import 'package:dartterm/colors.dart';
import 'package:dartterm/cp437.dart';
import 'package:dartterm/fonts.dart';
import 'package:dartterm/terminal_painter.dart';
import 'package:flutter/material.dart';

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

  late List<Tile> tiles;

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

  CustomPaint toWidget(BuildContext context) {
    var scalingFactor = MediaQuery.devicePixelRatioOf(context);
    return 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;
  }
}

class Cursor {
  final Terminal t;
  int x, y;
  Color? _bg, _fg;
  Font font = Font.normal;

  // TODO: Clip

  Cursor({required this.t, required this.x, required this.y});

  void clear() {
    t.tiles = [for (var i = 0; i < nTiles; i += 1) Tile.empty()];
  }

  void putc(int c) {
    for (var dx = 0; dx < font.cellWidth; dx += 1) {
      for (var dy = 0; dy < font.cellHeight; dy += 1) {
        var i = t.fromXY(x + dx, y + dy);

        if (i != null) {
          final (sourceCx, sourceCy) = (
            (c % font.nCellsW) * font.cellWidth + dx,
            (c ~/ font.nCellsW) * font.cellHeight + dy
          );

          t.tiles[i].content = Content(font.imageName, sourceCx, sourceCy);

          final (bg, fg) = (_bg, _fg);
          if (bg != null) {
            t.tiles[i].bg = bg;
          }
          if (fg != null) {
            t.tiles[i].fg = fg;
          }
        }
      }
    }
  }

  void puts(String s) {
    var startX = x;
    for (final c in toCp437String(s)) {
      if (c == 10) {
        // newline
        x = startX;
        y += font.cellHeight;
        continue;
      }
      if (c == 13) {
        // carriage return
        x = startX;
        continue;
      }
      putc(c);
      x += font.cellWidth;
    }
  }

  Cursor fg(Color c) {
    _fg = c;
    return this;
  }

  Cursor bg(Color c) {
    _bg = c;
    return this;
  }

  Cursor small() {
    font = Font.small;
    return this;
  }

  Cursor normal() {
    font = Font.normal;
    return this;
  }

  Cursor big() {
    font = Font.big;
    return this;
  }
}

class Clip {}

class Tile {
  Content? content;

  Color bg;
  Color fg;

  Tile(this.content, this.bg, this.fg);

  static Tile empty() => Tile(null, Palette.defaultBg, Palette.defaultFg);
}

class Content {
  final String sourceImage;
  final int sourceCx;
  final int sourceCy;

  const Content(this.sourceImage, this.sourceCx, this.sourceCy);
}

// reexports
Terminal _terminal = Terminal();
const int width = Terminal.width;
const int height = Terminal.height;
const int nTiles = Terminal.nTiles;

Widget toWidget(BuildContext context) {
  return _terminal.toWidget(context);
}

void clear() {
  at(0, 0).clear();
}

Cursor at(int x, int y) {
  return Cursor(t: _terminal, x: x, y: y);
}