import { Injectable } from '@nestjs/common';
import { NotFoundError } from '@task-stream/api/shared/domain';
import { ProjectRole } from '@task-stream/api/tracker/domain';
import { FindProjectsRepository } from '../ports/find-projects.repository';

/**
 * Authorisation for the read side, based on the projected memberships:
 * members read their projects; anyone (also anonymous, `viewerId` null)
 * reads public ones.
 */
@Injectable()
export class ReadAccess {
  constructor(private readonly findProjects: FindProjectsRepository) {}

  /**
   * The viewer's role, or null when they read a public project as an outsider.
   * `asked` is what the caller looked for: the error names it, never the
   * project behind it (that would confirm a private project exists).
   */
  async assertCanView(
    projectId: string,
    viewerId: string | null,
    asked: { entity: string; ref: string } = {
      entity: 'Project',
      ref: projectId,
    },
  ): Promise<ProjectRole | null> {
    const role = viewerId
      ? await this.findProjects.findRole(projectId, viewerId)
      : null;
    if (role) return role;
    const project = await this.findProjects.findById(projectId);
    // Same answer for "doesn't exist" and "not yours": don't leak projects.
    if (!project?.isPublic) throw new NotFoundError(asked.entity, asked.ref);
    return null;
  }

  async canView(projectId: string, viewerId: string | null): Promise<boolean> {
    try {
      await this.assertCanView(projectId, viewerId);
      return true;
    } catch (error) {
      if (error instanceof NotFoundError) return false;
      throw error;
    }
  }

  assertFound<T>(value: T | null, entity: string, id: string): T {
    if (!value) throw new NotFoundError(entity, id);
    return value;
  }
}

export const UUID =
  /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;