import 'dart:async';
import 'dart:convert';
import 'dart:ffi';
import 'dart:typed_data';

import 'package:ffi/ffi.dart';

import '../../image/card_image.dart';
import 'pavo_ffi.dart';

/// 携带 HiTi 状态码的打印异常（错误码进任务 status，文案进 statusText）。
class HitiException implements Exception {
  HitiException(this.statusCode, this.message);

  final int statusCode;
  final String message;

  @override
  String toString() => message;
}

/// HiTi CS-2xx 打印机高层操作：枚举、状态、设备信息、单卡直打。
///
/// PavoApi 直打链路（对齐 SDK DemoCSharp buttonDirectPrint 与 C# Hiti/PavoPrinter.cs）：
/// PAVO_PrintOneCard(打印机名, 分层 BITMAP, 默认加热能量, 默认设置) → 轮询 CheckPrinterStatus 直到非忙碌。
/// 全部为同步 ffi 调用，必须在独立 isolate 中运行（见 PavoPrintBackend）。
class PavoPrinter {
  /// 枚举 USB 连接的证卡打印机名。SDK 缓冲可能是 UTF-8 或 UTF-16，两种都尝试解析。
  static List<String> enumUsbPrinters(PavoApi api) {
    final sizePtr = calloc<Uint32>();
    try {
      var ret = api.enumUsbCardPrinters(nullptr, sizePtr);
      if (ret != 0 || sizePtr.value == 0) {
        return const [];
      }
      final buf = calloc<Uint8>(sizePtr.value);
      try {
        final size = sizePtr.value;
        sizePtr.value = size;
        ret = api.enumUsbCardPrinters(buf, sizePtr);
        if (ret != 0) {
          return const [];
        }
        return decodeAuto(buf.asTypedList(size))
            .split(RegExp('[\x00\n\r,]'))
            .map((s) => s.trim())
            .where((s) => s.isNotEmpty)
            .toList();
      } finally {
        calloc.free(buf);
      }
    } finally {
      calloc.free(sizePtr);
    }
  }

  /// 按可打印字符占比自动判断 UTF-8 / UTF-16 编码。
  static String decodeAuto(Uint8List buf) {
    final utf8Text = utf8.decode(buf, allowMalformed: true);
    if (printableRatio(utf8Text) >= 0.9) {
      return utf8Text;
    }
    final codes = <int>[];
    for (var i = 0; i + 1 < buf.length; i += 2) {
      codes.add(buf[i] | (buf[i + 1] << 8));
    }
    final utf16Text = String.fromCharCodes(codes);
    return printableRatio(utf16Text) >= 0.9 ? utf16Text : utf8Text;
  }

  static double printableRatio(String s) {
    if (s.isEmpty) return 0;
    var ok = 0;
    for (final c in s.codeUnits) {
      if ((c >= 0x20 && c <= 0x7e) || (c >= 0x4e00 && c <= 0x9fff) || c == 0) ok++;
    }
    return ok / s.length;
  }

  /// 查询设备状态码，0 = 就绪；API 调用失败时返回的就是错误码本身。
  static int getStatus(PavoApi api, Pointer<Utf16> printer) {
    final statusPtr = calloc<Uint32>();
    try {
      final ret = api.checkPrinterStatus(printer, statusPtr);
      return ret != 0 ? ret : statusPtr.value;
    } finally {
      calloc.free(statusPtr);
    }
  }

  /// 读字符串型设备信息（序列号/型号/固件，UTF-16LE）。
  static String getDeviceInfoText(PavoApi api, Pointer<Utf16> printer, int infoType) {
    final buf = calloc<Uint8>(512);
    final lenPtr = calloc<Uint32>()..value = 512;
    try {
      final ret = api.getDeviceInfo(printer, infoType, buf, lenPtr);
      if (ret != 0 || lenPtr.value == 0) {
        return '';
      }
      final n = lenPtr.value;
      final codes = <int>[];
      for (var i = 0; i + 1 < n; i += 2) {
        final c = buf[i] | (buf[i + 1] << 8);
        if (c != 0) codes.add(c);
      }
      return String.fromCharCodes(codes);
    } finally {
      calloc.free(buf);
      calloc.free(lenPtr);
    }
  }

