Add shopping mode for focused single-store shopping (#34)

- Full-screen view for one store at a time
- Tap items to toggle completion
- Completed items greyed and sorted to bottom
- Quick-add form at bottom of screen
- Store switcher pills for easy navigation
- "Shop" button on each store in shopping tab

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

5 files changed, 297 insertions, 8 deletions

diff --git a/cmd/dashboard/main.go b/cmd/dashboard/main.go
index 6c735d8..a02ece4 100644
--- a/cmd/dashboard/main.go
+++ b/cmd/dashboard/main.go
@@ -182,6 +182,10 @@ func main() {
 		// Shopping quick-add
 		r.Post("/shopping/add", h.HandleShoppingQuickAdd)
 		r.Post("/shopping/toggle", h.HandleShoppingToggle)
+
+		// Shopping mode (focused single-store view)
+		r.Get("/shopping/mode/{store}", h.HandleShoppingMode)
+		r.Post("/shopping/mode/{store}/toggle", h.HandleShoppingModeToggle)
 	})
 
 	// Start server
diff --git a/internal/handlers/handlers.go b/internal/handlers/handlers.go
index a1a12e7..115d903 100644
--- a/internal/handlers/handlers.go
+++ b/internal/handlers/handlers.go
@@ -6,12 +6,15 @@ import (
 	"html/template"
 	"log"
 	"net/http"
+	"net/url"
 	"path/filepath"
 	"sort"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/go-chi/chi/v5"
+
 	"task-dashboard/internal/api"
 	"task-dashboard/internal/auth"
 	"task-dashboard/internal/config"
@@ -1147,25 +1150,51 @@ func (h *Handler) HandleShoppingQuickAdd(w http.ResponseWriter, r *http.Request)
 	}
 
 	name := strings.TrimSpace(r.FormValue("name"))
-	store := strings.TrimSpace(r.FormValue("store"))
+	storeName := strings.TrimSpace(r.FormValue("store"))
+	mode := r.FormValue("mode") // "shopping-mode" if from shopping mode page
 
 	if name == "" {
 		JSONError(w, http.StatusBadRequest, "Name is required", nil)
 		return
 	}
-	if store == "" {
-		store = "Quick Add"
+	if storeName == "" {
+		storeName = "Quick Add"
 	}
 
-	if err := h.store.SaveUserShoppingItem(name, store); err != nil {
+	if err := h.store.SaveUserShoppingItem(name, storeName); err != nil {
 		JSONError(w, http.StatusInternalServerError, "Failed to save item", err)
 		return
 	}
 
-	// Return refreshed shopping tab
 	ctx := r.Context()
-	stores := h.aggregateShoppingLists(ctx)
-	HTMLResponse(w, h.templates, "shopping-tab", struct{ Stores []models.ShoppingStore }{stores})
+	allStores := h.aggregateShoppingLists(ctx)
+
+	// If called from shopping mode, return just the items for that store
+	if mode == "shopping-mode" {
+		var items []models.UnifiedShoppingItem
+		for _, store := range allStores {
+			if strings.EqualFold(store.Name, storeName) {
+				for _, cat := range store.Categories {
+					items = append(items, cat.Items...)
+				}
+			}
+		}
+		// Sort: unchecked first, then checked
+		sort.Slice(items, func(i, j int) bool {
+			if items[i].Checked != items[j].Checked {
+				return !items[i].Checked
+			}
+			return items[i].Name < items[j].Name
+		})
+		HTMLResponse(w, h.templates, "shopping-mode-items", struct {
+			StoreName string
+			Items     []models.UnifiedShoppingItem
+		}{storeName, items})
+		return
+	}
+
+	// Return refreshed shopping tab
+	HTMLResponse(w, h.templates, "shopping-tab", struct{ Stores []models.ShoppingStore }{allStores})
 }
 
