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("/test", {
				method: "POST",
				headers: {
					"Content-Number": i,
					"Content-Range": `bytes ${contentRange}/${file.byteLength}`,
					"File-Hash": hash
				},
				body: chunkForm
		}))

	}
	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

			Promise.all(splitter(e.target.result,hashAsString))
			.then((values) => {
				fetch(`/finish`, {
					method: "POST",
					headers: {
						"Content-Type": "json",
					},
					body: JSON.stringify({"hash": hashAsString, "type": file.type})
				})
			})
		})
	})

}

submit.addEventListener("click", e => {
	e.preventDefault();
	let fd = new FormData();
	
	for (const file of form.media.files){

		processFile(file)

		fd.append('file', file)
		console.log(file)
	}
})