import { race, safeRun, sleep } from "@silverbulletmd/silverbullet/lib/async";
import {
  notAuthenticatedError,
  offlineError,
} from "@silverbulletmd/silverbullet/constants";
import { initLogger } from "./lib/logger.ts";
import { extractSpaceLuaFromPageText, loadConfig } from "./boot_config.ts";
import { Client } from "./client.ts";
import type { Config } from "./config.ts";
import {
  flushCachesAndUnregisterServiceWorker,
  unregisterServiceWorkers,
} from "./service_worker/util.ts";
import "./lib/polyfills.ts";
import type { BootConfig, ServiceWorkerTargetMessage } from "./types/ui.ts";
import { BoxProxy } from "./lib/box_proxy.ts";
import { importKey } from "@silverbulletmd/silverbullet/lib/crypto";
import "./debug.ts";
const logger = initLogger("[Client]");

if (!crypto.subtle) {
  alert(
    "You are likely accessing SilverBullet via HTTP (rather than HTTPS or localhost), this is not a supported configuration. See https://silverbullet.md/TLS",
  );
}

safeRun(async () => {
  // First we attempt to fetch the config from the server
  let bootConfig: BootConfig | undefined;
  let config: Config | undefined;
  // Placeholder proxy for Client object to be swapped in later
  const clientProxy = new BoxProxy({});
  let bootstrapLuaScriptPages: string[] = [];
  // Try loading config and scripts
  try {
    let configJSONText: string;
    [configJSONText, ...bootstrapLuaScriptPages] = await Promise.all([
      cachedFetch(".config"),
      // Some minimal bootstrap Lua: schema definition
      cachedFetch(".fs/Library/Std/APIs/Schema.md"),
      // Configuration option definitions and defaults
      cachedFetch(".fs/Library/Std/Config.md"),
      // Tag definition API
      cachedFetch(".fs/Library/Std/APIs/Tag.md"),
      // Custom configuration
      cachedFetch(".fs/CONFIG.md"),
    ]);
    bootConfig = JSON.parse(configJSONText);
  } catch (e: any) {
    if (e.message === offlineError.message) {
      alert(
        "Could not process config and no cached copy, please connect to the Internet",
      );
      // Not recoverable
      return;
    }
  }
  // Concatenate and evaluate
  try {
    config = await loadConfig(
      bootstrapLuaScriptPages.map(extractSpaceLuaFromPageText).join("\n"),
      clientProxy.buildProxy(),
      !!bootConfig?.readOnly,
    );
  } catch (e: any) {
    alert(
      `Failed to run Space Lua code (likely CONFIG), will attempt to boot without. Error: ${e.message}`,
    );
    console.error("Error evaluating Space Lua script on boot:", e);
    try {
      config = await loadConfig(
        // Everything but CONFIG (at the end)
        bootstrapLuaScriptPages
          .slice(0, bootstrapLuaScriptPages.length - 1)
          .map(extractSpaceLuaFromPageText)
          .join("\n"),
        clientProxy.buildProxy(),
        false,
      );
    } catch (e: any) {
      console.error("Boot error", e);
      alert(
        "Could not load boot scripts, even without CONFIG, check your browser's logs",
      );
      return;
    }
  }

