(* -*- mode: tuareg; -*- *)

module Store = Git_unix.Store
open Lwt_result.Syntax
open Config

let full_path path = Filename.concat config.git_project_root path

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

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

type user = Git.User.t

(* let all_authors store = *)
(*   let* store = store repo in *)

type commit = {
  hash : string;
  short_hash : string;
  parents : string list;
  author : user;
  message : string option;
}

let to_commit store hash =
  let* v = Store.read store hash in
  match v with
  | Git.Value.Commit c ->
      let hash = Store.Hash.to_hex hash in
      Lwt_result.return
        {
          hash;
          short_hash = String.sub hash 0 8;
          parents = Store.Value.Commit.parents c |> List.map Store.Hash.to_hex;
          author = Store.Value.Commit.author c;
          message = Store.Value.Commit.message c;
        }
  | _ -> Lwt_result.fail (`Msg "value is not a commit")

let commit_of_id repo id =
  let* store = store repo in
  let hash = Store.Hash.of_hex id in
  to_commit store hash

let recent_commits repo n =
  let* store = store repo 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
      let* commit = to_commit store hash in
      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

type branch = { hash : string; name : string }

let all_branches repo =
  let* store = store repo in
  let open Lwt.Syntax in
  let* refs = Store.Ref.list store in
  let branches =
    List.map
      (fun (ref, hash) ->
        { name = Git.Reference.to_string ref; hash = Store.Hash.to_hex hash })
      refs
  in
  Lwt_result.return branches

type tree_entry = {
  hash : string;
  short_hash : string;
  name : string;
  perm : int;
}

type tree = { hash : string; short_hash : string; entries : tree_entry list }

let to_entry _ =
  {
    hash = "foo";
    short_hash = String.sub "foobar" 0 8;
    name = "foobarbino";
    perm = 122;
  }

let present_tree tree = Store.Value.Tree.to_list tree |> List.map to_entry

let to_tree store hash =
  let* v = Store.read store hash in
  match v with
  | Git.Value.Tree tree ->
      let hash = Store.Hash.to_hex hash in
      Lwt_result.return
        { hash; short_hash = String.sub hash 0 8; entries = present_tree tree }
  | _ ->
      Dream.log "Value is not a tree";
      Lwt_result.fail (`Msg "value is not a tree")

let head_tree_id store =
  let* commit_hash = Store.Ref.resolve store Git.Reference.head in
  let* v = Store.read store commit_hash in
  match v with
  | Git.Value.Commit commit ->
      Store.Value.Commit.tree commit |> Lwt_result.return
  | _ ->
      Dream.log "no head tree id";
      Lwt_result.fail (`Msg "")

let head_tree repo =
  let* store = store repo in
  let* hash = head_tree_id store in
  to_tree store hash

let tree_of_id repo id =
  let* store = store repo in
  let* hash = Lwt_result.return (Store.Hash.of_hex id) in
  to_tree store hash