import { api, describeError } from "./api.js";
import { element } from "./dom.js";
import { notificationsEnabled, setNotificationsEnabled } from "./notify.js";

const themeStorageKey = "ddc-theme";

const fields = {
  dialog: document.getElementById("settings-dialog"),
  form: document.getElementById("settings-form"),
  closeButton: document.getElementById("settings-close"),
  cancelButton: document.getElementById("settings-cancel"),
  error: document.getElementById("settings-error"),
  concurrent: document.getElementById("setting-concurrent"),
  connections: document.getElementById("setting-connections"),
  notifications: document.getElementById("setting-notifications"),
  minFree: document.getElementById("setting-min-free"),
  ports: document.getElementById("setting-ports"),
  autoExtract: document.getElementById("setting-auto-extract"),
  cleanup: document.getElementById("setting-cleanup"),
  downloadPaths: document.getElementById("setting-download-paths"),
  theme: document.getElementById("setting-theme"),
  downloadDir: document.getElementById("info-download-dir"),
  roots: document.getElementById("info-roots"),
};

export function setupSettings(onSaved) {
  fields.closeButton.addEventListener("click", () => fields.dialog.close());
  fields.cancelButton.addEventListener("click", () => fields.dialog.close());
  fields.form.addEventListener("submit", (event) => saveSettings(event, onSaved));
  fields.theme.addEventListener("change", () => applyTheme(fields.theme.value));
  fields.dialog.addEventListener("close", () => applyTheme(readTheme()));
}

export async function loadSettings() {
  const data = await api.settings();
  return data.settings;
}

export async function openSettings() {
  fields.error.textContent = "";
  const data = await api.settings();
  fillForm(data);
  fields.dialog.showModal();
}

function fillForm(data) {
  const settings = data.settings;
  fields.concurrent.value = settings.maxConcurrentDownloads;
  fields.connections.value = settings.connectionsPerDownload;
  fields.notifications.checked = notificationsEnabled();
  fields.minFree.value = settings.minFreeGB;
  fields.ports.value = settings.allowedPorts.length > 0 ? settings.allowedPorts.join(", ") : "*";
  fields.autoExtract.checked = settings.autoExtract;
  fields.cleanup.checked = settings.cleanupAfterMove;
  fields.downloadPaths.value = (settings.downloadPaths || []).join("\n");
  fields.theme.value = readTheme();
  fields.downloadDir.textContent = data.downloadDir;
  fields.roots.replaceChildren(...data.libraryRoots.map((root) => element("div", "mono", root)));
}

async function saveSettings(event, onSaved) {
  event.preventDefault();
  fields.error.textContent = "";
  try {
    const payload = {
      maxConcurrentDownloads: Number(fields.concurrent.value),
      connectionsPerDownload: Number(fields.connections.value),
      minFreeGB: Number(fields.minFree.value),
      allowedPorts: parsePorts(fields.ports.value),
      autoExtract: fields.autoExtract.checked,
      cleanupAfterMove: fields.cleanup.checked,
      downloadPaths: parseDownloadPaths(fields.downloadPaths.value),
    };
    await setNotificationsEnabled(fields.notifications.checked);
    const data = await api.saveSettings(payload);
    storeTheme(fields.theme.value);
    fields.dialog.close();
    onSaved(data.settings);
  } catch (error) {
    fields.error.textContent = describeError(error);
  }
}

function parsePorts(text) {
  const trimmed = text.trim();
  if (trimmed === "*") return [];
  const ports = trimmed.split(/[\s,]+/).filter(Boolean).map(Number);
  const invalid = ports.length === 0 || ports.some((port) => !Number.isInteger(port) || port < 1 || port > 65535);
  if (invalid) throw new Error("Allowed ports must be numbers between 1 and 65535, or * for any port.");
  return ports;
}

function parseDownloadPaths(text) {
  return text.split("\n").map((line) => line.trim()).filter(Boolean);
}

function readTheme() {
  try {
    return localStorage.getItem(themeStorageKey) || "system";
  } catch {
    return "system";
  }
}

function storeTheme(theme) {
  try {
    localStorage.setItem(themeStorageKey, theme);
  } catch {
    return;
  } finally {
    applyTheme(theme);
  }
}

function applyTheme(theme) {
  if (theme === "light" || theme === "dark") document.documentElement.dataset.theme = theme;
  else delete document.documentElement.dataset.theme;
}