import { Injectable, signal, computed } from '@angular/core';
import {
  applyThemeToCss,
  BootstrapPayload,
  PasswordPolicyInfo,
  Theme,
} from './bootstrap.types';

export {
  applyThemeToCss,
  clearThemeCss,
  THEME_CSS_PROPERTIES,
  Theme,
  ThemeTokens,
  ThemeCssTarget,
  BootstrapPayload,
  PasswordPolicyInfo,
} from './bootstrap.types';

const DEFAULT_POLICY: PasswordPolicyInfo = {
  minLength: 12,
  requireMixed: true,
  description: 'At least 12 characters with upper, lower, digit and symbol',
};

@Injectable({ providedIn: 'root' })
export class BootstrapService {
  readonly payload = signal<BootstrapPayload | null>(null);
  readonly initialized = signal<boolean>(false);
  readonly passwordPolicy = computed<PasswordPolicyInfo>(
    () => this.payload()?.passwordPolicy ?? DEFAULT_POLICY,
  );

  private loadPromise: Promise<BootstrapPayload | null> | null = null;

  async load(): Promise<BootstrapPayload | null> {
    if (!this.loadPromise) {
      this.loadPromise = this._load();
    }
    return this.loadPromise;
  }

  private async _load(): Promise<BootstrapPayload | null> {
    try {
      const data = await this.fetchAndApply('/api/v1/bootstrap');
      return data;
    } catch (e) {
      console.error('Bootstrap load failed', e);
      return null;
    }
  }

  ready(): Promise<BootstrapPayload | null> {
    if (!this.loadPromise) {
      this.loadPromise = this._load();
    }
    return this.loadPromise;
  }

  async refresh(): Promise<BootstrapPayload> {
    const data = await this.fetchAndApply('/api/v1/bootstrap');
    return data;
  }

  markInitialized(): void {
    this.initialized.set(true);
  }

  applyTheme(theme: Theme | null | undefined): void {
    applyThemeToCss(theme);
  }

  private async fetchAndApply(url: string): Promise<BootstrapPayload> {
    const res = await fetch(url, { credentials: 'include' });
    if (!res.ok) {
      throw new Error(`Bootstrap request failed: ${res.status}`);
    }
    const data = (await res.json()) as BootstrapPayload;
    this.payload.set(data);
    this.initialized.set(data.initialized);
    this.applyTheme(data.theme);
    return data;
  }
}