Previous-year-paper mode: year+shift picker builds the full actual paper (exam.rs past branch, build-page mode cards wired)

src/exam.rs

@@ -62,6 +62,12 @@ pub struct BuildForm {
     /// "jee" means 3 subjects × 60 min each; otherwise one flat timer.
     #[serde(default)]
     pub mode: String,
+    /// When "1", take every question of the given year+shift (past-paper mode).
+    #[serde(default)]
+    pub past: String,
+    /// Shift filter for past-paper mode ("S1" or "S2"); "ALL" means any.
+    #[serde(default)]
+    pub shift: String,
 }
 
 impl BuildForm {
@@ -87,9 +93,16 @@ impl BuildForm {
     pub fn is_jee_mode(&self) -> bool {
         self.mode == "jee"
     }
+    pub fn is_past_mode(&self) -> bool {
+        self.past == "1"
+    }
 }
 
 pub async fn build_paper(pool: &SqlitePool, uid: &str, f: &BuildForm) -> anyhow::Result<(String, String)> {
+    // Past-paper mode: every question of one year+shift, no chapter picking.
+    if f.is_past_mode() {
+        return build_past_paper(pool, uid, f).await;
+    }
     let chapters = f.chapter_ids();
     if chapters.is_empty() {
         anyhow::bail!("Pick at least one chapter");
@@ -432,4 +445,53 @@ pub async fn finalize(pool: &SqlitePool, attempt: &str) -> anyhow::Result<(i32,
     }
     tx.commit().await?;
     Ok((score, max, used))
-}
+}
+
+/// Past-paper mode: take every question from the chosen year (and shift when
+/// given), in a stable year-major order — mirrors sitting an actual paper.
+async fn build_past_paper(pool: &SqlitePool, uid: &str, f: &BuildForm) -> anyhow::Result<(String, String)> {
+    let years = f.year_list();
+    let year = match years.first() {
+        Some(y) => *y,
+        None => anyhow::bail!("Pick a year for the past paper"),
+    };
+    let shift = f.shift.trim();
+    let (sql, binds): (&str, Vec<String>) = if shift.is_empty() || shift == "ALL" {
+        ("SELECT id FROM questions WHERE year=? ORDER BY subject, id", vec![year.to_string()])
+    } else {
+        ("SELECT id FROM questions WHERE year=? AND shift=? ORDER BY subject, id", vec![year.to_string(), shift.to_string()])
+    };
+    let mut q = sqlx::query_scalar::<_, i64>(sql);
+    for b in &binds { q = q.bind(b); }
+    let mut ids: Vec<i64> = q.fetch_all(pool).await?;
+    if ids.is_empty() {
+        anyhow::bail!("No questions in the bank for that year and shift.");
+    }
+    ids.sort_unstable();
+    ids.dedup();
+    // Past papers are not shuffled: the real paper's order is part of the
+    // practice. Cap at 75 for the same reason as build mode.
+    ids.truncate(75);
+
+    let paper = uuid::Uuid::new_v4().to_string();
+    let share = uuid::Uuid::new_v4().simple().to_string()[..10].to_string();
+    let title = if shift.is_empty() || shift == "ALL" {
+        format!("JEE Main {year}")
+    } else {
+        format!("JEE Main {year} {shift}")
+    };
+    let mut tx = pool.begin().await?;
+    sqlx::query("INSERT INTO papers(id, user_id, title, duration_min, created_at, share_token) VALUES(?,?,?,?,?,?)")
+        .bind(&paper).bind(uid).bind(&title).bind(180).bind(chrono::Utc::now().to_rfc3339()).bind(&share)
+        .execute(&mut *tx).await?;
+    for (ord, qid) in ids.iter().enumerate() {
+        sqlx::query("INSERT INTO paper_questions(paper_id, question_id, ord) VALUES(?,?,?)")
+            .bind(&paper).bind(qid).bind(ord as i64)
+            .execute(&mut *tx).await?;
+        sqlx::query("INSERT OR REPLACE INTO seen_questions(user_id, question_id, seen_at) VALUES(?,?,?)")
+            .bind(uid).bind(qid).bind(chrono::Utc::now().to_rfc3339())
+            .execute(&mut *tx).await?;
+    }
+    tx.commit().await?;
+    Ok((paper, share))
+}

src/main.rs

@@ -315,6 +315,8 @@ async fn build_page(State(ctx): State<CtxArc>, h: HeaderMap) -> axum::response::
         duration: Some(30),
         unseen_only: Some("on".into()),
         mode: String::new(),
+        past: String::new(),
+        shift: String::new(),
     };
     hx(views::build(&ctx, &name, blocks, &form, available, None), StatusCode::OK).into_response()
 }

src/views.rs

@@ -496,6 +496,25 @@ pub fn build(ctx: &Ctx, user: &str, blocks: Vec<SubjectBlock>, _form: &BuildForm
     </div>
   </div>
 
