import { Injectable } from '@angular/core';
import { HttpClient, HttpParams } from '@angular/common/http';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';
import { Category, Item, Subcategory } from '../models';
import { environment } from '../../environments/environment';

@Injectable({
  providedIn: 'root'
})
export class ApiService {
  private readonly baseUrl = environment.apiUrl;

  constructor(private http: HttpClient) {}

  /**
   * Normalize an item from the API response — supports both
   * legacy marketplace format and the new backOffice API format.
   */
  private normalizeItem(raw: any): Item {
    const item: Item = { ...raw };

    // Map backOffice string id → legacy numeric itemID
    if (raw.id != null && raw.itemID == null) {
      item.id = String(raw.id);
      item.itemID = typeof raw.id === 'number' ? raw.id : 0;
    }

    // Map backOffice imgs[] → legacy photos[]
    if (raw.imgs && (!raw.photos || raw.photos.length === 0)) {
      item.photos = raw.imgs.map((url: string) => ({ url }));
    }
    item.imgs = raw.imgs || raw.photos?.map((p: any) => p.url) || [];

    // Map backOffice description (key-value array) → legacy description string
    if (Array.isArray(raw.description)) {
      item.descriptionFields = raw.description;
      item.description = raw.description.map((d: any) => `${d.key}: ${d.value}`).join('\n');
    } else {
      item.description = raw.description || raw.simpleDescription || '';
    }

    // Map backOffice comments → legacy callbacks
    if (raw.comments && (!raw.callbacks || raw.callbacks.length === 0)) {
      item.callbacks = raw.comments.map((c: any) => ({
        rating: c.stars,
        content: c.text,
        userID: c.author,
        timestamp: c.createdAt,
      }));
    }
    item.comments = raw.comments || raw.callbacks?.map((c: any) => ({
      id: c.userID,
      text: c.content,
      author: c.userID,
      stars: c.rating,
      createdAt: c.timestamp,
    })) || [];

    // Compute average rating from comments if not present
    if (raw.rating == null && item.comments && item.comments.length > 0) {
      const rated = item.comments.filter(c => c.stars != null);
      item.rating = rated.length > 0
        ? rated.reduce((sum, c) => sum + (c.stars || 0), 0) / rated.length
        : 0;
    }
    item.rating = item.rating || 0;

    // Defaults
    item.discount = item.discount || 0;
    item.remainings = item.remainings || (raw.quantity != null
      ? (raw.quantity <= 0 ? 'out' : raw.quantity <= 5 ? 'low' : raw.quantity <= 20 ? 'medium' : 'high')
      : 'high');
    item.currency = item.currency || 'RUB';

    // Preserve new backOffice fields
    item.badges = raw.badges || [];
    item.tags = raw.tags || [];
    item.simpleDescription = raw.simpleDescription || '';
    item.translations = raw.translations || {};
    item.visible = raw.visible ?? true;
    item.priority = raw.priority ?? 0;

    return item;
  }

  private normalizeItems(items: any[] | null | undefined): Item[] {
    if (!items || !Array.isArray(items)) {
      return [];
    }
    return items.map(item => this.normalizeItem(item));
  }

  /**
   * Normalize a category from the API response — supports both
   * the flat legacy format and nested backOffice format.
   */
  private normalizeCategory(raw: any): Category {
    const cat: Category = { ...raw };

    if (raw.id != null && raw.categoryID == null) {
      cat.id = String(raw.id);
      cat.categoryID = typeof raw.id === 'number' ? raw.id : 0;
    }

    // Map backOffice img → legacy icon
    if (raw.img && !raw.icon) {
      cat.icon = raw.img;
    }
    cat.img = raw.img || raw.icon;

    cat.parentID = raw.parentID ?? 0;
    cat.visible = raw.visible ?? true;
    cat.priority = raw.priority ?? 0;

    if (raw.subcategories && Array.isArray(raw.subcategories)) {
      cat.subcategories = raw.subcategories;
    }

    return cat;
  }

  private normalizeCategories(cats: any[] | null | undefined): Category[] {
    if (!cats || !Array.isArray(cats)) return [];
    return cats.map(c => this.normalizeCategory(c));
  }

