Lexivo: vocabulary learning app with SM-2 spaced repetition

- Word import (multi-format: word, word-def, word:def, word|def)
- Flashcard filter UI (swipe + keyboard arrows + Space to flip)
- SM-2 spaced repetition review queue
- Stimulus flashcard controller with 3D flip animation

app/assets/stylesheets/application.css

@@ -121,3 +121,313 @@ h1 {
   color: #b91c1c;
   font-size: 0.9rem;
 }
+
+/* ── Lexivo ── */
+
+body { background: #f0f0f7; }
+
+.topnav {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 0 24px;
+  height: 52px;
+  background: #1a1a2e;
+  color: #fff;
+}
+
+.nav-brand {
+  font-weight: 700;
+  font-size: 1.1rem;
+  color: #a5b4fc;
+  text-decoration: none;
+  letter-spacing: 0.05em;
+}
+
+.nav-links { display: flex; gap: 4px; }
+
+.nav-link {
+  color: #cbd5e1;
+  text-decoration: none;
+  padding: 6px 12px;
+  border-radius: 6px;
+  font-size: 0.9rem;
+  transition: background 0.15s, color 0.15s;
+}
+.nav-link:hover { background: #2d2d4e; color: #fff; }
+
+main .container { max-width: 700px; margin: 32px auto; padding: 0 20px; }
+
+/* Stats */
+.stats-grid {
+  display: flex;
+  gap: 10px;
+  flex-wrap: wrap;
+  margin-bottom: 24px;
+}
+
+.stat-card {
+  flex: 1 1 90px;
+  background: #fff;
+  border-radius: 10px;
+  padding: 16px 12px;
+  text-align: center;
+  border-top: 3px solid transparent;
+  box-shadow: 0 1px 4px rgba(0,0,0,.06);
+}
+
+.stat-number { font-size: 2rem; font-weight: 700; line-height: 1; }
+.stat-label  { font-size: 0.75rem; color: #6b7280; margin-top: 4px; }
+
+.stat-total    { border-color: #6366f1; }
+.stat-unseen   { border-color: #94a3b8; }
+.stat-learning { border-color: #f59e0b; }
+.stat-known    { border-color: #22c55e; }
+.stat-due      { border-color: #ef4444; }
+
+.stat-total    .stat-number { color: #6366f1; }
+.stat-due      .stat-number { color: #ef4444; }
+.stat-learning .stat-number { color: #f59e0b; }
+.stat-known    .stat-number { color: #22c55e; }
+
+.action-row {
+  display: flex;
+  gap: 10px;
+  margin-bottom: 28px;
+  flex-wrap: wrap;
+}
+
+.btn-success { background: #22c55e; color: #fff; }
+.btn-outline {
+  background: transparent;
+  color: #6366f1;
+  border: 1.5px solid #6366f1;
+}
+
+/* Import */
+.section { margin-bottom: 36px; }
+.section h2 { font-size: 1.1rem; font-weight: 600; margin-bottom: 8px; color: #111; }
+.hint { font-size: 0.82rem; color: #6b7280; margin-bottom: 10px; }
+.hint code { background: #e5e7eb; padding: 1px 4px; border-radius: 3px; font-family: monospace; }
+
+.import-textarea {
+  width: 100%;
+  padding: 10px 12px;
+  border: 1px solid #d1d5db;
+  border-radius: 8px;
+  font-family: monospace;
+  font-size: 0.9rem;
+  resize: vertical;
+  margin-bottom: 8px;
+  outline: none;
+  transition: border-color 0.15s;
+}
+.import-textarea:focus { border-color: #6366f1; }
+
+/* Word table */
+.word-table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
+.word-row { border-bottom: 1px solid #e5e7eb; }
+.word-row:hover { background: #f9fafb; }
+.word-text { padding: 8px 6px; font-weight: 600; width: 28%; }
+.word-def  { padding: 8px 6px; color: #4b5563; width: 50%; }
+.word-status { padding: 8px 6px; width: 14%; }
+.word-actions { padding: 8px 4px; text-align: right; width: 8%; }
+
+.badge {
+  display: inline-block;
+  padding: 2px 7px;
+  border-radius: 99px;
+  font-size: 0.72rem;
+  font-weight: 600;
+  text-transform: uppercase;
+}
+.badge-new      { background: #e5e7eb; color: #374151; }
+.badge-known    { background: #dcfce7; color: #166534; }
+.badge-learning { background: #fef3c7; color: #92400e; }
+.badge-skipped  { background: #f1f5f9; color: #64748b; }
+
+.due-info { font-size: 0.72rem; color: #ef4444; margin-left: 4px; }
