/*
 * Copyright (C)2005-2019 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package haxe.io;

@:coreApi
class Bytes {
	public var length(default, null):Int;

	var b:js.lib.Uint8Array;
	var data:js.lib.DataView;

	function new(data:BytesData) {
		this.length = data.byteLength;
		this.b = new js.lib.Uint8Array(data);
		untyped {
			b.bufferValue = data; // some impl does not return the same instance in .buffer
			data.hxBytes = this;
			data.bytes = this.b;
		}
	}

	public inline function get(pos:Int):Int {
		return b[pos];
	}

	public inline function set(pos:Int, v:Int):Void {
		b[pos] = v;
	}

	public function blit(pos:Int, src:Bytes, srcpos:Int, len:Int):Void {
		if (pos < 0 || srcpos < 0 || len < 0 || pos + len > length || srcpos + len > src.length)
			throw Error.OutsideBounds;
		if (srcpos == 0 && len == src.b.byteLength)
			b.set(src.b, pos);
		else
			b.set(src.b.subarray(srcpos, srcpos + len), pos);
	}

	public function fill(pos:Int, len:Int, value:Int):Void {
		for (i in 0...len)
			set(pos++, value);
	}

	public function sub(pos:Int, len:Int):Bytes {
		if (pos < 0 || len < 0 || pos + len > length)
			throw Error.OutsideBounds;
		return new Bytes(b.buffer.slice(pos + b.byteOffset, pos + b.byteOffset + len));
	}

	public function compare(other:Bytes):Int {
		var b1 = b;
		var b2 = other.b;
		var len = (length < other.length) ? length : other.length;
		for (i in 0...len)
			if (b1[i] != b2[i])
				return b1[i] - b2[i];
		return length - other.length;
	}

	inline function initData():Void {
		if (data == null)
			data = new js.lib.DataView(b.buffer, b.byteOffset, b.byteLength);
	}

	public function getDouble(pos:Int):Float {
		initData();
		return data.getFloat64(pos, true);
	}

	public function getFloat(pos:Int):Float {
		initData();
		return data.getFloat32(pos, true);
	}

	public function setDouble(pos:Int, v:Float):Void {
		initData();
		data.setFloat64(pos, v, true);
	}

	public function setFloat(pos:Int, v:Float):Void {
		initData();
		data.setFloat32(pos, v, true);
	}

	public function getUInt16(pos:Int):Int {
		initData();
		return data.getUint16(pos, true);
	}

	public function setUInt16(pos:Int, v:Int):Void {
		initData();
		data.setUint16(pos, v, true);
	}

	public function getInt32(pos:Int):Int {
		initData();
		return data.getInt32(pos, true);
	}

	public function setInt32(pos:Int, v:Int):Void {
		initData();
		data.setInt32(pos, v, true);
	}

	public function getInt64(pos:Int):haxe.Int64 {
		return Int64.make(getInt32(pos + 4), getInt32(pos));
	}

	public function setInt64(pos:Int, v:haxe.Int64):Void {
		setInt32(pos, v.low);
		setInt32(pos + 4, v.high);
	}

	public function getString(pos:Int, len:Int, ?encoding:Encoding):String {
		if (pos < 0 || len < 0 || pos + len > length)
			throw Error.OutsideBounds;
		if (encoding == null)
			encoding = UTF8;

		var dec = switch (encoding) {
			case UTF8: new js.html.TextDecoder("utf-8");
			case RawNative: new js.html.TextDecoder("utf-16");
		};
		return dec.decode(b.subarray(pos, pos + len));
	}

	@:deprecated("readString is deprecated, use getString instead")
	@:noCompletion
	public inline function readString(pos:Int, len:Int):String {
		return getString(pos, len);
	}

	public function toString():String {
		return getString(0, length);
	}

	public function toHex():String {
		var s = new StringBuf();
		var chars = [];
		var str = "0123456789abcdef";
		for (i in 0...str.length)
			chars.push(str.charCodeAt(i));
		for (i in 0...length) {
			var c = get(i);
			s.addChar(chars[c >> 4]);
			s.addChar(chars[c & 15]);
		}
		return s.toString();
	}

	public inline function getData():BytesData {
		return untyped b.bufferValue;
	}

	public static inline function alloc(length:Int):Bytes {
		return new Bytes(new BytesData(length));
	}

	public static function ofString(s:String, ?encoding:Encoding):Bytes {
		if (encoding == RawNative) {
			var buf = new js.lib.Uint8Array(s.length << 1);
			for (i in 0...s.length) {
				var c:Int = StringTools.fastCodeAt(s, i);
				buf[i << 1] = c & 0xFF;
				buf[(i << 1) | 1] = c >> 8;
			}
			return new Bytes(buf.buffer);
		} else {
			var enc = new js.html.TextEncoder();
			return new Bytes(enc.encode(s).buffer);
		}
	}

	public static function ofData(b:BytesData):Bytes {
		var hb = untyped b.hxBytes;
		if (hb != null)
			return hb;
		return new Bytes(b);
	}

	public static function ofHex(s:String):Bytes {
		if ((s.length & 1) != 0)
			throw "Not a hex string (odd number of digits)";
		var a = new Array();
		var i = 0;
		var len = s.length >> 1;
		while (i < len) {
			var high = StringTools.fastCodeAt(s, i * 2);
			var low = StringTools.fastCodeAt(s, i * 2 + 1);
			high = (high & 0xF) + ((high & 0x40) >> 6) * 9;
			low = (low & 0xF) + ((low & 0x40) >> 6) * 9;
			a.push(((high << 4) | low) & 0xFF);
			i++;
		}

		return new Bytes(new js.lib.Uint8Array(a).buffer);
	}

	public inline static function fastGet(b:BytesData, pos:Int):Int {
		// this requires that we have wrapped it with haxe.io.Bytes beforehand
		return untyped b.bytes[pos];
	}
}
