import {
  Component,
  computed,
  effect,
  inject,
  input,
  linkedSignal,
  untracked,
  afterNextRender,
} from '@angular/core';
import { form as createForm, FormField, FormRoot } from '@angular/forms/signals';
import { MatButtonModule } from '@angular/material/button';
import { MatCheckboxModule } from '@angular/material/checkbox';
import { MatDialog } from '@angular/material/dialog';
import { MatDividerModule } from '@angular/material/divider';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatInputModule } from '@angular/material/input';
import { MatSnackBar } from '@angular/material/snack-bar';
import { Router } from '@angular/router';

import { ConfirmDialogComponent } from '../../shared/confirm-dialog/confirm-dialog.component';
import { ErrorStateComponent } from '../../shared/error-state/error-state.component';
import { SkeletonLoaderComponent } from '../../shared/skeleton-loader/skeleton-loader.component';
import { Permission } from '../permission';
import { Role, RoleItem } from '../role';
import { RoleService } from '../role.service';

export interface RoleDetailFormData {
  name: string;
  permissions: {
    id: string;
    name: string;
    permission: boolean;
    direct: boolean;
    disabled: boolean;
  }[];
  includedRoles: {
    id: string;
    name: string;
    role: boolean;
    permissionIds: string[];
  }[];
}

@Component({
  selector: 'app-role-detail',
  templateUrl: './role-detail.component.html',
  styleUrls: ['./role-detail.component.css'],
  imports: [
    FormField,
    FormRoot,
    MatFormFieldModule,
    MatInputModule,
    MatDividerModule,
    MatCheckboxModule,
    MatButtonModule,
    SkeletonLoaderComponent,
    ErrorStateComponent,
  ],
})
export class RoleDetailComponent {
  private router = inject(Router);
  private snackBar = inject(MatSnackBar);
  private dialog = inject(MatDialog);
  private ser = inject(RoleService);

  id = input(null, { transform: (v: string | null | undefined) => v ?? null });
  itemResource = this.ser.get(this.id);
  item = computed(() => this.itemResource.value() ?? new Role());

  model = linkedSignal({
    source: this.item,
    computation: (itemVal): RoleDetailFormData => {
      const implied = new Set<string>();
      (itemVal.includedRoles || []).forEach((r) => {
        if (r.enabled) {
          (r.permissionIds || []).forEach((pid) => implied.add(pid));
        }
      });

      return {
        name: itemVal.name ?? '',
        permissions: (itemVal.permissions || []).map((p) => {
          const isImplied = implied.has(p.id as string);
          const isDirect = p.enabled === true;
          return {
            id: p.id ?? '',
            name: p.name,
            permission: isImplied || isDirect,
            direct: isDirect,
            disabled: isImplied,
          };
        }),
        includedRoles: (itemVal.includedRoles || []).map((r) => ({
          id: r.id ?? '',
          name: r.name,
          role: r.enabled === true,
          permissionIds: r.permissionIds || [],
        })),
      };
    },
  });

  form = createForm(this.model);

  private enabledIncludedRoleIds = computed(() => {
    return this.model()
      .includedRoles.filter((r) => r.role)
      .map((r) => r.id)
      .sort()
      .join(',');
  });

  constructor() {
    afterNextRender(() => {
      this.form.name().focusBoundControl();
    });

    effect(() => {
      // Recompute permission locks whenever the set of enabled included roles changes
      this.enabledIncludedRoleIds();
      untracked(() => {
        this.applyIncludedRolePermissionLocks();
      });
    });
  }

  private applyIncludedRolePermissionLocks(): void {
    this.model.update((currentModel) => {
      const implied = new Set<string>();
      currentModel.includedRoles.forEach((role) => {
        if (role.role) {
          (role.permissionIds || []).forEach((pid) => implied.add(pid));
        }
      });

      let changed = false;
      const newPerms = currentModel.permissions.map((p) => {
        // If not disabled, direct state tracks the user's checkbox value
        const currentDirect = p.disabled ? p.direct : p.permission;
        const isImplied = implied.has(p.id);

        const newPermission = isImplied ? true : currentDirect;
        const newDisabled = isImplied;

        if (
          p.direct !== currentDirect ||
          p.permission !== newPermission ||
          p.disabled !== newDisabled
        ) {
          changed = true;
          return {
            ...p,
            direct: currentDirect,
            permission: newPermission,
            disabled: newDisabled,
          };
        }
        return p;
      });

      if (changed) {
        return { ...currentModel, permissions: newPerms };
      }
      return currentModel;
    });
  }

  save() {
    this.ser.saveOrUpdate(this.getItem()).subscribe({
      next: () => {
        this.snackBar.open('', 'Success');
        this.router.navigateByUrl('/roles');
      },
      error: (error) => {
        this.snackBar.open(error as string, 'Danger');
      },
    });
  }

  delete() {
    this.ser.delete(this.item().id as string).subscribe({
      next: () => {
        this.snackBar.open('', 'Success');
        this.router.navigateByUrl('/roles');
      },
      error: (error) => {
        this.snackBar.open(error as string, 'Danger');
      },
    });
  }

  confirmDelete(): void {
    const dialogRef = this.dialog.open(ConfirmDialogComponent, {
      width: '250px',
      data: { title: 'Delete Role?', content: 'Are you sure? This cannot be undone.' },
    });

    dialogRef.afterClosed().subscribe((result: boolean) => {
      if (result) {
        this.delete();
      }
    });
  }

  getItem(): Role {
    const formModel = this.model();
    return new Role({
      ...this.item(),
      name: formModel.name.trim(),
      permissions: formModel.permissions.map(
        (p) =>
          new Permission({
            id: p.id,
            name: p.name,
            enabled: p.disabled ? p.direct : p.permission,
          }),
      ),
      includedRoles: formModel.includedRoles.map(
        (r) =>
          new RoleItem({
            id: r.id,
            name: r.name,
            enabled: r.role,
            permissionIds: r.permissionIds,
          }),
      ),
    });
  }
}