+
+.btn-del {
+  background: none;
+  border: none;
+  color: #9ca3af;
+  cursor: pointer;
+  font-size: 0.9rem;
+  padding: 2px 6px;
+}
+.btn-del:hover { color: #ef4444; }
+
+/* Flash */
+.flash {
+  padding: 10px 14px;
+  border-radius: 8px;
+  margin-bottom: 16px;
+  font-size: 0.9rem;
+}
+.flash-notice { background: #dcfce7; color: #166534; }
+.flash-alert  { background: #fef3c7; color: #92400e; }
+
+/* ── Flashcard ── */
+
+.filter-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 20px;
+  font-size: 0.85rem;
+  color: #6b7280;
+}
+.link-muted { color: #9ca3af; text-decoration: none; }
+.link-muted:hover { color: #6b7280; }
+
+.flashcard-wrap {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 20px;
+  padding: 12px 0 32px;
+}
+
+/* 3D card container */
+.flashcard {
+  width: 100%;
+  max-width: 480px;
+  height: 240px;
+  perspective: 1000px;
+  cursor: pointer;
+  position: relative;
+  transform-style: preserve-3d;
+  transition: transform 0.38s ease, opacity 0.22s ease, translate 0.22s ease;
+}
+
+.flashcard.is-flipped { transform: rotateY(180deg); }
+
+.flashcard.slide-right {
+  translate: 120% 0;
+  opacity: 0;
+}
+.flashcard.slide-left {
+  translate: -120% 0;
+  opacity: 0;
+}
+.flashcard.slide-up {
+  translate: 0 -80px;
+  opacity: 0;
+}
+
+.card-face {
+  position: absolute;
+  inset: 0;
+  backface-visibility: hidden;
+  -webkit-backface-visibility: hidden;
+  border-radius: 14px;
+  background: #fff;
+  box-shadow: 0 4px 24px rgba(0,0,0,.1);
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  padding: 28px 24px;
+  text-align: center;
+  user-select: none;
+}
+
+.card-back { transform: rotateY(180deg); }
+
+.card-word {
+  font-size: 2rem;
+  font-weight: 700;
+  color: #1a1a2e;
+  margin-bottom: 10px;
+}
+
+.card-definition {
+  font-size: 1.1rem;
+  color: #374151;
+  line-height: 1.5;
+}
+.card-definition.muted { color: #9ca3af; font-style: italic; }
+
+.card-example {
+  margin-top: 10px;
+  font-size: 0.9rem;
+  color: #6b7280;
+}
+
+.card-interval {
+  font-size: 0.75rem;
+  color: #9ca3af;
+  margin-bottom: 8px;
+}
+
+.flip-hint {
+  position: absolute;
+  bottom: 12px;
+  font-size: 0.72rem;
+  color: #d1d5db;
+  pointer-events: none;
+}
+
+/* Action buttons */
+.card-actions {
+  display: flex;
+  gap: 10px;
+  justify-content: center;
+  flex-wrap: wrap;
+}
+
+.inline-form { display: inline; }
+
+.btn-learning { background: #6366f1; color: #fff; min-width: 110px; justify-content: center; }
+.btn-known    { background: #22c55e; color: #fff; min-width: 110px; justify-content: center; }
+.btn-skip     { background: #e5e7eb; color: #374151; min-width: 90px; justify-content: center; }
+
+/* Keyboard hint row */
+.key-hint {
+  font-size: 0.8rem;
+  color: #9ca3af;
+}
+kbd {
+  display: inline-block;
+  padding: 1px 6px;
+  border: 1px solid #d1d5db;
+  border-radius: 4px;
+  background: #f9fafb;
+  font-size: 0.75rem;
+  font-family: monospace;
+  color: #374151;
+}
+
+/* Empty state */
+.empty-state {
+  text-align: center;
+  padding: 60px 20px;
+}
+.empty-icon {
+  font-family: monospace;
+  font-size: 2rem;
+  color: #d1d5db;
+  margin-bottom: 16px;
+}
+.empty-state h2 { margin-bottom: 10px; }
+.empty-state p  { color: #6b7280; margin-bottom: 24px; }
+
+/* Upcoming list */
+.upcoming-list {
+  max-width: 320px;
+  margin: 0 auto 24px;
+  text-align: left;
+}
+.upcoming-item {
+  display: flex;
+  justify-content: space-between;
+  padding: 6px 0;
+  border-bottom: 1px solid #e5e7eb;
+  font-size: 0.9rem;
+}
+.upcoming-word { font-weight: 600; }
+.upcoming-when { color: #9ca3af; }
+
+.progress-text { font-size: 0.85rem; color: #6b7280; }
+

