const state = {
  history: [],
  lastTables: []
};

const els = {
  messages: document.querySelector("#messages"),
  form: document.querySelector("#chatForm"),
  input: document.querySelector("#messageInput"),
  inputCount: document.querySelector("#inputCount"),
  sendBtn: document.querySelector("#sendBtn"),
  statusDot: document.querySelector("#statusDot"),
  sessionStatus: document.querySelector("#sessionStatus"),
  mcpStatus: document.querySelector("#mcpStatus"),
  mcpEndpoint: document.querySelector("#mcpEndpoint"),
  toolCount: document.querySelector("#toolCount"),
  toolList: document.querySelector("#toolList"),
  traceList: document.querySelector("#traceList"),
  refreshBtn: document.querySelector("#refreshBtn")
};

boot();

function boot() {
  addAssistantMessage(
    "你好，我是市民请集合智能助手 Web 测试版。你可以直接问业务系统里的订单、商品、会员、月结等问题，我会通过 MCP 工具查询后再回答。"
  );
  bindEvents();
  refreshStatus();
}

function bindEvents() {
  els.form.addEventListener("submit", (event) => {
    event.preventDefault();
    sendMessage();
  });
  els.input.addEventListener("input", () => {
    els.inputCount.textContent = `${els.input.value.trim().length} 字`;
  });
  els.input.addEventListener("keydown", (event) => {
    if (event.key === "Enter" && (event.ctrlKey || event.metaKey)) {
      event.preventDefault();
      sendMessage();
    }
  });
  els.refreshBtn.addEventListener("click", refreshStatus);
  document.querySelector("[data-scroll-tools]").addEventListener("click", () => {
    document.querySelector("#toolsPanel").scrollIntoView({ behavior: "smooth" });
  });
  document.querySelector("[data-scroll-trace]").addEventListener("click", () => {
    document.querySelector("#tracePanel").scrollIntoView({ behavior: "smooth" });
  });
}

async function refreshStatus() {
  setStatus("checking", "检查中", "MCP 连接检测中");
  try {
    const health = await getJson("/api/health");
    const tools = await getJson("/api/tools");
    const mcp = health.mcp || {};
    els.mcpEndpoint.textContent = mcp.path ? `${mcp.name || "mcp"} ${mcp.path}` : "-";
    els.toolCount.textContent = `${tools.tools?.length || 0} 个`;
    renderTools(tools.tools || []);
    if (health.ok) {
      setStatus("ok", "已连接", `${mcp.environmentName || "MCP"} 可用`);
    } else {
      setStatus("error", "未连接", mcp.message || "MCP 不可用");
    }
  } catch (error) {
    setStatus("error", "未连接", error.message || "状态检查失败");
  }
}

function setStatus(mode, title, detail) {
  els.statusDot.classList.toggle("ok", mode === "ok");
  els.statusDot.classList.toggle("error", mode === "error");
  els.sessionStatus.textContent = title;
  els.mcpStatus.textContent = detail;
}

async function sendMessage() {
  const message = els.input.value.trim();
  if (!message) {
    return;
  }

  addUserMessage(message);
  els.input.value = "";
  els.inputCount.textContent = "0 字";
  setBusy(true);
  const thinkingId = addThinkingMessage();

  try {
    const response = await postJson("/api/chat", {
      message,
      history: state.history.slice(-12)
    });
    removeMessage(thinkingId);
    if (!response.ok) {
      throw new Error(response.message || "请求失败");
    }
    const result = response.result;
    addAssistantMessage(result.content, result.tables || []);
    renderTrace(result.trace || [], result.toolCalls || []);
    state.history.push({ role: "user", content: message });
    state.history.push({ role: "assistant", content: result.content });
  } catch (error) {
    removeMessage(thinkingId);
    addAssistantMessage(`暂时无法完成：${error.message || error}`);
  } finally {
    setBusy(false);
  }
}

function setBusy(busy) {
  els.sendBtn.disabled = busy;
  els.sendBtn.querySelector(".send-text").textContent = busy ? "处理中" : "发送";
}

function addUserMessage(content) {
  appendMessage({ role: "user", content });
}

function addAssistantMessage(content, tables = []) {
  appendMessage({ role: "assistant", content, tables });
}

function addThinkingMessage() {
  const id = `msg-${Date.now()}-${Math.random().toString(16).slice(2)}`;
  appendMessage({
    id,
    role: "assistant",
    content: '<span class="typing">正在处理 <i></i><i></i><i></i></span>',
    trustedHtml: true
  });
  return id;
}

function removeMessage(id) {
  const node = document.querySelector(`[data-message-id="${id}"]`);
  node?.remove();
}

