// @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&dn=expat.txt MIT

import * as fastboot from "./fastboot/dist/fastboot.min.mjs?1";

const RELEASES_URL = "https://releases.grapheneos.org";

const CACHE_DB_NAME = "BlobStore";
const CACHE_DB_VERSION = 1;

class BlobStore {
    constructor() {
        this.db = null;
    }

    async _wrapReq(request, onUpgrade = null) {
        return new Promise((resolve, reject) => {
            request.onsuccess = () => {
                resolve(request.result);
            };
            request.oncomplete = () => {
                resolve(request.result);
            };
            request.onerror = (event) => {
                reject(event);
            };

            if (onUpgrade !== null) {
                request.onupgradeneeded = onUpgrade;
            }
        });
    }

    async init() {
        if (this.db === null) {
            this.db = await this._wrapReq(
                indexedDB.open(CACHE_DB_NAME, CACHE_DB_VERSION),
                (event) => {
                    let db = event.target.result;
                    db.createObjectStore("files", { keyPath: "name" });
                    /* no index needed for such a small database */
                }
            );
        }
    }

    async saveFile(name, blob) {
        this.db.transaction(["files"], "readwrite").objectStore("files").add({
            name: name,
            blob: blob,
        });
    }

    async loadFile(name) {
        try {
            let obj = await this._wrapReq(
                this.db.transaction("files").objectStore("files").get(name)
            );
            return obj.blob;
        } catch (error) {
            return null;
        }
    }

    async close() {
        this.db.close();
    }

    /**
     * Downloads the file from the given URL and saves it to this BlobStore.
     *
     * @param {string} url - URL of the file to download.
     * @returns {blob} Blob containing the downloaded data.
     */
    async download(url) {
        let filename = url.split("/").pop();
        let blob = await this.loadFile(filename);
        if (blob === null) {
            console.log(`Downloading ${url}`);
            let resp = await fetch(new Request(url));
            blob = await resp.blob();
            console.log("File downloaded, saving...");
            await this.saveFile(filename, blob);
            console.log("File saved");
        } else {
            console.log(
                `Loaded ${filename} from blob store, skipping download`
            );
        }

        return blob;
    }
}

let device = new fastboot.FastbootDevice();
let blobStore = new BlobStore();

async function ensureConnected(setProgress) {
    if (!device.isConnected) {
        setProgress("Connecting to device...");
        await device.connect();
    }
}

async function unlockBootloader(setProgress) {
    await ensureConnected(setProgress);

    // Trying to unlock when the bootloader is already unlocked results in a FAIL,
    // so don't try to do it.
    if (await device.getVariable("unlocked") === "yes") {
        return "Bootloader is already unlocked.";
    }

    setProgress("Unlocking bootloader...");
    try {
        await device.runCommand("flashing unlock");
    } catch (error) {
        // FAIL = user rejected unlock
        if (error instanceof fastboot.FastbootError && error.status === "FAIL") {
            throw new Error("Bootloader was not unlocked, please try again!");
        } else {
            throw error;
        }
    }

    return "Bootloader unlocked.";
}

async function getLatestRelease() {
    let product = await device.getVariable("product");

    let metadataResp = await fetch(`${RELEASES_URL}/${product}-stable`);
    let metadata = await metadataResp.text();
    let releaseId = metadata.split(" ")[0];

    return `${product}-factory-${releaseId}.zip`;
}

async function downloadRelease(setProgress) {
    await ensureConnected(setProgress);

    setProgress("Finding latest release...");
    let latestZip = await getLatestRelease();

    // Download and cache the zip as a blob
    setProgress(`Downloading ${latestZip}...`);
    await blobStore.init();
    await blobStore.download(`${RELEASES_URL}/${latestZip}`);
    return `Downloaded ${latestZip} release.`;
}

async function flashRelease(setProgress) {
    await ensureConnected(setProgress);

    // Need to do this again because the user may not have clicked download if
    // it was cached
    setProgress("Finding latest release...");
    let latestZip = await getLatestRelease();
    await blobStore.init();
    let blob = await blobStore.loadFile(latestZip);
    if (blob === null) {
        throw new Error("You need to download a release first!");
    }

    setProgress("Flashing release...");
    await fastboot.FactoryImages.flashZip(device, blob, true, (action, item) => {
        let userAction = fastboot.FactoryImages.USER_ACTION_MAP[action];
        let userItem = item === "avb_custom_key" ? "verified boot key" : item;
        setProgress(`${userAction} ${userItem}...`);
    });

    return `Flashed ${latestZip} to device.`;
}

async function lockBootloader(setProgress) {
    await ensureConnected(setProgress);

    setProgress("Locking bootloader...");
    try {
        await device.runCommand("flashing lock");
    } catch (error) {
        // FAIL = user rejected lock
        if (error instanceof fastboot.FastbootError && error.status === "FAIL") {
            throw new Error("Bootloader was not locked, please try again!");
        } else {
            throw error;
        }
    }

    // We can't explicitly validate the bootloader lock state because it reboots
    // to recovery after locking. Assume that the device would've replied with
    // FAIL if if it wasn't locked.
    return "Bootloader locked.";
}

function addButtonHook(id, callback) {
    let statusField = document.getElementById(`${id}-status`);
    let statusCallback = (status) => {
        statusField.textContent = status;
        statusField.className = "";
    };

    let button = document.getElementById(`${id}-button`);
    button.disabled = false;
    button.onclick = async () => {
        try {
            let finalStatus = await callback(statusCallback);
            statusCallback(finalStatus);
        } catch (error) {
            statusCallback(`Error: ${error.message}`);
            statusField.className = "error-text";
            // Rethrow the error so it shows up in the console
            throw error;
        }
    };
}

// This doesn't really hurt, and because this page is exclusively for web install,
// we can tolerate extra logging in the console in case something goes wrong.
fastboot.setDebugMode(true);

fastboot.FactoryImages.configureZip({
    workerScripts: {
        inflate: ["/js/fastboot/dist/vendor/z-worker-pako.js", "pako_inflate.min.js"],
    },
});

if ("usb" in navigator) {
    console.log("WebUSB available");

    addButtonHook("unlock-bootloader", unlockBootloader);
    addButtonHook("download-release", downloadRelease);
    addButtonHook("flash-release", flashRelease);
    addButtonHook("lock-bootloader", lockBootloader);
} else {
    console.log("WebUSB unavailable");
}

// @license-end