import { Injectable, signal, computed } from '@angular/core';
import { Filament, classifyStockLevel } from '../models/filament.model';

/**
 * FilamentService — shared reactive state for filament inventory.
 *
 * Provides a single source of truth for filament data across components.
 * Both FilamentTableComponent and InventorySummaryComponent read from this service.
 * Data is updated via setFilaments() — called by SignalR handlers or HTTP load.
 */
@Injectable({
  providedIn: 'root',
})
export class FilamentService {
  /** Primary data store — reactive signal */
  private readonly _filaments = signal<Filament[]>([
    {
      id: '1',
      materialBaseId: 'm1',
      materialBaseName: 'PLA',
      materialFinishId: 'f1',
      materialFinishName: 'Basic',
      materialModifierId: null,
      materialModifierName: null,
      brand: 'Bambu Lab',
      colorName: 'White',
      colorHex: '#F5F5F5',
      weightTotalGrams: 1000,
      weightRemainingGrams: 850,
      filamentDiameterMm: 1.75,
      spoolSerial: 'SN-001',
      purchasePrice: 25.00,
      purchaseDate: '2026-01-15T00:00:00Z',
      isActive: true,
      createdAt: '2026-01-15T00:00:00Z',
      updatedAt: '2026-04-20T00:00:00Z',
      qrCodeUrl: '',
    },
    {
      id: '2',
      materialBaseId: 'm2',
      materialBaseName: 'PETG',
      materialFinishId: 'f2',
      materialFinishName: 'Matte',
      materialModifierId: 'mod1',
      materialModifierName: 'Carbon Fiber',
      brand: 'Polymaker',
      colorName: 'Fire Engine Red',
      colorHex: '#FF0000',
      weightTotalGrams: 1000,
      weightRemainingGrams: 80,
      filamentDiameterMm: 1.75,
      spoolSerial: 'SN-002',
      purchasePrice: 35.00,
      purchaseDate: '2026-02-01T00:00:00Z',
      isActive: true,
      createdAt: '2026-02-01T00:00:00Z',
      updatedAt: '2026-04-25T00:00:00Z',
      qrCodeUrl: '',
    },
    {
      id: '3',
      materialBaseId: 'm1',
      materialBaseName: 'PLA',
      materialFinishId: 'f1',
      materialFinishName: 'Basic',
      materialModifierId: null,
      materialModifierName: null,
      brand: 'eSun',
      colorName: 'Sky Blue',
      colorHex: '#87CEEB',
      weightTotalGrams: 1000,
      weightRemainingGrams: 200,
      filamentDiameterMm: 1.75,
      spoolSerial: 'SN-003',
      purchasePrice: 20.00,
      purchaseDate: '2026-03-10T00:00:00Z',
      isActive: true,
      createdAt: '2026-03-10T00:00:00Z',
      updatedAt: '2026-04-26T00:00:00Z',
      qrCodeUrl: '',
    },
    {
      id: '4',
      materialBaseId: 'm3',
      materialBaseName: 'ABS',
      materialFinishId: 'f1',
      materialFinishName: 'Basic',
      materialModifierId: null,
      materialModifierName: null,
      brand: 'Hatchbox',
      colorName: 'Black',
      colorHex: '#1A1A1A',
      weightTotalGrams: 1000,
      weightRemainingGrams: 450,
      filamentDiameterMm: 1.75,
      spoolSerial: 'SN-004',
      purchasePrice: 22.00,
      purchaseDate: null,
      isActive: true,
      createdAt: '2026-01-20T00:00:00Z',
      updatedAt: '2026-04-18T00:00:00Z',
      qrCodeUrl: '',
    },
    {
      id: '5',
      materialBaseId: 'm1',
      materialBaseName: 'PLA',
      materialFinishId: 'f3',
      materialFinishName: 'Silk',
      materialModifierId: null,
      materialModifierName: null,
      brand: 'Overturn',
      colorName: 'Gold',
      colorHex: '#FFD700',
      weightTotalGrams: 500,
      weightRemainingGrams: 15,
      filamentDiameterMm: 1.75,
      spoolSerial: 'SN-005',
      purchasePrice: 28.00,
      purchaseDate: null,
      isActive: false,
      createdAt: '2025-12-01T00:00:00Z',
      updatedAt: '2026-04-01T00:00:00Z',
      qrCodeUrl: '',
    },
  ]);

  /** Public read-only view of all filaments */
  readonly filaments = this._filaments.asReadonly();

  /**
   * Replace the full filament list.
   * Called by SignalR handlers, HTTP responses, or test setup.
   */
  setFilaments(data: Filament[]): void {
    this._filaments.set(data);
  }

  /**
   * Update or insert a single filament by id.
   * Called when a real-time SignalR update arrives for one spool.
   */
  upsertFilament(updated: Filament): void {
    this._filaments.update((current) => {
      const idx = current.findIndex((f) => f.id === updated.id);
      if (idx === -1) {
        return [...current, updated];
      }
      const copy = [...current];
      copy[idx] = updated;
      return copy;
    });
  }

  /**
   * Remove a filament by id.
   * Called when a spool is deleted via real-time event.
   */
  removeFilament(id: string): void {
    this._filaments.update((current) => current.filter((f) => f.id !== id));
  }

  /** Computed: count of active spools */
  readonly activeCount = computed(() =>
    this._filaments().filter((f) => f.isActive).length
  );

  /** Computed: count of low or critical stock spools */
  readonly lowStockCount = computed(() =>
    this._filaments().filter((f) => {
      const level = classifyStockLevel(f);
      return level === 'low' || level === 'critical';
    }).length
  );
}