import * as THREE from "three";
import { OrbitControls } from "three/addons/controls/OrbitControls.js";
import { STLLoader } from "three/addons/loaders/STLLoader.js";
import { ThreeMFLoader } from "three/addons/loaders/3MFLoader.js";

const view = document.getElementById("view");
const crumbs = document.getElementById("crumbs");
const homeLink = document.getElementById("home-link");
const logoutBtn = document.getElementById("logout-btn");

const stlLoader = new STLLoader();
const mfLoader = new ThreeMFLoader();

// Files above this size are not auto-loaded into a 3D preview, since
// parsing a huge mesh can freeze the browser tab. The user can opt in
// via a button instead.
const PREVIEW_SIZE_LIMIT = 150 * 1024 * 1024; // 150 MB

let currentProject = null;
const activeViewers = []; // track for cleanup / resize

// ---------- Routing ----------

homeLink.addEventListener("click", (e) => {
  e.preventDefault();
  navigateHome();
});

function navigateHome() {
  currentProject = null;
  crumbs.innerHTML = "";
  renderDashboard();
}

function navigateToProject(name) {
  currentProject = name;
  crumbs.innerHTML = `<span class="sep">/</span><span class="current"></span>`;
  crumbs.querySelector(".current").textContent = name;
  renderProject(name);
}

// ---------- API helpers ----------

async function api(path, options = {}) {
  const res = await fetch(path, options);
  if (res.status === 401) {
    window.location.href = "/login.html";
    throw new Error("Nicht angemeldet");
  }
  if (!res.ok) {
    let detail = res.statusText;
    try {
      const body = await res.json();
      detail = body.detail || detail;
    } catch (_) {}
    throw new Error(detail);
  }
  if (res.status === 204) return null;
  return res.json();
}

function showToast(message, isError = false) {
  const el = document.createElement("div");
  el.className = "toast" + (isError ? " toast--error" : "");
  el.textContent = message;
  document.body.appendChild(el);
  setTimeout(() => el.remove(), 3000);
}

function formatSize(bytes) {
  if (bytes < 1024) return `${bytes} B`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
}

// ---------- Dashboard ----------

async function renderDashboard() {
  view.innerHTML = "";

  const header = document.createElement("div");
  header.className = "view-header";
  header.innerHTML = `
    <div>
      <h1 class="view-title">Projekte</h1>
      <div class="view-subtitle">Lege ein Projekt an, um STL- und 3MF-Dateien zu verwalten.</div>
    </div>
  `;
  view.appendChild(header);

  let projects = [];
  try {
    projects = await api("/api/projects");
  } catch (err) {
    showToast("Projekte konnten nicht geladen werden: " + err.message, true);
  }

  const grid = document.createElement("div");
  grid.className = "project-grid";

  const newCardTpl = document.getElementById("tpl-new-project-card");
  const newCard = newCardTpl.content.firstElementChild.cloneNode(true);
  newCard.addEventListener("click", () => showNewProjectForm(grid, newCard));
  grid.appendChild(newCard);

  const cardTpl = document.getElementById("tpl-project-card");
  for (const project of projects) {
    const card = cardTpl.content.firstElementChild.cloneNode(true);
    card.querySelector(".project-card-name").textContent = project.name;
    card.querySelector(".project-card-meta").textContent =
      project.file_count === 1 ? "1 Datei" : `${project.file_count} Dateien`;
    card.addEventListener("click", () => navigateToProject(project.name));
    grid.appendChild(card);
  }

  view.appendChild(grid);
}

function showNewProjectForm(grid, anchorCard) {
  if (document.querySelector(".new-project-form")) return;

  const form = document.createElement("div");
  form.className = "new-project-form";
  form.innerHTML = `
    <input type="text" placeholder="Projektname" maxlength="80" />
    <button class="btn" type="button" data-action="create">Anlegen</button>
    <button class="btn" type="button" data-action="cancel">Abbrechen</button>
  `;
  view.insertBefore(form, grid);

  const input = form.querySelector("input");
  input.focus();

  const cleanup = () => form.remove();

  form.querySelector('[data-action="cancel"]').addEventListener("click", cleanup);

  const submit = async () => {
    const name = input.value.trim();
    if (!name) return;
    try {
      await api("/api/projects", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ name }),
      });
      cleanup();
      renderDashboard();
    } catch (err) {
      showToast("Projekt konnte nicht angelegt werden: " + err.message, true);
    }
  };

  form.querySelector('[data-action="create"]').addEventListener("click", submit);
  input.addEventListener("keydown", (e) => {
    if (e.key === "Enter") submit();
    if (e.key === "Escape") cleanup();
  });
}