  let encryptionKey: CryptoKey | undefined;
  // If client encryption is enabled (from auth page) AND the server signals it
  if (
    localStorage.getItem("enableEncryption") &&
    bootConfig?.enableClientEncryption
  ) {
    // Init encryption
    console.log("Initializing encryption");
    const swController = navigator.serviceWorker.controller;
    if (swController) {
      // Service is already running, let's see if has an encryption key for me
      console.log(
        "Service worker already running, querying it for an encryption key",
      );
      swController.postMessage({
        type: "get-encryption-key",
      } as ServiceWorkerTargetMessage);
      await race([
        new Promise<void>((resolve) => {
          function keyListener(e: any) {
            if (e.data.type === "encryption-key") {
              navigator.serviceWorker.removeEventListener(
                "message",
                keyListener,
              );
              void importKey(e.data.key).then((key) => {
                encryptionKey = key;
                resolve();
              });
            }
          }
          navigator.serviceWorker.addEventListener("message", keyListener);
        }),
        sleep(200),
      ]);
      if (!encryptionKey) {
        // No encryption key, redirecting to the auth page
        console.warn("Not authenticated, redirecting to auth page");
        location.href = ".auth";
        throw new Error("Not authenticated");
      }
    } else {
      // No service worker, no encryption key, redirecting to the auth page
      console.warn("Not authenticated, redirecting to auth page");
      location.href = ".auth";
      throw new Error("Not authenticated");
    }
  } else {
    bootConfig!.enableClientEncryption = false;
  }

  await augmentBootConfig(bootConfig!, config!);

  const isHeadless = new URLSearchParams(location.search).has("headless");
  // Expose headless flag globally so client.init() can detect it after URL params are stripped
  if (isHeadless) {
    (globalThis as any).__sbHeadless = true;
  }

  // Update the browser URL to no longer contain the query parameters using pushState
  if (location.search) {
    const newURL = new URL(location.href);
    newURL.search = "";
    history.pushState({}, "", newURL.toString());
  }
  console.log("Booting SilverBullet client");
  console.log("Boot config", bootConfig, config.values);

  // If Tauri or headless: skip service worker
  const isTauri = !!(window as any).__TAURI__;
  if (
    !isHeadless &&
    !isTauri &&
    localStorage.getItem("enableSW") !== "0" &&
    navigator.serviceWorker
  ) {
    // Register service worker
    const workerURL = new URL("service_worker.js", document.baseURI);
    let startNotificationCount = 0;
    let lastStartNotification = 0;
    navigator.serviceWorker.addEventListener("message", (event) => {
      if (event.data.type === "service-worker-started") {
        // Service worker started, let's make sure it has the current config
        console.log(
          "Got notified that service worker has just started, sending config",
          bootConfig,
        );
        navigator.serviceWorker.ready.then((registration) => {
          registration.active!.postMessage({
            type: "config",
            config: bootConfig,
          });
        });
        // Check for weird restart behavior
        startNotificationCount++;
        if (Date.now() - lastStartNotification > 5000) {
          // Last restart was longer than 5s ago: this is fine
          startNotificationCount = 0;
        }
        if (startNotificationCount > 2) {
          // This is not normal. Safari sometimes gets stuck on a database connection if the service worker is updated which means it cannot boot properly
          // the only know fix is to quit the browser and restart it
          console.warn(
            "Something is wrong with the sync engine, please quit your browser and restart it.",
          );
        }
        lastStartNotification = Date.now();
      }
    });
    navigator.serviceWorker
      .register(workerURL, {
        type: "module",
        //limit the scope of the service worker to any potential URL prefix
        scope: workerURL.pathname.substring(
          0,
          workerURL.pathname.lastIndexOf("/") + 1,
        ),
      })
      .then((registration) => {
        console.log("Service worker registered...");

        // Send the config
        registration.active?.postMessage({
          type: "config",
          config: bootConfig,
        });

        // Set up update detection
        registration.addEventListener("updatefound", () => {
          const newWorker = registration.installing;
          console.log("New service worker installing...");

          if (newWorker) {
            newWorker.addEventListener("statechange", () => {
              if (
                newWorker.state === "installed" &&
                navigator.serviceWorker.controller
              ) {
                console.log(
                  "New service worker installed and ready to take over.",
                );
                // Force the new service worker to activate immediately
                newWorker.postMessage({ type: "skip-waiting" });
              }
            });
          }
        });
      });
  } else {
    console.info("Service worker disabled.");
  }
  const client = new Client(
    document.getElementById("sb-root")!,
    bootConfig!,
    config!,
  );
  if (bootConfig!.logPush) {
    setInterval(() => {
      void logger.postToServer(".logs", "client");
    }, 1000);
  }
  globalThis.client = client;
  clientProxy.setTarget(client);
  await client.init(encryptionKey);
  if (navigator.serviceWorker) {
    navigator.serviceWorker.addEventListener("message", (event) => {
      void client.handleServiceWorkerMessage(event.data);
    });
  }
});