app/controllers/filter_controller.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class FilterController < ApplicationController
+  def show
+    @word      = Word.unseen.order(:id).first
+    @remaining = Word.unseen.count
+    @total     = Word.count
+  end
+
+  def known
+    Word.find(params[:id]).review.mark_known!
+    redirect_to filter_path
+  end
+
+  def learning
+    Word.find(params[:id]).review.mark_learning!
+    redirect_to filter_path
+  end
+
+  def skip
+    Word.find(params[:id]).review.mark_skipped!
+    redirect_to filter_path
+  end
+end

app/controllers/reviews_controller.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class ReviewsController < ApplicationController
+  def show
+    @review        = Review.due.includes(:word).first
+    @due_count     = Review.due.count
+    @upcoming      = Review.upcoming.includes(:word).limit(5)
+    @upcoming_count = Review.upcoming.count
+  end
+
+  def rate
+    review  = Review.find(params[:id])
+    quality = case params[:rating]
+              when "easy"   then 5
+              when "good"   then 4
+              when "hard"   then 3
+              when "forgot" then 1
+              else params[:quality].to_i
+              end
+    review.sm2_update!(quality)
+    redirect_to review_path
+  end
+end

app/controllers/words_controller.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+class WordsController < ApplicationController
+  def index
+    @stats = {
+      total:    Word.count,
+      unseen:   Review.where(status: "new").count,
+      known:    Review.where(status: "known").count,
+      learning: Review.where(status: "learning").count,
+      skipped:  Review.where(status: "skipped").count,
+      due:      Review.due.count
+    }
+    @words = Word.includes(:review).by_text
+  end
+
+  def create
+    raw   = params[:word_list].to_s.strip
+    lines = raw.split("\n").map(&:strip).reject { |l| l.blank? || l.start_with?("#") }
+
+    imported = 0
+    skipped  = 0
+
+    lines.each do |line|
+      text, definition = parse_line(line)
+      next if text.blank?
+
+      w = Word.new(text: text.strip, definition: definition&.strip.presence)
+      if w.save
+        imported += 1
+      else
+        skipped += 1
+      end
+    end
+
+    flash[:notice] = "Imported #{imported} word#{"s" unless imported == 1}."
+    flash[:alert]  = "Skipped #{skipped} (duplicates or invalid)." if skipped > 0
+    redirect_to words_path
+  end
+
+  def destroy
+    Word.find(params[:id]).destroy
+    redirect_to words_path, notice: "Removed."
+  end
+
+  private
+
+  def parse_line(line)
+    # "word - definition", "word: definition", "word | definition", "word\tdefinition"
+    if (m = line.match(/\A(.+?)\s*(?:\t|-{1,2}|:{1,2}|\|)\s*(.+)\z/))
+      [ m[1], m[2] ]
+    else
+      [ line, nil ]
+    end
+  end
+end

