import type { Project } from '../model/Project';

export interface ProjectSummary {
  id: string;
  name: string;
  revision: number;
  updatedAt: string;
}

export interface LoadedProject {
  project: Project;
  revision: number;
}

/** Thrown by `save` when the server holds a newer revision (edited elsewhere). */
export class StaleRevisionError extends Error {
  constructor(readonly serverRevision: number) {
    super(`Project was modified elsewhere (server revision ${serverRevision})`);
    this.name = 'StaleRevisionError';
  }
}

/** Persistence boundary. The editor only talks to this interface. */
export interface ProjectStore {
  list(): Promise<ProjectSummary[]>;
  load(id: string): Promise<LoadedProject>;
  /** Saves the project and returns the new revision. Rejects with StaleRevisionError on conflict. */
  save(project: Project, revision: number): Promise<number>;
  create(name: string): Promise<LoadedProject>;
  delete(id: string): Promise<void>;
}