/**
 * Augments the boot config with values from the page's search params
 * as well as well as Lua-based configuration from CONFIG
 */
async function augmentBootConfig(bootConfig: BootConfig, config: Config) {
  // Pull out sync configuration
  bootConfig.syncDocuments = config.get<boolean>(["sync", "documents"], false);
  let syncIgnore = config!.get<string | string[]>(["sync", "ignore"], "");
  if (Array.isArray(syncIgnore)) {
    syncIgnore = syncIgnore.join("\n");
  }
  bootConfig.syncIgnore = syncIgnore;

  // Then we augment the config based on the URL arguments
  const urlParams = new URLSearchParams(location.search);
  if (urlParams.has("readOnly")) {
    bootConfig.readOnly = true;
  }
  if (urlParams.has("disableSpaceLua")) {
    bootConfig.disableSpaceLua = true;
  }
  if (urlParams.has("disablePlugs")) {
    bootConfig.disablePlugs = true;
  }
  if (urlParams.has("disableSpaceStyle")) {
    bootConfig.disableSpaceStyle = true;
  }
  if (urlParams.has("wipeClient")) {
    bootConfig.performWipe = true;
  }
  if (urlParams.has("resetClient")) {
    bootConfig.performReset = true;
  }
  if (urlParams.has("enableSW")) {
    const val = urlParams.get("enableSW")!;
    localStorage.setItem("enableSW", val);
    if (val === "0") {
      await flushCachesAndUnregisterServiceWorker();
    }
  }
}

if (!globalThis.indexedDB) {
  alert(
    "SilverBullet requires IndexedDB to operate and it is not available in your browser. Please use a recent version of Chrome, Firefox (not in private mode) or Safari.",
  );
}

async function cachedFetch(path: string): Promise<string> {
  const cacheKey = `silverbullet.${document.baseURI}.${path}`;
  try {
    const response = await fetch(path, {
      // We don't want to follow redirects, we want to get the redirect header in case of auth issues
      redirect: "manual",
      // Add short timeout in case of a bad internet connection, this would block loading of the UI
      signal: AbortSignal.timeout(1000),
      headers: {
        "X-Sync-Mode": "1",
      },
    });
    if (response.status >= 500 && response.status < 600) {
      const text = localStorage.getItem(cacheKey);
      if (text) {
        console.info("Falling back to cache for", path);
        return text;
      } else {
        throw offlineError;
      }
    }
    if (response.type === "opaqueredirect") {
      // We received an opaque redirect, there's little sensible we can do than unregister service workers and reload
      console.log(
        "Got opaque redirect, going to unregister service workers and reload",
      );
      await unregisterServiceWorkers();
      console.log("Ok, now going to reload, let's hope for the best");
      location.reload();
      throw notAuthenticatedError;
    }
    const redirectHeader = response.headers.get("location");
    if (redirectHeader) {
      console.info(
        "Received an (authentication) redirect, redirecting to URL: " +
          redirectHeader,
      );
      location.href = redirectHeader;
      throw notAuthenticatedError;
    }
    const text = await response.text();
    // Persist to localStorage
    localStorage.setItem(cacheKey, text);
    return text;
  } catch (e: any) {
    console.info("Falling back to cache for", path);
    // We may be offline, let's see if we have a cached config
    const text = localStorage.getItem(cacheKey);
    if (text) {
      // Yep! Let's use it
      return text;
    } else {
      throw e;
    }
  }
}