  /// 色带信息：(类型码, 剩余张数)。
  static (int, int) getRibbonInfo(PavoApi api, Pointer<Utf16> printer) {
    final buf = calloc<Uint8>(64);
    final lenPtr = calloc<Uint32>()..value = 64;
    try {
      final ret = api.getDeviceInfo(printer, PavoApi.devinfoRibbonInfo, buf, lenPtr);
      if (ret != 0 || lenPtr.value < 8) {
        return (PavoApi.ribbonMissing, 0);
      }
      final v = buf.asTypedList(8);
      final type = v[0] | (v[1] << 8) | (v[2] << 16) | (v[3] << 24);
      final count = v[4] | (v[5] << 8) | (v[6] << 16) | (v[7] << 24);
      return (type, count);
    } finally {
      calloc.free(buf);
      calloc.free(lenPtr);
    }
  }

  static String ribbonTypeName(int type) => switch (type) {
        PavoApi.ribbonTypeYmcko => 'YMCKO',
        PavoApi.ribbonTypeK => 'Resin K',
        PavoApi.ribbonTypeKo => 'KO',
        PavoApi.ribbonTypeYmckok => 'YMCKOK',
        PavoApi.ribbonTypeHalfYmcko => '1/2 YMCKO',
        PavoApi.ribbonTypeYmckfo => 'YMCKFO',
        PavoApi.ribbonMissing => '未安装',
        _ => '未知($type)',
      };

  /// 常见状态码中文文案，与前端翻译表一致。
  static String statusTextOf(int status) => switch (status) {
        0 => '就绪',
        PavoApi.dsPrinting => '打印机正在打印',
        PavoApi.dsProcessingData => '正在处理打印数据',
        PavoApi.dsSendingData => '正在向打印机发送数据',
        PavoApi.dsWriteFail => '向打印机发送命令失败',
        PavoApi.dsReadFail => '打印机响应失败',
        PavoApi.dsOffline => '打印机已断开连接或已关机',
        PavoApi.dsCardJam1 => '卡片通道卡纸，请开盖取出卡片',
        PavoApi.dsCardJam2 => '翻卡器处卡纸，请开盖取出卡片',
        PavoApi.dsCardJam3 => '出卡槽卡纸，请取出卡片',
        PavoApi.dsCmdSeqError => '命令序列错误，请重启打印机',
        PavoApi.dsCoverOpen => '打印机盖未关闭',
        PavoApi.dsCardOut => '缺卡或进卡失败，请补充卡片',
        PavoApi.dsCardLow => '卡量不足，请及时补充卡片',
        PavoApi.dsCardThickWrong => '卡片厚度选择器未正确安装',
        PavoApi.dsBusy => '设备忙碌，请稍候',
        PavoApi.dsRibbonMissing => '色带未安装',
        PavoApi.dsOutOfRibbon => '色带已用尽，请更换色带',
        PavoApi.dsUnsupportRibbon => '不支持的色带类型',
        PavoApi.dsUnknownRibbon => '无法识别色带',
        PavoApi.dsNoFlipperModule => '翻卡模块未安装',
        PavoApi.locked => '打印机已被锁定，请先解锁',
        _ => '设备状态异常 0x${status.toRadixString(16).padLeft(8, '0').toUpperCase()}',
      };

