Source file albumParticipant.ml

(*****************************************************************************)
(*                                                                           *)
(*  Copyright (C) 2026 Yves Ndiaye                                           *)
(*                                                                           *)
(* This Source Code Form is subject to the terms of the Mozilla Public       *)
(* License, v. 2.0. If a copy of the MPL was not distributed with this       *)
(* file, You can obtain one at https://mozilla.org/MPL/2.0/.                 *)
(*                                                                           *)
(*****************************************************************************)

type t = { album_id : Int64.t; artist_id : Int64.t; role : Role.t }

let table_name = "album_participants"
let foreign_album_id = "album_id"
let foreign_artist_id = "artist_id"
let key_role = "role"
let p_album_id = Printf.sprintf "%s.%s" table_name foreign_album_id
let p_artist_id = Printf.sprintf "%s.%s" table_name foreign_artist_id
let p_role = Printf.sprintf "%s.%s" table_name key_role

let sql_table =
  Printf.sprintf
    {|CREATE TABLE IF NOT EXISTS %s (
      %s INTEGER NOT NULL,
      %s INTEGER NOT NULL,
      %s INTEGER,
      UNIQUE (%s, %s, %s),
      FOREIGN KEY (%s) REFERENCES %s (%s) ON UPDATE CASCADE ON DELETE CASCADE
      FOREIGN KEY (%s) REFERENCES %s (%s) ON UPDATE CASCADE ON DELETE CASCADE
  );|}
    table_name foreign_album_id foreign_artist_id key_role foreign_album_id
    foreign_artist_id key_role foreign_album_id Album.table_name
    Album.primary_key foreign_artist_id Artist.table_name Artist.primary_key

let init ~album_id ~artist_id role = { album_id; artist_id; role }

let update_artist database old new' =
  let ( let* ) rc f =
    match rc with
    | Sqlite3.Rc.OK | Sqlite3.Rc.DONE ->
        f ()
    | rc ->
        let message = Sqlite3.errmsg database in
        Error (rc, message)
  in
  let statement =
    Printf.sprintf "UPDATE %s SET %s = ?1 WHERE %s = ?2;" table_name
      foreign_artist_id foreign_artist_id
  in
  let statement = Sqlite3.prepare database statement in
  let* () = Sqlite3.bind_int64 statement 1 new' in
  let* () = Sqlite3.bind_int64 statement 2 old in
  match Sqlite3.step statement with
  | Sqlite3.Rc.OK | Sqlite3.Rc.DONE | Sqlite3.Rc.CONSTRAINT ->
      let* () = Sqlite3.finalize statement in
      Ok ()
  | rc ->
      let message = Sqlite3.errmsg database in
      Error (rc, message)

let insert database t =
  let { album_id; artist_id; role } = t in
  let statement' =
    Printf.sprintf
      "INSERT INTO %s (album_id, artist_id, role) VALUES (?, ?, ?);" table_name
  in
  let ( let* ) rc f =
    match rc with
    | Sqlite3.Rc.OK | Sqlite3.Rc.DONE ->
        f ()
    | rc ->
        let message = Sqlite3.errmsg database in
        Error (rc, message)
  in
  let statement = Sqlite3.prepare database statement' in
  let* () = Sqlite3.bind_int64 statement 1 album_id in
  let* () = Sqlite3.bind_int64 statement 2 artist_id in
  let* () = Sqlite3.bind_int statement 3 (Role.to_int role) in
  match Sqlite3.step statement with
  | Sqlite3.Rc.OK | Sqlite3.Rc.DONE | Sqlite3.Rc.CONSTRAINT ->
      let* () = Sqlite3.finalize statement in
      Ok ()
  | rc ->
      let message = Sqlite3.errmsg database in
      Error (rc, message)

(** [find_or_insert ~compilation database artists album] tries to find an album
    in [database] with the name [album.name] and at least an arist with the name
    is in [artists] unless [compilation], in this case only the [album.name] is
    check to discriminate albums *)
let find_or_insert ~compilation database (artists : (Artist.t * Role.t) list)
    (album : Album.t) =
  let module Albums = Set.Make (struct
    type t = Album.t

    let compare (lhs : Album.t) (rhs : Album.t) = compare lhs.id rhs.id
  end) in
  let ( let* ) = Result.bind in
  let query =
    Printf.sprintf
      "SELECT %s.*, %s FROM %s INNER JOIN %s ON %s = %s INNER JOIN %s ON %s = \
       %s;"
      Album.table_name Artist.p_name table_name Album.table_name p_album_id
      Album.p_id Artist.table_name p_artist_id Artist.p_id
  in
  let statement = Sqlite3.prepare database query in

  let _rc, albums =
    Sqlite3.fold statement ~init:Albums.empty ~f:(fun albums _ ->
        let qalbum, offset = Album.columns statement 0 in
        let artist_name = Sqlite3.column_text statement offset in
        let artists () =
          compilation
          || List.exists
               (fun ((artist : Artist.t), _) -> artist.name = artist_name)
               artists
        in
        let matched = qalbum.name = album.name && artists () in
        match matched with true -> Albums.add qalbum albums | false -> albums
    )
  in
  match Albums.min_elt_opt albums with
  | None ->
      let* qalbum = Album.insert database album in
      let () =
        List.iter
          (fun ((artist : Artist.t), role) ->
            let t = { album_id = qalbum.id; artist_id = artist.id; role } in
            match insert database t with Ok () -> () | Error _e -> ()
          )
          artists
      in
      Ok qalbum
  | Some qalbum ->
      Ok qalbum

(* Test *)
let equal : t -> t -> bool = ( = )
let compare : t -> t -> int = Stdlib.compare