open Lwt.Infix
module Store = Git_unix.Store
module Value = Git.Value

type user_record = { name : string; email : string }

let full_path path = Filename.concat Config.git_directory path

let store repo_path =
  let path = Fpath.v @@ full_path repo_path in
  Store.v ~dotgit:path path

let short_hash hash = String.sub hash 0 8

let repo_description repo_path =
  let description_path = Filename.concat (full_path repo_path) "description" in
  In_channel.with_open_text description_path In_channel.input_all

module Commit = struct
  type t = {
    hash : string;
    parents : string list;
    author : Git.User.t;
    message : string option;
  }

  let of_hash store h =
    Store.read store h >>= function
    | Ok (Value.Commit c) ->
        Lwt_result.return
          {
            hash = Store.Hash.to_hex h;
            parents = Store.Value.Commit.parents c |> List.map Store.Hash.to_hex;
            author = Store.Value.Commit.author c;
            message = Store.Value.Commit.message c;
          }
    | Ok _ -> Lwt_result.fail (`Msg "object is not a commit")
    | Error e -> Lwt_result.fail e

  let recent_commits repo_path n =
    let open Lwt_result.Syntax in
    let* store = store repo_path in
    let* head = Store.Ref.resolve store Git.Reference.head in
    let rec walk acc hash count =
      if count = 0 then Lwt_result.return (List.rev acc)
      else
        of_hash store hash >>= function
        | Error e -> Lwt_result.fail e
        | Ok commit -> (
            match commit.parents with
            | parent :: _ ->
                walk (commit :: acc) (Store.Hash.of_hex parent) (count - 1)
            | [] -> Lwt_result.return (List.rev (commit :: acc)))
    in
    walk [] head n

  let of_id repo_path id =
    let open Lwt_result.Syntax in
    let* store = store repo_path in
    let id = Store.Hash.of_hex id in
    of_hash store id
end

module Branch = struct
  type t = { name : string }

  let all_branches repo_path =
    let open Lwt_result.Syntax in
    let* store = Git_unix.Store.v (Fpath.v repo_path) in
    let open Lwt.Syntax in
    let* refs = Store.Ref.list store in
    let branches =
      (* Filter these references for branches! *)
      List.map (function _, x -> x |> Store.Hash.to_hex) refs
    in
    Lwt_result.return branches
end