const { app, BrowserWindow, dialog, ipcMain, shell, nativeImage } = require("electron");
const path = require("path");
const fs = require("fs");
const { spawn } = require("child_process");

const BACKEND_URL = "http://127.0.0.1:8008/health";
let backendProcess = null;

function projectRoot() {
  return path.resolve(__dirname, "..", "..");
}

function isDev() {
  return process.env.IMAGEFORGE_DEV === "1";
}

function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

async function waitForBackend(timeoutMs = 20000) {
  const start = Date.now();
  while (Date.now() - start < timeoutMs) {
    try {
      const response = await fetch(BACKEND_URL);
      if (response.ok) {
        return true;
      }
    } catch (_) {}
    await sleep(500);
  }
  return false;
}

function startBackend() {
  const root = projectRoot();
  const backendModule = "backend.app.main";
  const pythonCandidates = process.platform === "win32"
    ? [
        path.join(root, ".venv", "Scripts", "python.exe"),
        path.join(root, "..", ".venv", "Scripts", "python.exe"),
        "py",
        "python",
      ]
    : [
        path.join(root, ".venv", "bin", "python"),
        path.join(root, "..", ".venv", "bin", "python"),
        "python3",
        "python",
      ];

  for (const command of pythonCandidates) {
    if (command.includes(path.sep) && !fs.existsSync(command)) {
      continue;
    }
    try {
      const args = command === "py" ? ["-3", "-m", backendModule] : ["-m", backendModule];
      const child = spawn(command, args, {
        cwd: root,
        env: {
          ...process.env,
          IMAGEFORGE_HOST: process.env.IMAGEFORGE_HOST || "127.0.0.1",
          IMAGEFORGE_PORT: process.env.IMAGEFORGE_PORT || "8008",
          IMAGEFORGE_CORS_ORIGINS: process.env.IMAGEFORGE_CORS_ORIGINS || "http://localhost:5173",
          IMAGEFORGE_CACHE_ROOT: process.env.IMAGEFORGE_CACHE_ROOT || path.join(root, ".cache"),
          IMAGEFORGE_TMP_ROOT: process.env.IMAGEFORGE_TMP_ROOT || path.join(root, ".cache", "tmp"),
        },
        stdio: "ignore",
        detached: false,
      });
      child.once("error", () => {});
      backendProcess = child;
      return;
    } catch (_) {}
  }
}

async function createWindow() {
  startBackend();
  const healthy = await waitForBackend();
  if (!healthy) {
    dialog.showErrorBox(
      "Backend not reachable",
      "ImageForge konnte das lokale Backend nicht starten. Bitte Python und requirements installieren."
    );
  }

  const win = new BrowserWindow({
    width: 1600,
    height: 920,
    minWidth: 1100,
    minHeight: 700,
    webPreferences: {
      contextIsolation: true,
      preload: path.join(__dirname, "preload.js"),
      nodeIntegration: false,
    },
  });

  const devServerUrl = process.env.VITE_DEV_SERVER_URL;
  if (devServerUrl) {
    await win.loadURL(devServerUrl);
  } else {
    await win.loadFile(path.join(__dirname, "..", "dist", "index.html"));
  }
}

ipcMain.handle("open-folder", async (_event, folderPath) => {
  await shell.openPath(folderPath);
});

ipcMain.handle("save-image", async (_event, sourcePath, defaultName) => {
  const result = await dialog.showSaveDialog({
    title: "Save image",
    defaultPath: defaultName,
    filters: [
      { name: "PNG", extensions: ["png"] },
      { name: "JPEG", extensions: ["jpg", "jpeg"] },
    ],
  });
  if (result.canceled || !result.filePath) {
    return false;
  }

  const ext = path.extname(result.filePath).toLowerCase();
  if (ext === ".jpg" || ext === ".jpeg") {
    const img = nativeImage.createFromPath(sourcePath);
    fs.writeFileSync(result.filePath, img.toJPEG(92));
  } else {
    fs.copyFileSync(sourcePath, result.filePath);
  }
  return true;
});

ipcMain.handle("show-error", async (_event, title, message) => {
  await dialog.showMessageBox({
    type: "error",
    title,
    message,
  });
});

ipcMain.handle("pick-image", async () => {
  const result = await dialog.showOpenDialog({
    title: "Select source image",
    properties: ["openFile"],
    filters: [{ name: "Images", extensions: ["png", "jpg", "jpeg", "webp", "bmp"] }],
  });
  if (result.canceled || result.filePaths.length === 0) {
    return null;
  }
  return result.filePaths[0];
});

ipcMain.handle("read-image-data-url", async (_event, sourcePath) => {
  try {
    const root = projectRoot();
    const outputRoot = path.resolve(root, "output");
    const resolved = path.resolve(String(sourcePath || ""));
    if (resolved !== outputRoot && !resolved.startsWith(`${outputRoot}${path.sep}`)) {
      return null;
    }
    if (!fs.existsSync(resolved)) {
      return null;
    }
    const ext = path.extname(resolved).toLowerCase();
    const mimeMap = {
      ".png": "image/png",
      ".jpg": "image/jpeg",
      ".jpeg": "image/jpeg",
      ".webp": "image/webp",
      ".bmp": "image/bmp",
    };
    const mime = mimeMap[ext] || "application/octet-stream";
    const data = fs.readFileSync(resolved);
    return `data:${mime};base64,${data.toString("base64")}`;
  } catch {
    return null;
  }
});

app.whenReady().then(createWindow);

app.on("window-all-closed", () => {
  if (backendProcess && !backendProcess.killed) {
    backendProcess.kill();
  }
  if (process.platform !== "darwin") {
    app.quit();
  }
});