import { fileTypeFromBuffer } from 'file-type'
import hljs from 'highlight.js'
import { humanFileSize } from './shared'

async function decrypt(encryptedContent: ArrayBuffer, password: string): Promise<ArrayBuffer> {
    const encryptedArray = new Uint8Array(encryptedContent)
    const salt = encryptedArray.slice(0, 16)
    const iv = encryptedArray.slice(16, 32)
    const keyMaterial = await crypto.subtle.importKey(
        "raw",
        new TextEncoder().encode(password),
        { name: "PBKDF2" },
        false,
        ["deriveBits", "deriveKey"]
    )
    const key = await crypto.subtle.deriveKey(
        {
            name: "PBKDF2",
            salt: salt,
            iterations: 100000,
            hash: "SHA-512"
        },
        keyMaterial,
        { name: "AES-CBC", length: 256 },
        false,
        ["decrypt"]
    )
    const decryptedContent = await crypto.subtle.decrypt(
        { name: "AES-CBC", iv: iv },
        key,
        encryptedArray.slice(32)
    )
    return decryptedContent
}

function isValidUTF8(buf: ArrayBuffer) {
    try {
        new TextDecoder("utf-8", { fatal: true }).decode(buf)
        return true
    } catch (e) {
        return false
    }
}

async function showContent(content: ArrayBuffer, filetype: string) {
    const filesize = document.getElementById("filesize") as HTMLDivElement | null
    if (filesize) {
        filesize.textContent = `size: ${humanFileSize(content.byteLength)}`
    }

    const mediaBox = document.getElementById("mediabox") as HTMLDivElement | null
    if (!mediaBox) {
        console.error("Missing mediaBox element.")
        return
    }
    let preview: HTMLElement = document.createElement("div")
    preview.textContent = "This file can't be previewed"
    if (isValidUTF8(content) && filetype !== "blob") {
        preview = document.createElement("pre")
        if (filetype === "none") {
            preview.textContent = new TextDecoder().decode(content)
        } else {
            preview.innerHTML = hljs.highlight(new TextDecoder("utf-8").decode(content), { language: filetype }).value
        }
    } else {
        const filetype = await fileTypeFromBuffer(content)
        if (filetype) {
            const blob = new Blob([content], { type: filetype.mime })
            const url = URL.createObjectURL(blob)
            if (filetype.mime.startsWith("audio/")) {
                preview = document.createElement("audio")
                preview.setAttribute("controls", "")
                preview.setAttribute("src", url)
            } else if (filetype.mime.startsWith("video/")) {
                preview = document.createElement("video")
                preview.setAttribute("controls", "")
                preview.setAttribute("src", url)
            } else if (filetype.mime.startsWith("image/")) {
                preview = document.createElement("img")
                preview.setAttribute("src", url)
            }
        }
    }
    mediaBox.innerHTML = ""
    mediaBox.appendChild(preview)
}

let content: ArrayBuffer
let filetype: string
let filename: string

async function onPasswordSubmit() {
    const passwordInput = document.getElementById("password") as HTMLInputElement | null
    const passwordLabel = document.getElementById("password-label") as HTMLLabelElement | null
    if (!passwordInput || !passwordLabel) {
        console.error("Missing passwordInput or passwordLabel element.")
        return
    }
    try {
        content = await decrypt(content, passwordInput.value)
    } catch (e) {
        passwordLabel.textContent = "Incorrect password"
        return
    }
    const dialog = document.getElementById("password-dialog") as HTMLDialogElement | null
    dialog?.close()
    const downloadForm = document.getElementById("download-form") as HTMLFormElement | null
    downloadForm?.setAttribute("action", "")
    downloadForm?.addEventListener("submit", (e) => {
        e.preventDefault()
        const blob = new Blob([content])
        const url = URL.createObjectURL(blob)
        const link = document.createElement("a")
        link.download = filename
        link.href = url
        link.click();
    })
    showContent(content, filetype)
}

const uuid = window.location.pathname.split("/").filter((x) => x !== "").reverse()[0]

fetch("/raw/" + uuid + "?ignore_password=true").then(async (response) => {
    content = await response.arrayBuffer()
    const mediaBox = document.getElementById("mediabox")
    if(mediaBox) {
       mediaBox.innerHTML = "" 
    }
    filetype = response.headers.get("filetype") || "none"
    filename = response.headers.get("filename") || ""
    if (response.headers.get("encrypted") === "true") {
        const dialog = document.getElementById("password-dialog") as HTMLDialogElement | null
        dialog?.showModal()
    } else {
        showContent(content, filetype)
    }
});

(window as any).onPasswordSubmit = onPasswordSubmit