const adminHealthText = document.querySelector("#adminHealthText");
const refreshBtn = document.querySelector("#refreshBtn");
const panels = {
  accounts: document.querySelector("#accountsPanel"),
  reviews: document.querySelector("#reviewsPanel"),
  register: document.querySelector("#registerPanel"),
};
const accountForm = document.querySelector("#accountForm");
const accountQuery = document.querySelector("#accountQuery");
const accountStatus = document.querySelector("#accountStatus");
const accountMeta = document.querySelector("#accountMeta");
const accountRows = document.querySelector("#accountRows");
const accountEditor = document.querySelector("#accountEditor");
const accountEditorTitle = document.querySelector("#accountEditorTitle");
const accountEditForm = document.querySelector("#accountEditForm");
const accountEditError = document.querySelector("#accountEditError");
const cancelAccountEditBtn = document.querySelector("#cancelAccountEditBtn");
const newAccountBtn = document.querySelector("#newAccountBtn");
const editStudentId = document.querySelector("#editStudentId");
const editStudent = document.querySelector("#editStudent");
const editRemaining = document.querySelector("#editRemaining");
const editStatus = document.querySelector("#editStatus");
const editPayments = document.querySelector("#editPayments");
const editNote = document.querySelector("#editNote");
const reviewStatus = document.querySelector("#reviewStatus");
const reviewMeta = document.querySelector("#reviewMeta");
const reviewRows = document.querySelector("#reviewRows");
const classRegisterForm = document.querySelector("#classRegisterForm");
const classRegisterLines = document.querySelector("#classRegisterLines");
const classRegisterStatus = document.querySelector("#classRegisterStatus");
const paymentRegisterForm = document.querySelector("#paymentRegisterForm");
const paymentRegisterLines = document.querySelector("#paymentRegisterLines");
const paymentRegisterStatus = document.querySelector("#paymentRegisterStatus");

let currentAccounts = [];
let editingAccountId = "";

function fmtHours(value) {
  return Number(value || 0).toLocaleString("zh-CN", { maximumFractionDigits: 2 });
}

function fmtTime(seconds) {
  if (!seconds) return "未知";
  return new Date(seconds * 1000).toLocaleString("zh-CN", { hour12: false });
}

function escapeHtml(value) {
  return String(value ?? "")
    .replaceAll("&", "&")
    .replaceAll("<", "&lt;")
    .replaceAll(">", "&gt;")
    .replaceAll('"', "&quot;")
    .replaceAll("'", "&#039;");
}

function metric(label, value) {
  return `<div class="metric"><span>${escapeHtml(label)}</span><strong>${escapeHtml(value)}</strong></div>`;
}

function statusClass(status) {
  if (status === "欠费") return "debt";
  if (status === "预警") return "warning";
  if (status === "正常") return "normal";
  return "closed";
}

function renderPayments(payments) {
  if (!payments.length) return "暂无";
  return payments.map((item) => `${escapeHtml(item.date)}：${fmtHours(item.hours)} 小时`).join("<br>");
}

async function fetchJson(url, options = {}) {
  const response = await fetch(url, { cache: "no-store", ...options });
  if (!response.ok) {
    let detail = `${response.status} ${response.statusText}`;
    try {
      const payload = await response.json();
      detail = payload.detail || detail;
    } catch (_error) {
      detail = response.statusText || detail;
    }
    throw new Error(detail);
  }
  return response.json();
}

function setActiveTab(tabName) {
  document.querySelectorAll("[data-admin-tab]").forEach((button) => {
    button.classList.toggle("is-active", button.dataset.adminTab === tabName);
  });
  Object.entries(panels).forEach(([name, panel]) => {
    panel.hidden = name !== tabName;
  });
  if (tabName === "accounts") loadAccounts();
  if (tabName === "reviews") loadReviews();
}

async function loadAdminHealth() {
  try {
    const data = await fetchJson("/api/account-health");
    adminHealthText.textContent = `账户 ${data.accounts_count} 人；数据更新时间 ${fmtTime(data.accounts.mtime)}`;
  } catch (error) {
    adminHealthText.textContent = `读取失败：${error.message}`;
  }
}

function renderAccountSummary(summary, count) {
  accountMeta.innerHTML = [
    metric("当前结果", `${count} 人`),
    metric("欠费", summary.debt),
    metric("预警", summary.warning),
    metric("正常", summary.normal),
  ].join("");
}

