let () = Printexc.record_backtrace true
module Store = Git_kv.Make (Pclock)

let reporter ppf =
  let report src level ~over k msgf =
    let k _ =
      over () ;
      k () in
    let with_metadata header _tags k ppf fmt =
      Format.kfprintf k ppf
        ("[%a]%a[%a]: " ^^ fmt ^^ "\n%!")
        Fmt.(styled `Blue int)
        (Unix.getpid ()) Logs_fmt.pp_header (level, header)
        Fmt.(styled `Magenta string)
        (Logs.Src.name src) in
    msgf @@ fun ?header ?tags fmt -> with_metadata header tags k ppf fmt in
  { Logs.report }

(*
let () = Fmt_tty.setup_std_outputs ~style_renderer:`Ansi_tty ~utf_8:true ()
let () = Logs.set_reporter (reporter Fmt.stderr)
let () = Logs.set_level ~all:true (Some Logs.Debug)
*)

open Rresult
open Lwt.Infix

let get ~quiet store key =
  Store.get store key >>= function
  | Ok contents when not quiet ->
    Fmt.pr "@[<hov>%a@]\n%!" (Hxd_string.pp Hxd.default) contents ;
    Lwt.return (Ok 0)
  | Ok _ -> Lwt.return (Ok 0)
  | Error err ->
    if not quiet then Fmt.epr "%a.\n%!" Store.pp_error err ;
    Lwt.return (Ok 1)

let exists ~quiet store key =
  Store.exists store key >>= function
  | Ok k when not quiet ->
    ( match k with
    | None -> Fmt.pr "%a does not exists\n%!" Mirage_kv.Key.pp key
    | Some `Dictionary -> Fmt.pr "%a exists as a dictionary\n%!" Mirage_kv.Key.pp key
    | Some `Value -> Fmt.pr "%a exists as a value\n%!" Mirage_kv.Key.pp key ) ;
    Lwt.return (Ok 0)
  | Ok _ -> Lwt.return (Ok 0)
  | Error err ->
    if not quiet then Fmt.epr "%a.\n%!" Store.pp_error err ;
    Lwt.return (Ok 1)

let value_of_string str =
  let v = ref None in
  match Scanf.sscanf str "%S" (fun str -> v := Some str) with
  | () -> Option.get !v
  | exception _ ->
    Scanf.sscanf str "%s" (fun str -> v := Some str) ;
    Option.get !v 

let set ~quiet store key str =
  let value = value_of_string str in
  Store.set store key value >>= function
  | Ok () -> Lwt.return (Ok 0)
  | Error err ->
    if not quiet then Fmt.epr "%a.\n%!" Store.pp_write_error err ;
    Lwt.return (Ok 1)

let remove ~quiet store key =
  Store.remove store key >>= function
  | Ok () -> Lwt.return (Ok 0)
  | Error err ->
    if not quiet then Fmt.epr "%a.\n%!" Store.pp_write_error err ;
    Lwt.return (Ok 1)

let list ~quiet store key =
  Store.list store key >>= function
  | Ok lst when not quiet ->
    List.iter (fun (name, k) -> match k with
    | `Dictionary -> Fmt.pr "d %s\n%!" name
    | `Value -> Fmt.pr "- %s\n%!" name) lst ;
    Lwt.return (Ok 0)
  | Ok _ -> Lwt.return (Ok 0)
  | Error err ->
    if not quiet then Fmt.epr "%a.\n%!" Store.pp_error err ;
    Lwt.return (Ok 1)

let pull ~quiet store =
  Git_kv.pull store >>= function
  | Error (`Msg err) -> if not quiet then Fmt.epr "%s.\n%!" err ; Lwt.return (Ok 1)
  | Ok diff when not quiet ->
    List.iter (function
    | `Add key -> Fmt.pr "+ %a\n%!" Mirage_kv.Key.pp key
    | `Remove key -> Fmt.pr "- %a\n%!" Mirage_kv.Key.pp key
    | `Change key -> Fmt.pr "* %a\n%!" Mirage_kv.Key.pp key) diff ;
    Lwt.return (Ok 0)
  | Ok _ -> Lwt.return (Ok 0)

let save store filename =
  let oc = open_out filename in
  Git_kv.to_octets store >>= fun contents ->
  output_string oc contents ;
  close_out oc ;
  Lwt.return (Ok 0)

let trim lst =
  List.fold_left (fun acc -> function
    | "" -> acc
    | str -> str :: acc) [] lst |> List.rev

let with_key ~f key =
  match Mirage_kv.Key.v key with
  | key -> f key
  | exception _ ->
    Fmt.epr "Invalid key: %S.\n%!" key ;
    Lwt.return (Ok 1)

let repl store fd_in =
  let is_a_tty = Unix.isatty fd_in in
  let ic = Unix.in_channel_of_descr fd_in in
  let rec go store0 =
    if is_a_tty then Fmt.pr "# %!" ;
    match String.split_on_char ' ' (input_line ic) |> trim with
    | [ "get"; key; ] ->
      with_key ~f:(get ~quiet:false store0) key
      >|= ignore >>= fun () -> go store0
    | [ "exists"; key; ] ->
      with_key ~f:(exists ~quiet:false store0) key
      >|= ignore >>= fun () -> go store0
    | "set" :: key :: data ->
      let data = String.concat " " data in
      with_key ~f:(fun key -> set ~quiet:false store0 key data) key
      >|= ignore >>= fun () -> go store0
    | [ "remove"; key; ] ->
      with_key ~f:(remove ~quiet:false store0) key
      >|= ignore >>= fun () -> go store0
    | [ "list"; key; ] ->
      with_key ~f:(list ~quiet:false store0) key
      >|= ignore >>= fun () -> go store0
    | [ "pull"; ] ->
      if is_a_tty then Fmt.pr "\n%!" ; pull ~quiet:false store0
      >|= ignore >>= fun () -> go store0
    | [ "quit"; ] -> Lwt.return ()
    | [ "fold"; ] ->
      Store.change_and_push store0 (fun store1 -> go store1)
      >>= fun () -> go store0
    | [ "save"; filename ] ->
      save store0 filename >|= ignore
      >>= fun _ -> if is_a_tty then Fmt.pr "\n%!" ; go store0
    | _ -> Fmt.epr "Invalid command.\n%!" ; go store0
    | exception End_of_file -> Lwt.return () in
  go store

let run remote = function
  | None ->
    Lwt_main.run @@
    (Git_unix.ctx (Happy_eyeballs_lwt.create ()) >>= fun ctx ->
     Git_kv.connect ctx remote >>= fun t ->
     repl t Unix.stdin)
  | Some filename ->
    let contents =
      let ic = open_in filename in
      let ln = in_channel_length ic in
      let bs = Bytes.create ln in
      really_input ic bs 0 ln ;
      Bytes.unsafe_to_string bs in
    Lwt_main.run
    ( Git_unix.ctx (Happy_eyeballs_lwt.create ()) >>= fun ctx ->
      Git_kv.of_octets ctx ~remote contents >>= function
    | Ok t -> repl t Unix.stdin
    | Error (`Msg err) -> Fmt.failwith "%s." err )

let () = match Sys.argv with
  | [| _; remote; |] -> run remote None
  | [| _; remote; filename; |] when Sys.file_exists filename ->
    run remote (Some filename)
  | _ -> Fmt.epr "%s <remote> [<filename>]\n%!" Sys.argv.(0)