import { Injectable, signal, computed } from '@angular/core';

export interface PasswordPolicyInfo {
  minLength: number;
  requireMixed: boolean;
  description: string;
}

export interface BootstrapPayload {
  initialized: boolean;
  pageTitle: string;
  logo: string;
  welcomeMarkdown: string;
  theme: any;
  defaultChallengeIp: string;
  registrationsEnabled: boolean;
  passwordPolicy: PasswordPolicyInfo;
}

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 res = await fetch('/api/v1/bootstrap', { credentials: 'include' });
      const data = (await res.json()) as BootstrapPayload;
      this.payload.set(data);
      this.initialized.set(data.initialized);
      this.applyTheme(data.theme);
      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;
  }

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

  private applyTheme(theme: any): void {
    if (!theme?.tokens) return;
    const root = document.documentElement.style;
    const t = theme.tokens;
    root.setProperty('--color-primary', t.primary);
    root.setProperty('--color-secondary', t.secondary);
    root.setProperty('--color-accent', t.accent);
    root.setProperty('--color-surface', t.surface);
    root.setProperty('--color-text', t.text);
    root.setProperty('--color-success', t.success);
    root.setProperty('--color-warning', t.warning);
    root.setProperty('--color-danger', t.danger);
    root.setProperty('--font-family', t.fontFamily);
    root.setProperty('--radius-sm', t.radii.sm);
    root.setProperty('--radius-md', t.radii.md);
    root.setProperty('--radius-lg', t.radii.lg);
  }
}