(** Tests for I/O module *)

let test_create_database () =
  let path = Filename.temp_file "lithos_test" ".db" in
  Unix.unlink path;
  let cleanup () =
    try Unix.unlink path with
    | _ -> ()
  in

  let open Lithos.Io in
  match create_database path 4096 with
  | Ok () ->
    Alcotest.(check bool) "File exists" true (Sys.file_exists path);
    cleanup ()
  | Error err ->
    cleanup ();
    Alcotest.fail (Lithos.Error.to_string err)
;;

let test_read_header () =
  let path = Filename.temp_file "lithos_test" ".db" in
  Unix.unlink path;
  let cleanup () =
    try Unix.unlink path with
    | _ -> ()
  in

  let open Lithos.Io in
  match create_database path 4096 with
  | Error err ->
    cleanup ();
    Alcotest.fail (Lithos.Error.to_string err)
  | Ok () ->
    (match read_header path with
     | Ok meta ->
       Alcotest.(check int) "Page size" 4096 meta.Lithos.Types.page_size;
       Alcotest.(check int) "Version" 1 meta.Lithos.Types.version;
       cleanup ()
     | Error err ->
       cleanup ();
       Alcotest.fail (Lithos.Error.to_string err))
;;

let test_invalid_database () =
  let path = Filename.temp_file "lithos_test" ".txt" in
  let cleanup () =
    try Unix.unlink path with
    | _ -> ()
  in

  let oc = open_out path in
  output_string oc "not a database file";
  close_out oc;

  let open Lithos.Io in
  match read_header path with
  | Ok _ ->
    cleanup ();
    Alcotest.fail "Should have failed on invalid database"
  | Error (Invalid_database _) -> cleanup ()
  | Error err ->
    cleanup ();
    Alcotest.fail ("Wrong error: " ^ Lithos.Error.to_string err)
;;

let suite =
  [ "create_database", `Quick, test_create_database
  ; "read_header", `Quick, test_read_header
  ; "invalid_database", `Quick, test_invalid_database
  ]
;;