app/javascript/controllers/flashcard_controller.js

@@ -0,0 +1,125 @@
+import { Controller } from "@hotwired/stimulus"
+
+// Handles flashcard flip + keyboard + swipe for both filter and review pages.
+// Expected DOM:
+//   data-controller="flashcard"
+//   data-flashcard-target="card"  (the 3D flippable element)
+//
+// Hidden forms in the same element:
+//   id="form-right"  — known / easy
+//   id="form-left"   — learning / forgot
+//   id="form-skip"   — skip (filter only)
+//   id="form-q3"     — hard (review only)
+
+export default class extends Controller {
+  static targets = ["card"]
+
+  connect() {
+    this.flipped   = false
+    this.animating = false
+    this.touchStartX = 0
+    this.touchStartY = 0
+
+    this._keydown = this.handleKeydown.bind(this)
+    document.addEventListener("keydown", this._keydown)
+  }
+
+  disconnect() {
+    document.removeEventListener("keydown", this._keydown)
+  }
+
+  // ── Keyboard ──────────────────────────────────────────────────────────────
+
+  handleKeydown(e) {
+    if (this.animating) return
+
+    switch (e.key) {
+      case " ":
+        e.preventDefault()
+        this.flip()
+        break
+      case "ArrowDown":
+        e.preventDefault()
+        this.flip()
+        break
+      case "ArrowRight":
+        e.preventDefault()
+        this.slideAndSubmit("slide-right", "form-right")
+        break
+      case "ArrowLeft":
+        e.preventDefault()
+        this.slideAndSubmit("slide-left", "form-left")
+        break
+      case "s":
+      case "S":
+      case "ArrowUp":
+        e.preventDefault()
+        this.slideAndSubmit("slide-up", "form-skip")
+        break
+      case "1":
+        e.preventDefault()
+        this.slideAndSubmit("slide-left", "form-left")
+        break
+      case "2":
+        e.preventDefault()
+        this.slideAndSubmit("slide-up", "form-q3")
+        break
+      case "3":
+        e.preventDefault()
+        this.slideAndSubmit("slide-right", "form-right")
+        break
+    }
+  }
+
+  // ── Touch / swipe ─────────────────────────────────────────────────────────
+
+  touchstart(e) {
+    const t = e.changedTouches[0]
+    this.touchStartX = t.clientX
+    this.touchStartY = t.clientY
+  }
+
+  touchend(e) {
+    if (this.animating) return
+    const t  = e.changedTouches[0]
+    const dx = t.clientX - this.touchStartX
+    const dy = t.clientY - this.touchStartY
+
+    // Small movement = tap, handled by click -> flip
+    if (Math.abs(dx) < 20 && Math.abs(dy) < 20) return
+
+    e.preventDefault() // prevent the click event that follows
+
+    if (Math.abs(dx) >= Math.abs(dy) && Math.abs(dx) > 40) {
+      dx > 0
+        ? this.slideAndSubmit("slide-right", "form-right")
+        : this.slideAndSubmit("slide-left",  "form-left")
+    }
+  }
+
+  // ── Card flip ─────────────────────────────────────────────────────────────
+
+  flip(e) {
+    if (e) e.stopPropagation()
+    this.flipped = !this.flipped
+    this.cardTarget.classList.toggle("is-flipped", this.flipped)
+  }
+
+  // ── Form submission ───────────────────────────────────────────────────────
+
+  slideAndSubmit(animClass, formId) {
+    this.animating = true
+    this.cardTarget.classList.add(animClass)
+
+    setTimeout(() => {
+      const form = this.element.querySelector(`#${formId}`)
+      if (form) {
+        form.requestSubmit()
+      } else {
+        // form not present on this page variant — ignore silently
+        this.animating = false
+        this.cardTarget.classList.remove(animClass)
+      }
+    }, 220)
+  }
+}

