import { Injectable } from '@nestjs/common';
import * as fs from 'fs';
import * as path from 'path';
import { ConfigService } from '@nestjs/config';
import { SettingsService } from '../settings/settings.module';
import { ThemeLoaderService } from '../../common/utils/theme-loader.service';
import { SseHubService } from '../../common/services/sse-hub.service';
import { SETTINGS_KEYS } from '../../config/env.schema';
import { GeneralSettingsPayload } from './dto/general.dto';

export interface GeneralSettingsView {
  pageTitle: string;
  logo: string;
  welcomeMarkdown: string;
  themeKey: string;
  eventStartUtc: string;
  eventEndUtc: string;
  defaultChallengeIp: string;
  registrationsEnabled: boolean;
}

export interface ThemeView {
  id: string;
  key: string;
  name: string;
}

@Injectable()
export class AdminGeneralService {
  constructor(
    private readonly settings: SettingsService,
    private readonly themes: ThemeLoaderService,
    private readonly hub: SseHubService,
    private readonly config: ConfigService,
  ) {}

  async getSettings(): Promise<GeneralSettingsView> {
    const [pageTitle, logo, welcomeMarkdown, themeKey, eventStartUtc, eventEndUtc, defaultChallengeIp, registrationsEnabled] =
      await Promise.all([
        this.settings.get(SETTINGS_KEYS.PAGE_TITLE, 'HIPCTF'),
        this.settings.get(SETTINGS_KEYS.LOGO, ''),
        this.settings.get(SETTINGS_KEYS.WELCOME_MARKDOWN, ''),
        this.settings.get(SETTINGS_KEYS.THEME_KEY, 'classic'),
        this.settings.get(SETTINGS_KEYS.EVENT_START_UTC, ''),
        this.settings.get(SETTINGS_KEYS.EVENT_END_UTC, ''),
        this.settings.get(SETTINGS_KEYS.DEFAULT_CHALLENGE_IP, '127.0.0.1'),
        this.settings.get(SETTINGS_KEYS.REGISTRATIONS_ENABLED, 'false'),
      ]);
    return {
      pageTitle,
      logo,
      welcomeMarkdown,
      themeKey,
      eventStartUtc,
      eventEndUtc,
      defaultChallengeIp,
      registrationsEnabled: registrationsEnabled === 'true',
    };
  }

  async updateSettings(payload: GeneralSettingsPayload): Promise<GeneralSettingsView> {
    await Promise.all([
      this.settings.set(SETTINGS_KEYS.PAGE_TITLE, payload.pageTitle),
      this.settings.set(SETTINGS_KEYS.LOGO, payload.logo),
      this.settings.set(SETTINGS_KEYS.WELCOME_MARKDOWN, payload.welcomeMarkdown),
      this.settings.set(SETTINGS_KEYS.THEME_KEY, payload.themeKey),
      this.settings.set(SETTINGS_KEYS.EVENT_START_UTC, payload.eventStartUtc),
      this.settings.set(SETTINGS_KEYS.EVENT_END_UTC, payload.eventEndUtc),
      this.settings.set(SETTINGS_KEYS.DEFAULT_CHALLENGE_IP, payload.defaultChallengeIp),
      this.settings.set(SETTINGS_KEYS.REGISTRATIONS_ENABLED, payload.registrationsEnabled ? 'true' : 'false'),
    ]);
    this.hub.emitEvent({
      topic: 'general',
      themeKey: payload.themeKey,
      registrationsEnabled: payload.registrationsEnabled,
    });
    return this.getSettings();
  }

  listThemes(): ThemeView[] {
    const themesDir = path.resolve(this.config.get<string>('THEMES_DIR', './themes'));
    let present = new Set<string>();
    try {
      if (fs.existsSync(themesDir)) {
        for (const f of fs.readdirSync(themesDir)) {
          if (!f.endsWith('.json')) continue;
          try {
            const raw = fs.readFileSync(path.join(themesDir, f), 'utf-8');
            const parsed = JSON.parse(raw) as { id?: string };
            if (parsed?.id) present.add(parsed.id);
          } catch {
            /* skip unreadable */
          }
        }
      }
    } catch {
      /* swallow */
    }
    return this.themes
      .listThemes()
      .filter((t) => present.has(t.id))
      .map((t) => ({ id: t.id, key: t.id, name: t.name }));
  }
}