import { isWriteOutcomeUnknown } from '@/utils/request-outcome.js'

const messages = {
  submitted:
    "反馈已提交。以下内容为本次提交记录；修改任一项后可提交新反馈。",
  submittedWithEdits: "上一份反馈已提交，当前修改尚未提交。",
  uncertain:
    "暂时无法确认是否提交成功，请不要重复提交相同内容。你可以修改内容后再提交一份反馈。",
  uncertainWithEdits: "上一份反馈暂未确认，当前修改尚未提交。",
};

const normalizeFeedback = (form) => ({
  feedbackType: String(form?.feedbackType || "").trim(),
  feedbackContent: String(form?.feedbackContent || "").trim(),
  contactInfo: String(form?.contactInfo || "").trim(),
});

// 字段顺序固定的快照既用于脏数据判断，也用于阻止非幂等 POST 重复提交。
// 不能改成对象引用比较，否则 Vue 表单原地修改时无法识别同一份内容。
const snapshotOf = (form) => JSON.stringify(normalizeFeedback(form));

const errorMessage = (error) => {
  if (error?.httpStatus === 401) {
    return "登录状态已失效，请重新登录后再提交。";
  }
  return "提交未完成，请稍后再试。";
};

const submitLabelFor = (phase) => {
  if (phase === "submitting") return "正在提交";
  if (phase === "success") return "反馈已提交";
  if (phase === "uncertain") return "暂未确认";
  if (phase === "error") return "重新提交";
  return "提交反馈";
};

export const createFeedbackSubmissionSession = (initialForm) => {
  let baselineSnapshot = snapshotOf(initialForm);
  let lastSubmittedSnapshot = "";
  let lastUncertainSnapshot = "";
  let phase = "ready";
  let message = "";
  let tone = "";

  const view = (currentForm) => {
    const currentSnapshot = snapshotOf(currentForm);
    const isRepeatedSubmission =
      currentSnapshot === lastSubmittedSnapshot ||
      currentSnapshot === lastUncertainSnapshot;
    return {
      phase,
      message,
      tone,
      isDirty: currentSnapshot !== baselineSnapshot,
      isSubmitDisabled: phase === "submitting" || isRepeatedSubmission,
      submitLabel: submitLabelFor(phase),
    };
  };

  const begin = (currentForm) => {
    const currentSnapshot = snapshotOf(currentForm);
    if (
      phase === "submitting" ||
      currentSnapshot === lastSubmittedSnapshot ||
      currentSnapshot === lastUncertainSnapshot
    ) {
      return null;
    }
    phase = "submitting";
    message = "";
    tone = "";
    return {
      snapshot: currentSnapshot,
      payload: normalizeFeedback(currentForm),
    };
  };

  const succeed = (submission, currentForm) => {
    baselineSnapshot = submission.snapshot;
    lastSubmittedSnapshot = submission.snapshot;
    tone = "success";
    if (snapshotOf(currentForm) === submission.snapshot) {
      phase = "success";
      message = messages.submitted;
    } else {
      phase = "ready";
      message = messages.submittedWithEdits;
    }
  };

  const fail = (submission, error, currentForm) => {
    if (!isWriteOutcomeUnknown(error)) {
      phase = "error";
      message = errorMessage(error);
      tone = "error";
      return;
    }

    // 超时或异常 2xx 可能已经被后端写入。记录原快照并禁用原样重试，
    // 避免用户在网络恢复后生成两条内容完全相同的反馈。
    lastUncertainSnapshot = submission.snapshot;
    tone = "uncertain";
    if (snapshotOf(currentForm) === submission.snapshot) {
      phase = "uncertain";
      message = messages.uncertain;
    } else {
      phase = "ready";
      message = messages.uncertainWithEdits;
    }
  };

  const reconcile = (currentForm) => {
    if (phase === "submitting") return;
    const currentSnapshot = snapshotOf(currentForm);
    if (lastSubmittedSnapshot && currentSnapshot === lastSubmittedSnapshot) {
      phase = "success";
      message = messages.submitted;
      tone = "success";
      return;
    }
    if (lastUncertainSnapshot && currentSnapshot === lastUncertainSnapshot) {
      phase = "uncertain";
      message = messages.uncertain;
      tone = "uncertain";
      return;
    }
    phase = "ready";
    if (lastUncertainSnapshot) {
      message = messages.uncertainWithEdits;
      tone = "uncertain";
    } else if (lastSubmittedSnapshot) {
      message = messages.submittedWithEdits;
      tone = "success";
    } else {
      message = "";
      tone = "";
    }
  };

  return { begin, succeed, fail, reconcile, view };
};