// QR Processing Module for EmblemScanner
// Self-contained WASM-based QR code processing

var qrtool = null;
var qrtool_ready = false;

/**
 * Load qrtool WASM module
 */
function load_qrtool() {
  var m = require('./qrtool.wx.js');
  m.onRuntimeInitialized = () => {
    console.log("QRTool runtime initialized");
    qrtool_ready = true;
    qrtool = m;
  }
}

/**
 * Check if qrtool is ready for processing
 */
function is_qrtool_ready() {
  return qrtool_ready;
}

/**
 * Process camera frame for QR code detection
 */
function process_frame(width, height, image_data, camera_sensitivity) {
  if (!qrtool_ready) {
    console.log("qrtool not ready");
    return null;
  }

  try {
    // Allocate buffer for image data
    var buf = qrtool._malloc(image_data.length * image_data.BYTES_PER_ELEMENT);
    qrtool.HEAPU8.set(image_data, buf);
    
    // Process QR code detection with angle
    var result_str = qrtool.ccall('qrtool_angle', 'string', 
      ['number', 'number', 'number', 'number', 'number'], 
      [buf, width, height, 0, camera_sensitivity || 1.0]
    );
    
    // Clean up buffer
    qrtool._free(buf);
    
    // Parse result
    var result = JSON.parse(result_str);
    
    return {
      qrcode: result.qrcode || '',
      angle: result.angle || 0,
      ok: result.ok || false,
      err: result.err || '',
      valid_pattern: is_emblem_qr_pattern(result.qrcode || '')
    };
  } catch (error) {
    console.error('QR processing error:', error);
    return null;
  }
}

/**
 * Process frame with dot area extraction (for debug visualization)
 */
function process_frame_with_debug(width, height, image_data, camera_sensitivity) {
  if (!qrtool_ready) {
    console.log("qrtool not ready");
    return null;
  }

  try {
    // Allocate buffer for image data
    var buf = qrtool._malloc(image_data.length * image_data.BYTES_PER_ELEMENT);
    qrtool.HEAPU8.set(image_data, buf);
    
    // Allocate buffer for debug dot area
    const dot_area_size = 32;
    const da_len = dot_area_size * dot_area_size * image_data.BYTES_PER_ELEMENT * 4;
    var dot_area_buf = qrtool._malloc(da_len);
    
    // Process QR code detection with debug output
    var result_str = qrtool.ccall('qrtool_angle', 'string', 
      ['number', 'number', 'number', 'number', 'number'], 
      [buf, width, height, dot_area_buf, camera_sensitivity || 1.0]
    );
    
    // Extract debug image
    var debug_view = qrtool.HEAPU8.subarray(dot_area_buf, dot_area_buf + da_len);
    var debug_data_url = data_url_from_frame(dot_area_size, dot_area_size, debug_view);
    
    // Clean up buffers
    qrtool._free(buf);
    qrtool._free(dot_area_buf);
    
    // Parse result
    var result = JSON.parse(result_str);
    
    return {
      qrcode: result.qrcode || '',
      angle: result.angle || 0,
      ok: result.ok || false,
      err: result.err || '',
      valid_pattern: is_emblem_qr_pattern(result.qrcode || ''),
      debug_data_url: debug_data_url
    };
  } catch (error) {
    console.error('QR processing error:', error);
    return null;
  }
}

/**
 * Create offscreen canvas for debug image generation
 */
const offscreenCanvas = wx.createOffscreenCanvas({
  type: '2d',
  width: 100,
  height: 100,
});

/**
 * Convert raw frame data to data URL for debug visualization
 */
function data_url_from_frame(width, height, image_data) {
  offscreenCanvas.width = width;
  offscreenCanvas.height = height;
  var ctx = offscreenCanvas.getContext('2d');
  var imgd = ctx.createImageData(width, height);
  imgd.data.set(image_data);
  ctx.putImageData(imgd, 0, 0);
  return offscreenCanvas.toDataURL("image/jpeg", 1.0);
}

/**
 * Check if QR code matches Emblem pattern
 */
function is_emblem_qr_pattern(p) {
  if (!p) return false;
  if (p.search(/code=[0-9a-zA-Z]+/) >= 0) return true;
  if (p.search(/id=[0-9a-zA-Z]+/) >= 0) return true;
  if (p.search(/c=[0-9a-zA-Z]+/) >= 0) return true;
  if (p.search(/https:\/\/xy\.ltd\/v\/[0-9a-zA-Z]+/) >= 0) return true;
  return false;
}

/**
 * Generate hint text based on QR processing result
 */
function make_hint_text(result) {
  if (!result) {
    return "查找二维码";
  }
  
  if (result.qrcode && result.qrcode.length > 0) {
    if (!result.valid_pattern) {
      return "无效编码";
    }
    
    if (result.ok) {
      return "识别成功";
    }
    
    // Check specific error conditions
    var err = result.err || "";
    if (err.includes("margin too small")) {
      return "对齐定位点";
    } else if (err.includes("energy check failed") || err.includes("cannot detect angle")) {
      return "移近一点";
    }
  }
  
  return "对齐定位点";
}

module.exports = {
  load_qrtool,
  is_qrtool_ready,
  process_frame,
  process_frame_with_debug,
  data_url_from_frame,
  is_emblem_qr_pattern,
  make_hint_text
};