const state = {
  sessions: [],
  messages: [],
  tasks: [],
  approvals: [],
  workers: [],
  events: [],
  selectedSessionId: null,
};

const elements = {
  sessionList: document.querySelector("#session-list"),
  workerList: document.querySelector("#worker-list"),
  messageList: document.querySelector("#message-list"),
  taskList: document.querySelector("#task-list"),
  approvalList: document.querySelector("#approval-list"),
  eventList: document.querySelector("#event-list"),
  planHint: document.querySelector("#plan-hint"),
  sessionTitleDisplay: document.querySelector("#session-title-display"),
  sessionSummary: document.querySelector("#session-summary"),
  createSessionForm: document.querySelector("#create-session-form"),
  sessionTitleInput: document.querySelector("#session-title"),
  createWorkerForm: document.querySelector("#create-worker-form"),
  workerName: document.querySelector("#worker-name"),
  workerOs: document.querySelector("#worker-os"),
  workerCapabilities: document.querySelector("#worker-capabilities"),
  messageForm: document.querySelector("#message-form"),
  messageInput: document.querySelector("#message-input"),
  resetDemo: document.querySelector("#reset-demo"),
  archiveSession: document.querySelector("#archive-session"),
};

function escapeHtml(input) {
  return String(input)
    .replaceAll("&", "&")
    .replaceAll("<", "&lt;")
    .replaceAll(">", "&gt;")
    .replaceAll('"', "&quot;")
    .replaceAll("'", "&#39;");
}

async function request(url, options = {}) {
  const response = await fetch(url, {
    headers: { "Content-Type": "application/json" },
    ...options,
  });

  let payload = {};
  try {
    payload = await response.json();
  } catch {
    payload = {};
  }

  if (!response.ok) {
    throw new Error(payload.error || `${response.status} ${response.statusText}`);
  }

  return payload;
}

function selectedSession() {
  return state.sessions.find((session) => session.id === state.selectedSessionId) ?? null;
}

function tasksForSelectedSession() {
  return state.tasks.filter((task) => task.sessionId === state.selectedSessionId);
}

function messagesForSelectedSession() {
  return state.messages.filter((message) => message.sessionId === state.selectedSessionId);
}

function approvalsForSelectedSession() {
  return state.approvals.filter((approval) => approval.sessionId === state.selectedSessionId);
}

function eventsForSelectedSession() {
  return state.events
    .filter((event) => event.sessionId === null || event.sessionId === state.selectedSessionId)
    .slice(-50)
    .reverse();
}

function renderSessions() {
  if (state.sessions.length === 0) {
    elements.sessionList.innerHTML = `<p class="muted">先创建一个项目会话。</p>`;
    return;
  }

  elements.sessionList.innerHTML = state.sessions
    .map((session) => {
      const active = session.id === state.selectedSessionId ? "active" : "";
      const archived = session.status === "archived" ? "archived" : "";
      return `
        <button class="session-item ${active} ${archived}" data-session-id="${session.id}">
          <strong>${escapeHtml(session.title)}</strong>
          <span>${escapeHtml(session.activeObjective || "暂无目标")}</span>
          <span class="muted">${escapeHtml(session.status)}</span>
        </button>
      `;
    })
    .join("");

  elements.sessionList.querySelectorAll("[data-session-id]").forEach((button) => {
    button.addEventListener("click", async () => {
      state.selectedSessionId = button.dataset.sessionId;
      await loadSession(state.selectedSessionId);
      render();
    });
  });
}

function renderWorkers() {
  if (state.workers.length === 0) {
    elements.workerList.innerHTML = `<p class="muted">还没有 worker。可以手动注册，或直接运行 \`npm run demo\`。</p>`;
    return;
  }

  elements.workerList.innerHTML = state.workers
    .map(
      (worker) => `
        <div class="card">
          <div class="row between">
            <strong>${escapeHtml(worker.name)}</strong>
            <span class="badge ${worker.status}">${escapeHtml(worker.status)}</span>
          </div>
          <div class="muted">${escapeHtml(worker.os)}</div>
          <div class="muted">current: ${escapeHtml(worker.currentTaskId || "idle")}</div>
          <div class="muted">last seen: ${new Date(worker.lastSeenAt).toLocaleTimeString()}</div>
          <div class="tags">
            ${worker.capabilities.map((capability) => `<span>${escapeHtml(capability)}</span>`).join("")}
          </div>
        </div>
      `,
    )
    .join("");
}

