export type ProjectSettingsIssue = {
  code?: string;
  field?: string;
  message?: string;
};

export type ProjectSettingsErrorRecovery =
  | 'refresh_and_freeze'
  | 'reload_revision'
  | 'retry_after_switch'
  | 'show_message';

export class ProjectSettingsApiError extends Error {
  readonly status: number;
  readonly code: string;
  readonly issues: ProjectSettingsIssue[];

  constructor(input: {
    status: number;
    code: string;
    message: string;
    issues?: ProjectSettingsIssue[];
  }) {
    super(input.message);
    this.name = 'ProjectSettingsApiError';
    this.status = input.status;
    this.code = input.code;
    this.issues = input.issues ?? [];
  }
}

export function parseProjectSettingsErrorBody(text: string): {
  message: string;
  code: string;
  issues: ProjectSettingsIssue[];
} {
  try {
    const parsed = JSON.parse(text) as {
      error?: string;
      message?: string;
      issues?: ProjectSettingsIssue[];
    };
    const issues = Array.isArray(parsed.issues) ? parsed.issues : [];
    const issueText = issues
      .map((issue) => issue.message)
      .filter((msg): msg is string => Boolean(msg))
      .join('；');
    return {
      code: String(parsed.error || ''),
      message: issueText || parsed.message || parsed.error || text || '请求失败',
      issues,
    };
  } catch {
    return { code: '', message: text || '请求失败', issues: [] };
  }
}

export function projectSettingsErrorFromResponse(
  status: number,
  text: string,
  fallback: string,
): ProjectSettingsApiError {
  const parsed = parseProjectSettingsErrorBody(text);
  return new ProjectSettingsApiError({
    status,
    code: parsed.code,
    message: parsed.message || fallback,
    issues: parsed.issues,
  });
}

export function recoverFromProjectSettingsError(
  err: Pick<ProjectSettingsApiError, 'code' | 'status'>,
): ProjectSettingsErrorRecovery {
  if (err.code === 'PLAN_FROZEN') return 'refresh_and_freeze';
  if (err.code === 'PLAN_REVISION_CONFLICT') return 'reload_revision';
  if (err.code === 'ERR_CONCURRENT_SWITCH') return 'retry_after_switch';
  return 'show_message';
}

export function retainDraftOnFrozenConflict<T>(draft: T): T {
  return draft;
}