module Grep = Grep
module Common = Common
open Notty
module Input_prompt = Input_prompt
module Help_screen = Help_screen

type state =
  { pos : int * int
  ; scroll : int
  ; content : (string * int * string * int) array
  ; go_back : unit -> unit
  ; content_pretty : (int * Grep.display_type) array
  ; goto_todos_view : (unit -> unit) -> unit
  ; goto_done_view : (unit -> unit) -> unit
  ; output : string option
  ; tag : string
  }

let title ~tag =
  match tag with
  | "" -> I.strf ~attr:A.(st bold) "%s" "Notes" |> I.pad ~l:0 ~t:0
  | a -> I.strf ~attr:A.(st bold) "%s > %s" "Notes" a |> I.pad ~l:0 ~t:0


let content_start = 1

(* TODO: Use grep -l to filter notes by regexp and rerender those files*)
let rec render
  t
  ({ output
   ; pos
   ; scroll
   ; content_pretty
   ; go_back
   ; content
   ; goto_todos_view
   ; goto_done_view
   ; tag
   } as state)
  =
  let size_x, size_y = Common.Term.size t in
  let x, y = pos in
  let img =
    let output_info =
      match output with
      | Some line ->
        I.strf "%s%s" (String.escaped line) (String.make size_x ' ')
        |> I.pad ~t:(size_y - 1)
      | None -> I.empty
    and elements =
      Array.mapi
        (fun i (_, el) -> Compontent.current_line size_x y scroll el (i + content_start))
        (* TODO: Fix this ugly slow conversion *)
        (Array.to_seq content_pretty |> Seq.drop scroll |> Array.of_seq)
    in
    let open I in
    output_info </> Array.fold_left (fun sum el -> el </> sum) (title ~tag) elements
  in
  Common.Term.image t img;
  let content_length = Array.length content_pretty in
  let scroll_up () =
    let scroll = if y - content_start - scroll = 0 then max (scroll - 1) 0 else scroll in
    render t @@ { state with pos = x, max (y - 1) content_start; scroll; output = None }
  in
  let scroll_down () =
    let scroll = if y - scroll >= size_y - 1 then scroll + 1 else scroll in
    render t
    @@ { state with pos = x, min (y + 1) (content_length - 1); scroll; output = None }
  in
  match Common.Term.event t with
  | `End | `Key (`Escape, []) | `Key (`ASCII 'q', []) | `Key (`ASCII 'C', [ `Ctrl ]) -> ()
  | `Mouse (`Press (`Scroll s), _, _) ->
    (match s with
     | `Down -> scroll_down ()
     | `Up -> scroll_up ())
  | `Resize _ -> render t state
  | `Key (`ASCII 'f', []) -> go_back ()
  | `Mouse ((`Press _ | `Drag), (_, y), _) ->
    render t { state with pos = 0, min y content_length }
  | `Key (`ASCII 'j', []) | `Key (`ASCII 'N', [ `Ctrl ]) -> scroll_down ()
  | `Key (`ASCII 'k', []) | `Key (`ASCII 'P', [ `Ctrl ]) -> scroll_up ()
  | `Key (`ASCII '!', []) ->
    let file_number_offset, content_line = Array.get content_pretty (y - content_start) in
    let content_line = Grep.display_type_line content_line in
    let selected_file, _, _, _ =
      Array.get content (y - content_start - file_number_offset)
    in
    let selected_file = Grep.execution_directory ^ "/" ^ selected_file in
    let (input_state : Input_prompt.state) =
      { screen = img
      ; user_input = ""
      ; prompt = "COMMAND"
      ; on_enter =
          (fun command ->
            if String.equal (String.trim command) String.empty
            then (
              Common.Term.cursor t None;
              render t state)
            else (
              let content = Grep.get_file_names tag |> Array.of_list in
              let content =
                Array.map
                  (fun file_name -> Grep.get_full_file_content_content file_name)
                  content
                |> Array.to_list
              in
              let content = Grep.parse_full_content content in
              let content_pretty =
                Grep.pretty_print_parsed_content content |> Array.of_list
              in
              Arbitrary_command.run
                t
                ~command:(Scanf.unescaped command)
                ~content:content_line
                ~selected_file
                ~on_return:(fun result ->