app/models/review.rb

@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+class Review < ApplicationRecord
+  belongs_to :word
+
+  EASE_MIN   = 1.3
+  EASE_START = 2.5
+
+  # status: new | known | learning | skipped
+
+  scope :due,      -> { where(status: "learning").where("due_at <= ?", Time.current).order(:due_at) }
+  scope :upcoming, -> { where(status: "learning").order(:due_at) }
+
+  def mark_known!
+    update!(status: "known", last_reviewed_at: Time.current, due_at: nil)
+  end
+
+  def mark_learning!
+    update!(
+      status: "learning",
+      interval: 1,
+      repetitions: 0,
+      ease_factor: EASE_START,
+      due_at: 1.day.from_now,
+      last_reviewed_at: Time.current
+    )
+  end
+
+  def mark_skipped!
+    update!(status: "skipped", last_reviewed_at: Time.current)
+  end
+
+  # SM-2 algorithm: quality 0-5
+  # 0-2 = forgot/hard  3-5 = remembered
+  def sm2_update!(quality)
+    quality = quality.to_i.clamp(0, 5)
+
+    new_ease = [EASE_MIN, ease_factor + 0.1 - (5 - quality) * (0.08 + (5 - quality) * 0.02)].max.round(3)
+
+    if quality < 3
+      update!(
+        status: "learning",
+        repetitions: 0,
+        interval: 1,
+        ease_factor: new_ease,
+        due_at: 1.day.from_now,
+        last_reviewed_at: Time.current
+      )
+    else
+      new_reps = repetitions + 1
+      new_interval = case repetitions
+        when 0 then 1
+        when 1 then 6
+        else [ (interval * new_ease).ceil, 1 ].max
+      end
+      update!(
+        status: "learning",
+        repetitions: new_reps,
+        interval: new_interval,
+        ease_factor: new_ease,
+        due_at: new_interval.days.from_now,
+        last_reviewed_at: Time.current
+      )
+    end
+  end
+
+  def due_label
+    return "Now" unless due_at
+    return "Now" if due_at <= Time.current
+
+    days = ((due_at - Time.current) / 1.day).ceil
+    case days
+    when 0 then "Today"
+    when 1 then "Tomorrow"
+    else "#{days} days"
+    end
+  end
+end

app/models/word.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class Word < ApplicationRecord
+  has_one :review, dependent: :destroy
+
+  validates :text, presence: true, uniqueness: { case_sensitive: false }
+  validates :text, length: { maximum: 255 }
+
+  after_create :create_initial_review
+
+  scope :unseen,   -> { joins(:review).where(reviews: { status: "new" }) }
+  scope :known,    -> { joins(:review).where(reviews: { status: "known" }) }
+  scope :learning, -> { joins(:review).where(reviews: { status: "learning" }) }
+  scope :by_text,  -> { order(:text) }
+
+  private
+
+  def create_initial_review
+    create_review!(status: "new")
+  end
+end

