import 'dart:async';
import 'dart:math' as math;
import 'dart:ui' as ui;

import 'package:dartterm/assets.dart';
import 'package:dartterm/colors.dart';
import 'package:dartterm/cp437.dart';
import 'package:dartterm/fonts.dart';
import 'package:dartterm/input.dart';
import 'package:dartterm/skreek.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';

part 'terminal/action_oriented.dart';
part 'terminal/cursor.dart';
part 'terminal/painter.dart';
part 'terminal/reexports.dart';
part 'terminal/tile.dart';

enum _State {
  baseState,
  waitMenu,
}

class Terminal {
  static const int width = 88;
  static const int height = 50;
  static const int nTiles = width * height;

  late List<Tile> _tiles;
  (int, int)? _lastSeenMouse;
  ScreenDimensions? _screenDimensions;

  final StreamController<Input> _inputSink =
      StreamController<Input>.broadcast();
  late final Stream<Input> _inputSource = _inputSink.stream.asBroadcastStream();
  // ignore: prefer_final_fields
  _State _state = _State.baseState;

  Terminal() {
    _tiles = [for (var i = 0; i < nTiles; i += 1) Tile()];
  }

  Widget toWidget(BuildContext context) {
    var scalingFactor = MediaQuery.devicePixelRatioOf(context);
    return MouseRegion(
        onExit: _onPointerExit,
        child: Listener(
            onPointerDown: _onPointerDown,
            onPointerHover: _onPointerHover,
            child: CustomPaint(
                painter: TerminalCustomPainter(this, scalingFactor))));
  }

  (int, int)? _toXY(int i) {
    if (i < 0 || i > nTiles) {
      return null;
    }
    return (i % width, i ~/ width);
  }

  int? _fromXY(int x, int y) {
    if (x < 0 || x >= width) {
      return null;
    }
    if (y < 0 || y >= height) {
      return null;
    }

    return x + y * width;
  }

  void _notifyInput(Input i) {
    _inputSink.add(i);
  }

  void _notifyScreenDimensions(ScreenDimensions sd) {
    _screenDimensions = sd;
  }

  Stream<Input> rawInput() {
    return _inputSource;
  }

  bool _onPointerDown(PointerDownEvent me) {
    final Button button;
    if (me.buttons & kPrimaryMouseButton != 0) {
      button = Button.left;
    } else if (me.buttons & kSecondaryMouseButton != 0) {
      button = Button.right;
    } else {
      return false;
    }

    var localPosition = me.localPosition;
    final xy = _relativizeMouse(localPosition.dx, localPosition.dy);
    _lastSeenMouse = xy;
    if (xy != null) {
      final (x, y) = xy;
      _notifyInput(Click(button, x, y));
    }
    return true;
  }

  bool _onPointerExit(PointerExitEvent me) {
    _lastSeenMouse = null;
    return true;
  }

  bool _onPointerHover(PointerHoverEvent me) {
    var localPosition = me.localPosition;
    _lastSeenMouse = _relativizeMouse(localPosition.dx, localPosition.dy);
    return true;
  }

  (int, int)? _relativizeMouse(double localX, double localY) {
    final sd = _screenDimensions;
    if (sd == null) return null;
    if (sd.xSz == 0 || sd.ySz == 0) return null;

    final tx = ((localX - sd.x0) * width) ~/ sd.xSz;
    final ty = ((localY - sd.y0) * height) ~/ sd.ySz;

    if (tx < 0 || tx >= width) return null;
    if (ty < 0 || ty >= height) return null;

    return (tx, ty);
  }
}

class ScreenDimensions {
  final double x0, y0, xSz, ySz;

  const ScreenDimensions(
      {required this.x0,
      required this.y0,
      required this.xSz,
      required this.ySz});
}