export type AccountLanguage = "zh-CN" | "en-US";
export type AccountAnswerDepth = "concise" | "balanced" | "deep";
export type AccountEvidenceDisplay = "summary" | "inline" | "full";
export type AccountNotificationKey = "pendingConfirmation" | "executionWriteback" | "releaseGate" | "failureAlert";
export type AccountSettingsSaveScope = "local" | "account";

export interface AccountProfileSettings {
  displayName: string;
  roleTitle: string;
  email: string;
  defaultLanguage: AccountLanguage;
}

export interface AccountAiPreferenceSettings {
  answerDepth: AccountAnswerDepth;
  evidenceDisplay: AccountEvidenceDisplay;
}

export interface AccountNotificationPreference {
  enabled: boolean;
  desktop: boolean;
  emailDigest: boolean;
}

export type AccountNotificationSettings = Record<AccountNotificationKey, AccountNotificationPreference>;

export interface AccountSettings {
  profile: AccountProfileSettings;
  aiPreferences: AccountAiPreferenceSettings;
  notifications: AccountNotificationSettings;
  saveScope: AccountSettingsSaveScope;
  updatedAt: string;
}

export interface AccountSettingsSeed {
  displayName?: string | null;
  roleTitle?: string | null;
  email?: string | null;
}

const STORAGE_KEY = "pmflow:account-settings:v1";

export const accountNotificationLabels: Record<AccountNotificationKey, { title: string; detail: string }> = {
  pendingConfirmation: {
    title: "待确认",
    detail: "AI 生成草案、变更项或写入前确认需要你拍板时提醒。",
  },
  executionWriteback: {
    title: "执行回写",
    detail: "Agent、IDE 或集成系统回传开发进度、分支、PR 与测试结果时提醒。",
  },
  releaseGate: {
    title: "发布门禁",
    detail: "发布校验、合规检查、验收项阻塞或通过时提醒。",
  },
  failureAlert: {
    title: "失败提醒",
    detail: "AI 调用、同步任务、执行回写或外部集成失败时提醒。",
  },
};

export const accountNotificationKeys: AccountNotificationKey[] = [
  "pendingConfirmation",
  "executionWriteback",
  "releaseGate",
  "failureAlert",
];

export function createDefaultAccountSettings(seed: AccountSettingsSeed = {}): AccountSettings {
  return {
    profile: {
      displayName: seed.displayName?.trim() || "张子墨",
      roleTitle: seed.roleTitle?.trim() || "产品负责人",
      email: seed.email?.trim() || "",
      defaultLanguage: "zh-CN",
    },
    aiPreferences: {
      answerDepth: "balanced",
      evidenceDisplay: "inline",
    },
    notifications: {
      pendingConfirmation: { enabled: true, desktop: true, emailDigest: false },
      executionWriteback: { enabled: true, desktop: true, emailDigest: false },
      releaseGate: { enabled: true, desktop: true, emailDigest: true },
      failureAlert: { enabled: true, desktop: true, emailDigest: true },
    },
    saveScope: "local",
    updatedAt: new Date().toISOString(),
  };
}

function isBrowserStorageAvailable(): boolean {
  return typeof window !== "undefined" && typeof window.localStorage !== "undefined";
}

function readStoredAccountSettings(): Partial<AccountSettings> | null {
  if (!isBrowserStorageAvailable()) return null;
  const raw = window.localStorage.getItem(STORAGE_KEY);
  if (!raw) return null;
  try {
    const parsed = JSON.parse(raw) as Partial<AccountSettings>;
    return parsed && typeof parsed === "object" ? parsed : null;
  } catch {
    return null;
  }
}

function persistAccountSettings(settings: AccountSettings): void {
  if (!isBrowserStorageAvailable()) {
    throw new Error("当前环境不支持本机暂存");
  }
  window.localStorage.setItem(STORAGE_KEY, JSON.stringify(settings));
}

function mergeAccountSettings(base: AccountSettings, stored: Partial<AccountSettings> | null): AccountSettings {
  if (!stored) return base;
  return {
    ...base,
    ...stored,
    profile: {
      ...base.profile,
      ...stored.profile,
    },
    aiPreferences: {
      ...base.aiPreferences,
      ...stored.aiPreferences,
    },
    notifications: {
      ...base.notifications,
      ...stored.notifications,
    },
  };
}

export async function getAccountSettings(seed?: AccountSettingsSeed): Promise<AccountSettings> {
  const defaults = createDefaultAccountSettings(seed);
  return mergeAccountSettings(defaults, readStoredAccountSettings());
}

export async function updateAccountSettings(nextSettings: AccountSettings): Promise<AccountSettings> {
  const persisted = {
    ...nextSettings,
    saveScope: "local" as const,
    updatedAt: new Date().toISOString(),
  };
  persistAccountSettings(persisted);
  return persisted;
}