  // ─── Core Marketplace Endpoints ───────────────────────────

  ping(): Observable<{ message: string }> {
    return this.http.get<{ message: string }>(`${this.baseUrl}/ping`);
  }

  getCategories(): Observable<Category[]> {
    return this.http.get<any[]>(`${this.baseUrl}/category`)
      .pipe(map(cats => this.normalizeCategories(cats)));
  }

  getCategoryItems(categoryID: number, count: number = 50, skip: number = 0): Observable<Item[]> {
    const params = new HttpParams()
      .set('count', count.toString())
      .set('skip', skip.toString());
    return this.http.get<any[]>(`${this.baseUrl}/category/${categoryID}`, { params })
      .pipe(map(items => this.normalizeItems(items)));
  }

  getItem(itemID: number): Observable<Item> {
    return this.http.get<any>(`${this.baseUrl}/item/${itemID}`)
      .pipe(map(item => this.normalizeItem(item)));
  }

  searchItems(search: string, count: number = 50, skip: number = 0): Observable<{ items: Item[], total: number }> {
    const params = new HttpParams()
      .set('search', search)
      .set('count', count.toString())
      .set('skip', skip.toString());
    return this.http.get<any>(`${this.baseUrl}/searchitems`, { params })
      .pipe(
        map(response => ({
          items: this.normalizeItems(response?.items || []),
          total: response?.total || 0
        }))
      );
  }

  addToCart(itemID: number, quantity: number = 1): Observable<{ message: string }> {
    return this.http.post<{ message: string }>(`${this.baseUrl}/cart`, { itemID, quantity });
  }

  updateCartQuantity(itemID: number, quantity: number): Observable<{ message: string }> {
    return this.http.patch<{ message: string }>(`${this.baseUrl}/cart`, { itemID, quantity });
  }

  removeFromCart(itemIDs: number[]): Observable<{ message: string }> {
    return this.http.delete<{ message: string }>(`${this.baseUrl}/cart`, { body: itemIDs });
  }

  getCart(): Observable<Item[]> {
    return this.http.get<any[]>(`${this.baseUrl}/cart`)
      .pipe(map(items => this.normalizeItems(items)));
  }

  // Review submission
  submitReview(reviewData: {
    itemID: number;
    rating: number;
    comment: string;
    username: string | null;
    userId: number | null;
    timestamp: string;
  }): Observable<{ message: string }> {
    return this.http.post<{ message: string }>(`${this.baseUrl}/comment`, reviewData);
  }

  // Payment - SBP Integration
  createPayment(paymentData: {
    amount: number;
    currency: string;
    siteuserID: string;
    siteorderID: string;
    redirectUrl: string;
    telegramUsername: string;
    items: Array<{ itemID: number; price: number; name: string }>;
  }): Observable<{
    qrId: string;
    qrStatus: string;
    qrExpirationDate: string;
    payload: string;
    qrUrl: string;
  }> {
    return this.http.post<{
      qrId: string;
      qrStatus: string;
      qrExpirationDate: string;
      payload: string;
      qrUrl: string;
    }>(`${this.baseUrl}/cart`, paymentData);
  }

  checkPaymentStatus(qrId: string): Observable<{
    additionalInfo: string;
    paymentPurpose: string;
    amount: number;
    code: string;
    createDate: string;
    currency: string;
    order: string;
    paymentStatus: string;
    qrId: string;
    transactionDate: string;
    transactionId: number;
    qrExpirationDate: string;
    phoneNumber: string;
  }> {
    return this.http.get<{
      additionalInfo: string;
      paymentPurpose: string;
      amount: number;
      code: string;
      createDate: string;
      currency: string;
      order: string;
      paymentStatus: string;
      qrId: string;
      transactionDate: string;
      transactionId: number;
      qrExpirationDate: string;
      phoneNumber: string;
    }>(`${this.baseUrl}/qr/payment/${qrId}`);
  }

  submitPurchaseEmail(emailData: {
    email: string;
    telegramUserId: string | null;
    items: Array<{ itemID: number; name: string; price: number; currency: string }>;
  }): Observable<{ message: string }> {
    return this.http.post<{ message: string }>(`${this.baseUrl}/purchase-email`, emailData);
  }

  getRandomItems(count: number = 5, categoryID?: number): Observable<Item[]> {
    let params = new HttpParams().set('count', count.toString());
    if (categoryID) {
      params = params.set('category', categoryID.toString());
    }
    return this.http.get<any[]>(`${this.baseUrl}/randomitems`, { params })
      .pipe(map(items => this.normalizeItems(items)));
  }
}