import chokidar from "chokidar";
import path from "path";
import { existsSync, mkdirSync, writeFileSync } from "fs";
import grabDirNames from "../../utils/grab-dir-names";
import fullRebuild from "./full-rebuild";
import { AppData } from "../../data/app-data";
import checkExcludedPatterns from "../../utils/check-excluded-patterns";
import allPagesESBuildContextBundler, { isHydrationEntryPage, } from "../bundler/all-pages-esbuild-context-bundler";
import grabAllPages from "../../utils/grab-all-pages";
import serverPostBuildFn from "./server-post-build-fn";
import { log } from "../../utils/log";
import { logBuildErrorsOnce } from "../../utils/build-error-log";
const { ROOT_DIR } = grabDirNames();
// The watchdog writes this file and expects the watcher to report it. It
// sits under the dist directory (otherwise ignored), so only this path is
// watched.
function grabWatchPaths() {
    const { BUNX_CWD_DIR } = grabDirNames();
    const WATCH_PROBE_DIR = path.join(BUNX_CWD_DIR, "watch-probe");
    const WATCH_PROBE_FILE = path.join(WATCH_PROBE_DIR, "probe");
    return { BUNX_CWD_DIR, WATCH_PROBE_DIR, WATCH_PROBE_FILE };
}
// Dedupes near-simultaneous restarts (fullRebuild, watchdog).
let last_watcher_restart = 0;
// The current watcher finished its initial scan; probes written before
// that may not produce events.
let watcher_ready = false;
// A probe was written and the watcher hasn't reported it yet.
let probe_pending = false;
/**
 * Closes and re-creates the FS watcher. Deduped: callers that restart the
 * watcher around the same time (fullRebuild, reloadWatcher, watchdog) only
 * trigger a single re-creation.
 */
export function restartWatcher() {
    if (!global.BUNEXT_PAGES_SRC_WATCHER)
        return;
    if (Date.now() - last_watcher_restart < 1000)
        return;
    // Files created between close() and the new watcher's initial scan
    // completing emit no `add` (ignoreInitial treats them as pre-existing).
    // Snapshot the page set so the new watcher can detect them on `ready`.
    const pages_snapshot = grabPagesSnapshot();
    try {
        global.BUNEXT_PAGES_SRC_WATCHER.close();
    }
    catch (error) { }
    global.BUNEXT_PAGES_SRC_WATCHER = undefined;
    last_watcher_restart = Date.now();
    watcherEsbuildCTX({ pages_snapshot });
}
function grabPagesSnapshot() {
    try {
        return grabAllPages()
            .map((p) => p.local_path)
            .sort()
            .join("\n");
    }
    catch (error) {
        return undefined;
    }
}
/**
 * Called periodically by the dev server. Re-creates the watcher only when it
 * failed to report the probe written on the previous tick, i.e. when it went
 * stale. A healthy watcher is left alone: re-creating it rescans the whole
 * project tree.
 */
export function watcherWatchdogTick() {
    const { WATCH_PROBE_DIR, WATCH_PROBE_FILE } = grabWatchPaths();
    if (!global.BUNEXT_PAGES_SRC_WATCHER || !watcher_ready)
        return;
    if (probe_pending) {
        restartWatcher();
        return;
    }
    try {
        mkdirSync(WATCH_PROBE_DIR, { recursive: true });
        writeFileSync(WATCH_PROBE_FILE, String(Date.now()));
        probe_pending = true;
    }
    catch (error) { }
}
function isWatchProbePath(p) {
    const { WATCH_PROBE_DIR, WATCH_PROBE_FILE } = grabWatchPaths();
    return (p === WATCH_PROBE_FILE ||
        p === WATCH_PROBE_DIR ||
        isDistDirOrAncestor(p));
}
/**
 * The dist directory and the folders between it and the project root must
 * stay watched for the watcher to reach the probe, even when an ignore rule
 * matches them (dot folders, `dist`, a custom `dist_dir`).
 */
function isDistDirOrAncestor(p) {
    const { BUNX_CWD_DIR } = grabDirNames();
    if (p === ROOT_DIR)
        return false;
    return p === BUNX_CWD_DIR || BUNX_CWD_DIR.startsWith(p + path.sep);
}
function isInDistDir(p) {
    const { BUNX_CWD_DIR } = grabDirNames();
    return p === BUNX_CWD_DIR || p.startsWith(BUNX_CWD_DIR + path.sep);
}
const TARGET_FILES_MATCH = /\.(tsx?|jsx?|css)$/;
// Rebuild coalescing: editors emit bursts of events per save (change +
// atomic-swap noise), and edits can land while a rebuild is running.
