"use strict";

//TextEncoder polyfil from MDN (https://developer.mozilla.org/en-US/docs/Web/API/TextEncoder):
if (typeof TextEncoder === "undefined") {
    TextEncoder=function TextEncoder(){};
    TextEncoder.prototype.encode = function encode(str) {
        "use strict";
        var Len = str.length, resPos = -1;
        var resArr = typeof Uint8Array === "undefined" ? new Array(Len * 2) : new Uint8Array(Len * 3);
        for (var point=0, nextcode=0, i = 0; i !== Len; ) {
            point = str.charCodeAt(i), i += 1;
            if (point >= 0xD800 && point <= 0xDBFF) {
                if (i === Len) {
                    resArr[resPos += 1] = 0xef/*0b11101111*/; resArr[resPos += 1] = 0xbf/*0b10111111*/;
                    resArr[resPos += 1] = 0xbd/*0b10111101*/; break;
                }
                // https://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
                nextcode = str.charCodeAt(i);
                if (nextcode >= 0xDC00 && nextcode <= 0xDFFF) {
                    point = (point - 0xD800) * 0x400 + nextcode - 0xDC00 + 0x10000;
                    i += 1;
                    if (point > 0xffff) {
                        resArr[resPos += 1] = (0x1e/*0b11110*/<<3) | (point>>>18);
                        resArr[resPos += 1] = (0x2/*0b10*/<<6) | ((point>>>12)&0x3f/*0b00111111*/);
                        resArr[resPos += 1] = (0x2/*0b10*/<<6) | ((point>>>6)&0x3f/*0b00111111*/);
                        resArr[resPos += 1] = (0x2/*0b10*/<<6) | (point&0x3f/*0b00111111*/);
                        continue;
                    }
                } else {
                    resArr[resPos += 1] = 0xef/*0b11101111*/; resArr[resPos += 1] = 0xbf/*0b10111111*/;
                    resArr[resPos += 1] = 0xbd/*0b10111101*/; continue;
                }
            }
            if (point <= 0x007f) {
                resArr[resPos += 1] = (0x0/*0b0*/<<7) | point;
            } else if (point <= 0x07ff) {
                resArr[resPos += 1] = (0x6/*0b110*/<<5) | (point>>>6);
                resArr[resPos += 1] = (0x2/*0b10*/<<6)  | (point&0x3f/*0b00111111*/);
            } else {
                resArr[resPos += 1] = (0xe/*0b1110*/<<4) | (point>>>12);
                resArr[resPos += 1] = (0x2/*0b10*/<<6)    | ((point>>>6)&0x3f/*0b00111111*/);
                resArr[resPos += 1] = (0x2/*0b10*/<<6)    | (point&0x3f/*0b00111111*/);
            }
        }
        if (typeof Uint8Array!=="undefined") return new Uint8Array(resArr.buffer.slice(0, resPos+1));
        else return resArr.length === resPos+1 ? resArr : resArr.slice(0, resPos+1); // IE 6-9
    };
    TextEncoder.prototype.toString = function(){return "[object TextEncoder]"};
    try { // Object.defineProperty only works on DOM prototypes in IE8
        Object.defineProperty(TextEncoder.prototype,"encoding",{
            get:function(){if(TextEncoder.prototype.isPrototypeOf(this)) return"utf-8";
                           else throw TypeError("Illegal invocation");}
        });
    } catch(e) { /*IE6-8 fallback*/ TextEncoder.prototype.encoding = "utf-8"; }
    if(typeof Symbol!=="undefined")TextEncoder.prototype[Symbol.toStringTag]="TextEncoder";
}

//----------------------------

function EntryForm() {
	//Connect to document:
	this.div = document.getElementById("EntryForm");
	this.name = document.getElementById("EntryForm-name"),
	this.author = document.getElementById("EntryForm-author"),
	this.url = document.getElementById("EntryForm-url"),
	this.file = document.getElementById("EntryForm-file")
	this.button = document.getElementById("EntryForm-button");
	this.status = document.getElementById("EntryForm-status");

