import {
  ChangeDetectionStrategy,
  Component,
  computed,
  DestroyRef,
  inject,
  signal,
  viewChild,
} from '@angular/core';
import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
import { Router } from '@angular/router';
import { ToastrService } from 'ngx-toastr';
import { catchError, finalize, of } from 'rxjs';
import {
  OnboardingStep,
  OnboardingStepper
} from './components/onboarding-stepper/onboarding-stepper';
import { OrganizationBasicsStepComponent } from './steps/organization-basics/organization-basics';
import { OrganizationLocalizationStepComponent } from './steps/organization-localization/organization-localization';
import { OrganizationPlanLimitsStepComponent } from './steps/organization-plan-limits/organization-plan-limits';
import { OrganizationAdminStepComponent } from './steps/organization-admin/organization-admin';
import { OrganizationOnboardingStateService } from './services/organization-onboarding-state.service';
import { OrganizationOnboardingService } from './services/organization-onboarding.service';
import { ConfirmDialog } from '../../../shared/components/confirm-dialog/confirm-dialog';
import { OnboardingStepForm } from './models/organization-onboarding.model';
import { OrganizationProvisioningRequest } from './models/organization-provisioning.model';

@Component({
  selector: 'app-organization-onboarding',
  standalone: true,
  imports: [
    OnboardingStepper,
    OrganizationBasicsStepComponent,
    OrganizationLocalizationStepComponent,
    OrganizationPlanLimitsStepComponent,
    OrganizationAdminStepComponent,
    ConfirmDialog,
  ],
  templateUrl: './organization-onboarding.html',
  styleUrl: './organization-onboarding.scss',
  changeDetection: ChangeDetectionStrategy.OnPush,
  providers: [OrganizationOnboardingStateService, OrganizationOnboardingService]
})
export class OrganizationOnboarding {
  private readonly destroyRef = inject(DestroyRef);
  private readonly router = inject(Router);
  private readonly toastr = inject(ToastrService);
  readonly stateService = inject(OrganizationOnboardingStateService);
  private readonly onboardingService = inject(OrganizationOnboardingService);

  readonly steps: readonly OnboardingStep[] = this.stateService.createStepDefinitions();

  readonly savingDraft = signal(false);
  readonly finishing = signal(false);

  private readonly basicsStep = viewChild(OrganizationBasicsStepComponent);
  private readonly localizationStep = viewChild(OrganizationLocalizationStepComponent);
  private readonly planLimitsStep = viewChild(OrganizationPlanLimitsStepComponent);
  private readonly adminStep = viewChild(OrganizationAdminStepComponent);
  private readonly cancelConfirmDialog = viewChild<ConfirmDialog>('cancelConfirmDialog');
  private readonly finishConfirmDialog = viewChild<ConfirmDialog>('finishConfirmDialog');
  private savedDraftSnapshot = '';

  readonly provisioningRequest = signal<OrganizationProvisioningRequest | null>(null);

  readonly currentStepIndex = this.stateService.currentStepIndex;
  readonly completedStepIndexes = this.stateService.completedStepIndexes;

  readonly currentStep = computed(
    () => this.steps[this.currentStepIndex()]
  );

  readonly navigationDisabled = computed(
    () => this.savingDraft() || this.finishing()
  );

  constructor() {
    this.onboardingService.loadDraft()
      .pipe(
        catchError(() => {
          this.toastr.error('Unable to restore the onboarding draft.', 'Draft restore failed');
          return of(null);
        }),
        takeUntilDestroyed(this.destroyRef)
      )
      .subscribe(draft => {
        if (!draft) {
          this.savedDraftSnapshot = this.serializeDraftState();
          return;
        }

        this.stateService.restoreDraft(draft);
        this.savedDraftSnapshot = this.serializeDraftState();
        this.hydrateActiveStep();
      });
  }

  onStepSelected(index: number): void {
    if (!this.stateService.canOpenStep(index)) {
      return;
    }

    this.captureActiveStepDraft();
    this.stateService.setCurrentStepIndex(index);
    this.hydrateActiveStep();
  }

  onBack(): void {
    const currentIndex = this.currentStepIndex();

    if (currentIndex <= 0) {
      return;
    }

    this.captureActiveStepDraft();
    this.stateService.setCurrentStepIndex(currentIndex - 1);
    this.hydrateActiveStep();
  }

  onNext(): void {
    const currentIndex = this.currentStepIndex();

    if (currentIndex >= this.steps.length - 1) {
      return;
    }

    const activeStep = this.getActiveStep();
    if (!activeStep?.validate()) {
      this.stateService.unmarkStepCompleted(currentIndex);
      return;
    }

    this.storeValidatedActiveStep(activeStep);
    this.stateService.markStepCompleted(currentIndex);
    this.stateService.setCurrentStepIndex(currentIndex + 1);
    this.hydrateActiveStep();
  }

  onSaveDraft(): void {
    if (this.savingDraft()) {
      return;
    }

    this.captureActiveStepDraft();

    this.savingDraft.set(true);

    this.onboardingService.saveDraft(this.stateService.buildDraft())
      .pipe(
        finalize(() => {
          this.savingDraft.set(false);
        }),
        takeUntilDestroyed(this.destroyRef)
      )
      .subscribe({
        next: () => {
          this.savedDraftSnapshot = this.serializeDraftState();
          this.toastr.success('Onboarding draft saved successfully.', 'Draft saved');
        },
        error: () => {
          this.toastr.error('Unable to save the onboarding draft.', 'Draft save failed');
        }
      });
  }

