/**
 * User-visible personal-report failure copy, derived only from allowlisted
 * error codes and section row status. Never include prompts, model text,
 * bundle contents, or user profile fields.
 */

export type PersonalReportSectionFailureRow = Readonly<{
  status: string;
  lastErrorCode: string | null;
}>;

export type PersonalReportFailureSummary = Readonly<{
  summary: string;
  innerReason: string | null;
  lastErrorCodes: readonly string[];
  appendixLastErrorCode: string | null;
}>;

const SECTION_ERROR_LABELS: Readonly<Record<string, string>> = {
  section_output_truncated: "输出被截断",
  section_refs_mismatch: "证据引用未对齐",
  section_identity_mismatch: "章节身份未对齐",
  section_evidence_insufficient: "证据不足",
  section_output_invalid: "输出未通过校验",
};

const APPENDIX_ERROR_LABELS: Readonly<Record<string, string>> = {
  upstream_unavailable: "计算引擎暂时不可用，请稍后重试",
  upstream_busy: "计算引擎繁忙，请稍后重试",
  empty_markdown: "计算引擎返回了空文，请稍后重试",
  generation_failed: "报告生成超时或中断，请稍后重试",
  appendix_persist_failed: "报告正文未能保存，请稍后重试",
  longform_appendix_persist_failed: "报告正文未能保存，请稍后重试",
};

function uniqueLabels(codes: readonly string[]): string[] {
  const labels: string[] = [];
  for (const code of codes) {
    const label = SECTION_ERROR_LABELS[code] ?? "输出未通过校验";
    if (!labels.includes(label)) labels.push(label);
  }
  return labels;
}

export function summarizePersonalReportFailure(input: Readonly<{
  themeCount?: number;
  sections: readonly PersonalReportSectionFailureRow[];
  failureCode?: string | null;
  appendixLastErrorCode?: string | null;
}>): PersonalReportFailureSummary {
  const sections = input.sections;
  const blocked = sections.filter((row) => row.status === "blocked");
  const pending = sections.filter((row) => row.status === "pending");
  const ready = sections.filter((row) => row.status === "ready");
  const lastErrorCodes = blocked
    .map((row) => row.lastErrorCode)
    .filter((code): code is string => typeof code === "string" && code.length > 0);
  const appendixLastErrorCode = textCode(input.appendixLastErrorCode);
  const total = input.themeCount && input.themeCount > 0 ? input.themeCount : sections.length;
  const labels = uniqueLabels(lastErrorCodes);
  const labelText = labels.length > 0
    ? labels.join("、")
    : input.failureCode === "report_schema_invalid"
      ? "结构校验失败"
      : "生成失败";

  let summary: string;
  if (total > 0 && blocked.length > 0 && pending.length > 0) {
    summary = `${total} 个主题中 ${blocked.length} 个写作失败：${labelText}，${pending.length} 个未开始`;
  } else if (total > 0 && blocked.length > 0) {
    summary = `${total} 个主题中 ${blocked.length} 个写作失败：${labelText}`;
  } else if (ready.length > 0 && input.failureCode === "report_schema_invalid") {
    summary = `${ready.length} 个主题已写成，整份报告未完成装配`;
  } else if (input.failureCode === "report_schema_invalid") {
    summary = "报告未通过结构校验";
  } else if (appendixLastErrorCode && APPENDIX_ERROR_LABELS[appendixLastErrorCode]) {
    summary = APPENDIX_ERROR_LABELS[appendixLastErrorCode];
  } else {
    summary = "本次生成没有产出可用报告";
  }

  let innerReason: string | null = null;
  if (blocked.length > 0 && pending.length === 0 && (total === 0 || blocked.length === total)) {
    innerReason = "all_sections_blocked";
  } else if ((blocked.length > 0 && pending.length > 0) || (ready.length > 0 && blocked.length + pending.length < total)) {
    innerReason = "section_generation_incomplete";
  }

  return { summary, innerReason, lastErrorCodes, appendixLastErrorCode };
}

function textCode(value: unknown): string | null {
  if (typeof value !== "string") return null;
  const trimmed = value.trim();
  return trimmed.length > 0 ? trimmed : null;
}