                  Common.Term.cursor t None;
                  render
                    t
                    { state with
                      content = Array.of_list content
                    ; content_pretty
                    ; pos = 0, content_start
                    ; scroll = 0
                    ; output = Some result
                    })))
      ; on_cancel =
          (fun _ ->
            Common.Term.cursor t None;
            render t state)
      }
    in
    Input_prompt.render t input_state
  | `Key (`ASCII 's', []) ->
    let (input_state : Input_prompt.state) =
      { screen = img
      ; user_input = ""
      ; prompt = "REGEXP"
      ; on_enter =
          (fun tag ->
            try
              let content = Grep.get_file_names tag |> Array.of_list in
              let oc = open_out "/tmp/stitch-output" in
              Printf.fprintf oc "%s\n" (String.concat "\n" (content |> Array.to_list));
              close_out oc;
              let content =
                Array.map
                  (fun file_name -> Grep.get_full_file_content_content file_name)
                  content
                |> Array.to_list
              in
              let content = Grep.parse_full_content content in
              let content_pretty =
                Grep.pretty_print_parsed_content content |> Array.of_list
              in
              Common.Term.cursor t None;
              render
                t
                { state with
                  content = content |> Array.of_list
                ; content_pretty
                ; pos = 0, content_start
                ; scroll = 0
                ; tag
                }
            with
            | _ ->
              let oc = open_out "/tmp/stitch-error" in
              Printf.fprintf oc "%s\n" (Printexc.get_backtrace ());
              close_out oc;
              raise (Invalid_argument "FAILURE"))
      ; on_cancel =
          (fun _ ->
            Common.Term.cursor t None;
            render t state)
      }
    in
    Input_prompt.render t input_state
  | `Key (`ASCII '?', []) -> Help_screen.render t { go_back = (fun () -> render t state) }
  | `Key (`ASCII '2', []) -> goto_todos_view (fun () -> render t state)
  | `Key (`ASCII '3', []) -> goto_done_view (fun () -> render t state)
  | `Key (`ASCII 'e', []) | `Key (`Enter, []) ->
    (* Editor might be set with extra args, in that case we need to separate these *)
    let[@warning "-8"] (editor :: args) =
      String.split_on_char ' ' (Sys.getenv "EDITOR")
    in
    let file_number_offset, _ = Array.get content_pretty (y - content_start) in
    let selected_file, line_number, _, _ =
      Array.get content (y - content_start - file_number_offset)
    in
    let full_path_file = Grep.execution_directory ^ "/" ^ selected_file in
    (* Because each file title consists of two lines, we need to account for the offset
       it adds by removing the file_number *)
    let line_number_arg = "+" ^ Int.to_string line_number in
    let full_args =
      Array.append (Array.of_list args) [| ""; line_number_arg; full_path_file |]
    in
    Common.Term.cursor t (Some (0, 0));
    let _ =
      Unix.create_process_env
        editor
        full_args
        (Unix.environment ())
        Unix.stdin
        Unix.stdout
        Unix.stderr
    in
    let rec run_editor () =
      match Unix.wait () with
      | _, _ ->
        Common.Term.cursor t None;
        render t state
      (* Capture resizing events *)
      | exception Unix.Unix_error (Unix.EINTR, _, _) -> run_editor ()
      | exception Unix.Unix_error (_, str_err, str_err_2) ->
        let oc = open_out "/tmp/stitch-error" in
        Printf.fprintf oc "%s: %s" str_err str_err_2;
        close_out oc;
        failwith "ERROR"
    in
    run_editor ()
  | `Key (`Arrow d, _) ->
    (match d with
     | `Up -> scroll_up ()
     | `Down -> scroll_down ()
     | _ -> render t state)
  | _ -> render t state