const state = {
  session: null,
  selectedQuestion: null,
  lastAnswer: null,
  progress: null,
  ontology: null,
  assetPrompt: null,
};

const els = {
  loginView: document.querySelector("#login-view"),
  workspaceView: document.querySelector("#workspace-view"),
  loginError: document.querySelector("#login-error"),
  sessionForm: document.querySelector("#session-form"),
  answerForm: document.querySelector("#answer-form"),
  answerText: document.querySelector("#answer-text"),
  answerButton: document.querySelector("#answer-button"),
  questions: document.querySelector("#questions"),
  feedback: document.querySelector("#feedback"),
  progress: document.querySelector("#progress"),
  refreshProgress: document.querySelector("#refresh-progress"),
  materialForm: document.querySelector("#material-form"),
  assetForm: document.querySelector("#asset-form"),
  ontology: document.querySelector("#ontology"),
  assetOutput: document.querySelector("#asset-output"),
  assetConcept: document.querySelector("#asset-concept"),
  assetButton: document.querySelector("#asset-button"),
  status: document.querySelector("#status-line"),
  error: document.querySelector("#error-line"),
  title: document.querySelector("#session-title"),
  userInfo: document.querySelector("#user-info"),
  logoutButton: document.querySelector("#logout-button"),
};

const readinessClassMap = {
  unknown: "pill-neutral",
  fragile: "pill-weak",
  improving: "pill-warn",
  interview_ready: "pill-good",
  strong_signal: "pill-strong",
};

const reviewClassMap = {
  candidate: "pill-neutral",
  reviewed: "pill-good",
};

const gradeClassMap = {
  miss: "grade-miss",
  partial: "grade-partial",
  solid: "grade-solid",
  strong: "grade-strong",
};

function setButtonLoading(button, loadingText) {
  button.disabled = true;
  button.classList.add("is-loading");
  const textEl = button.querySelector(".btn-text");
  if (textEl && loadingText) {
    textEl.dataset.originalText = textEl.textContent;
    textEl.textContent = loadingText;
  }
}

function clearButtonLoading(button) {
  button.disabled = false;
  button.classList.remove("is-loading");
  const textEl = button.querySelector(".btn-text");
  if (textEl && textEl.dataset.originalText) {
    textEl.textContent = textEl.dataset.originalText;
    delete textEl.dataset.originalText;
  }
}

els.sessionForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  clearError();
  setStatus(t("creatingSession"), true);
  setButtonLoading(
    event.submitter || document.querySelector("#start-button"),
    t("starting")
  );

  const payload = {
    user_id: value("#user-id"),
    target_role: value("#target-role"),
    stack: value("#stack")
      .split(",")
      .map((item) => item.trim())
      .filter(Boolean),
    interview_timeline: value("#timeline"),
  };

  try {
    const session = await request("/api/v1/diagnostic-sessions", {
      method: "POST",
      body: JSON.stringify(payload),
    });
    state.session = session;
    state.selectedQuestion = session.questions[0] || null;
    state.lastAnswer = null;
    renderSession();
    renderFeedback();
    renderProgress();
    setStatus(t("sessionReady", session.id));
  } catch (error) {
    showError(error.message);
    setStatus(t("ready"));
  } finally {
    clearButtonLoading(document.querySelector("#start-button"));
  }
});

els.refreshProgress.addEventListener("click", async () => {
  clearError();
  await refreshProgress();
});

els.answerForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  clearError();
  if (!state.session || !state.selectedQuestion) return;

  setStatus(t("submittingAnswer"), true);
  setButtonLoading(event.submitter || els.answerButton, t("grading"));

  try {
    const answer = await request(
      `/api/v1/diagnostic-sessions/${state.session.id}/answers`,
      {
        method: "POST",
        body: JSON.stringify({
          question_id: state.selectedQuestion.id,
          answer_text: els.answerText.value,
        }),
      }
    );
    state.lastAnswer = answer;
    renderFeedback();
    await refreshProgress();
    setStatus(t("answerGraded", answer.grade.overall));
  } catch (error) {
    showError(error.message);
    setStatus(t("sessionReadyShort"));
  } finally {
    clearButtonLoading(els.answerButton);
    els.answerButton.disabled = !state.selectedQuestion;
  }
});

