// ──────────────────────────────────────────────────────────
// ErpAttachViewer — 첨부 모달
//   사용:
//     ErpAttachViewer.openFor(itemId, { title })
//   동작:
//     - GET /expense/api/items/{itemId}/attachments
//     - 이미지: 캔버스 위 펜 주석, 다운로드(원본+주석 합성)
//     - 비이미지: 새 창 다운로드 링크
// ──────────────────────────────────────────────────────────

(function () {
  if (window.ErpAttachViewer) return;

  const IMG_EXTS = new Set(["png", "jpg", "jpeg", "gif", "webp", "bmp"]);
  const COLORS = ["#c22b10", "#0a0a0a", "#1d4ed8", "#10c22b"];
  const SIZES = [2, 4, 8];

  let overlay = null;
  let state = {
    items: [],
    currentIdx: -1,
    tool: "pen",          // pen | erase
    color: COLORS[0],
    size: SIZES[1],
    drawing: false,
    last: null,
    title: "",
  };

  function ensureOverlay() {
    if (overlay) return overlay;
    overlay = document.createElement("div");
    overlay.className = "eav-overlay";
    overlay.innerHTML = `
      <div class="eav-modal" role="dialog" aria-modal="true">
        <div class="eav-head">
          <div class="eav-title" data-role="title">첨부 보기</div>
          <div class="eav-toolbar" data-role="toolbar"></div>
          <button class="eav-close" data-role="close" aria-label="닫기">✕</button>
        </div>
        <div class="eav-body">
          <div class="eav-list" data-role="list"></div>
          <div class="eav-canvas-wrap" data-role="stage"></div>
        </div>
      </div>
    `;
    document.body.appendChild(overlay);

    overlay.addEventListener("click", (e) => {
      if (e.target === overlay) close();
    });
    overlay.querySelector('[data-role="close"]').addEventListener("click", close);
    document.addEventListener("keydown", (e) => {
      if (overlay.dataset.open === "true" && e.key === "Escape") close();
    });
    return overlay;
  }

  function buildToolbar() {
    const tb = overlay.querySelector('[data-role="toolbar"]');
    tb.innerHTML = "";

    const tools = [
      { key: "pen", label: "✏️ 펜" },
      { key: "erase", label: "🩹 지우개" },
    ];
    tools.forEach((t) => {
      const b = document.createElement("button");
      b.className = "eav-btn" + (state.tool === t.key ? " is-active" : "");
      b.textContent = t.label;
      b.onclick = () => { state.tool = t.key; buildToolbar(); };
      tb.appendChild(b);
    });

    COLORS.forEach((c) => {
      const b = document.createElement("button");
      b.className = "eav-color" + (state.color === c ? " is-active" : "");
      b.style.background = c;
      b.title = c;
      b.onclick = () => { state.color = c; buildToolbar(); };
      tb.appendChild(b);
    });

    SIZES.forEach((s) => {
      const b = document.createElement("button");
      b.className = "eav-btn" + (state.size === s ? " is-active" : "");
      b.textContent = `${s}px`;
      b.onclick = () => { state.size = s; buildToolbar(); };
      tb.appendChild(b);
    });

    const clear = document.createElement("button");
    clear.className = "eav-btn";
    clear.textContent = "전체 지우기";
    clear.onclick = clearAnnot;
    tb.appendChild(clear);

    const dl = document.createElement("button");
    dl.className = "eav-btn";
    dl.textContent = "💾 저장";
    dl.onclick = downloadComposite;
    tb.appendChild(dl);

    const original = document.createElement("a");
    original.className = "eav-btn";
    original.textContent = "원본";
    const cur = state.items[state.currentIdx];
    if (cur) {
      original.href = `/expense/api/attachments/${cur.id}`;
      original.target = "_blank";
    }
    tb.appendChild(original);
  }

  function buildList() {
    const list = overlay.querySelector('[data-role="list"]');
    list.innerHTML = "";
    state.items.forEach((a, i) => {
      const item = document.createElement("button");
      item.className = "eav-item" + (i === state.currentIdx ? " is-active" : "");
      const ext = (a.filename.split(".").pop() || "").toLowerCase();
      const isImg = IMG_EXTS.has(ext);
      item.innerHTML = `
        <span class="eav-item-thumb">${
          isImg
            ? `<img src="/expense/api/attachments/${a.id}" alt="" />`
            : "📄"
        }</span>
        <span class="eav-item-meta">
          <span class="eav-item-name">${escapeHtml(a.filename)}</span>
          <span class="eav-item-sub">${a.kind === "receipt" ? "영수증" : "기타"} · ${fmtSize(a.size_bytes)}</span>
        </span>
      `;
      item.onclick = () => { state.currentIdx = i; renderCurrent(); buildList(); buildToolbar(); };
      list.appendChild(item);
    });
  }

  function renderCurrent() {
    const stage = overlay.querySelector('[data-role="stage"]');
    stage.innerHTML = "";
    const cur = state.items[state.currentIdx];
    if (!cur) {
      stage.innerHTML = `<div class="eav-fallback">첨부가 없습니다.</div>`;
      return;
    }
    const ext = (cur.filename.split(".").pop() || "").toLowerCase();
    if (!IMG_EXTS.has(ext)) {
      stage.innerHTML = `
        <div class="eav-fallback">
          이미지 파일이 아닙니다.<br/>
          <a href="/expense/api/attachments/${cur.id}" target="_blank">다운로드 / 새 창 열기</a>
        </div>
      `;
      return;
    }