  onFinish(): void {
    if (this.finishing()) {
      return;
    }

    const activeStep = this.adminStep();
    if (!activeStep?.validate()) {
      this.stateService.unmarkStepCompleted(3);
      return;
    }

    this.stateService.updateAdmin(activeStep.getValue());
    this.stateService.markStepCompleted(3);

    const data = this.stateService.onboardingData();
    if (!data.basics || !data.localization || !data.planLimits || !data.admin) {
      this.toastr.error('Complete and validate every onboarding step before provisioning.');
      return;
    }

    this.provisioningRequest.set({
      basics: data.basics,
      localization: data.localization,
      planLimits: data.planLimits,
      admin: data.admin,
    });
    void this.finishConfirmDialog()?.open();
  }

  onCancel(): void {
    this.captureActiveStepDraft();
    if (this.serializeDraftState() !== this.savedDraftSnapshot) {
      void this.cancelConfirmDialog()?.open();
      return;
    }

    void this.leaveOnboarding(false);
  }

  onDiscardAndLeave(): void {
    void this.leaveOnboarding(true);
  }

  onProvisioningConfirmed(): void {
    this.toastr.info(
      'The provisioning request is ready. Backend provisioning is not connected yet.',
      'Provisioning pending'
    );
  }

  private getActiveStep(): OnboardingStepForm<unknown> | undefined {
    switch (this.currentStepIndex()) {
      case 0:
        return this.basicsStep();
      case 1:
        return this.localizationStep();
      case 2:
        return this.planLimitsStep();
      case 3:
        return this.adminStep();
      default:
        return undefined;
    }
  }

  private storeValidatedActiveStep(step: OnboardingStepForm<unknown>): void {
    switch (this.currentStepIndex()) {
      case 0:
        this.stateService.updateBasics((step as OrganizationBasicsStepComponent).getValue());
        break;
      case 1:
        this.stateService.updateLocalization((step as OrganizationLocalizationStepComponent).getValue());
        break;
      case 2:
        this.stateService.updatePlanLimits((step as OrganizationPlanLimitsStepComponent).getValue());
        break;
      case 3:
        this.stateService.updateAdmin((step as OrganizationAdminStepComponent).getValue());
        break;
    }
  }

  private captureActiveStepDraft(): void {
    const currentIndex = this.currentStepIndex();
    const validatedValue = this.getValidatedStepValue(currentIndex);

    switch (currentIndex) {
      case 0:
        this.stateService.updateBasicsDraft(this.basicsStep()?.getDraftValue() ?? null);
        break;
      case 1:
        this.stateService.updateLocalizationDraft(this.localizationStep()?.getDraftValue() ?? null);
        break;
      case 2:
        this.stateService.updatePlanLimitsDraft(this.planLimitsStep()?.getDraftValue() ?? null);
        break;
      case 3:
        this.stateService.updateAdminDraft(this.adminStep()?.getDraftValue() ?? null);
        break;
    }

    const draftValue = this.getDraftStepValue(currentIndex);
    if (
      this.stateService.isStepCompleted(currentIndex) &&
      JSON.stringify(draftValue) !== JSON.stringify(validatedValue)
    ) {
      this.stateService.invalidateStep(currentIndex);
    }
  }

  private getValidatedStepValue(index: number): unknown {
    const data = this.stateService.onboardingData();
    return [data.basics, data.localization, data.planLimits, data.admin][index] ?? null;
  }

  private getDraftStepValue(index: number): unknown {
    const draft = this.stateService.onboardingDraft();
    return [draft.basics, draft.localization, draft.planLimits, draft.admin][index] ?? null;
  }

  private hydrateActiveStep(): void {
    queueMicrotask(() => {
      const draft = this.stateService.onboardingDraft();
      switch (this.currentStepIndex()) {
        case 0:
          if (draft.basics) this.basicsStep()?.patchValue(draft.basics);
          break;
        case 1:
          if (draft.localization) {
            this.localizationStep()?.patchValue(draft.localization);
          }
          this.applyCountryDefaults();
          break;
        case 2:
          if (draft.planLimits) this.planLimitsStep()?.patchValue(draft.planLimits);
          break;
        case 3:
          if (draft.admin) this.adminStep()?.patchValue(draft.admin);
          break;
      }
    });
  }

  private applyCountryDefaults(): void {
    const countryIso2 = this.stateService.basics()?.registrationCountry.iso2 ?? null;
    this.onboardingService.getCountryLocalizationDefaults(countryIso2)
      .pipe(takeUntilDestroyed(this.destroyRef))
      .subscribe(defaults => {
        if (defaults) {
          this.localizationStep()?.applyCountryDefaults(defaults, false);
        }
      });
  }

  private serializeDraftState(): string {
    const draft = this.stateService.buildDraft();
    return JSON.stringify({
      currentStepIndex: draft.currentStepIndex,
      completedStepIndexes: draft.completedStepIndexes,
      basics: draft.basics,
      localization: draft.localization,
      planLimits: draft.planLimits,
      admin: draft.admin,
    });
  }

  private async leaveOnboarding(clearDraft: boolean): Promise<void> {
    if (clearDraft) {
      try {
        await new Promise<void>((resolve, reject) => {
          this.onboardingService.clearDraft()
            .pipe(takeUntilDestroyed(this.destroyRef))
            .subscribe({ next: resolve, error: reject });
        });
      } catch {
        this.toastr.error('Unable to clear the saved draft.');
        return;
      }
    }

    this.stateService.clear();
    await this.router.navigate(['/organizations']);
  }
}