// 兼容
window.URL = window.URL || window.webkitURL;
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;

export function init(stream, config) {
	config = config || {};
	config.sampleBits = config.sampleBits || 16; // 采样数位 8, 16
	config.sampleRate = config.sampleRate || (16000); // 采样率(1/6 44100)

	var context = new (window.webkitAudioContext || window.AudioContext)();
	var audioInput = context.createMediaStreamSource(stream);
	var createScript = context.createScriptProcessor || context.createJavaScriptNode;
	var recorder = createScript.apply(context, [4096, 1, 1]);

	var audioData = {
		size: 0, // 录音文件长度
		buffer: [], // 录音缓存
		inputSampleRate: context.sampleRate, // 输入采样率
		inputSampleBits: 16, // 输入采样数位 8, 16
		outputSampleRate: config.sampleRate, // 输出采样率
		oututSampleBits: config.sampleBits, // 输出采样数位 8, 16
		input: function (data) {
			this.buffer.push(new Float32Array(data));
			this.size += data.length;
		},
		compress: function () { // 合并压缩
			// 合并
			var data = new Float32Array(this.size);
			var offset = 0;
			for (var i = 0; i < this.buffer.length; i++) {
				data.set(this.buffer[i], offset);
				offset += this.buffer[i].length;
			}
			// 压缩
			var compression = parseInt(this.inputSampleRate / this.outputSampleRate);
			var length = data.length / compression;
			var result = new Float32Array(length);
			var index = 0; var j = 0;
			while (index < length) {
				result[index] = data[j];
				j += compression;
				index++;
			}
			return result;
		},
		encodeWAV: function () {
			var sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate);
			var sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits);
			var bytes = this.compress();
			var dataLength = bytes.length * (sampleBits / 8);
			var buffer = new ArrayBuffer(44 + dataLength);
			var data = new DataView(buffer);

			var channelCount = 1;// 单声道
			var offset = 0;

			var writeString = function (str) {
				for (var i = 0; i < str.length; i++) {
					data.setUint8(offset + i, str.charCodeAt(i));
				}
			};

			// 资源交换文件标识符
			writeString('RIFF'); offset += 4;
			// 下个地址开始到文件尾总字节数,即文件大小-8
			data.setUint32(offset, 36 + dataLength, true); offset += 4;
			// WAV文件标志
			writeString('WAVE'); offset += 4;
			// 波形格式标志
			writeString('fmt '); offset += 4;
			// 过滤字节,一般为 0x10 = 16
			data.setUint32(offset, 16, true); offset += 4;
			// 格式类别 (PCM形式采样数据)
			data.setUint16(offset, 1, true); offset += 2;
			// 通道数
			data.setUint16(offset, channelCount, true); offset += 2;
			// 采样率,每秒样本数,表示每个通道的播放速度
			data.setUint32(offset, sampleRate, true); offset += 4;
			// 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8
			data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true); offset += 4;
			// 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8
			data.setUint16(offset, channelCount * (sampleBits / 8), true); offset += 2;
			// 每样本数据位数
			data.setUint16(offset, sampleBits, true); offset += 2;
			// 数据标识符
			writeString('data'); offset += 4;
			// 采样数据总数,即数据总大小-44
			data.setUint32(offset, dataLength, true); offset += 4;
			// 写入采样数据
			if (sampleBits === 8) {
				for (let i = 0; i < bytes.length; i++, offset++) {
					const s = Math.max(-1, Math.min(1, bytes[i]));
					let val = s < 0 ? s * 0x8000 : s * 0x7FFF;
					val = parseInt(255 / (65535 / (val + 32768)));
					data.setInt8(offset, val, true);
				}
			} else {
				for (let i = 0; i < bytes.length; i++, offset += 2) {
					const s = Math.max(-1, Math.min(1, bytes[i]));
					data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);
				}
			}

			return new Blob([data], { type: 'audio/wav' });
		}
	};

	// 开始录音
	this.start = function () {
		audioInput.connect(recorder);
		recorder.connect(context.destination);
	};

	// 停止
	this.stop = function () {
		recorder.disconnect();
	};

	// 获取音频文件
	this.getBlob = function () {
		this.stop();
		return audioData.encodeWAV();
	};

	// 回放
	this.play = function (audio) {
		audio.src = window.URL.createObjectURL(this.getBlob());
	};

	// 上传
	this.upload = function (url, callback) {
		var fd = new FormData();
		fd.append('audioData', this.getBlob());
		var xhr = new XMLHttpRequest();
		if (callback) {
			xhr.upload.addEventListener('progress', function (e) {
				callback('uploading', e);
			}, false);
			xhr.addEventListener('load', function (e) {
				callback('ok', e);
			}, false);
			xhr.addEventListener('error', function (e) {
				callback('error', e);
			}, false);
			xhr.addEventListener('abort', function (e) {
				callback('cancel', e);
			}, false);
		}
		xhr.open('POST', url);
		xhr.send(fd);
	};

	// 音频采集
	recorder.onaudioprocess = function (e) {
		audioData.input(e.inputBuffer.getChannelData(0));
		// record(e.inputBuffer.getChannelData(0));
	};

}
// 抛出异常
init.throwError = function (message, callback) {
	alert(message);
	callback('1001');
	// throw new function () { this.toString = function () { return message; }; };
};
// 是否支持录音
init.canRecording = (navigator.getUserMedia != null);
// 获取录音机
init.get = function (callback, config) {
	if (callback) {
		if (navigator.getUserMedia) {
			navigator.getUserMedia(
				{ audio: true } // 只启用音频
				, function (stream) {
					var rec = new init(stream, config);
					callback(rec);
				}
				, function (error) {
					switch (error.code || error.name) {
					case 'PERMISSION_DENIED':
					case 'PermissionDeniedError':
						init.throwError('用户拒绝提供信息。');
						break;
					case 'NOT_SUPPORTED_ERROR':
					case 'NotSupportedError':
						init.throwError('浏览器不支持硬件设备。', callback);
						break;
					case 'MANDATORY_UNSATISFIED_ERROR':
					case 'MandatoryUnsatisfiedError':
						init.throwError('无法发现指定的硬件设备。', callback);
						break;
					default:
						init.throwError('无法打开麦克风。', callback);
						break;
					}
				});
		} else {
			init.throwErr('当前浏览器不支持录音功能。'); return;
		}
	}
};

export default { init };