptz NOT NULL,
+    PRIMARY KEY (member_id, source, track_id)
+);
+
+CREATE INDEX ON listens (member_id, heard_at DESC);

db/queries/listens.sql

@@ -0,0 +1,57 @@
+-- name: LockListeners :many
+-- 按 ID 的顺序锁住开启了记录的成员：同一个成员的历史依次写入，删掉超出上限的部分时不会多删或少删；
+-- 加锁的顺序固定，同时写几个成员的事务之间不会死锁。
+SELECT id FROM members WHERE id = ANY(@ids::uuid[]) AND record_listens ORDER BY id FOR NO KEY UPDATE;
+
+-- name: UpsertListens :exec
+INSERT INTO listens (member_id, source, track_id, title, artist, album, cover_url, cover_key, duration_ms, page_url, heard_at)
+SELECT m, @source::text, @track_id::text, @title::text, sqlc.narg(artist)::text, sqlc.narg(album)::text, sqlc.narg(cover_url)::text,
+       sqlc.narg(cover_key)::text, @duration_ms::bigint, @page_url::text, @heard_at::timestamptz
+FROM unnest(@member_ids::uuid[]) AS m
+ON CONFLICT (member_id, source, track_id) DO UPDATE
+SET title = excluded.title, artist = excluded.artist, album = excluded.album, cover_url = excluded.cover_url,
+    cover_key = excluded.cover_key, duration_ms = excluded.duration_ms, page_url = excluded.page_url,
+    heard_at = greatest(listens.heard_at, excluded.heard_at);
+
+-- name: MoveListens :exec
+-- 并入的规则与 UpsertListens 相同，并入的那份算新写入的；to_id 关闭了记录时只删不并。
+WITH moved AS (
+    DELETE FROM listens WHERE member_id = sqlc.arg(from_id)::uuid
+    RETURNING source, track_id, title, artist, album, cover_url, cover_key, duration_ms, page_url, heard_at
+)
+INSERT INTO listens (member_id, source, track_id, title, artist, album, cover_url, cover_key, duration_ms, page_url, heard_at)
+SELECT sqlc.arg(to_id)::uuid, source, track_id, title, artist, album, cover_url, cover_key, duration_ms, page_url, heard_at
+FROM moved
+WHERE EXISTS (SELECT FROM members WHERE id = sqlc.arg(to_id)::uuid AND record_listens)
+ON CONFLICT (member_id, source, track_id) DO UPDATE
+SET title = excluded.title, artist = excluded.artist, album = excluded.album, cover_url = excluded.cover_url,
+    cover_key = excluded.cover_key, duration_ms = excluded.duration_ms, page_url = excluded.page_url,
+    heard_at = greatest(listens.heard_at, excluded.heard_at);
+
+-- name: TrimListens :exec
+-- 排序与 MemberListens 相同：留下的正是读取时返回的那些。
+DELETE FROM listens l
+USING (
+    SELECT member_id, source, track_id,
+           row_number() OVER (PARTITION BY member_id ORDER BY heard_at DESC, source, track_id) AS n
+    FROM listens WHERE member_id = ANY(@member_ids::uuid[])
+) ranked
+WHERE l.member_id = ranked.member_id AND l.source = ranked.source AND l.track_id = ranked.track_id AND ranked.n > @keep::bigint;
+
+-- name: MemberListens :many
+SELECT source, track_id, title, artist, album, cover_url, cover_key, duration_ms, page_url, heard_at
+FROM listens WHERE member_id = @member_id
+ORDER BY heard_at DESC, source, track_id
+LIMIT @max;
+
+-- name: DeleteListen :exec
+DELETE FROM listens WHERE member_id = @member_id AND source = @source AND track_id = @track_id;
+
+-- name: ClearListens :exec
+DELETE FROM listens WHERE member_id = @member_id;
+
+-- name: ListenRecording :one
+SELECT record_listens FROM members WHERE id = @id;
+
+-- name: SetListenRecording :execrows
+UPDATE members SET record_listens = @record_listens WHERE id = @id;

db/queries/members.sql

@@ -40,11 +40,15 @@ SELECT EXISTS (SELECT FROM member_sessions WHERE token_hash = @token_hash AND me
 
 -- name: LockMemberPassword :one
 -- 让修改密码等到这次登录提交之后，它随后删除会话时会删掉这次登录签发的会话。
+-- 用互斥的 FOR NO KEY UPDATE，不用 FOR SHARE：同一个账号的几次登录依次并入游客的历史，否则两边会按相反的顺序抢同一批历史行而死锁。
 SELECT coalesce(password_hash, '')::text AS password_hash FROM members WHERE id = @id FOR NO KEY UPDATE;
 
 -- name: DeleteSession :execrows
 DELETE FROM member_sessions WHERE token_hash = @token_hash;
 
+-- name: TakeSession :one
+DELETE FROM member_sessions WHERE token_hash = @token_hash RETURNING member_id;
+
 -- name: DeleteMemberSessions :many
 -- keep 为 NULL 时删除这个成员的全部会话。
 DELETE FROM member_sessions WHERE member_id = @member_id AND token_hash IS DISTINCT FROM sqlc.narg(keep)::bytea