  /// 打印一张卡。frontBgr 为彩色层（BGR），frontK 可选（树脂黑文字层）。
  /// isLandscape 由正面图纵横比得出：横向 2 / 纵向 1（SDK byOrientation）。
  /// copies 大于 1 时循环提交（直打接口无份数参数）。
  static Future<void> printOneCard(
    PavoApi api,
    Pointer<Utf16> printer, {
    required Uint8List frontBgr,
    Uint8List? frontK,
    Uint8List? backBgr,
    Uint8List? backK,
    required bool isLandscape,
    required int copies,
  }) async {
    final width = isLandscape ? CardImage.landscapeWidth : CardImage.landscapeHeight;
    final height = isLandscape ? CardImage.landscapeHeight : CardImage.landscapeWidth;
    final n = copies < 1 ? 1 : copies;
    for (var i = 0; i < n; i++) {
      final holder = LayerHolder();
      final para = calloc<HitiCardPrintParameter>();
      final heat = calloc<HitiHeatingEnergy>();
      final settings = calloc<HitiSettings>();
      try {
        para.ref
          ..dwSize = sizeOf<HitiCardPrintParameter>()
          ..byOrientation = isLandscape ? 2 : 1
          ..byCardThickness = 1 // 0.5mm 标准 PVC 卡
          ..lpFrontBGR = holder.pin(frontBgr, 24, width, height)
          ..lpFrontK = frontK == null ? nullptr : holder.pin(frontK, 8, width, height)
          ..lpBackBGR = backBgr == null ? nullptr : holder.pin(backBgr, 24, width, height)
          ..lpBackK = backK == null ? nullptr : holder.pin(backK, 8, width, height);
        // heat/settings 由 calloc 零初始化，等价 C# 全 0（驱动默认能量/设置）

        final ret = api.printOneCard(printer, para, heat, settings);
        if (ret != 0) {
          throw HitiException(ret, 'PAVO_PrintOneCard 返回错误 0x${_hex8(ret)}');
        }

        // 对齐 C# Demo（using 块内轮询）：等固件处理数据后轮询，直到打印机脱离忙碌/打印态；
        // 像素内存在轮询完成后才释放（finally）
        await Future<void>.delayed(const Duration(seconds: 3));
        final status = await waitIdle(api, printer);
        if (status != 0) {
          throw HitiException(status, '打印中断，设备状态 0x${_hex8(status)}');
        }
      } finally {
        holder.dispose();
        calloc.free(para);
        calloc.free(heat);
        calloc.free(settings);
      }
    }
  }

  /// 轮询直到非 BUSY/PRINTING/PROCESSING/SENDING；超时 3 分钟抛错。
  static Future<int> waitIdle(PavoApi api, Pointer<Utf16> printer) async {
    final deadline = DateTime.now().add(const Duration(minutes: 3));
    while (DateTime.now().isBefore(deadline)) {
      final status = getStatus(api, printer);
      if (status != PavoApi.dsBusy &&
          status != PavoApi.dsPrinting &&
          status != PavoApi.dsProcessingData &&
          status != PavoApi.dsSendingData) {
        return status;
      }
      await Future<void>.delayed(const Duration(seconds: 1));
    }
    throw TimeoutException('等待打印机完成超时（3 分钟）');
  }

  static String _hex8(int v) => v.toRadixString(16).padLeft(8, '0').toUpperCase();
}

/// 打印期间持有非托管像素内存，dispose 统一释放（对齐 C# LayerHolder）。
class LayerHolder {
  final _allocations = <Pointer>[];

  /// 把像素缓冲包成 GDI BITMAP 结构并拷贝像素到非托管内存，返回 BITMAP 指针。
  Pointer<Uint8> pin(Uint8List pixels, int bitsPerPixel, int width, int height) {
    final widthBytes = width * (bitsPerPixel ~/ 8);
    final bits = malloc<Uint8>(pixels.length);
    bits.asTypedList(pixels.length).setAll(0, pixels);
    final bmp = malloc<GdiBitmap>();
    bmp.ref
      ..bmType = 0
      ..bmWidth = width
      ..bmHeight = height
      ..bmWidthBytes = widthBytes
      ..bmPlanes = 1
      ..bmBitsPixel = bitsPerPixel
      ..bmBits = bits;
    _allocations
      ..add(bits)
      ..add(bmp);
    return bmp.cast();
  }

  void dispose() {
    for (final p in _allocations) {
      malloc.free(p);
    }
    _allocations.clear();
  }
}