els.materialForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  clearError();
  setStatus(t("ingestingMaterial"), true);
  setButtonLoading(
    event.submitter || document.querySelector("#material-button"),
    t("ingesting")
  );

  try {
    const result = await request("/api/v1/materials", {
      method: "POST",
      body: JSON.stringify({
        title: value("#material-title"),
        source_type: value("#material-source"),
        body: value("#material-body"),
      }),
    });
    state.ontology = result.snapshot;
    renderOntology();
    setStatus(t("materialIngested", result.material.id));
  } catch (error) {
    showError(error.message);
    setStatus(t("contentReady"));
  } finally {
    clearButtonLoading(document.querySelector("#material-button"));
  }
});

els.assetForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  clearError();
  setStatus(t("generatingPrompt"), true);
  setButtonLoading(event.submitter || els.assetButton, t("generating"));

  try {
    const prompt = await request("/api/v1/teaching-assets/prompts", {
      method: "POST",
      body: JSON.stringify({
        concept_id: els.assetConcept.value,
        asset_type: value("#asset-type"),
      }),
    });
    state.assetPrompt = prompt;
    renderAssetPrompt();
    setStatus(t("promptGenerated", prompt.id));
  } catch (error) {
    showError(error.message);
    setStatus(t("contentReady"));
  } finally {
    clearButtonLoading(els.assetButton);
  }
});

function renderSession() {
  if (!state.session) return;
  els.title.textContent = `${state.session.target_role} — ${state.session.questions.length} ${t("questionsSuffix")}`;
  els.questions.className = "question-list";
  els.questions.innerHTML = "";

  state.session.questions.forEach((question) => {
    const button = document.createElement("button");
    button.type = "button";
    button.className = "question-button";
    button.setAttribute(
      "aria-pressed",
      String(state.selectedQuestion?.id === question.id)
    );
    button.innerHTML = `<span class="question-id">${escapeHTML(question.id)}</span>${escapeHTML(question.prompt)}`;
    button.addEventListener("click", () => {
      state.selectedQuestion = question;
      els.answerText.value = "";
      renderSession();
      setStatus(t("selected", question.id));
    });
    els.questions.append(button);
  });

  els.answerButton.disabled = !state.selectedQuestion;
}

async function refreshProgress() {
  if (!state.session) return;
  setStatus(t("refreshingProgress"), true);

  try {
    const userID = encodeURIComponent(state.session.user_id);
    const [memory, readiness, challenge] = await Promise.all([
      request(`/api/v1/learners/${userID}/memory`),
      request(`/api/v1/learners/${userID}/readiness-map`),
      request(`/api/v1/learners/${userID}/next-challenge`),
    ]);
    state.progress = { memory, readiness, challenge };
    renderProgress();
    setStatus(t("progressUpdated"));
  } catch (error) {
    showError(error.message);
    renderProgress();
  }
}

function renderProgress() {
  els.refreshProgress.disabled = !state.session;
  if (!state.progress) {
    els.progress.className = "feedback empty-state";
    els.progress.innerHTML = `<span class="empty-hint">${t("emptyProgress")}</span>`;
    return;
  }

  const { memory, readiness, challenge } = state.progress;
  const mastery = memory.mastery || [];
  els.progress.className = "feedback";
  els.progress.innerHTML = `
    <section>
      <div class="readiness-value">${readiness.readiness_percentage}%</div>
      <p class="status-line">${escapeHTML(memory.profile.target_role)} ${t("readiness")}</p>
    </section>
    <section>
      <h2>${t("conceptMemory")}</h2>
      <div>${mastery
        .map((item) => {
          const cls = readinessClassMap[item.state] || "pill-neutral";
          return `<span class="concept-pill ${cls}">${escapeHTML(item.concept.label)} — ${escapeHTML(item.state)}</span>`;
        })
        .join("")}</div>
    </section>
    <section>
      <h2>${t("nextChallenge")}</h2>
      <p class="status-line">${escapeHTML(challenge.concept.label)} — ${escapeHTML(challenge.ladder_level)}</p>
      <p>${escapeHTML(challenge.question)}</p>
    </section>
  `;
}

