const form = document.getElementById("userform")
const submit = document.getElementById("submit")
const results = document.getElementById("results")

const chunksize = 1000000;

const splitter = (file, hash) => {
	let numberofChunks = Math.ceil(file.byteLength/chunksize);
	let left = 0
	let chunks = []

	for (let i = 0; i < numberofChunks; i++) {
		const chunkForm = new FormData();
		let contentRange = "";
		let chunk;
		if(left+chunksize <= file.byteLength){
			contentRange = `${left}-${left+chunksize}`
			chunk = file.slice(left,left+chunksize)
			left += chunksize
		} else {
			contentRange = `${left}-${file.byteLength}`
			chunk = file.slice(left,file.byteLength)
		}
		chunkForm.append('file', new Blob([chunk], {type:"video/webm"}))

		chunks.push(
			fetch("/uploadchunk", {
				method: "POST",
				headers: {
					"Content-Number": i,
					"Content-Range": `bytes ${contentRange}/${file.byteLength}`,
					"File-Hash": hash
				},
				body: chunkForm
			}).then(res => Promise.resolve(res.status))
		)

	}
	return chunks
}

async function digest(data){
	
	const hash = await crypto.subtle.digest("SHA-256", data);
	return hash

}

const processFile = file => {
	const fr = new FileReader()
	fr.readAsArrayBuffer(file)

	fr.addEventListener("loadend", e => {
		digest(e.target.result).then(digestBuffer => {
  			const hashAsString = Array.from(new Uint8Array(digestBuffer)).map((b) => b.toString(16).padStart(2, "0")).join(""); // hex the buffer for readability

  			let details = JSON.stringify({"usercode": "anonymous", "hash": hashAsString, "size": file.size, "type": file.type})

  			fetch(`/announce`, {
  				method: "POST",
  				headers:{
  					"Content-Type": "json",
  				},
  				body: details
  			})
  			.then(res => {
  				if(res.status == 200){
					Promise.all(splitter(e.target.result,hashAsString))
					.then((values) => {
						if(values.every(x => x === 200)){
							fetch(`/finish`, {
								method: "POST",
								headers: {
									"Content-Type": "json",
								},
								body: details
							}).then(res => res.json())
							.then(res => {
								console.log(res)
								results.innerHTML += `<a href="/${res.file}">https://i.hjmt.xyz/${res.file}</a><br>`
							})							
						}else{
							alert("upload failed")
						}
					})
				}else if(res.status == 409){
					alert("file exists!")
				}else if(res.status == 403){
					alert("get a usertoken for bigger files")
				}
			})
  		})

	})

}

submit.addEventListener("click", e => {
	e.preventDefault();	
	for (const file of form.media.files){
		processFile(file)
	}
})