 // HandleShoppingToggle toggles a shopping item's checked state
@@ -1206,6 +1235,115 @@ func (h *Handler) HandleShoppingToggle(w http.ResponseWriter, r *http.Request) {
 	HTMLResponse(w, h.templates, "shopping-tab", struct{ Stores []models.ShoppingStore }{stores})
 }
 
+// HandleShoppingMode renders the focused shopping mode for a single store
+func (h *Handler) HandleShoppingMode(w http.ResponseWriter, r *http.Request) {
+	storeName := chi.URLParam(r, "store")
+	if storeName == "" {
+		http.Redirect(w, r, "/?tab=shopping", http.StatusFound)
+		return
+	}
+
+	// URL decode the store name
+	storeName, _ = url.QueryUnescape(storeName)
+
+	ctx := r.Context()
+	allStores := h.aggregateShoppingLists(ctx)
+
+	// Find the requested store
+	var items []models.UnifiedShoppingItem
+	var storeNames []string
+	for _, store := range allStores {
+		storeNames = append(storeNames, store.Name)
+		if strings.EqualFold(store.Name, storeName) {
+			// Flatten categories into single item list
+			for _, cat := range store.Categories {
+				items = append(items, cat.Items...)
+			}
+		}
+	}
+
+	// Sort: unchecked first, then checked (both alphabetically within their group)
+	sort.Slice(items, func(i, j int) bool {
+		if items[i].Checked != items[j].Checked {
+			return !items[i].Checked // unchecked items first
+		}
+		return items[i].Name < items[j].Name
+	})
+
+	data := struct {
+		StoreName  string
+		Items      []models.UnifiedShoppingItem
+		StoreNames []string
+	}{
+		StoreName:  storeName,
+		Items:      items,
+		StoreNames: storeNames,
+	}
+
+	HTMLResponse(w, h.templates, "shopping-mode", data)
+}
+
+// HandleShoppingModeToggle toggles an item in shopping mode and returns updated list
+func (h *Handler) HandleShoppingModeToggle(w http.ResponseWriter, r *http.Request) {
+	storeName := chi.URLParam(r, "store")
+	if err := r.ParseForm(); err != nil {
+		JSONError(w, http.StatusBadRequest, "Failed to parse form", err)
+		return
+	}
+
+	id := r.FormValue("id")
+	source := r.FormValue("source")
+	checked := r.FormValue("checked") == "true"
+
+	// Toggle the item
+	switch source {
+	case "user":
+		var userID int64
+		if _, err := fmt.Sscanf(id, "user-%d", &userID); err != nil {
+			JSONError(w, http.StatusBadRequest, "Invalid user item ID", err)
+			return
+		}
+		if err := h.store.ToggleUserShoppingItem(userID, checked); err != nil {
+			JSONError(w, http.StatusInternalServerError, "Failed to toggle item", err)
+			return
+		}
+	case "trello", "plantoeat":
+		if err := h.store.SetShoppingItemChecked(source, id, checked); err != nil {
+			JSONError(w, http.StatusInternalServerError, "Failed to toggle item", err)
+			return
+		}
+	}
+
+	// URL decode the store name
+	storeName, _ = url.QueryUnescape(storeName)
+
+	// Return updated item list partial
+	ctx := r.Context()
+	allStores := h.aggregateShoppingLists(ctx)
+
+	var items []models.UnifiedShoppingItem
+	for _, store := range allStores {
+		if strings.EqualFold(store.Name, storeName) {
+			for _, cat := range store.Categories {
+				items = append(items, cat.Items...)
+			}
+		}
+	}
+
+	// Sort: unchecked first, then checked
+	sort.Slice(items, func(i, j int) bool {
+		if items[i].Checked != items[j].Checked {
+			return !items[i].Checked
+		}
+		return items[i].Name < items[j].Name
+	})
+
+	HTMLResponse(w, h.templates, "shopping-mode-items", struct {
+		StoreName string
+		Items     []models.UnifiedShoppingItem
+	}{storeName, items})
+}
+
 // aggregateShoppingLists combines Trello, PlanToEat, and user shopping items by store