async function loadAccounts() {
  accountRows.innerHTML = `<tr><td colspan="6" class="empty">正在读取</td></tr>`;
  const params = new URLSearchParams();
  if (accountQuery.value.trim()) params.set("q", accountQuery.value.trim());
  if (accountStatus.value) params.set("status", accountStatus.value);
  try {
    const data = await fetchJson(`/api/accounts?${params.toString()}`);
    currentAccounts = data.accounts;
    renderAccountSummary(data.summary, data.count);
    accountRows.innerHTML = data.accounts
      .map(
        (row) => `<tr>
          <td>${escapeHtml(row.student)}<br><small>${escapeHtml(row.student_id)}</small></td>
          <td><span class="status ${statusClass(row.account_status)}">${escapeHtml(row.account_status)}</span></td>
          <td class="num">${fmtHours(row.remaining)}</td>
          <td>${renderPayments(row.payments)}</td>
          <td class="note-cell">${escapeHtml(row.note || "")}</td>
          <td><button class="small-button account-edit" type="button" data-student-id="${escapeHtml(row.student_id)}">编辑</button></td>
        </tr>`,
      )
      .join("");
    if (!data.accounts.length) {
      accountRows.innerHTML = `<tr><td colspan="6" class="empty">没有符合条件的账户</td></tr>`;
    }
  } catch (error) {
    accountRows.innerHTML = `<tr><td colspan="6" class="empty">读取失败：${escapeHtml(error.message)}</td></tr>`;
  }
}

function paymentsToText(payments) {
  return payments.map((item) => `${item.date}:${item.hours}`).join("\n");
}

function parsePaymentsInput(value) {
  return value
    .split(/[\n,]+/)
    .map((item) => item.trim())
    .filter(Boolean)
    .map((item) => {
      const [date, hoursText] = item.split(":");
      if (!date || hoursText === undefined) {
        throw new Error(`缴费记录格式错误：${item}`);
      }
      const hours = Number(hoursText);
      if (!Number.isFinite(hours)) {
        throw new Error(`缴费课时格式错误：${item}`);
      }
      return { date: date.trim(), hours };
    });
}

function openNewAccountEditor() {
  editingAccountId = "";
  accountEditorTitle.textContent = "新增账户";
  editStudentId.value = "";
  editStudentId.placeholder = "保存时自动生成";
  editStudent.value = "";
  editRemaining.value = "0";
  editStatus.value = "正常";
  editPayments.value = "";
  editNote.value = "";
  accountEditError.hidden = true;
  accountEditor.hidden = false;
  editStudent.focus();
}

function openEditAccountEditor(studentId) {
  const account = currentAccounts.find((item) => item.student_id === studentId);
  if (!account) return;
  editingAccountId = account.student_id;
  accountEditorTitle.textContent = `编辑账户：${account.student}`;
  editStudentId.value = account.student_id;
  editStudentId.placeholder = "";
  editStudent.value = account.student;
  editRemaining.value = account.remaining;
  editStatus.value = account.account_status;
  editPayments.value = paymentsToText(account.payments);
  editNote.value = account.note || "";
  accountEditError.hidden = true;
  accountEditor.hidden = false;
  editStudent.focus();
}

function buildAccountPayload() {
  const remaining = Number(editRemaining.value);
  if (!Number.isFinite(remaining)) {
    throw new Error("剩余课时必须是数字");
  }
  return {
    student_id: editStudentId.value.trim(),
    student: editStudent.value.trim(),
    payments: parsePaymentsInput(editPayments.value),
    remaining,
    account_status: editStatus.value,
    note: editNote.value.trim(),
  };
}

async function saveAccount(event) {
  event.preventDefault();
  try {
    const payload = buildAccountPayload();
    const url = editingAccountId
      ? `/api/admin/accounts/${encodeURIComponent(editingAccountId)}`
      : "/api/admin/accounts";
    const method = editingAccountId ? "PUT" : "POST";
    await fetchJson(url, {
      method,
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    accountEditor.hidden = true;
    await loadAdminHealth();
    await loadAccounts();
  } catch (error) {
    accountEditError.textContent = error.message;
    accountEditError.hidden = false;
  }
}

function renderReviewLine(line) {
  return `<code class="line-code">${escapeHtml(line)}</code>`;
}

