open Pyops
open Pytypes
open Batteries
open Yojson.Safe
open Config
open Utils
open Pam

let issue_of_json (m_room: Datatypes.MatrixRoom.t) (json): Datatypes.forgejo_issue_data =
  let open Yojson.Safe.Util in
  let due_date = json |> member "due_date" |> to_option to_string in
  let record: Datatypes.forgejo_issue_data = { 
    url = json |> member "url" |> to_string;
    title = json |> member "title" |> to_string;
    body = json |> member "body" |> to_string;
    matrix_target = m_room;
    due_date = due_date
  }
  in record

let issues_of_json matrix_room json_str =
  let open Yojson.Safe.Util in
  try
    json_str |> from_string |> to_list |> List.map (issue_of_json matrix_room) |> Result.ok
  with
  | Yojson.Json_error msg -> Error [%string "JSON parsing error: %{msg}"]

module ForgejoUrl = struct
  type t = {url: string; page: int}
  let from_id repo_id =
    { url = [%string "https://salsa.lezzo.org/api/v1/repos/%{repo_id}/issues?state=open&type=issues&limit=50"];
      page = 0 }
  let next_page t = {t with page=t.page+1}
  let to_string t = [%string "%{t.url}&page=%{t.page#Int}"]
end

type repo_pytuple = {url: ForgejoUrl.t; headers: pyobject}
type http_actor = {requests: pyobject; repos: repo_pytuple StringMap.t}

let make_headers base64_password =
    let headers =
        [("accept", "application/json");
        ("authorization", [%string "Basic %{base64_password}"])] in
    headers 
    |> List.map (fun (k, v) -> (k, Py.String.of_string v))
    |> Py.Dict.of_bindings_string

let init (repos: Config.repo_data list) =
  let _ = Py.initialize () in
  let requests = Py.import "requests" in
  let urls =
    repos
    |> List.map (fun {forgejo_id; base64_password; matrix_room} ->
        (matrix_room, {url=ForgejoUrl.from_id forgejo_id; headers=make_headers base64_password}))
    |> StringMap.of_list
  in
  {requests=requests; repos=urls}

let pyprint () =
  let builtins = Py.Eval.get_builtins () in
  let p = Py.Dict.find_string builtins "print" in
  Py.Callable.to_function p

let extract_pagination resp =
  let key = Py.String.of_string "X-Total-Count" in
  resp
  .@$("headers")
  .&("get") [|key|] (* not really a pydict, so need to use `get` *)
  |> Py.Object.to_string
  |> int_of_string_opt

let make_get_request {requests; repos} =
  let get = Py.Module.get_function_with_keywords requests "get" in
  

  let rec fold_fn (accum: (Datatypes.forgejo_issue_data list)) = function
    | [] -> Ok accum
    | (m_room_string, {url; headers})::rest ->
      let pyurl = url |> ForgejoUrl.to_string |> Py.String.of_string in
      let resp = get [|pyurl|] [("headers", headers)] in
      let jsontext =
        resp.@$("text")
        |> Py.String.to_string
      in
      let target_items_total = extract_pagination resp in
      let matrix_room = Datatypes.MatrixRoom.make m_room_string in
      let issues = issues_of_json matrix_room jsontext in
      match target_items_total, issues with
      | None, _ -> Error "Can't extract pagination"
      | _, Error err ->
        Error err
      | Some target_items_total, Ok target_issues ->
        let n_received = List.length target_issues in
        let accum' = target_issues@accum in
        let urls = 
          if n_received <> target_items_total then
           (m_room_string, {url=ForgejoUrl.next_page url; headers=headers})::rest
          else
            rest
        in fold_fn accum' urls

  in
  StringMap.to_list repos
  |> fold_fn []