+  <!-- Past-paper picker (hidden until Previous-year mode) -->
+  <div class="zp-past-panel" id="zp-past-panel" hidden>
+    <span class="zp-filter-heading">PICK A YEAR</span>
+    <div class="zp-pill-row" id="past-year-row">
+      <label class="zp-filter-pill"><input type="radio" name="past-year" value="2025"><span>2025</span></label>
+      <label class="zp-filter-pill"><input type="radio" name="past-year" value="2024"><span>2024</span></label>
+      <label class="zp-filter-pill"><input type="radio" name="past-year" value="2023"><span>2023</span></label>
+      <label class="zp-filter-pill"><input type="radio" name="past-year" value="2022"><span>2022</span></label>
+      <label class="zp-filter-pill"><input type="radio" name="past-year" value="2021"><span>2021</span></label>
+      <label class="zp-filter-pill"><input type="radio" name="past-year" value="2020"><span>2020</span></label>
+    </div>
+    <span class="zp-filter-heading" style="margin-top:14px">SHIFT</span>
+    <div class="zp-pill-row" id="past-shift-row">
+      <label class="zp-filter-pill active"><input type="radio" name="past-shift" value="ALL" checked><span>any</span></label>
+      <label class="zp-filter-pill"><input type="radio" name="past-shift" value="S1"><span>shift 1</span></label>
+      <label class="zp-filter-pill"><input type="radio" name="past-shift" value="S2"><span>shift 2</span></label>
+    </div>
+  </div>
+
   <button type="button" class="zp-complete-btn" id="btn-complete-syllabus">complete syllabus</button>
   <p class="zp-complete-hint">Selects every chapter in all three subjects. You can still remove any you don't want.</p>
 
@@ -537,6 +556,8 @@ pub fn build(ctx: &Ctx, user: &str, blocks: Vec<SubjectBlock>, _form: &BuildForm
     <input type="hidden" name="difficulties" id="difficulties" value="Easy,Medium,Hard">
     <input type="hidden" name="years" id="years" value="2020,2021,2022,2023,2024,2025">
     <input type="hidden" name="mode" id="mode" value="jee">
+    <input type="hidden" name="past" id="past" value="">
+    <input type="hidden" name="shift" id="shift" value="">
 
     <!-- Chapter Rows Container -->
     <div class="zp-chapters-container">
@@ -616,6 +637,47 @@ pub fn build(ctx: &Ctx, user: &str, blocks: Vec<SubjectBlock>, _form: &BuildForm
   const btnDesc = document.getElementById('btn-desc');
   const searchInput = document.getElementById('zp-search-input');
 
+  // Mode cards: build vs past-paper
+  const modeBuild = document.getElementById('mode-build');
+  const modePast = document.getElementById('mode-past');
+  const pastPanel = document.getElementById('zp-past-panel');
+  const pastField = document.getElementById('past');
+  const shiftField = document.getElementById('shift');
+  const chaptersWrap = document.querySelector('.zp-two-col');
+  let pastMode = false;
+
+  function setMode(past) {{
+    pastMode = past;
+    modeBuild.classList.toggle('active', !past);
+    modePast.classList.toggle('active', past);
+    pastPanel.hidden = !past;
+    // In past mode the chapters list and quota sidebar are meaningless.
+    document.querySelector('.zp-chapters-container').style.display = past ? 'none' : '';
+    document.querySelectorAll('.zp-subject-pills-bar, .zp-search-row, #btn-complete-syllabus, .zp-complete-hint').forEach(el => {{
+      el.style.display = past ? 'none' : '';
+    }});
+    document.getElementById('diff-row').closest('.zp-filter-sec').style.display = past ? 'none' : '';
+    pastField.value = past ? '1' : '';
+    if (past) {{
+      // one flat 180-minute paper, all questions of the year
+      jeeBox.checked = false;
+      jeeBox.dispatchEvent(new Event('change'));
+      countInput.value = 75;
+    }}
+    sync();
+  }}
+  if (modeBuild) modeBuild.addEventListener('click', () => setMode(false));
+  if (modePast) modePast.addEventListener('click', () => setMode(true));
+
+  // Radio pills inside the past panel toggle their .active class
+  document.querySelectorAll('#zp-past-panel input[type=radio]').forEach(r => {{
+    r.addEventListener('change', () => {{
+      r.closest('.zp-pill-row').querySelectorAll('.zp-filter-pill').forEach(p => p.classList.remove('active'));
+      r.closest('.zp-filter-pill').classList.add('active');
+      sync();
+    }});
+  }});
+
   // 0. Complete syllabus: check every chapter across all subjects
   const completeBtn = document.getElementById('btn-complete-syllabus');
   if (completeBtn) {{
@@ -778,6 +840,18 @@ pub fn build(ctx: &Ctx, user: &str, blocks: Vec<SubjectBlock>, _form: &BuildForm
 
   // 11. Sync state, pill badges, and submit button
   function sync() {{
+    if (pastMode) {{
+      const yr = document.querySelector('input[name=past-year]:checked');
+      const sh = document.querySelector('input[name=past-shift]:checked');
+      yearField.value = yr ? yr.value : '';
+      shiftField.value = sh ? sh.value : 'ALL';
+      summaryText.innerHTML = yr
+        ? `<b>JEE Main ${{yr.value}}${{sh && sh.value !== 'ALL' ? ' ' + sh.value : ''}}</b><span class="dim">every question of that paper</span>`
+        : '<b>pick a year</b><span class="dim">above</span>';
+      submitBtn.disabled = !yr;
+      btnDesc.textContent = yr ? 'past paper · 180 minutes' : 'pick a year first';
+      return;
+    }}
     const checkedChaps = [...document.querySelectorAll('.chap:checked')];
     const checkedSubs = [...document.querySelectorAll('.subtopic:checked')];
     chapField.value = checkedChaps.map(c => c.value).join(',');

static/style.css

@@ -2797,3 +2797,25 @@ img.brand-logo {
     position: static;
   }
 }
+
+/* Past-paper picker panel */
+.zp-past-panel {
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  background: var(--panel);
+  padding: 14px 16px;
+  margin-bottom: 16px;
+}
+
+.zp-past-panel .zp-filter-heading {
+  display: block;
+  font-size: 0.7rem;
+  font-weight: 700;
+  letter-spacing: 0.08em;
+  color: var(--text-muted);
+  margin-bottom: 8px;
+}
+
+.zp-past-panel .zp-filter-pill input[type=radio] {
+  accent-color: #2563eb;
+}