app/views/filter/show.html.erb

@@ -0,0 +1,75 @@
+<% content_for :title, "Filter — Lexivo" %>
+
+<div class="container">
+  <% if @word.nil? %>
+    <div class="empty-state">
+      <div class="empty-icon">--o</div>
+      <h2>All words filtered!</h2>
+      <p>
+        Nothing left to sort.
+        <% learning_count = Review.where(status: "learning").count %>
+        <% if learning_count > 0 %>
+          You have <%= learning_count %> word<%= "s" unless learning_count == 1 %> in the learning queue.
+          <%= link_to "Go to review", review_path %>
+        <% end %>
+      </p>
+      <%= link_to "Back to words", words_path, class: "btn btn-outline" %>
+    </div>
+  <% else %>
+    <div class="filter-header">
+      <span class="progress-text">
+        <%= @remaining %> remaining
+        <% if @total > 0 %>
+          &nbsp;&middot;&nbsp;
+          <%= ((@total - @remaining).to_f / @total * 100).round %>% done
+        <% end %>
+      </span>
+      <%= link_to "word list", words_path, class: "link-muted" %>
+    </div>
+
+    <div class="flashcard-wrap" data-controller="flashcard">
+      <div class="flashcard" data-flashcard-target="card"
+           data-action="touchstart->flashcard#touchstart touchend->flashcard#touchend click->flashcard#flip">
+        <div class="card-face card-front">
+          <div class="card-word"><%= @word.text %></div>
+          <div class="flip-hint">Space / tap to flip</div>
+        </div>
+        <div class="card-face card-back">
+          <div class="card-word"><%= @word.text %></div>
+          <% if @word.definition.present? %>
+            <div class="card-definition"><%= @word.definition %></div>
+          <% else %>
+            <div class="card-definition muted">No definition</div>
+          <% end %>
+          <% if @word.example.present? %>
+            <div class="card-example"><em><%= @word.example %></em></div>
+          <% end %>
+        </div>
+      </div>
+
+      <div class="card-actions">
+        <%= form_with url: filter_learning_path(@word), method: :post, id: "form-left", class: "inline-form",
+              data: { turbo_frame: "_top" } do |f| %>
+          <%= f.submit "Learning  ←", class: "btn btn-learning" %>
+        <% end %>
+
+        <%= form_with url: filter_skip_path(@word), method: :post, id: "form-skip", class: "inline-form",
+              data: { turbo_frame: "_top" } do |f| %>
+          <%= f.submit "Skip  S", class: "btn btn-skip" %>
+        <% end %>
+
+        <%= form_with url: filter_known_path(@word), method: :post, id: "form-right", class: "inline-form",
+              data: { turbo_frame: "_top" } do |f| %>
+          <%= f.submit "Known  →", class: "btn btn-known" %>
+        <% end %>
+      </div>
+
+      <div class="key-hint">
+        <kbd>←</kbd> Learning &nbsp;&nbsp;
+        <kbd>Space</kbd> Flip &nbsp;&nbsp;
+        <kbd>→</kbd> Known &nbsp;&nbsp;
+        <kbd>S</kbd> Skip
+      </div>
+    </div>
+  <% end %>
+</div>

app/views/layouts/application.html.erb

@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
   <head>
-    <title><%= content_for(:title) || "Starter" %></title>
+    <title><%= content_for(:title) || "Lexivo" %></title>
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <meta name="apple-mobile-web-app-capable" content="yes">
     <meta name="application-name" content="Starter">
@@ -42,6 +42,16 @@
   </head>
 
   <body>
-    <%= yield %>
+    <nav class="topnav">
+      <%= link_to "Lexivo", root_path, class: "nav-brand" %>
+      <div class="nav-links">
+        <%= link_to "Words",  words_path,  class: "nav-link" %>
+        <%= link_to "Filter", filter_path, class: "nav-link" %>
+        <%= link_to "Review", review_path, class: "nav-link" %>
+      </div>
+    </nav>
+    <main>
+      <%= yield %>
+    </main>
   </body>
 </html>