function renderSessionHeader() {
  const session = selectedSession();
  if (!session) {
    elements.sessionTitleDisplay.textContent = "选择一个项目会话";
    elements.sessionSummary.textContent = "创建会话后，在这里持续对话并观察任务状态。";
    elements.archiveSession.disabled = true;
    elements.messageInput.disabled = true;
    elements.messageInput.placeholder = "先创建或选择一个项目会话。";
    return;
  }

  elements.sessionTitleDisplay.textContent = `${session.title} (${session.status})`;
  elements.sessionSummary.textContent =
    session.lastPlannerSummary || session.activeObjective || "等待用户输入。";
  elements.archiveSession.disabled = session.status === "archived";
  elements.messageInput.disabled = session.status === "archived";
  elements.messageInput.placeholder =
    session.status === "archived"
      ? "当前会话已归档，不能继续发送消息。"
      : "输入需求。示例：先调研登录失败根因，不要急着改代码。";
}

function renderMessages() {
  const messages = messagesForSelectedSession();
  elements.messageList.innerHTML = messages.length
    ? messages
        .map(
          (message) => `
            <article class="message ${message.role}">
              <header>
                <strong>${escapeHtml(message.role)}</strong>
                <span>${new Date(message.createdAt).toLocaleTimeString()}</span>
              </header>
              <p>${escapeHtml(message.content)}</p>
            </article>
          `,
        )
        .join("")
    : `<p class="muted">当前没有消息。</p>`;
}

function renderTasks() {
  const latestPlan = [...state.events]
    .reverse()
    .find((event) => event.sessionId === state.selectedSessionId && event.type === "plan.created");
  if (latestPlan) {
    const pausedCount = Array.isArray(latestPlan.payload.pausedTaskIds)
      ? latestPlan.payload.pausedTaskIds.length
      : 0;
    elements.planHint.textContent = `最新计划创建了 ${latestPlan.payload.taskIds.length} 个任务，自动暂停旧任务 ${pausedCount} 个。`;
  } else {
    elements.planHint.textContent = "";
  }

  const tasks = tasksForSelectedSession();
  elements.taskList.innerHTML = tasks.length
    ? tasks
        .map(
          (task) => `
            <div class="card">
              <div class="row between">
                <strong>${escapeHtml(task.title)}</strong>
                <span class="badge ${task.status}">${escapeHtml(task.status)}</span>
              </div>
              <p>${escapeHtml(task.description)}</p>
              <div class="muted">worker: ${escapeHtml(task.assignedWorkerId || "未分配")}</div>
              <div class="muted">progress: ${task.progressPercent}%</div>
              <div class="muted">summary: ${escapeHtml(task.summary || "暂无")}</div>
              <div class="muted">next: ${escapeHtml(task.nextStep || "暂无")}</div>
              <div class="actions">
                ${
                  ["queued", "assigned", "running"].includes(task.status)
                    ? `<button data-action="pause" data-task-id="${task.id}" class="ghost">暂停</button>`
                    : ""
                }
                ${
                  ["paused", "blocked"].includes(task.status)
                    ? `<button data-action="resume" data-task-id="${task.id}" class="ghost">续跑</button>`
                    : ""
                }
                ${
                  !["completed", "cancelled", "failed"].includes(task.status)
                    ? `<button data-action="cancel" data-task-id="${task.id}" class="ghost danger">取消</button>`
                    : ""
                }
              </div>
            </div>
          `,
        )
        .join("")
    : `<p class="muted">当前没有任务。</p>`;

  elements.taskList.querySelectorAll("[data-action]").forEach((button) => {
    button.addEventListener("click", async () => {
      const taskId = button.dataset.taskId;
      const action = button.dataset.action;
      await request(`/api/tasks/${taskId}/${action}`, { method: "POST", body: "{}" });
      await loadSession(state.selectedSessionId);
      await loadBootstrap();
      render();
    });
  });
}

function renderApprovals() {
  const approvals = approvalsForSelectedSession();
  elements.approvalList.innerHTML = approvals.length
    ? approvals
        .map(
          (approval) => `
            <div class="card">
              <div class="row between">
                <strong>${escapeHtml(approval.summary)}</strong>
                <span class="badge ${approval.status}">${escapeHtml(approval.status)}</span>
              </div>
              <div class="muted">risk: ${escapeHtml(approval.riskLevel)}</div>
              <div class="actions">
                <button data-approval-id="${approval.id}" data-approved="true">批准</button>
                <button data-approval-id="${approval.id}" data-approved="false" class="ghost danger">拒绝</button>
              </div>
            </div>
          `,
        )
        .join("")
    : `<p class="muted">当前没有待审批项。</p>`;