	//Event handling for submit button:
	let me = this;
	this.button.addEventListener('click', function(){
		me.submit();
	});
}

EntryForm.prototype.message = function EntryForm_message(message) {
	this.status.classList.remove('error');
	this.status.innerText = message;
	console.log(message);
};

EntryForm.prototype.error = function EntryForm_error(message) {
	if (!this.status.classList.contains("error")) this.status.classList.add('error');
	this.status.innerText = message;
	console.error(message);
};

EntryForm.prototype.submit = function EntryForm_submit() {
	this.button.disabled = true;
	this.message("");
	this.read();
};

EntryForm.prototype.read = function EntryForm_read() {
	//read file:
	if (this.file.files.length === 0) {
		this.error("Missing file!");
		this.button.disabled = false;
		return;
	} else if (this.file.files.length !== 1) {
		this.error("Too many files!");
		this.button.disabled = false;
		return;
	}
	this.message("Loading file...");

	let me = this;
	this.reader = new FileReader();
	this.reader.onerror = function(){
		me.error("File loading failed.");
		me.button.disabled = false;
		delete me.reader;
	};
	this.reader.onload = function(){
		//build+send message:
		me.send();
	};
	this.reader.readAsArrayBuffer(this.file.files[0]);
};
EntryForm.prototype.send = function EntryForm_send() {
	this.message("Sending entry...");

	//Build data to send:
	const encoder = new TextEncoder("utf-8");
	let nameBytes = encoder.encode(this.name.value);
	let authorBytes = encoder.encode(this.author.value);
	let urlBytes = encoder.encode(this.url.value);
	let fileBytes = new Uint8Array(this.reader.result);

	let data = new Uint8Array(nameBytes.length + 1 + authorBytes.length + 1 + urlBytes.length + 1 + fileBytes.length);

	let offset = 0;
	data.set(nameBytes, offset); offset += nameBytes.length;
	offset += 1;
	data.set(authorBytes, offset); offset += authorBytes.length;
	offset += 1;
	data.set(urlBytes, offset); offset += urlBytes.length;
	offset += 1;
	data.set(fileBytes, offset); offset += fileBytes.length;
	console.assert(offset === data.length, "filled data perfectly");

	//Build request to send data:
	this.xhr = new XMLHttpRequest();
	let me = this;
	this.xhr.upload.addEventListener('error', function() {
		me.error("Upload failed.");
		me.button.disabled = false;
		delete me.reader;
		delete me.xhr;
	});
	this.xhr.upload.addEventListener('abort', function() {
		me.error("Upload aborted.");
		me.button.disabled = false;
		delete me.reader;
		delete me.xhr;
	});
	this.xhr.upload.addEventListener('load', function() {
		me.message("Awaiting response...");
	});

	this.xhr.addEventListener('error', function() {
		me.error("Read failed.");
		me.button.disabled = false;
		delete me.reader;
		delete me.xhr;
	});
	this.xhr.addEventListener('abort', function() {
		me.error("Read aborted");
		me.button.disabled = false;
		delete me.reader;
		delete me.xhr;
	});
	this.xhr.addEventListener('load', function() {
		me.finish();
	});

	this.xhr.open("POST", "/" + this.div.dataset.contest + "/submit");
	this.xhr.send(data);
};
EntryForm.prototype.finish = function EntryForm_finish() {
	//return should be status URL for submission
	if (this.xhr.status === 200) {
		this.message("Success, redirecting to " + this.xhr.responseText);
		window.location.href = this.xhr.responseText;
	} else {
		this.error("Error: '" + this.xhr.responseText + "'");
	}
	delete this.reader;
	delete this.xhr;
	this.button.disabled = false;
};

window.EF = new EntryForm();