// ---------- Project view ----------

async function renderProject(name) {
  disposeViewers();
  view.innerHTML = "";

  const header = document.createElement("div");
  header.className = "view-header";
  header.innerHTML = `
    <div>
      <h1 class="view-title"></h1>
      <div class="view-subtitle">STL- und 3MF-Dateien dieses Projekts.</div>
    </div>
    <div class="header-actions">
      <a class="btn" data-action="download-project" download>Alle herunterladen</a>
      <button class="btn btn-danger" type="button" data-action="delete-project">Projekt löschen</button>
    </div>
  `;
  header.querySelector(".view-title").textContent = name;
  header.querySelector('[data-action="download-project"]').href =
    `/api/projects/${encodeURIComponent(name)}/download`;
  header.querySelector('[data-action="delete-project"]').addEventListener("click", async () => {
    if (!confirm(`Projekt "${name}" inklusive aller Dateien löschen?`)) return;
    try {
      await api(`/api/projects/${encodeURIComponent(name)}`, { method: "DELETE" });
      navigateHome();
    } catch (err) {
      showToast("Löschen fehlgeschlagen: " + err.message, true);
    }
  });
  view.appendChild(header);

  const dropzone = document.createElement("div");
  dropzone.className = "dropzone";
  dropzone.innerHTML = `<strong>STL- oder 3MF-Dateien hierher ziehen</strong> oder klicken zum Auswählen`;
  view.appendChild(dropzone);

  const fileInput = document.createElement("input");
  fileInput.type = "file";
  fileInput.multiple = true;
  fileInput.accept = ".stl,.3mf";
  fileInput.style.display = "none";
  view.appendChild(fileInput);

  dropzone.addEventListener("click", () => fileInput.click());
  fileInput.addEventListener("change", () => {
    if (fileInput.files.length) uploadFiles(name, fileInput.files);
    fileInput.value = "";
  });

  ["dragenter", "dragover"].forEach((evt) =>
    dropzone.addEventListener(evt, (e) => {
      e.preventDefault();
      dropzone.classList.add("is-dragover");
    })
  );
  ["dragleave", "drop"].forEach((evt) =>
    dropzone.addEventListener(evt, (e) => {
      e.preventDefault();
      dropzone.classList.remove("is-dragover");
    })
  );
  dropzone.addEventListener("drop", (e) => {
    const files = e.dataTransfer.files;
    if (files.length) uploadFiles(name, files);
  });

  const gridContainer = document.createElement("div");
  gridContainer.id = "file-grid-container";
  view.appendChild(gridContainer);

  await loadFileGrid(name, gridContainer);
}

function createProgressBar(afterNode, label) {
  const wrap = document.createElement("div");
  wrap.className = "upload-progress";
  wrap.innerHTML = `
    <div class="upload-progress-row">
      <span class="upload-progress-name"></span>
      <div class="upload-progress-track"><div class="upload-progress-fill"></div></div>
      <span class="upload-progress-pct">0%</span>
    </div>
  `;
  wrap.querySelector(".upload-progress-name").textContent = label;
  afterNode.insertAdjacentElement("afterend", wrap);

  const fill = wrap.querySelector(".upload-progress-fill");
  const pct = wrap.querySelector(".upload-progress-pct");

  return {
    update(percent) {
      fill.style.width = `${percent}%`;
      pct.textContent = `${percent}%`;
    },
    done() {
      fill.style.width = "100%";
      fill.classList.add("is-done");
      pct.textContent = "100%";
    },
    remove() {
      wrap.remove();
    },
  };
}

async function uploadFiles(projectName, fileList) {
  const formData = new FormData();
  const names = [];
  for (const file of fileList) {
    const ext = "." + file.name.split(".").pop().toLowerCase();
    if (ext === ".stl" || ext === ".3mf") {
      formData.append("files", file);
      names.push(file.name);
    }
  }
  if (!names.length) {
    showToast("Nur .stl und .3mf Dateien werden unterstützt.", true);
    return;
  }

