Perfect! Now I have a comprehensive understanding. Let me create a detailed report of my findings:

## GmailAI-iOS Filtering System Analysis

I've thoroughly explored the GmailAI-iOS codebase and mapped out the current filtering architecture. Here's what I found:

---

### 1. CURRENT FILTERING IMPLEMENTATION

#### **Filter Properties** (EmailStore.swift, lines 26-30)
The current filtering system uses three @Published properties:
```swift
@Published var searchQuery = ""
@Published var selectedCategory: EmailAnalysis.Category?
@Published var selectedPriority: EmailAnalysis.Priority?
@Published var showUnreadOnly = false
```

#### **Filtered Emails Computed Property** (EmailStoreFiltering.swift, lines 9-27)
The core filtering logic uses a chain of predicates:
```swift
var filteredEmails: [Email] {
    emails.filter { email in
        // Search query check
        let matchesSearch = searchQuery.isEmpty ||
            email.subject.localizedCaseInsensitiveContains(searchQuery) ||
            email.from.localizedCaseInsensitiveContains(searchQuery) ||
            email.snippet.localizedCaseInsensitiveContains(searchQuery)

        // Category check
        let matchesCategory = selectedCategory == nil ||
            email.analysis?.category == selectedCategory

        // Priority check
        let matchesPriority = selectedPriority == nil ||
            email.analysis?.priority == selectedPriority

        // Unread check
        let matchesUnread = !showUnreadOnly || !email.isRead

        return matchesSearch && matchesCategory && matchesPriority && matchesUnread
    }
    .sorted { $0.date > $1.date }  // Descending date order
}
```

---

### 2. FILTERING UI IMPLEMENTATION

#### **FilterSheet Component** (InboxComponents.swift, lines 21-82)
The UI sheet is a Form-based navigation interface with three sections:

```swift
struct FilterSheet: View {
    @EnvironmentObject var emailStore: EmailStore
    @Environment(\.dismiss) var dismiss
    @AppStorage("groupByThread") private var groupByThread = false

    var body: some View {
        NavigationStack {
            Form {
                Section("Category") {
                    Picker("Category", selection: $emailStore.selectedCategory) {
                        Text("All").tag(nil as EmailAnalysis.Category?)
                        ForEach(EmailAnalysis.Category.allCases, id: \.self) { category in
                            Label(category.rawValue.capitalized, systemImage: category.icon)
                                .tag(category as EmailAnalysis.Category?)
                        }
                    }
                    .pickerStyle(.navigationLink)
                }

                Section("Priority") {
                    Picker("Priority", selection: $emailStore.selectedPriority) {
                        Text("All").tag(nil as EmailAnalysis.Priority?)
                        ForEach(EmailAnalysis.Priority.allCases, id: \.self) { priority in
                            Text(priority.rawValue.capitalized)
                                .tag(priority as EmailAnalysis.Priority?)
                        }
                    }
                    .pickerStyle(.segmented)
                }

                Section("Display") {
                    Toggle("Unread Only", isOn: $emailStore.showUnreadOnly)
                    Toggle(isOn: $groupByThread) {
                        Label("Group by Thread", systemImage: "text.bubble")
                    }
                }

                Section {
                    Button("Clear Filters") {
                        emailStore.selectedCategory = nil
                        emailStore.selectedPriority = nil
                        emailStore.showUnreadOnly = false
                    }
                    .foregroundStyle(.red)
                }
            }
            .navigationTitle("Filters")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button("Done") {
                        dismiss()
                    }
                }
            }
        }
        .presentationDetents([.medium])
    }
}
```

#### **Filter Trigger** (InboxView.swift, lines 122-128)
The filter button is in the toolbar with active state indicator:
```swift
Button {
    showingFilters.toggle()
} label: {
    Image(systemName: "line.3.horizontal.decrease.circle")
        .symbolVariant(hasActiveFilters ? .fill : .none)
}
```

#### **Active Filters Check** (InboxView.swift, lines 240-244)
```swift
private var hasActiveFilters: Bool {
    emailStore.selectedCategory != nil ||
    emailStore.selectedPriority != nil ||
    emailStore.showUnreadOnly
}
```

---

### 3. DATE-BASED SMART FOLDERS (Existing Pattern)

There's already a date-filtering example in the codebase! See EmailStoreFiltering.swift lines 69-76:

```swift
/// Old unread emails (> 7 days, unread)
var oldUnreadEmails: [Email] {
    let sevenDaysAgo = Calendar.current.date(byAdding: .day, value: -7, to: Date()) ?? Date()
    return emails.filter { email in
        !email.isRead && email.date < sevenDaysAgo
    }
    .sorted { $0.date < $1.date }
}
```

This shows the pattern you can follow for date range calculations.

