const path = require("path");
const chokidar = require("chokidar");
const browserSync = require("browser-sync").create();
const { build } = require("./build");

const ROOT_DIR = path.resolve(__dirname, "..");
const SOURCE_GLOBS = [
    path.join(ROOT_DIR, "css/**/*.css"),
    path.join(ROOT_DIR, "js/**/*.js")
];
const EXAMPLE_GLOBS = [
    path.join(ROOT_DIR, "examples/**/*.html")
];

let isBuilding = false;
let hasPendingBuild = false;

async function queueBuild(trigger) {
    if (isBuilding) {
        hasPendingBuild = true;
        return;
    }

    isBuilding = true;

    try {
        await build();
        console.log(`[watch] Built after ${trigger}`);
        browserSync.reload();
    } catch (error) {
        console.error("[watch] Build failed");
        console.error(error);
    } finally {
        isBuilding = false;
    }

    if (hasPendingBuild) {
        hasPendingBuild = false;
        await queueBuild("queued change");
    }
}

async function start() {
    await build();

    browserSync.init({
        server: ROOT_DIR,
        startPath: "examples/generic.html",
        notify: false,
        open: false
    });

    chokidar.watch(SOURCE_GLOBS, { ignoreInitial: true }).on("all", (event, filePath) => {
        const relativePath = path.relative(ROOT_DIR, filePath);
        queueBuild(`${event}: ${relativePath}`);
    });

    chokidar.watch(EXAMPLE_GLOBS, { ignoreInitial: true }).on("all", () => {
        browserSync.reload();
    });

    console.log("[watch] Watching css/, js/, and examples/.");
}

start().catch((error) => {
    console.error("[watch] Failed to start");
    console.error(error);
    process.exit(1);
});