// content.js — Injected into every page
// Manages the screen selection overlay and sidebar panel

let overlayActive = false;
let sidebarFrame  = null;

// ── Listen for messages from background / popup ───────────────────────────────

chrome.runtime.onMessage.addListener((msg, _sender, sendResponse) => {

  if (msg.type === "START_SELECTION") {
    if (!overlayActive) startSelection();
    sendResponse({ ok: true });
    return false;
  }

  if (msg.type === "SHOW_SIDEBAR") {
    showSidebar({});
    return false;
  }

  if (msg.type === "SHOW_RESULT") {
    showSidebar(msg.data);
    return false;
  }

});

// ── Selection overlay ─────────────────────────────────────────────────────────

function startSelection() {
  overlayActive = true;

  // Dim the page
  const overlay = document.createElement("div");
  overlay.id = "glmocr-overlay";

  // Crosshair hint
  const hint = document.createElement("div");
  hint.id = "glmocr-hint";
  hint.textContent = "Drag to select text region — Press Esc to cancel";
  overlay.appendChild(hint);

  // Selection box
  const selBox = document.createElement("div");
  selBox.id = "glmocr-selbox";
  overlay.appendChild(selBox);

  document.body.appendChild(overlay);

  let startX = 0, startY = 0, isDragging = false;

  function onMouseDown(e) {
    if (e.button !== 0) return;
    isDragging = true;
    startX = e.clientX;
    startY = e.clientY;
    selBox.style.cssText = `left:${startX}px; top:${startY}px; width:0; height:0; display:block`;
    hint.style.opacity = "0";
    e.preventDefault();
  }

  function onMouseMove(e) {
    if (!isDragging) return;
    const x = Math.min(e.clientX, startX);
    const y = Math.min(e.clientY, startY);
    const w = Math.abs(e.clientX - startX);
    const h = Math.abs(e.clientY - startY);
    selBox.style.cssText = `left:${x}px; top:${y}px; width:${w}px; height:${h}px; display:block`;
  }

  function onMouseUp(e) {
    if (!isDragging) return;
    isDragging = false;

    const x = Math.min(e.clientX, startX);
    const y = Math.min(e.clientY, startY);
    const w = Math.abs(e.clientX - startX);
    const h = Math.abs(e.clientY - startY);

    cleanup();

    if (w < 10 || h < 10) {
      showToast("Selection too small — try again.");
      return;
    }

    const dpr = window.devicePixelRatio || 1;
    const rect = {
      x:      x + window.scrollX,
      y:      y + window.scrollY,
      width:  w,
      height: h,
      dpr,
    };

    runOcr(rect);
  }

  function onKeyDown(e) {
    if (e.key === "Escape") {
      cleanup();
      showToast("Cancelled.");
    }
  }

  function cleanup() {
    overlayActive = false;
    overlay.removeEventListener("mousedown", onMouseDown);
    overlay.removeEventListener("mousemove", onMouseMove);
    overlay.removeEventListener("mouseup",   onMouseUp);
    document.removeEventListener("keydown",  onKeyDown);
    overlay.remove();
  }

  overlay.addEventListener("mousedown", onMouseDown);
  overlay.addEventListener("mousemove", onMouseMove);
  overlay.addEventListener("mouseup",   onMouseUp);
  document.addEventListener("keydown",  onKeyDown);
}

// ── Send region to background for capture + OCR ───────────────────────────────

function runOcr(rect) {
  // Show a loading sidebar immediately
  showSidebar({ loading: true });

  chrome.runtime.sendMessage({ type: "CAPTURE_REGION", rect }, (response) => {
    if (chrome.runtime.lastError) {
      showSidebar({ error: chrome.runtime.lastError.message });
      return;
    }
    if (response.success) {
      showSidebar(response);
    } else {
      showSidebar({ error: response.error });
    }
  });
}

// ── Sidebar panel ─────────────────────────────────────────────────────────────

function showSidebar(data) {
  // Remove existing sidebar if any
  if (sidebarFrame) sidebarFrame.remove();

  const frame = document.createElement("iframe");
  frame.id  = "glmocr-sidebar";
  frame.src = chrome.runtime.getURL("sidebar.html");

  document.body.appendChild(frame);
  sidebarFrame = frame;

  // Wait for iframe to load, then send data
  frame.onload = () => {
    frame.contentWindow.postMessage({ type: "SIDEBAR_DATA", data }, "*");
  };

  // Close button via message from sidebar
  window.addEventListener("message", (e) => {
    if (e.data?.type === "CLOSE_SIDEBAR") {
      frame.remove();
      sidebarFrame = null;
    }
    if (e.data?.type === "START_NEW_SELECTION") {
      frame.remove();
      sidebarFrame = null;
      startSelection();
    }
  });
}

// ── Toast notification ────────────────────────────────────────────────────────

function showToast(msg) {
  const existing = document.getElementById("glmocr-toast");
  if (existing) existing.remove();

  const toast = document.createElement("div");
  toast.id = "glmocr-toast";
  toast.textContent = msg;
  document.body.appendChild(toast);
  setTimeout(() => toast?.remove(), 3000);
}