// Events are debounced into a single runner; the runner loops until the
// event queue drains, so a mid-build edit is never silently dropped.
const REBUILD_DEBOUNCE_MS = 50;
let pending_structural = false;
let pending_content_file = undefined;
let debounce_timer = undefined;
// Guards against overlapping runners: BUNEXT_RECOMPILING alone is not enough
// since the artifact tracker clears it mid-run.
let runner_active = false;
function scheduleRebuild() {
    if (debounce_timer) {
        clearTimeout(debounce_timer);
    }
    debounce_timer = setTimeout(async () => {
        debounce_timer = undefined;
        // Another rebuild (fullRebuild, or a runner already looping) owns the
        // bundler. Retry later rather than dropping the pending events.
        if (runner_active || global.BUNEXT_RECOMPILING) {
            scheduleRebuild();
            return;
        }
        try {
            await runRebuilds();
        }
        catch (error) {
            const msg = String(error?.message || error || "");
            if (!msg.startsWith("Build failed with")) {
                logBuildErrorsOnce([{ text: `Watcher rebuild failed: ${msg}` }], (line) => log.error(line));
            }
        }
    }, REBUILD_DEBOUNCE_MS);
}
/**
 * Processes the pending event batch. Structural changes go through the
 * all-pages bundler (which re-creates esbuild contexts only when the entry
 * set really changed, so atomic-swap saves resolve to incremental rebuilds).
 * Content changes rebuild the hydration context incrementally; its artifact
 * tracker then queues the single-flighted SSR rebuild and pushes HMR updates.
 */
async function runRebuilds() {
    runner_active = true;
    global.BUNEXT_RECOMPILING = true;
    global.BUNEXT_IS_SERVER_COMPONENT = false;
    try {
        while (true) {
            const structural = pending_structural;
            const content_file = pending_content_file;
            pending_structural = false;
            pending_content_file = undefined;
            if (!structural && !content_file) {
                break;
            }
            if (structural) {
                global.BUNEXT_ROUTER.reload();
                await allPagesESBuildContextBundler({
                    post_build_fn: async (params) => {
                        await serverPostBuildFn(params);
                    },
                });
            }
            else if (content_file) {
                if (global.BUNEXT_BUNDLER_CTX &&
                    !global.BUNEXT_BUNDLER_CTX_DISPOSED) {
                    await global.BUNEXT_BUNDLER_CTX.rebuild();
                }
                else if (global.BUNEXT_BUNDLER_CTX_DISPOSED) {
                    await fullRebuild({
                        msg: `Restarting Bundler ...`,
                    });
                    break;
                }
                if (content_file.match(/(404|500)\.tsx?$/)) {
                    for (let i = global.BUNEXT_HMR_CONTROLLERS.length - 1; i >= 0; i--) {
                        const controller = global.BUNEXT_HMR_CONTROLLERS[i];
                        try {
                            controller?.controller?.enqueue(`event: update\ndata: ${JSON.stringify({ reload: true })}\n\n`);
                        }
                        catch {
                            global.BUNEXT_HMR_CONTROLLERS.splice(i, 1);
                        }
                    }
                }
            }
        }
    }
    finally {
        runner_active = false;
        global.BUNEXT_RECOMPILING = false;
        global.BUNEXT_IS_SERVER_COMPONENT = false;
    }
}
function isPathExcluded(filename, full_file_path) {
    const user_patterns = global.BUNEXT_CONFIG?.exclude_watch_patterns;
    if (!user_patterns)
        return false;
    for (let i = 0; i < user_patterns.length; i++) {
        const watch_pattern = user_patterns[i];
        if (watch_pattern instanceof RegExp) {
            if (watch_pattern.test(filename))
                return true;
        }
        else {
            const excluded_path = path.resolve(ROOT_DIR, watch_pattern);
            if (excluded_path == full_file_path)
                return true;
        }
    }
    return false;
}
// Heavy directories are filtered at the watcher level so inotify doesn't
// install watches (and deliver events) for trees the bundler never reads.