    const wrap = document.createElement("div");
    wrap.className = "eav-canvas-stack";
    const img = new Image();
    img.className = "eav-img";
    img.crossOrigin = "anonymous";
    img.onload = () => {
      const canvas = document.createElement("canvas");
      canvas.className = "eav-canvas";
      canvas.width = img.naturalWidth;
      canvas.height = img.naturalHeight;
      // 표시 크기는 img 의 렌더링 크기 따라감
      canvas.style.width = img.clientWidth + "px";
      canvas.style.height = img.clientHeight + "px";
      wrap.appendChild(canvas);
      attachDrawing(canvas, img);
      // 창 리사이즈 시 캔버스 표시 크기 재조정
      const ro = new ResizeObserver(() => {
        canvas.style.width = img.clientWidth + "px";
        canvas.style.height = img.clientHeight + "px";
      });
      ro.observe(img);
      state.canvas = canvas;
      state.image = img;
    };
    img.onerror = () => {
      stage.innerHTML = `<div class="eav-fallback">이미지 로드 실패</div>`;
    };
    img.src = `/expense/api/attachments/${cur.id}`;
    wrap.appendChild(img);
    stage.appendChild(wrap);
  }

  function attachDrawing(canvas, img) {
    const ctx = canvas.getContext("2d");

    function posToCanvas(ev) {
      const rect = canvas.getBoundingClientRect();
      const x = (ev.clientX - rect.left) * (canvas.width / rect.width);
      const y = (ev.clientY - rect.top) * (canvas.height / rect.height);
      return { x, y };
    }

    function start(ev) {
      ev.preventDefault();
      state.drawing = true;
      state.last = posToCanvas(ev);
    }
    function move(ev) {
      if (!state.drawing) return;
      ev.preventDefault();
      const p = posToCanvas(ev);
      ctx.lineCap = "round";
      ctx.lineJoin = "round";
      if (state.tool === "erase") {
        ctx.globalCompositeOperation = "destination-out";
        ctx.lineWidth = state.size * 4;
      } else {
        ctx.globalCompositeOperation = "source-over";
        ctx.strokeStyle = state.color;
        ctx.lineWidth = state.size;
      }
      ctx.beginPath();
      ctx.moveTo(state.last.x, state.last.y);
      ctx.lineTo(p.x, p.y);
      ctx.stroke();
      state.last = p;
    }
    function end(ev) {
      if (ev) ev.preventDefault();
      state.drawing = false;
      state.last = null;
    }

    canvas.addEventListener("pointerdown", start);
    canvas.addEventListener("pointermove", move);
    canvas.addEventListener("pointerup", end);
    canvas.addEventListener("pointerleave", end);
  }

  function clearAnnot() {
    if (!state.canvas) return;
    const ctx = state.canvas.getContext("2d");
    ctx.clearRect(0, 0, state.canvas.width, state.canvas.height);
  }

  async function downloadComposite() {
    if (!state.canvas || !state.image) {
      alert("이미지가 로드되지 않았습니다.");
      return;
    }
    const cur = state.items[state.currentIdx];
    const out = document.createElement("canvas");
    out.width = state.canvas.width;
    out.height = state.canvas.height;
    const octx = out.getContext("2d");
    try {
      octx.drawImage(state.image, 0, 0);
    } catch (e) {
      alert("이미지 합성 실패 (CORS): 원본만 다운로드하세요.");
      return;
    }
    octx.drawImage(state.canvas, 0, 0);
    out.toBlob((blob) => {
      const url = URL.createObjectURL(blob);
      const a = document.createElement("a");
      a.href = url;
      const base = cur.filename.replace(/\.[^.]+$/, "");
      a.download = `${base}_주석.png`;
      a.click();
      setTimeout(() => URL.revokeObjectURL(url), 1000);
    }, "image/png");
  }

  function fmtSize(b) {
    b = Number(b || 0);
    if (b < 1024) return `${b} B`;
    if (b < 1024 * 1024) return `${(b / 1024).toFixed(1)} KB`;
    return `${(b / 1024 / 1024).toFixed(2)} MB`;
  }
  function escapeHtml(s) {
    return String(s || "").replace(/[&<>"']/g, (c) =>
      ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" }[c])
    );
  }

  function open(items, opts) {
    ensureOverlay();
    state.items = items || [];
    state.currentIdx = state.items.length ? 0 : -1;
    state.title = (opts && opts.title) || "첨부 보기";
    overlay.querySelector('[data-role="title"]').textContent = state.title;
    overlay.dataset.open = "true";
    buildList();
    buildToolbar();
    renderCurrent();
  }

  function close() {
    if (!overlay) return;
    overlay.dataset.open = "false";
    state.items = [];
    state.currentIdx = -1;
    state.canvas = null;
    state.image = null;
  }

  async function openFor(itemId, opts) {
    try {
      const res = await fetch(`/expense/api/items/${itemId}/attachments`);
      if (!res.ok) throw new Error((await res.json()).detail || res.status);
      const { attachments } = await res.json();
      if (!attachments || !attachments.length) {
        alert("첨부 파일이 없습니다.");
        return;
      }
      open(attachments, opts);
    } catch (err) {
      alert(`첨부 로드 실패: ${err.message || err}`);
    }
  }

  window.ErpAttachViewer = { open, openFor, close };
})();