// 使用 IIFE 避免重复注入时的变量冲突
(function () {
  // 检查是否已经注入过
  if (window.__PROXYCAST_CONTENT_SCRIPT_LOADED__) {
    return;
  }
  window.__PROXYCAST_CONTENT_SCRIPT_LOADED__ = true;

let refCounter = 0;
const REF_ATTR = "proxycast-id";

function nextRefId() {
  refCounter += 1;
  return `proxycast-${refCounter}`;
}

function resetRefs() {
  refCounter = 0;
  document.querySelectorAll(`[${REF_ATTR}]`).forEach((el) => {
    el.removeAttribute(REF_ATTR);
  });
}

function normalizeText(value) {
  return String(value || "").replace(/\s+/g, " ").trim();
}

function isElementVisible(element) {
  if (!element) {
    return false;
  }
  const style = window.getComputedStyle(element);
  if (
    style.display === "none" ||
    style.visibility === "hidden" ||
    style.opacity === "0"
  ) {
    return false;
  }
  const rect = element.getBoundingClientRect();
  return rect.width > 0 && rect.height > 0;
}

function isInteractiveElement(element) {
  if (!element || !isElementVisible(element)) {
    return false;
  }

  const tag = element.tagName.toLowerCase();
  const role = element.getAttribute("role");
  if (["a", "button", "input", "textarea", "select", "option"].includes(tag)) {
    return true;
  }
  if (
    role &&
    [
      "button",
      "link",
      "checkbox",
      "radio",
      "menuitem",
      "tab",
      "switch",
      "option",
      "searchbox",
      "textbox",
      "combobox",
    ].includes(role)
  ) {
    return true;
  }

  if (element.hasAttribute("onclick")) {
    return true;
  }

  const style = window.getComputedStyle(element);
  return style.cursor === "pointer";
}

function interactiveLabel(element) {
  const tag = element.tagName.toLowerCase();
  const role = element.getAttribute("role");
  const text = normalizeText(
    element.innerText ||
      element.value ||
      element.placeholder ||
      element.getAttribute("aria-label") ||
      element.title ||
      element.name ||
      element.id,
  );

  if (tag === "a") {
    return `链接: ${text || "无标题链接"}`;
  }
  if (tag === "button" || role === "button") {
    return `按钮: ${text || "无标题按钮"}`;
  }
  if (tag === "input" || tag === "textarea") {
    return `输入框: ${text || "未命名输入框"}`;
  }
  if (tag === "select") {
    return `下拉框: ${text || "未命名下拉框"}`;
  }
  return `可交互元素: ${text || tag}`;
}

function buildMarkdown() {
  resetRefs();

  const lines = [];
  lines.push(`# ${document.title || "Untitled"}`);
  lines.push(`URL: ${window.location.href}`);
  lines.push("");

  const bodyText = normalizeText(document.body ? document.body.innerText : "");
  if (bodyText) {
    lines.push("## 页面文本");
    lines.push(bodyText.slice(0, 6000));
    lines.push("");
  }

  lines.push("## 可交互元素");
  const allElements = Array.from(document.querySelectorAll("*")).filter(isInteractiveElement);

  for (const element of allElements.slice(0, 300)) {
    const refId = nextRefId();
    element.setAttribute(REF_ATTR, refId);
    lines.push(`- [${interactiveLabel(element)}](${refId})`);
  }

  return lines.join("\n").trim();
}

function findElement(target) {
  if (!target || typeof target !== "string") {
    return null;
  }
  const trimmed = target.trim();
  if (!trimmed) {
    return null;
  }

  let element = document.querySelector(`[${REF_ATTR}="${CSS.escape(trimmed)}"]`);
  if (element) {
    return element;
  }

  try {
    element = document.querySelector(trimmed);
    if (element) {
      return element;
    }
  } catch (_) {}

  element = Array.from(document.querySelectorAll("button,a,input,textarea,select,[role='button']")).find(
    (candidate) => normalizeText(candidate.innerText || candidate.value || candidate.placeholder || "") === trimmed,
  );
  if (element) {
    return element;
  }

  element = Array.from(document.querySelectorAll("[aria-label]")).find(
    (candidate) => normalizeText(candidate.getAttribute("aria-label")) === trimmed,
  );
  return element || null;
}

function scrollPage(text) {
  const input = normalizeText(text);
  let direction = "down";
  let amount = 500;

  if (input.includes(":")) {
    const parts = input.split(":");
    direction = normalizeText(parts[0]) || "down";
    const parsed = Number(parts[1]);
    if (!Number.isNaN(parsed) && parsed > 0) {
      amount = parsed;
    }
  }

  if (direction === "up") {
    window.scrollBy(0, -amount);
  } else if (direction === "left") {
    window.scrollBy(-amount, 0);
  } else if (direction === "right") {
    window.scrollBy(amount, 0);
  } else {
    window.scrollBy(0, amount);
  }
}

async function executeCommand(commandData) {
  const command = String(commandData.command || "").trim();
  const target = commandData.target;
  const text = commandData.text;

  switch (command) {
    case "click": {
      const element = findElement(target);
      if (!element) {
        return { status: "error", error: `未找到点击目标: ${target}` };
      }
      element.click();
      return { status: "success", message: "click 执行成功" };
    }
    case "type": {
      const element = findElement(target);
      if (!element) {
        return { status: "error", error: `未找到输入目标: ${target}` };
      }
      const value = text == null ? "" : String(text);
      if ("value" in element) {
        element.focus();
        element.value = value;
        element.dispatchEvent(new Event("input", { bubbles: true }));
        element.dispatchEvent(new Event("change", { bubbles: true }));
      } else {
        element.textContent = value;
      }
      return { status: "success", message: "type 执行成功" };
    }
    case "scroll":
    case "scroll_page": {
      scrollPage(text);
      return { status: "success", message: "scroll 执行成功" };
    }
    case "get_page_info": {
      await sendPageInfo("get_page_info");
      return { status: "success", message: "页面信息已回传" };
    }
    case "refresh_page": {
      window.location.reload();
      return { status: "success", message: "页面刷新中" };
    }
    case "go_back": {
      window.history.back();
      return { status: "success", message: "执行后退" };
    }
    case "go_forward": {
      window.history.forward();
      return { status: "success", message: "执行前进" };
    }
    default:
      return { status: "error", error: `不支持的命令: ${command}` };
  }
}

async function sendPageInfo(reason) {
  const markdown = buildMarkdown();
  const payload = {
    type: "PAGE_INFO_UPDATE",
    data: {
      reason,
      title: document.title || "",
      url: window.location.href,
      markdown,
    },
  };
  await chrome.runtime.sendMessage(payload);
}

chrome.runtime.onMessage.addListener((request, _sender, sendResponse) => {
  const type = request?.type;

  if (type === "REQUEST_PAGE_CAPTURE") {
    sendPageInfo(request?.data?.reason || "manual")
      .then(() => sendResponse({ status: "success" }))
      .catch((error) =>
        sendResponse({ status: "error", error: error?.message || String(error) }),
      );
    return true;
  }

  if (type === "EXECUTE_COMMAND") {
    executeCommand(request?.data || {})
      .then(async (result) => {
        if (request?.data?.wait_for_page_info === true) {
          setTimeout(() => {
            sendPageInfo("wait_for_page_info");
          }, 400);
        }
        sendResponse(result);
      })
      .catch((error) =>
        sendResponse({ status: "error", error: error?.message || String(error) }),
      );
    return true;
  }

  return true;
});

setTimeout(() => {
  sendPageInfo("content_script_ready").catch(() => {});
}, 800);

})(); // 结束 IIFE