/* =========================================================================
   Bangla Text Analyzer — frontend logic
   ========================================================================= */

const $ = (sel) => document.querySelector(sel);

const textInput = $("#text-input");
const dropZone = $("#drop-zone");
const fileInput = $("#file-input");
const fileBtn = $("#file-btn");
const fileName = $("#file-name");
const charCount = $("#char-count");
const taskSelect = $("#task-select");
const modelWrap = $("#model-wrap");
const modelSelect = $("#model-select");
const runBtn = $("#run-btn");
const outputBody = $("#output-body");
const outputDot = $(".output-head__dot");

// Holds a dropped/selected file so we can send it instead of textarea text.
let pendingFile = null;

/* ---------------- character counter ---------------- */
function updateCount() {
  const n = textInput.value.length;
  charCount.textContent = `${n.toLocaleString("bn-BD")} অক্ষর`;
}
textInput.addEventListener("input", () => {
  // If the user types, we abandon any previously attached file.
  if (pendingFile && textInput.value.trim()) clearFile();
  updateCount();
});

/* ---------------- file handling ---------------- */
function clearFile() {
  pendingFile = null;
  fileName.textContent = "";
  fileInput.value = "";
}

function attachFile(file) {
  pendingFile = file;
  fileName.textContent = "📎 " + file.name;
  // Show a preview of the file's text in the textarea.
  const reader = new FileReader();
  reader.onload = (e) => {
    textInput.value = e.target.result;
    updateCount();
  };
  reader.readAsText(file, "utf-8");
}

fileBtn.addEventListener("click", () => fileInput.click());
fileInput.addEventListener("change", (e) => {
  if (e.target.files.length) attachFile(e.target.files[0]);
});

// Drag & drop onto the text area.
["dragenter", "dragover"].forEach((evt) =>
  dropZone.addEventListener(evt, (e) => {
    e.preventDefault();
    dropZone.classList.add("dragover");
  })
);
["dragleave", "drop"].forEach((evt) =>
  dropZone.addEventListener(evt, (e) => {
    e.preventDefault();
    if (evt === "dragleave" && dropZone.contains(e.relatedTarget)) return;
    dropZone.classList.remove("dragover");
  })
);
dropZone.addEventListener("drop", (e) => {
  const file = e.dataTransfer.files[0];
  if (file) attachFile(file);
});

/* ---------------- running analysis ---------------- */
async function analyze() {
  const task = taskSelect.value;
  const text = textInput.value.trim();
  // Only the hate-speech task offers a model choice; default otherwise.
  const model = task === "hate_speech" ? modelSelect.value : "banglabert";

  if (!text) {
    renderError("দয়া করে কিছু টেক্সট লিখুন বা একটি ফাইল দিন।");
    return;
  }

  setLoading(true);

  try {
    let response;
    if (pendingFile) {
      // Send the raw file via multipart form-data.
      const fd = new FormData();
      fd.append("file", pendingFile);
      fd.append("task", task);
      fd.append("model", model);
      response = await fetch("/analyze", { method: "POST", body: fd });
    } else {
      // Send typed text as JSON.
      response = await fetch("/analyze", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ text, task, model }),
      });
    }

    const data = await response.json();
    if (!response.ok) {
      renderError(data.error || "একটি ত্রুটি ঘটেছে।");
    } else {
      renderResult(data);
    }
  } catch (err) {
    renderError("সার্ভারের সাথে সংযোগ ব্যর্থ হয়েছে: " + err.message);
  } finally {
    setLoading(false);
  }
}

function setLoading(on) {
  runBtn.disabled = on;
  outputDot.classList.toggle("live", on);
  if (on) {
    outputBody.className = "output-body";
    outputBody.innerHTML =
      '<span class="spinner"></span> বিশ্লেষণ চলছে…';
  }
}

/* ---------------- rendering ---------------- */
function renderError(msg) {
  outputBody.className = "output-body";
  outputBody.innerHTML = `<div class="error-box">${escapeHtml(msg)}</div>`;
}

function classifyLabel(label) {
  const l = (label || "").toLowerCase();
  if (/(not|human|positive|neutral|নয়|মানব|ইতিবাচক)/.test(l)) return "is-good";
  if (/(hate|offensive|ai|negative|generated|ঘৃণা|নেতিবাচক|কৃত্রিম)/.test(l))
    return "is-bad";
  return "";
}

function renderResult(data) {
  const r = data.result || {};
  const label = r.label ?? "—";
  const score = typeof r.score === "number" ? r.score : null;
  const labelClass = classifyLabel(label);

  let html = `<div class="result-card">`;
  html += `<div class="result-card__top">
             <span class="result-label ${labelClass}">${escapeHtml(label)}</span>
             <span class="result-task">${escapeHtml(data.task_name || "")}</span>
           </div>`;

  if (score !== null) {
    const pct = Math.round(score * 100);
    html += `<div class="confidence">
               <div class="confidence__bar"><div class="confidence__fill" style="width:0%"></div></div>
               <div class="confidence__num">আত্মবিশ্বাস · confidence: ${pct}%</div>
             </div>`;
  }

  // Render any extra details the model returned.
  const details = r.details || {};
  const keys = Object.keys(details);
  if (keys.length) {
    html += `<div class="details-grid">`;
    for (const k of keys) {
      let v = details[k];
      if (typeof v === "number") v = (v * 100).toFixed(1) + "%";
      html += `<div class="detail-row"><span class="k">${escapeHtml(
        k
      )}</span><span class="v">${escapeHtml(String(v))}</span></div>`;
    }
    html += `</div>`;
  }

  html += `</div>`;

  outputBody.className = "output-body";
  outputBody.innerHTML = html;

  // Animate the confidence bar after it's in the DOM.
  if (score !== null) {
    requestAnimationFrame(() => {
      const fill = outputBody.querySelector(".confidence__fill");
      if (fill) fill.style.width = Math.round(score * 100) + "%";
    });
  }
}

function escapeHtml(str) {
  return String(str)
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;");
}

/* ---------------- events ---------------- */
runBtn.addEventListener("click", analyze);

// Show the model picker only when the hate-speech task is selected.
function updateModelVisibility() {
  modelWrap.hidden = taskSelect.value !== "hate_speech";
}
taskSelect.addEventListener("change", updateModelVisibility);
updateModelVisibility(); // set correct state on page load

// Ctrl/Cmd + Enter (or plain Enter when not adding a newline) runs analysis.
textInput.addEventListener("keydown", (e) => {
  if (e.key === "Enter" && (e.ctrlKey || e.metaKey)) {
    e.preventDefault();
    analyze();
  }
});

updateCount();