async function loadReviews() {
  reviewRows.innerHTML = `<tr><td colspan="6" class="empty">正在读取</td></tr>`;
  const params = new URLSearchParams({ type: "class_record_correction" });
  if (reviewStatus.value) params.set("status", reviewStatus.value);
  try {
    const data = await fetchJson(`/api/admin/tasks?${params.toString()}`);
    reviewMeta.innerHTML = [metric("当前结果", `${data.count} 条`)].join("");
    reviewRows.innerHTML = data.items
      .map((item) => {
        const canReview = item.status === "pending" || item.status === "conflict";
        return `<tr>
          <td>#${escapeHtml(item.id)}</td>
          <td><span class="status ${item.status === "approved" ? "normal" : item.status === "rejected" ? "closed" : item.status === "conflict" ? "debt" : "warning"}">${escapeHtml(item.status)}</span>${item.message ? `<br><small>${escapeHtml(item.message)}</small>` : ""}</td>
          <td>${renderReviewLine(item.original_line)}</td>
          <td>${renderReviewLine(item.corrected_line)}</td>
          <td>${escapeHtml(item.created_at || "")}</td>
          <td class="record-action-cell">
            <div class="record-actions">
              <button class="small-button review-approve" type="button" data-task-id="${escapeHtml(item.id)}" ${canReview ? "" : "disabled"}>批准</button>
              <button class="small-button review-reject" type="button" data-task-id="${escapeHtml(item.id)}" ${canReview ? "" : "disabled"}>驳回</button>
            </div>
          </td>
        </tr>`;
      })
      .join("");
    if (!data.items.length) {
      reviewRows.innerHTML = `<tr><td colspan="6" class="empty">没有符合条件的审核项</td></tr>`;
    }
  } catch (error) {
    reviewRows.innerHTML = `<tr><td colspan="6" class="empty">读取失败：${escapeHtml(error.message)}</td></tr>`;
  }
}

async function reviewTask(taskId, action) {
  try {
    await fetchJson(`/api/admin/tasks/${encodeURIComponent(taskId)}/${action}`, { method: "POST" });
  } catch (error) {
    alert(error.message);
  }
  loadReviews();
}

function linesFromTextarea(textarea) {
  return textarea.value
    .split("\n")
    .map((line) => line.trim())
    .filter(Boolean);
}

async function submitRegister(event, textarea, statusNode, url) {
  event.preventDefault();
  statusNode.textContent = "正在提交";
  try {
    const data = await fetchJson(url, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ lines: linesFromTextarea(textarea) }),
    });
    statusNode.textContent = `已登记 ${data.registered} 条；备份 ${data.backup_id}`;
    textarea.value = "";
    await loadAdminHealth();
    await loadAccounts();
  } catch (error) {
    statusNode.textContent = `提交失败：${error.message}`;
  }
}

document.querySelectorAll("[data-admin-tab]").forEach((button) => {
  button.addEventListener("click", () => setActiveTab(button.dataset.adminTab));
});

accountForm.addEventListener("submit", (event) => {
  event.preventDefault();
  loadAccounts();
});
accountStatus.addEventListener("change", loadAccounts);
newAccountBtn.addEventListener("click", openNewAccountEditor);
cancelAccountEditBtn.addEventListener("click", () => {
  accountEditor.hidden = true;
});
accountEditForm.addEventListener("submit", saveAccount);
accountRows.addEventListener("click", (event) => {
  const button = event.target.closest(".account-edit");
  if (!button) return;
  openEditAccountEditor(button.dataset.studentId);
});
reviewStatus.addEventListener("change", loadReviews);
reviewRows.addEventListener("click", (event) => {
  const approve = event.target.closest(".review-approve");
  const reject = event.target.closest(".review-reject");
  if (approve) reviewTask(approve.dataset.taskId, "approve");
  if (reject) reviewTask(reject.dataset.taskId, "reject");
});
classRegisterForm.addEventListener("submit", (event) => {
  submitRegister(event, classRegisterLines, classRegisterStatus, "/api/register/class-records");
});
paymentRegisterForm.addEventListener("submit", (event) => {
  submitRegister(event, paymentRegisterLines, paymentRegisterStatus, "/api/register/payments");
});
refreshBtn.addEventListener("click", () => {
  loadAdminHealth();
  if (!panels.accounts.hidden) loadAccounts();
  if (!panels.reviews.hidden) loadReviews();
});

loadAdminHealth();
loadAccounts();