function appendMessage({ id = "", role, content, tables = [], trustedHtml = false }) {
  const row = document.createElement("div");
  row.className = `message-row ${role}`;
  if (id) {
    row.dataset.messageId = id;
  }

  const avatar = document.createElement("div");
  avatar.className = "avatar";
  if (role === "assistant") {
    const img = document.createElement("img");
    img.src = "/assets/logo.png";
    img.alt = "";
    avatar.appendChild(img);
  } else {
    avatar.textContent = "我";
  }

  const bubble = document.createElement("div");
  bubble.className = "bubble";
  if (trustedHtml) {
    bubble.innerHTML = content;
  } else {
    bubble.textContent = content;
  }

  if (tables.length) {
    state.lastTables = tables;
    tables.forEach((table, index) => {
      bubble.appendChild(renderTable(table, index));
    });
  }

  row.append(avatar, bubble);
  els.messages.appendChild(row);
  els.messages.scrollTop = els.messages.scrollHeight;
}

function renderTable(table, index) {
  const card = document.createElement("div");
  card.className = "table-card";

  const head = document.createElement("div");
  head.className = "table-head";
  const title = document.createElement("strong");
  title.textContent = table.title || "结果表格";
  const download = document.createElement("button");
  download.type = "button";
  download.textContent = "下载 CSV";
  download.addEventListener("click", () => downloadCsv(table, index));
  head.append(title, download);

  const wrap = document.createElement("div");
  wrap.className = "table-wrap";
  const el = document.createElement("table");
  const thead = document.createElement("thead");
  const tr = document.createElement("tr");
  for (const column of table.columns || []) {
    const th = document.createElement("th");
    th.textContent = column;
    tr.appendChild(th);
  }
  thead.appendChild(tr);
  el.appendChild(thead);

  const tbody = document.createElement("tbody");
  for (const row of table.rows || []) {
    const bodyTr = document.createElement("tr");
    for (const column of table.columns || []) {
      const td = document.createElement("td");
      td.textContent = row[column] ?? "";
      bodyTr.appendChild(td);
    }
    tbody.appendChild(bodyTr);
  }
  el.appendChild(tbody);
  wrap.appendChild(el);
  card.append(head, wrap);
  return card;
}

function downloadCsv(table, index) {
  const rows = [
    table.columns,
    ...(table.rows || []).map((row) => table.columns.map((column) => row[column] ?? ""))
  ];
  const csv = rows.map((row) => row.map(csvCell).join(",")).join("\r\n");
  const blob = new Blob(["\ufeff", csv], { type: "text/csv;charset=utf-8" });
  const url = URL.createObjectURL(blob);
  const link = document.createElement("a");
  link.href = url;
  link.download = `${safeFileName(table.title || "agent-table")}-${index + 1}.csv`;
  link.click();
  URL.revokeObjectURL(url);
}

function csvCell(value) {
  const text = String(value ?? "");
  return `"${text.replace(/"/g, '""')}"`;
}

function safeFileName(value) {
  return String(value).replace(/[\\/:*?"<>|]+/g, "_").slice(0, 60);
}

function renderTools(tools) {
  els.toolList.innerHTML = "";
  for (const tool of tools) {
    const item = document.createElement("div");
    item.className = "tool-item";
    const title = document.createElement("strong");
    title.textContent = tool.title || tool.name;
    const desc = document.createElement("span");
    desc.textContent = `${tool.name}${tool.description ? ` · ${tool.description}` : ""}`;
    item.append(title, desc);
    els.toolList.appendChild(item);
  }
}

function renderTrace(trace, toolCalls) {
  els.traceList.innerHTML = "";
  const rows = trace.length ? trace : toolCalls.map((item) => ({
    phase: item.ok ? "tool" : "error",
    title: item.name,
    detail: item.error || `${item.durationMs || 0}ms`
  }));

  for (const item of rows.slice(-12).reverse()) {
    const node = document.createElement("div");
    node.className = `trace-item phase-${item.phase}`;
    const title = document.createElement("strong");
    title.textContent = item.title || item.phase;
    const detail = document.createElement("span");
    detail.textContent = item.detail || item.at || "";
    node.append(title, detail);
    els.traceList.appendChild(node);
  }
}

async function getJson(url) {
  const response = await fetch(url);
  const payload = await response.json();
  if (!response.ok) {
    throw new Error(payload.message || `HTTP ${response.status}`);
  }
  return payload;
}

async function postJson(url, body) {
  const response = await fetch(url, {
    method: "POST",
    headers: {
      "Content-Type": "application/json"
    },
    body: JSON.stringify(body)
  });
  const payload = await response.json();
  if (!response.ok) {
    throw new Error(payload.message || `HTTP ${response.status}`);
  }
  return payload;
}