  const dropzone = document.querySelector(".dropzone");
  const label = names.length === 1 ? names[0] : `${names.length} Dateien`;
  const progress = createProgressBar(dropzone, label);

  try {
    const result = await uploadWithProgress(projectName, formData, (percent) => progress.update(percent));
    progress.done();
    showToast(`${result.saved.length} Datei(en) hochgeladen`);
    setTimeout(() => progress.remove(), 600);
    const container = document.getElementById("file-grid-container");
    if (container) await loadFileGrid(projectName, container);
  } catch (err) {
    progress.remove();
    showToast("Upload fehlgeschlagen: " + err.message, true);
  }
}

function uploadWithProgress(projectName, formData, onProgress) {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    xhr.open("POST", `/api/projects/${encodeURIComponent(projectName)}/upload`);

    xhr.upload.addEventListener("progress", (e) => {
      if (e.lengthComputable) {
        onProgress(Math.round((e.loaded / e.total) * 100));
      }
    });

    xhr.addEventListener("load", () => {
      if (xhr.status >= 200 && xhr.status < 300) {
        try {
          resolve(JSON.parse(xhr.responseText));
        } catch (err) {
          reject(new Error("Ungültige Antwort vom Server"));
        }
      } else {
        let message = xhr.statusText;
        try {
          message = JSON.parse(xhr.responseText).detail || message;
        } catch (_) {}
        reject(new Error(message));
      }
    });

    xhr.addEventListener("error", () => reject(new Error("Netzwerkfehler")));
    xhr.send(formData);
  });
}

async function loadFileGrid(projectName, container) {
  disposeViewers();
  container.innerHTML = "";

  let files = [];
  try {
    files = await api(`/api/projects/${encodeURIComponent(projectName)}/files`);
  } catch (err) {
    showToast("Dateien konnten nicht geladen werden: " + err.message, true);
    return;
  }

  if (!files.length) {
    const empty = document.createElement("div");
    empty.className = "empty-state";
    empty.textContent = "Noch keine Dateien in diesem Projekt.";
    container.appendChild(empty);
    return;
  }

  const grid = document.createElement("div");
  grid.className = "file-grid";
  container.appendChild(grid);

  const tpl = document.getElementById("tpl-file-card");
  for (const file of files) {
    const card = tpl.content.firstElementChild.cloneNode(true);
    card.querySelector(".file-card-name").textContent = file.name;
    card.querySelector(".file-card-meta").textContent =
      `${file.type.toUpperCase()} · ${formatSize(file.size)}`;

    const fileUrl = `/api/projects/${encodeURIComponent(projectName)}/files/${encodeURIComponent(file.name)}`;
    const downloadLink = card.querySelector(".file-card-download");
    downloadLink.href = fileUrl;
    downloadLink.download = file.name;

    card.querySelector(".file-card-delete").addEventListener("click", async (e) => {
      e.stopPropagation();
      if (!confirm(`"${file.name}" löschen?`)) return;
      try {
        await api(
          `/api/projects/${encodeURIComponent(projectName)}/files/${encodeURIComponent(file.name)}`,
          { method: "DELETE" }
        );
        await loadFileGrid(projectName, container);
      } catch (err) {
        showToast("Löschen fehlgeschlagen: " + err.message, true);
      }
    });

    grid.appendChild(card);
    const canvasHost = card.querySelector(".file-card-canvas");
    const fileUrlForViewer = `/api/projects/${encodeURIComponent(projectName)}/files/${encodeURIComponent(file.name)}`;

    if (file.size > PREVIEW_SIZE_LIMIT) {
      renderLazyPreviewPlaceholder(canvasHost, fileUrlForViewer, file.type, file.size);
    } else {
      initViewer(canvasHost, fileUrlForViewer, file.type);
    }
  }
}

function renderLazyPreviewPlaceholder(host, url, type, size) {
  host.style.position = "relative";
  const wrap = document.createElement("div");
  wrap.className = "preview-placeholder";
  wrap.innerHTML = `
    <span class="preview-placeholder-text">Große Datei (${formatSize(size)})<br />keine automatische Vorschau</span>
    <button class="btn preview-load-btn" type="button">Vorschau laden</button>
  `;
  host.appendChild(wrap);

  wrap.querySelector(".preview-load-btn").addEventListener("click", () => {
    wrap.remove();
    initViewer(host, url, type);
  });
}