function renderOntology() {
  if (!state.ontology) {
    els.ontology.className = "ontology-view empty-state";
    els.ontology.innerHTML = `<span class="empty-hint">${t("emptyOntology")}</span>`;
    return;
  }

  const concepts = state.ontology.concepts || [];
  els.ontology.className = "ontology-view";
  els.ontology.innerHTML = `
    <div class="summary-strip">
      <span class="summary-chip">${concepts.length} ${t("conceptsSuffix")}</span>
      <span class="summary-chip">${(state.ontology.edges || []).length} ${t("edgesSuffix")}</span>
      <span class="summary-chip">${(state.ontology.gaps || []).length} ${t("gapsSuffix")}</span>
    </div>
    <section>
      <h2>${t("candidateConcepts")}</h2>
      <div>${concepts
        .map((item) => {
          const cls = reviewClassMap[item.review_state] || "pill-neutral";
          return `<span class="concept-pill ${cls}">${escapeHTML(item.concept.label)} — ${escapeHTML(item.review_state)}</span>`;
        })
        .join("") || t("noCandidates")}</div>
    </section>
  `;

  els.assetConcept.innerHTML = concepts
    .map(
      (item) =>
        `<option value="${escapeHTML(item.concept.id)}">${escapeHTML(item.concept.label)}</option>`
    )
    .join("");
  els.assetConcept.disabled = concepts.length === 0;
  els.assetButton.disabled = concepts.length === 0;
}

function renderAssetPrompt() {
  if (!state.assetPrompt) {
    els.assetOutput.className = "ontology-view empty-state";
    els.assetOutput.innerHTML = `<span class="empty-hint">${t("emptyAsset")}</span>`;
    return;
  }

  const prompt = state.assetPrompt;
  els.assetOutput.className = "ontology-view";
  els.assetOutput.innerHTML = `
    <div class="summary-strip">
      <span class="summary-chip">${escapeHTML(prompt.model_key)}</span>
      <span class="summary-chip">${escapeHTML(prompt.review_state)}</span>
      <span class="summary-chip">${t("verifyModelId")}: ${prompt.requires_model_id_verification ? t("yes") : t("no")}</span>
    </div>
    <pre class="prompt-text">${escapeHTML(prompt.prompt)}</pre>
    ${evidenceBlock(prompt.source_evidence)}
  `;
}

function renderFeedback() {
  if (!state.lastAnswer) {
    els.feedback.className = "feedback empty-state";
    els.feedback.innerHTML = `<span class="empty-hint">${t("emptyFeedback")}</span>`;
    return;
  }

  const grade = state.lastAnswer.grade;
  const gradeClass = gradeClassMap[grade.overall] || "";
  els.feedback.className = "feedback";
  els.feedback.innerHTML = `
    <div>
      <div class="grade ${gradeClass}">${escapeHTML(grade.overall)}</div>
      <p class="status-line">${escapeHTML(grade.strengths?.[0] || t("answerWasGraded"))}</p>
    </div>
    ${scoreRows(grade.scores)}
    ${listBlock(t("gaps"), grade.gaps)}
    ${followUpBlock(grade.follow_up)}
    ${evidenceBlock(grade.evidence)}
  `;
}

function scoreRows(scores) {
  return Object.entries(scores || {})
    .map(
      ([label, score]) => `
      <div class="metric-row">
        <span>${escapeHTML(label.replaceAll("_", " "))}</span>
        <strong>${score}/4</strong>
      </div>
    `
    )
    .join("");
}

function listBlock(title, items = []) {
  if (!items.length) return "";
  return `<section><h2>${title}</h2><ul class="small-list">${items.map((item) => `<li>${escapeHTML(item)}</li>`).join("")}</ul></section>`;
}

function followUpBlock(followUp) {
  if (!followUp?.needed) return "";
  return `<section><h2>${t("followUp")}</h2><p class="status-line">${escapeHTML(followUp.question)}</p></section>`;
}

function evidenceBlock(evidence = []) {
  if (!evidence.length) return "";
  return `<section><h2>${t("evidence")}</h2><ul class="small-list">${evidence.map((item) => `<li>${escapeHTML(item.quote || item.id)}</li>`).join("")}</ul></section>`;
}