function buildIgnoredPatterns() {
    const builtin_patterns = [
        /(^|[\/\\])\../,
        /(^|[\/\\])node_modules([\/\\]|$)/,
        /(^|[\/\\])public([\/\\]|$)/,
        /(^|[\/\\])dist([\/\\]|$)/,
        /bun\.lockb$/,
    ];
    const ignored = [
        (p) => !isWatchProbePath(p) &&
            (isInDistDir(p) || builtin_patterns.some((re) => re.test(p))),
        (p) => p.endsWith(AppData["BunextTmpFileExt"]),
    ];
    const user_patterns = global.BUNEXT_CONFIG?.exclude_watch_patterns;
    if (user_patterns) {
        for (let i = 0; i < user_patterns.length; i++) {
            const pattern = user_patterns[i];
            if (pattern instanceof RegExp) {
                ignored.push((p) => pattern.test(path.relative(ROOT_DIR, p)));
            }
            else {
                const excluded_path = path.resolve(ROOT_DIR, pattern);
                ignored.push((p) => p === excluded_path);
            }
        }
    }
    return ignored;
}
export default async function watcherEsbuildCTX(params) {
    const { WATCH_PROBE_DIR } = grabWatchPaths();
    try {
        mkdirSync(WATCH_PROBE_DIR, { recursive: true });
    }
    catch (error) { }
    watcher_ready = false;
    probe_pending = false;
    const pages_src_watcher = chokidar.watch(ROOT_DIR, {
        ignored: buildIgnoredPatterns(),
        persistent: true,
        ignoreInitial: true,
    });
    watcherHandlers(pages_src_watcher, (event, filePath) => handleEvent(event, filePath));
    const pages_snapshot = params?.pages_snapshot;
    pages_src_watcher.on("ready", () => {
        if (global.BUNEXT_PAGES_SRC_WATCHER === pages_src_watcher) {
            watcher_ready = true;
        }
        if (pages_snapshot === undefined)
            return;
        const current = grabPagesSnapshot();
        if (current !== undefined && current !== pages_snapshot) {
            pending_structural = true;
            scheduleRebuild();
        }
    });
    global.BUNEXT_PAGES_SRC_WATCHER = pages_src_watcher;
}
function handleEvent(event, filePath) {
    const { WATCH_PROBE_FILE } = grabWatchPaths();
    const { BUNX_BUNDLER_ERROR_EXIT_FILE } = grabDirNames();
    if (isWatchProbePath(filePath)) {
        if (filePath === WATCH_PROBE_FILE) {
            probe_pending = false;
        }
        return;
    }
    try {
        const filename = path.relative(ROOT_DIR, filePath);
        const full_file_path = filePath;
        if (isPathExcluded(filename, full_file_path)) {
            return;
        }
        if (existsSync(BUNX_BUNDLER_ERROR_EXIT_FILE)) {
            fullRebuild();
            return;
        }
        if (filename.endsWith(AppData["BunextTmpFileExt"])) {
            return;
        }
        if (full_file_path.match(/\/styles$/)) {
            pending_structural = false;
            pending_content_file = undefined;
            if (debounce_timer)
                clearTimeout(debounce_timer);
            setTimeout(() => {
                fullRebuild({
                    msg: `Detected new \`styles\` directory. Rebuilding ...`,
                });
            }, 1000);
            return;
        }
        if (filename.match(/bunext\.config\.ts/)) {
            pending_structural = false;
            pending_content_file = undefined;
            if (debounce_timer)
                clearTimeout(debounce_timer);
            fullRebuild({
                msg: `bunext.config.ts file changed. Rebuilding server ...`,
            });
            return;
        }
        if (event === "change") {
            if (!filename.match(TARGET_FILES_MATCH)) {
                return;
            }
            // A page that isn't a hydration entry yet (e.g. created empty,
            // then given its default export) needs the entry set recomputed;
            // an incremental rebuild of the existing context would miss it.
            if (filename.match(/^src\/pages\//) &&
                !filename.match(/^src\/pages\/api\/|\.server\.tsx?$/) &&
                !checkExcludedPatterns({ path: filename }) &&
                !isHydrationEntryPage(full_file_path)) {
                pending_structural = true;
            }
            else {
                pending_content_file = full_file_path;
            }
            scheduleRebuild();
            return;
        }
        // add / unlink / addDir / unlinkDir
        const is_dir_event = event === "addDir" || event === "unlinkDir";
        const is_file_of_interest = Boolean(filename.match(TARGET_FILES_MATCH)) || is_dir_event;
        if (!is_file_of_interest) {
            return;
        }
        // Only page routes and stylesheets are structural; anything else
        // (e.g. a component being added) is covered by the next content
        // rebuild and needs no context recreation.
        if (!filename.match(/^src\/pages\/|\.css$/) ||
            checkExcludedPatterns({ path: filename }) ||
            filename.match(/ /)) {
            return;
        }
        pending_structural = true;
        scheduleRebuild();
    }
    catch (error) {
        logBuildErrorsOnce([{ text: `Watcher error: ${error?.message || error}` }], (line) => log.error(line));
    }
}
function watcherHandlers(watcher, handleEvent) {
    watcher
        .on("add", (p) => handleEvent("add", p))
        .on("change", (p) => handleEvent("change", p))
        .on("unlink", (p) => handleEvent("unlink", p))
        .on("addDir", (p) => handleEvent("addDir", p))
        .on("unlinkDir", (p) => handleEvent("unlinkDir", p));
}