app/views/reviews/show.html.erb

@@ -0,0 +1,77 @@
+<% content_for :title, "Review — Lexivo" %>
+
+<div class="container">
+  <% if @review.nil? %>
+    <div class="empty-state">
+      <div class="empty-icon">zz</div>
+      <h2>Nothing due!</h2>
+      <% if @upcoming_count > 0 %>
+        <p>Next review: <%= @upcoming.first.due_label %> &mdash; <%= @upcoming_count %> upcoming.</p>
+        <div class="upcoming-list">
+          <% @upcoming.each do |r| %>
+            <div class="upcoming-item">
+              <span class="upcoming-word"><%= r.word.text %></span>
+              <span class="upcoming-when"><%= r.due_label %></span>
+            </div>
+          <% end %>
+        </div>
+      <% else %>
+        <p>No words in the learning queue yet. <%= link_to "Filter some words first", filter_path %>.</p>
+      <% end %>
+      <%= link_to "Back to words", words_path, class: "btn btn-outline" %>
+    </div>
+  <% else %>
+    <div class="filter-header">
+      <span class="progress-text">
+        <%= @due_count %> due &nbsp;&middot;&nbsp; <%= @upcoming_count %> upcoming
+      </span>
+      <%= link_to "word list", words_path, class: "link-muted" %>
+    </div>
+
+    <div class="flashcard-wrap" data-controller="flashcard">
+      <div class="flashcard" data-flashcard-target="card"
+           data-action="touchstart->flashcard#touchstart touchend->flashcard#touchend click->flashcard#flip">
+        <div class="card-face card-front">
+          <div class="card-word"><%= @review.word.text %></div>
+          <div class="card-interval">interval: <%= @review.interval %>d &nbsp;&middot;&nbsp; rep #<%= @review.repetitions %></div>
+          <div class="flip-hint">Space / tap to flip</div>
+        </div>
+        <div class="card-face card-back">
+          <div class="card-word"><%= @review.word.text %></div>
+          <% if @review.word.definition.present? %>
+            <div class="card-definition"><%= @review.word.definition %></div>
+          <% end %>
+          <% if @review.word.example.present? %>
+            <div class="card-example"><em><%= @review.word.example %></em></div>
+          <% end %>
+        </div>
+      </div>
+
+      <div class="card-actions">
+        <%= form_with url: rate_review_path(@review), method: :post, id: "form-left", class: "inline-form",
+              data: { turbo_frame: "_top" } do |f| %>
+          <%= f.hidden_field :rating, value: "forgot" %>
+          <%= f.submit "Forgot  1", class: "btn btn-learning" %>
+        <% end %>
+
+        <%= form_with url: rate_review_path(@review), method: :post, id: "form-q3", class: "inline-form",
+              data: { turbo_frame: "_top" } do |f| %>
+          <%= f.hidden_field :rating, value: "hard" %>
+          <%= f.submit "Hard  2", class: "btn btn-skip" %>
+        <% end %>
+
+        <%= form_with url: rate_review_path(@review), method: :post, id: "form-right", class: "inline-form",
+              data: { turbo_frame: "_top" } do |f| %>
+          <%= f.hidden_field :rating, value: "easy" %>
+          <%= f.submit "Easy  3", class: "btn btn-known" %>
+        <% end %>
+      </div>
+
+      <div class="key-hint">
+        <kbd>1</kbd> / <kbd>←</kbd> Forgot &nbsp;&nbsp;
+        <kbd>2</kbd> Hard &nbsp;&nbsp;
+        <kbd>3</kbd> / <kbd>→</kbd> Easy
+      </div>
+    </div>
+  <% end %>
+</div>

app/views/words/index.html.erb

@@ -0,0 +1,85 @@
+<% content_for :title, "Lexivo" %>
+
+<div class="container">
+  <% if notice.present? %>
+    <div class="flash flash-notice"><%= notice %></div>
+  <% end %>
+  <% if alert.present? %>
+    <div class="flash flash-alert"><%= alert %></div>
+  <% end %>
+
+  <div class="stats-grid">
+    <div class="stat-card stat-total">
+      <div class="stat-number"><%= @stats[:total] %></div>
+      <div class="stat-label">Total</div>
+    </div>
+    <div class="stat-card stat-unseen">
+      <div class="stat-number"><%= @stats[:unseen] %></div>
+      <div class="stat-label">Unseen</div>
+    </div>
+    <div class="stat-card stat-learning">
+      <div class="stat-number"><%= @stats[:learning] %></div>
+      <div class="stat-label">Learning</div>
+    </div>
+    <div class="stat-card stat-known">
+      <div class="stat-number"><%= @stats[:known] %></div>
+      <div class="stat-label">Known</div>
+    </div>
+    <div class="stat-card stat-due">
+      <div class="stat-number"><%= @stats[:due] %></div>
+      <div class="stat-label">Due Now</div>
+    </div>
+  </div>
+
+  <div class="action-row">
+    <% if @stats[:unseen] > 0 %>
+      <%= link_to "Filter words (#{@stats[:unseen]} unseen)", filter_path, class: "btn btn-primary" %>
+    <% end %>
+    <% if @stats[:due] > 0 %>
+      <%= link_to "Review (#{@stats[:due]} due)", review_path, class: "btn btn-success" %>
+    <% end %>
+    <% if @stats[:learning] > 0 && @stats[:due] == 0 %>
+      <%= link_to "Review queue (#{@stats[:learning]} upcoming)", review_path, class: "btn btn-outline" %>
+    <% end %>
+  </div>
+
+  <div class="section">
+    <h2>Import words</h2>
+    <p class="hint">
+      One entry per line. Formats: <code>word - definition</code> &nbsp;|&nbsp;
+      <code>word: definition</code> &nbsp;|&nbsp; <code>word | definition</code> &nbsp;|&nbsp;
+      just <code>word</code>
+    </p>
+    <%= form_with url: words_path, method: :post, local: false, data: { turbo: false } do |f| %>
+      <%= f.text_area :word_list, placeholder: "ephemeral - lasting for a very short time\npersistent\ntenacious: holding firmly to a purpose", rows: 8, class: "import-textarea" %>
+      <%= f.submit "Import", class: "btn btn-primary" %>
+    <% end %>
+  </div>
+
+  <% if @words.any? %>
+    <div class="section">
+      <h2>All words (<%= @words.count %>)</h2>
+      <table class="word-table">
+        <tbody>
+          <% @words.each do |word| %>
+            <tr class="word-row status-<%= word.review&.status || "new" %>">
+              <td class="word-text"><%= word.text %></td>
+              <td class="word-def"><%= word.definition.presence || "-" %></td>
+              <td class="word-status">
+                <span class="badge badge-<%= word.review&.status %>">
+                  <%= word.review&.status || "new" %>
+                </span>
+                <% if word.review&.status == "learning" && word.review.due_at %>
+                  <span class="due-info"><%= word.review.due_label %></span>
+                <% end %>
+              </td>
+              <td class="word-actions">
+                <%= button_to "x", word_path(word), method: :delete, class: "btn-del", data: { turbo_confirm: "Remove #{word.text}?" } %>
+              </td>
+            </tr>
+          <% end %>
+        </tbody>
+      </table>
+    </div>
+  <% end %>
+</div>