  elements.approvalList.querySelectorAll("[data-approval-id]").forEach((button) => {
    button.addEventListener("click", async () => {
      const approvalId = button.dataset.approvalId;
      const approved = button.dataset.approved === "true";
      await request(`/api/approvals/${approvalId}/respond`, {
        method: "POST",
        body: JSON.stringify({ approved, responder: "web-user" }),
      });
      await loadSession(state.selectedSessionId);
      await loadBootstrap();
      render();
    });
  });
}

function renderEvents() {
  const events = eventsForSelectedSession();
  elements.eventList.innerHTML = events.length
    ? events
        .map(
          (event) => `
            <article class="event">
              <header>
                <strong>${escapeHtml(event.type)}</strong>
                <span>${new Date(event.timestamp).toLocaleTimeString()}</span>
              </header>
              <pre>${escapeHtml(JSON.stringify(event.payload, null, 2))}</pre>
            </article>
          `,
        )
        .join("")
    : `<p class="muted">当前没有事件。</p>`;
}

function render() {
  renderSessions();
  renderWorkers();
  renderSessionHeader();
  renderMessages();
  renderTasks();
  renderApprovals();
  renderEvents();
}

async function loadBootstrap() {
  const bootstrap = await request("/api/bootstrap");
  state.sessions = bootstrap.sessions;
  state.messages = bootstrap.messages;
  state.tasks = bootstrap.tasks;
  state.workers = bootstrap.workers;
  state.approvals = bootstrap.approvals;
  state.events = bootstrap.events;
  if (!state.selectedSessionId && state.sessions[0]) {
    state.selectedSessionId = state.sessions[0].id;
  }
}

async function loadSession(sessionId) {
  if (!sessionId) return;
  const details = await request(`/api/sessions/${sessionId}`);
  state.sessions = state.sessions.map((session) => (session.id === sessionId ? details.session : session));
  state.messages = [
    ...state.messages.filter((message) => message.sessionId !== sessionId),
    ...details.messages,
  ];
  state.tasks = [
    ...state.tasks.filter((task) => task.sessionId !== sessionId),
    ...details.tasks,
  ];
  state.approvals = [
    ...state.approvals.filter((approval) => approval.sessionId !== sessionId),
    ...details.approvals,
  ];
}

elements.createSessionForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  const title = elements.sessionTitleInput.value.trim();
  const details = await request("/api/sessions", {
    method: "POST",
    body: JSON.stringify({ title }),
  });
  state.sessions.unshift(details.session);
  state.selectedSessionId = details.session.id;
  await loadSession(details.session.id);
  elements.sessionTitleInput.value = "";
  render();
});

elements.createWorkerForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  const name = elements.workerName.value.trim();
  if (!name) return;
  const os = elements.workerOs.value;
  const capabilities = elements.workerCapabilities.value
    .split(",")
    .map((item) => item.trim())
    .filter(Boolean);
  await request("/api/workers/register", {
    method: "POST",
    body: JSON.stringify({ name, os, capabilities }),
  });
  elements.workerName.value = "";
  elements.workerCapabilities.value = "terminal";
  await loadBootstrap();
  render();
});

elements.messageForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  if (!state.selectedSessionId) return;
  const content = elements.messageInput.value.trim();
  if (!content) return;
  await request(`/api/sessions/${state.selectedSessionId}/messages`, {
    method: "POST",
    body: JSON.stringify({ content, channel: "web" }),
  });
  elements.messageInput.value = "";
  await loadSession(state.selectedSessionId);
  await loadBootstrap();
  render();
});

elements.archiveSession.addEventListener("click", async () => {
  if (!state.selectedSessionId) return;
  await request(`/api/sessions/${state.selectedSessionId}/archive`, {
    method: "POST",
    body: "{}",
  });
  await loadSession(state.selectedSessionId);
  await loadBootstrap();
  render();
});

elements.resetDemo.addEventListener("click", async () => {
  await request("/api/demo/reset", { method: "POST", body: "{}" });
  state.sessions = [];
  state.messages = [];
  state.tasks = [];
  state.workers = [];
  state.approvals = [];
  state.events = [];
  state.selectedSessionId = null;
  render();
});

const stream = new EventSource("/api/events/stream");
stream.onmessage = async (event) => {
  const payload = JSON.parse(event.data);
  state.events.push(payload);
  if (payload.sessionId) {
    await loadSession(payload.sessionId);
  }
  await loadBootstrap();
  render();
};

loadBootstrap().then(render).catch((error) => {
  console.error(error);
  elements.sessionSummary.textContent = error.message;
});