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

const els = {
  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"),
  gSignIn: document.querySelector(".g_id_signin"),
  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("Creating diagnostic session...", true);
  setButtonLoading(event.submitter || document.querySelector("#start-button"), "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(`Session ${session.id} ready`);
  } catch (error) {
    showError(error.message);
    setStatus("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("Submitting answer...", true);
  setButtonLoading(event.submitter || els.answerButton, "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(`Answer graded as ${answer.grade.overall}`);
  } catch (error) {
    showError(error.message);
    setStatus("Session ready");
  } finally {
    clearButtonLoading(els.answerButton);
    els.answerButton.disabled = !state.selectedQuestion;
  }
});

els.materialForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  clearError();
  setStatus("Ingesting material...", true);
  setButtonLoading(event.submitter || document.querySelector("#material-button"), "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(`Material ${result.material.id} ingested`);
  } catch (error) {
    showError(error.message);
    setStatus("Content workspace ready");
  } finally {
    clearButtonLoading(document.querySelector("#material-button"));
  }
});

els.assetForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  clearError();
  setStatus("Generating prompt candidate...", true);
  setButtonLoading(event.submitter || els.assetButton, "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(`Prompt ${prompt.id} generated`);
  } catch (error) {
    showError(error.message);
    setStatus("Content workspace ready");
  } finally {
    clearButtonLoading(els.assetButton);
  }
});

function renderSession() {
  if (!state.session) return;
  els.title.textContent = `${state.session.target_role} — ${state.session.questions.length} questions`;
  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(`Selected ${question.id}`);
    });
    els.questions.append(button);
  });

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

async function refreshProgress() {
  if (!state.session) return;
  setStatus("Refreshing learning progress...", 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("Learning progress updated");
  } 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">Answer once to update learner memory and readiness.</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)} readiness</p>
    </section>
    <section>
      <h2>Concept memory</h2>
      <div>${mastery.map((item) => {
        const cls = readinessClassMap[item.state] || "pill-neutral";
        return `<span class="concept-pill ${cls}">${escapeHTML(item.concept.label)} — ${escapeHTML(item.state)}</span>`;
      }).join("")}</div>
    </section>
    <section>
      <h2>Next challenge</h2>
      <p class="status-line">${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">Ingest material to inspect ontology candidates.</span>`;
    return;
  }

  const concepts = state.ontology.concepts || [];
  els.ontology.className = "ontology-view";
  els.ontology.innerHTML = `
    <div class="summary-strip">
      <span class="summary-chip">${concepts.length} concepts</span>
      <span class="summary-chip">${(state.ontology.edges || []).length} edges</span>
      <span class="summary-chip">${(state.ontology.gaps || []).length} gaps</span>
    </div>
    <section>
      <h2>Candidate concepts</h2>
      <div>${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("") || "No candidates yet."}</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">Generate a prompt to inspect model key, review state, and evidence.</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">verify model id: ${prompt.requires_model_id_verification ? "yes" : "no"}</span>
    </div>
    <pre class="prompt-text">${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">Submit an answer to see grade, evidence, and follow-up.</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] || "Answer was graded.")}</p>
    </div>
    ${scoreRows(grade.scores)}
    ${listBlock("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>Follow-up</h2><p class="status-line">${escapeHTML(followUp.question)}</p></section>`;
}

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

window.handleCredentialResponse = async (response) => {
  try {
    const res = await request("/api/v1/auth/google", {
      method: "POST",
      body: JSON.stringify({ id_token: response.credential }),
    });
    localStorage.setItem("tutor_token", res.token);
    localStorage.setItem("tutor_user", JSON.stringify(res.user));
    setStatus(`Signed in as ${res.user.email}`);
    renderAuth();
  } catch (err) {
    showError(err.message);
  }
};

function renderAuth() {
  const user = JSON.parse(localStorage.getItem("tutor_user") || "null");
  const token = localStorage.getItem("tutor_token");
  if (user && token) {
    els.gSignIn.style.display = "none";
    els.userInfo.style.display = "block";
    els.userInfo.textContent = user.email;
    els.logoutButton.style.display = "inline-block";
  } else {
    els.gSignIn.style.display = "block";
    els.userInfo.style.display = "none";
    els.logoutButton.style.display = "none";
  }
}

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

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;");
}

renderAuth();