import { app } from 'electron';
import * as fs from 'fs';
import * as path from 'path';
import logManager from '@electron/service/logger';
import { PROVIDER_TYPE_INFO } from '@lib/providers';
import type {
  ProviderAccount,
  ProviderVendorInfo,
  ProviderWithKeyInfo,
} from '@lib/providers';

interface ProviderStore {
  accounts: ProviderAccount[];
  defaultAccountId: string | null;
}

const defaultStore: ProviderStore = {
  accounts: [],
  defaultAccountId: null,
};

const storePath = path.join(app.getPath('userData'), 'provider-accounts.json');
const keysPath = path.join(app.getPath('userData'), 'provider-keys.json');

function readJson<T>(filePath: string, defaultValue: T): T {
  try {
    if (fs.existsSync(filePath)) {
      return JSON.parse(fs.readFileSync(filePath, 'utf-8'));
    }
  } catch (e) {
    logManager.error(`Failed to read ${filePath}:`, e);
  }
  return defaultValue;
}

function writeJson(filePath: string, data: unknown) {
  try {
    fs.mkdirSync(path.dirname(filePath), { recursive: true });
    fs.writeFileSync(filePath, JSON.stringify(data, null, 2), 'utf-8');
  } catch (e) {
    logManager.error(`Failed to write ${filePath}:`, e);
  }
}

function getStore(): ProviderStore {
  return readJson(storePath, defaultStore);
}

function saveStore(store: ProviderStore) {
  writeJson(storePath, store);
}

function getKeys(): Record<string, string> {
  return readJson(keysPath, {});
}

function saveKeys(keys: Record<string, string>) {
  writeJson(keysPath, keys);
}

function mapToProviderWithKeyInfo(account: ProviderAccount): ProviderWithKeyInfo {
  const keys = getKeys();
  const hasKey = !!keys[account.id];
  return {
    id: account.id,
    name: account.label,
    type: account.vendorId as any,
    baseUrl: account.baseUrl,
    apiProtocol: account.apiProtocol,
    headers: account.headers,
    model: account.model,
    fallbackModels: account.fallbackModels,
    fallbackProviderIds: account.fallbackAccountIds,
    enabled: account.enabled,
    createdAt: account.createdAt,
    updatedAt: account.updatedAt,
    hasKey,
    keyMasked: hasKey ? '••••••••' : null,
  };
}

type ProviderChangeListener = () => void;
const listeners: ProviderChangeListener[] = [];

export function onProviderChange(listener: ProviderChangeListener): () => void {
  listeners.push(listener);
  return () => {
    const idx = listeners.indexOf(listener);
    if (idx > -1) listeners.splice(idx, 1);
  };
}

function notifyChange() {
  listeners.forEach((l) => l());
}

function mapToVendorInfo(info: typeof PROVIDER_TYPE_INFO[number]): ProviderVendorInfo {
  return {
    ...info,
    category:
      info.id === 'ollama'
        ? 'local'
        : info.id === 'custom'
        ? 'custom'
        : 'compatible',
    supportedAuthModes: info.requiresApiKey
      ? info.isOAuth
        ? ['api_key', 'oauth_browser']
        : ['api_key']
      : info.isOAuth
      ? ['local', 'oauth_browser']
      : ['local'],
    defaultAuthMode: info.requiresApiKey ? 'api_key' : 'local',
    supportsMultipleAccounts: true,
  } as ProviderVendorInfo;
}

function sanitizeAccount(account: ProviderAccount): ProviderAccount {
  let model = account.model;
  if (model) {
    // Fix corrupted DeepSeek model IDs stored in legacy accounts
    if (model === 'deepseek-chat/deepseek-reasoner' || model.startsWith('deepseek-chat/')) {
      model = 'deepseek-chat';
    } else if (model.startsWith('deepseek-reasoner/')) {
      model = 'deepseek-reasoner';
    }
  }
  if (model !== account.model) {
    return { ...account, model };
  }
  return account;
}

export const providerApiService = {
  getVendors(): ProviderVendorInfo[] {
    return PROVIDER_TYPE_INFO.map(mapToVendorInfo);
  },

  getAccounts(): ProviderAccount[] {
    return getStore().accounts.map(sanitizeAccount);
  },

  getProviders(): ProviderWithKeyInfo[] {
    return getStore().accounts.map(sanitizeAccount).map(mapToProviderWithKeyInfo);
  },

  getDefault(): { accountId: string | null } {
    return { accountId: getStore().defaultAccountId };
  },

  createAccount(body: { account: ProviderAccount; apiKey?: string }) {
    const store = getStore();
    const account = { ...body.account, updatedAt: new Date().toISOString() };
    store.accounts.push(account);
    if (body.apiKey) {
      const keys = getKeys();
      keys[account.id] = body.apiKey;
      saveKeys(keys);
    }
    saveStore(store);
    notifyChange();
    return { success: true };
  },

  updateAccount(
    accountId: string,
    body: { updates: Partial<ProviderAccount>; apiKey?: string }
  ) {
    const store = getStore();
    const idx = store.accounts.findIndex((a) => a.id === accountId);
    if (idx === -1) return { success: false, error: 'Account not found' };
    store.accounts[idx] = {
      ...store.accounts[idx],
      ...body.updates,
      updatedAt: new Date().toISOString(),
    };
    if (body.apiKey) {
      const keys = getKeys();
      keys[accountId] = body.apiKey;
      saveKeys(keys);
    }
    saveStore(store);
    notifyChange();
    return { success: true };
  },

  deleteAccount(accountId: string) {
    const store = getStore();
    store.accounts = store.accounts.filter((a) => a.id !== accountId);
    if (store.defaultAccountId === accountId) store.defaultAccountId = null;
    saveStore(store);
    const keys = getKeys();
    delete keys[accountId];
    saveKeys(keys);
    notifyChange();
    return { success: true };
  },

  setDefault(body: { accountId: string }) {
    const store = getStore();
    const accountExists = store.accounts.some((a) => a.id === body.accountId);
    if (!accountExists) {
      return { success: false, error: 'Account not found' };
    }
    store.defaultAccountId = body.accountId;
    saveStore(store);
    notifyChange();
    return { success: true };
  },

  validateApiKey(body: {
    providerId: string;
    apiKey: string;
    options?: { baseUrl?: string; apiProtocol?: string };
  }) {
    if (!body.apiKey || body.apiKey.trim().length === 0) {
      return { valid: false, error: 'API key is required' };
    }
    // TODO: perform real validation against provider endpoint
    return { valid: true };
  },

  getApiKey(providerId: string) {
    const keys = getKeys();
    return { apiKey: keys[providerId] || null };
  },

  deleteApiKey(accountId: string) {
    const keys = getKeys();
    delete keys[accountId];
    saveKeys(keys);
    notifyChange();
    return { success: true };
  },

  async getUsageHistory(limit?: number) {
    const { getRecentTokenUsageHistory } = await import('@electron/utils/token-usage');
    return getRecentTokenUsageHistory(limit);
  },
};