// ---------- Three.js viewer ----------

function initViewer(host, url, type) {
  const width = host.clientWidth || 260;
  const height = host.clientHeight || 195;

  const scene = new THREE.Scene();
  scene.background = new THREE.Color(0x20252b);

  const camera = new THREE.PerspectiveCamera(45, width / height, 0.1, 5000);

  const renderer = new THREE.WebGLRenderer({ antialias: true });
  renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
  renderer.setSize(width, height);
  host.appendChild(renderer.domElement);

  const ambient = new THREE.AmbientLight(0xffffff, 0.6);
  scene.add(ambient);
  const key = new THREE.DirectionalLight(0xffffff, 0.9);
  key.position.set(1, 1.5, 1);
  scene.add(key);
  const fill = new THREE.DirectionalLight(0xffffff, 0.4);
  fill.position.set(-1, -0.5, -1);
  scene.add(fill);

  const controls = new OrbitControls(camera, renderer.domElement);
  controls.enableDamping = true;
  controls.dampingFactor = 0.08;

  let frameId;
  const animate = () => {
    frameId = requestAnimationFrame(animate);
    controls.update();
    renderer.render(scene, camera);
  };
  animate();

  const viewer = { host, renderer, scene, camera, controls, frameId: () => frameId };
  activeViewers.push(viewer);

  const resizeObserver = new ResizeObserver(() => {
    const w = host.clientWidth;
    const h = host.clientHeight;
    if (w === 0 || h === 0) return;
    camera.aspect = w / h;
    camera.updateProjectionMatrix();
    renderer.setSize(w, h);
  });
  resizeObserver.observe(host);
  viewer.resizeObserver = resizeObserver;

  const material = new THREE.MeshStandardMaterial({
    color: 0xff6a35,
    metalness: 0.15,
    roughness: 0.55,
  });

  const fitAndAdd = (object3d) => {
    const box = new THREE.Box3().setFromObject(object3d);
    const size = new THREE.Vector3();
    const center = new THREE.Vector3();
    box.getSize(size);
    box.getCenter(center);
    object3d.position.sub(center);

    const maxDim = Math.max(size.x, size.y, size.z) || 1;
    const distance = maxDim * 2.2;
    camera.position.set(distance, distance * 0.75, distance);
    camera.near = maxDim / 100;
    camera.far = maxDim * 100;
    camera.updateProjectionMatrix();
    controls.target.set(0, 0, 0);
    controls.update();

    scene.add(object3d);
  };

  if (type === "stl") {
    stlLoader.load(
      url,
      (geometry) => {
        geometry.computeVertexNormals();
        const mesh = new THREE.Mesh(geometry, material);
        fitAndAdd(mesh);
      },
      undefined,
      () => showLoadError(host)
    );
  } else if (type === "3mf") {
    mfLoader.load(
      url,
      (object) => {
        fitAndAdd(object);
      },
      undefined,
      () => showLoadError(host)
    );
  }
}

function showLoadError(host) {
  const msg = document.createElement("div");
  msg.style.cssText =
    "position:absolute;inset:0;display:flex;align-items:center;justify-content:center;color:#8a929b;font-size:12px;padding:12px;text-align:center;";
  msg.textContent = "Vorschau konnte nicht geladen werden";
  host.style.position = "relative";
  host.appendChild(msg);
}

function disposeViewers() {
  while (activeViewers.length) {
    const v = activeViewers.pop();
    cancelAnimationFrame(v.frameId());
    v.resizeObserver.disconnect();
    v.controls.dispose();
    v.renderer.dispose();
    v.scene.traverse((obj) => {
      if (obj.geometry) obj.geometry.dispose();
      if (obj.material) {
        if (Array.isArray(obj.material)) obj.material.forEach((m) => m.dispose());
        else obj.material.dispose();
      }
    });
  }
}

// ---------- Init ----------

logoutBtn.addEventListener("click", async () => {
  try {
    await fetch("/api/logout", { method: "POST" });
  } finally {
    window.location.href = "/login.html";
  }
});

(async function init() {
  try {
    await api("/api/me");
    renderDashboard();
  } catch (err) {
    // api() already redirects to /login.html on 401
  }
})();