---

### 4. EMAIL DATA MODEL

**Key fields** (Email.swift):
- `id: String` - Unique identifier
- `threadId: String` - For threading
- `date: Date` - Email timestamp (already available for filtering)
- `isRead: Bool` - Read status
- `isStarred: Bool` - Star status
- `analysis: EmailAnalysis?` - Optional AI analysis

---

### 5. CURRENT FILTER OPTIONS

| Filter Type | Property | Options |
|-------------|----------|---------|
| **Search** | `searchQuery: String` | Text matching (subject, from, snippet) |
| **Category** | `selectedCategory: Category?` | work, personal, newsletter, promotional, social, finance, travel, other |
| **Priority** | `selectedPriority: Priority?` | low, medium, high, critical |
| **Read Status** | `showUnreadOnly: Bool` | Toggle for unread-only view |
| **Threading** | `@AppStorage("groupByThread")` | Toggle for conversation grouping |

---

### 6. KEY DESIGN PATTERNS TO FOLLOW

1. **@Published Properties in EmailStore** - Use for reactive filter state
2. **Observable Pattern** - Changes automatically update UI via filteredEmails
3. **Predicate Chain** - Multiple conditions combined with `&&`
4. **Nil Coalescing** - Use `selectedCategory == nil` to disable filters
5. **Sorted Results** - Always sort by date descending: `.sorted { $0.date > $1.date }`
6. **Form with Sections** - Use NavigationLink picker for category, segmented for priority
7. **Clear All Button** - Reset all filters at once
8. **Active Filter Indicator** - Visual feedback on filter button

---

### 7. KEY FILES TO MODIFY FOR DATE FILTERING

| File | Purpose | Lines |
|------|---------|-------|
| `/Users/neog/Apps/iOS/GmailAI-iOS/Models/EmailStore.swift` | Add date filter properties (@Published) | 26-30 |
| `/Users/neog/Apps/iOS/GmailAI-iOS/Models/EmailStoreFiltering.swift` | Add date matching logic to filteredEmails | 9-27 |
| `/Users/neog/Apps/iOS/GmailAI-iOS/Views/InboxComponents.swift` | Add date filter UI section in FilterSheet | 30-69 |
| `/Users/neog/Apps/iOS/GmailAI-iOS/Views/InboxView.swift` | Update hasActiveFilters to include date | 240-244 |

---

### 8. SUGGESTED DATE FILTER IMPLEMENTATION PATTERN

Based on the existing patterns, here's how to add date filtering:

**In EmailStore.swift:**
```swift
enum DateFilter: String, CaseIterable {
    case all = "All Time"
    case today = "Today"
    case yesterday = "Yesterday"
    case last7days = "Last 7 Days"
    case last30days = "Last 30 Days"
    case custom = "Custom Range"
}

@Published var selectedDateFilter: DateFilter = .all
@Published var customDateStart: Date = Date()
@Published var customDateEnd: Date = Date()
```

**In EmailStoreFiltering.swift:**
```swift
let matchesDate = matchesDateFilter()

// Add this helper method:
private func matchesDateFilter() -> Bool {
    let calendar = Calendar.current
    let now = Date()

    switch selectedDateFilter {
    case .all:
        return true
    case .today:
        let startOfDay = calendar.startOfDay(for: now)
        return email.date >= startOfDay
    case .yesterday:
        let yesterday = calendar.date(byAdding: .day, value: -1, to: now)!
        let startOfDay = calendar.startOfDay(for: yesterday)
        let endOfDay = calendar.date(byAdding: .day, value: 1, to: startOfDay)!
        return email.date >= startOfDay && email.date < endOfDay
    case .last7days:
        let sevenDaysAgo = calendar.date(byAdding: .day, value: -7, to: now)!
        return email.date >= sevenDaysAgo
    case .last30days:
        let thirtyDaysAgo = calendar.date(byAdding: .day, value: -30, to: now)!
        return email.date >= thirtyDaysAgo
    case .custom:
        return email.date >= customDateStart && email.date <= customDateEnd
    }
}
```

**In InboxComponents.swift FilterSheet:**
```swift
Section("Date Range") {
    Picker("Date", selection: $emailStore.selectedDateFilter) {
        ForEach(DateFilter.allCases, id: \.self) { filter in
            Text(filter.rawValue).tag(filter)
        }
    }
    .pickerStyle(.segmented)

    if emailStore.selectedDateFilter == .custom {
        DatePicker("From", selection: $emailStore.customDateStart, displayedComponents: .date)
        DatePicker("To", selection: $emailStore.customDateEnd, displayedComponents: .date)
    }
}
```

---

### Summary

The GmailAI-iOS filtering system is well-structured with:
- Clear separation of concerns (state in EmailStore, logic in EmailStoreFiltering, UI in InboxComponents)
- Reactive @Published properties triggering UI updates
- Simple predicate-based filtering
- Existing date calculation patterns (see oldUnreadEmails example)
- Consistent UI patterns (Form + Picker + Toggle)

You have all the patterns you need to add date filtering following the same architectural style.