 func (h *Handler) aggregateShoppingLists(ctx context.Context) []models.ShoppingStore {
 	storeMap := make(map[string]map[string][]models.UnifiedShoppingItem)
diff --git a/web/templates/partials/shopping-mode-items.html b/web/templates/partials/shopping-mode-items.html
new file mode 100644
index 0000000..fdf0674
--- /dev/null
+++ b/web/templates/partials/shopping-mode-items.html
@@ -0,0 +1,45 @@
+{{define "shopping-mode-items"}}
+<div class="space-y-2">
+    {{if .Items}}
+    {{range .Items}}
+    <div class="item-row flex items-center gap-3 p-4 bg-white/5 rounded-xl border border-white/10 cursor-pointer {{if .Checked}}item-checked{{end}}"
+         hx-post="/shopping/mode/{{$.StoreName}}/toggle"
+         hx-vals='{"id":"{{.ID}}","source":"{{.Source}}","checked":{{if .Checked}}false{{else}}true{{end}}}'
+         hx-target="#shopping-items"
+         hx-swap="innerHTML">
+
+        <!-- Checkbox visual -->
+        <div class="w-6 h-6 rounded-full border-2 flex items-center justify-center flex-shrink-0
+                    {{if .Checked}}bg-green-500/30 border-green-500{{else}}border-white/30{{end}}">
+            {{if .Checked}}
+            <svg class="w-4 h-4 text-green-400" fill="currentColor" viewBox="0 0 20 20">
+                <path fill-rule="evenodd" d="M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z" clip-rule="evenodd"></path>
+            </svg>
+            {{end}}
+        </div>
+
+        <!-- Item content -->
+        <div class="flex-1 min-w-0">
+            <span class="item-name text-white block">{{.Name}}</span>
+            {{if .Quantity}}
+            <span class="text-sm text-white/50">{{.Quantity}}</span>
+            {{end}}
+        </div>
+
+        <!-- Source badge -->
+        <span class="text-xs px-2 py-0.5 rounded flex-shrink-0
+                    {{if eq .Source "trello"}}bg-blue-900/50 text-blue-300
+                    {{else if eq .Source "user"}}bg-purple-900/50 text-purple-300
+                    {{else}}bg-green-900/50 text-green-300{{end}}">
+            {{.Source}}
+        </span>
+    </div>
+    {{end}}
+    {{else}}
+    <div class="text-center py-16 text-white/50">
+        <p class="text-lg mb-2">No items</p>
+        <p class="text-sm">Add items using the form below</p>
+    </div>
+    {{end}}
+</div>
+{{end}}
diff --git a/web/templates/partials/shopping-tab.html b/web/templates/partials/shopping-tab.html
index f247f3d..4d0ac02 100644
--- a/web/templates/partials/shopping-tab.html
+++ b/web/templates/partials/shopping-tab.html
@@ -29,7 +29,16 @@
     {{if .Stores}}
     {{range .Stores}}
     <section class="bg-panel backdrop-blur-sm rounded-xl p-4 sm:p-5">
-        <h2 class="text-xl font-medium mb-4 text-white">{{.Name}}</h2>
+        <div class="flex items-center justify-between mb-4">
+            <h2 class="text-xl font-medium text-white">{{.Name}}</h2>
+            <a href="/shopping/mode/{{.Name}}"
+               class="px-3 py-1.5 bg-white/10 hover:bg-white/20 rounded-lg text-sm text-white/70 hover:text-white transition-colors flex items-center gap-1.5">
+                <svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M3 3h2l.4 2M7 13h10l4-8H5.4M7 13L5.4 5M7 13l-2.293 2.293c-.63.63-.184 1.707.707 1.707H17m0 0a2 2 0 100 4 2 2 0 000-4zm-8 2a2 2 0 11-4 0 2 2 0 014 0z"></path>
+                </svg>
+                Shop
+            </a>
+        </div>
         {{range .Categories}}
         <div class="mb-4 last:mb-0">
             {{if .Name}}<h3 class="text-sm text-white/60 mb-2 uppercase tracking-wide">{{.Name}}</h3>{{end}}
diff --git a/web/templates/shopping-mode.html b/web/templates/shopping-mode.html