window._tutorGoogleCallback = async (response) => {
  console.log("[auth] Google callback fired");
  try {
    const res = await request("/api/v1/auth/google", {
      method: "POST",
      body: JSON.stringify({ id_token: response.credential }),
    });
    console.log("[auth] Backend login success", res.user?.email);
    localStorage.setItem("tutor_token", res.token);
    localStorage.setItem("tutor_user", JSON.stringify(res.user));
    if (els.loginError) {
      els.loginError.textContent = "";
      els.loginError.classList.remove("visible");
    }
    renderAuth();
  } catch (err) {
    console.error("[auth] Backend login failed", err);
    if (els.loginError) {
      els.loginError.textContent = err.message;
      els.loginError.classList.add("visible");
    }
  }
};

if (window._tutorPendingGoogleResponse) {
  window._tutorGoogleCallback(window._tutorPendingGoogleResponse);
  window._tutorPendingGoogleResponse = null;
}

function renderAuth() {
  const user = JSON.parse(localStorage.getItem("tutor_user") || "null");
  const token = localStorage.getItem("tutor_token");
  console.log("[auth] renderAuth", { hasUser: !!user, hasToken: !!token });
  if (user && token) {
    els.loginView.style.display = "none";
    els.workspaceView.style.display = "grid";
    els.userInfo.textContent = user.email || user.name || "User";
    setStatus(t("signedInAs", user.email || user.name));
    const userIdInput = document.querySelector("#user-id");
    if (userIdInput) userIdInput.value = user.email || user.id || "";
    if (els.loginError) els.loginError.classList.remove("visible");
  } else {
    els.loginView.style.display = "flex";
    els.workspaceView.style.display = "none";
  }
}

function setLanguage(lang) {
  localStorage.setItem("tutor_lang", lang);
  document.documentElement.lang = lang;
  updateStaticText();
  document.querySelectorAll(".lang-btn").forEach((btn) => {
    btn.classList.toggle("is-active", btn.dataset.lang === lang);
  });
  if (state.session) renderSession();
  renderFeedback();
  renderProgress();
  renderOntology();
  renderAssetPrompt();
  const user = JSON.parse(localStorage.getItem("tutor_user") || "null");
  const token = localStorage.getItem("tutor_token");
  if (user && token) {
    setStatus(t("signedInAs", user.email || user.name));
  } else {
    setStatus(t("ready"));
  }
}

els.logoutButton.addEventListener("click", () => {
  localStorage.removeItem("tutor_token");
  localStorage.removeItem("tutor_user");
  renderAuth();
  setStatus(t("signedOut"));
});

async function request(url, options = {}) {
  const token = localStorage.getItem("tutor_token");
  const headers = { "Content-Type": "application/json" };
  if (token) headers["Authorization"] = `Bearer ${token}`;
  const response = await fetch(url, { headers, ...options });
  const body = await response.json();
  if (!response.ok) {
    throw new Error(body.error || `Request failed: ${response.status}`);
  }
  return body;
}

function value(selector) {
  return document.querySelector(selector).value.trim();
}

function setStatus(message, busy = false) {
  const textEl = els.status.querySelector(".status-text");
  if (textEl) textEl.textContent = message;
  else els.status.textContent = message;
  els.status.classList.toggle("is-busy", busy);
}

function showError(message) {
  els.error.textContent = message;
}

function clearError() {
  els.error.textContent = "";
}

function escapeHTML(value) {
  return String(value)
    .replaceAll("&", "&amp;")
    .replaceAll("<", "&lt;")
    .replaceAll(">", "&gt;")
    .replaceAll('"', "&quot;")
    .replaceAll("'", "&#039;");
}

document.querySelectorAll(".lang-switch").forEach((group) => {
  group.addEventListener("click", (e) => {
    if (!e.target.dataset.lang) return;
    setLanguage(e.target.dataset.lang);
  });
});

if (!localStorage.getItem("tutor_lang")) {
  const browserLang = navigator.language || navigator.userLanguage || "";
  const lang = browserLang.toLowerCase().startsWith("ko") ? "ko" : "en";
  localStorage.setItem("tutor_lang", lang);
  document.documentElement.lang = lang;
}

updateStaticText();
window.renderAuth = renderAuth;
window.setLanguage = setLanguage;
renderAuth();