config/routes.rb

@@ -1,17 +1,19 @@
 # frozen_string_literal: true
 
 Rails.application.routes.draw do
-  get "up" => "rails/health#show", as: :rails_health_check
+  get  "up"             => "rails/health#show", as: :rails_health_check
+  get  "manifest"       => "rails/pwa#manifest", as: :pwa_manifest
+  get  "service-worker" => "rails/pwa#service_worker", as: :pwa_service_worker
 
-  # Render dynamic PWA files from app/views/pwa/*
+  resources :words, only: [ :index, :create, :destroy ]
-  get "manifest" => "rails/pwa#manifest", as: :pwa_manifest
-  get "service-worker" => "rails/pwa#service_worker", as: :pwa_service_worker
 
-  resources :todos, only: [:index, :create, :edit, :update, :destroy] do
+  get  "/filter",              to: "filter#show",     as: :filter
-    member do
+  post "/filter/:id/known",    to: "filter#known",    as: :filter_known
-      patch :toggle
+  post "/filter/:id/learning", to: "filter#learning", as: :filter_learning
-    end
+  post "/filter/:id/skip",     to: "filter#skip",     as: :filter_skip
-  end
 
-  root "todos#index"
+  get  "/review",          to: "reviews#show", as: :review
+  post "/review/:id/rate", to: "reviews#rate", as: :rate_review
+
+  root "words#index"
 end

db/migrate/20260422000001_create_words.rb

@@ -0,0 +1,11 @@
+class CreateWords < ActiveRecord::Migration[8.1]
+  def change
+    create_table :words do |t|
+      t.string :text, null: false
+      t.text :definition
+      t.text :example
+      t.timestamps
+    end
+    add_index :words, :text, unique: true
+  end
+end

db/migrate/20260422000002_create_reviews.rb

@@ -0,0 +1,16 @@
+class CreateReviews < ActiveRecord::Migration[8.1]
+  def change
+    create_table :reviews do |t|
+      t.references :word, null: false, foreign_key: true
+      t.string  :status,      null: false, default: "new"
+      t.integer :interval,    null: false, default: 0
+      t.integer :repetitions, null: false, default: 0
+      t.float   :ease_factor, null: false, default: 2.5
+      t.datetime :due_at
+      t.datetime :last_reviewed_at
+      t.timestamps
+    end
+    add_index :reviews, :status
+    add_index :reviews, [ :status, :due_at ]
+  end
+end