new file mode 100644
index 0000000..9e21ac6
--- /dev/null
+++ b/web/templates/shopping-mode.html
@@ -0,0 +1,93 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
+    <title>{{.StoreName}} - Shopping</title>
+    <link rel="icon" type="image/svg+xml" href="/static/favicon.svg">
+    <link rel="stylesheet" href="/static/css/output.css">
+    <script src="/static/js/htmx.min.js"></script>
+    <style>
+        body {
+            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
+            min-height: 100vh;
+            margin: 0;
+            padding: 0;
+        }
+        .item-row {
+            transition: all 0.2s ease;
+        }
+        .item-row:active {
+            transform: scale(0.98);
+            background: rgba(255,255,255,0.15);
+        }
+        .item-checked {
+            opacity: 0.5;
+        }
+        .item-checked .item-name {
+            text-decoration: line-through;
+            color: rgba(255,255,255,0.4);
+        }
+        .store-switcher {
+            scrollbar-width: none;
+            -ms-overflow-style: none;
+        }
+        .store-switcher::-webkit-scrollbar {
+            display: none;
+        }
+    </style>
+</head>
+<body class="text-white">
+    <!-- Header -->
+    <header class="sticky top-0 z-50 bg-black/40 backdrop-blur-lg border-b border-white/10">
+        <div class="flex items-center justify-between px-4 py-3">
+            <a href="/?tab=shopping" class="text-white/70 hover:text-white p-2 -ml-2">
+                <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 19l-7-7 7-7"></path>
+                </svg>
+            </a>
+            <h1 class="text-lg font-semibold">{{.StoreName}}</h1>
+            <div class="w-10"></div>
+        </div>
+
+        <!-- Store Switcher -->
+        {{if gt (len .StoreNames) 1}}
+        <div class="store-switcher flex gap-2 px-4 pb-3 overflow-x-auto">
+            {{range .StoreNames}}
+            <a href="/shopping/mode/{{.}}"
+               class="px-3 py-1.5 rounded-full text-sm whitespace-nowrap transition-colors
+                      {{if eq . $.StoreName}}bg-white/20 text-white{{else}}bg-white/5 text-white/60 hover:bg-white/10{{end}}">
+                {{.}}
+            </a>
+            {{end}}
+        </div>
+        {{end}}
+    </header>
+
+    <!-- Items List -->
+    <main class="p-4" id="shopping-items">
+        {{template "shopping-mode-items" .}}
+    </main>
+
+    <!-- Quick Add Form (Fixed at Bottom) -->
+    <div class="fixed bottom-0 left-0 right-0 bg-black/60 backdrop-blur-lg border-t border-white/10 p-4">
+        <form hx-post="/shopping/add"
+              hx-target="#shopping-items"
+              hx-swap="innerHTML"
+              hx-on::after-request="this.reset()"
+              class="flex gap-2">
+            <input type="hidden" name="store" value="{{.StoreName}}">
+            <input type="hidden" name="mode" value="shopping-mode">
+            <input type="text" name="name" placeholder="Add item..."
+                   class="flex-1 bg-white/10 border border-white/20 rounded-lg px-4 py-3 text-white placeholder-white/40 focus:outline-none focus:ring-2 focus:ring-white/30"
+                   required autocomplete="off">
+            <button type="submit" class="bg-white/20 hover:bg-white/30 text-white px-5 py-3 rounded-lg font-medium transition-colors">
+                Add
+            </button>
+        </form>
+    </div>
+
+    <!-- Spacer for fixed bottom form -->
+    <div class="h-24"></div>
+</body>
+</html>