Build your own Streaks.

# Build an original app inspired by Streaks

You are an experienced mobile product designer and mobile engineer. Build a working, polished MVP from the brief below. Implement the core journeys end to end; a static mockup is not sufficient. Inspect the current environment, make sensible implementation decisions, and get started. Ask a question only if a missing answer genuinely blocks implementation.

Starting platform: iOS. Explicit customized Product & audience and Tech stack requirements take precedence over this starting target.

## Product & audience
Build an original native iOS habit tracker called Daychain, inspired by Streaks. It is for individuals following a small set of self-chosen routines. The main journey is creating a habit, selecting its scheduled weekdays, marking it complete, and reviewing a durable calendar and streak. Deliver a SwiftUI app with actual date-based logic and local persistence; decorative counters without completed-day records are incomplete.

## Design
Create an original clean today screen with generous completion controls, readable habit names, and a small calendar preview. Use original icons and user-selectable accents without copying the reference layout. Distinguish due, completed, unscheduled, and missed days using labels as well as color. Offer buttons alongside gestures, Dynamic Type, VoiceOver, and reduced-motion feedback.

## Features
1. Habits: create a name, optional note, icon, accent, start date, and specific weekdays. Edit future scheduling, archive a habit without losing its history, and delete with confirmation. Keep the MVP to yes/no habits rather than partially specified measurement goals.

2. Today: list habits due on the current local date, mark or undo completion, and show optional unscheduled habits separately. Persist before confirming success, make repeated taps idempotent, and refresh today when the app becomes active after midnight.

3. History: inspect a habit calendar, correct a past completion with an explicit edit action, and derive current/best streaks from scheduled opportunities. Unscheduled days do not break a chain; future dates cannot be marked complete.

4. Reminders: set an optional time per habit, request notification access when enabled, and schedule supported local notifications. Cancel a day’s pending reminder when it is completed and cancel future reminders when the habit is archived. Handle denial or changed settings gracefully.

5. Portability: work fully offline, offer a versioned JSON backup through iOS sharing, and preview a validated import before applying it. Show the number of habits/history records affected; avoid silently duplicating existing IDs.

## Tech stack
Use Swift, SwiftUI, SwiftData or Core Data, and UserNotifications in a new Xcode project. Keep streak calculation as a pure calendar function with a documented time-zone policy and store scheduling changes as versions. Save completion transactions independently of view animations. Follow native navigation and accessibility patterns; do not embed a website as the app. The first version needs no account, network, HealthKit, Apple Watch extension, or remote notification service.

## Data & behavior
Habit {id, name, note, icon, accent, createdAt, archivedAt}; ScheduleVersion {habitId, effectiveLocalDate, weekdays, timeZone}; Completion {habitId, localDate, completedAt, timeZone}; ReminderSetting {habitId, localTime, enabled}; BackupManifest. Enforce a unique habit/date completion. Preserve historical schedules so editing weekdays does not retroactively rewrite a past streak. Define travel behavior as dates in the habit’s selected zone and expose that setting rather than silently changing old records.

Acceptance checks and scope:
Create a Monday/Wednesday habit, complete both dates, and verify Tuesday does not break the streak. Undo a completion, edit future weekdays, cross midnight, and reopen the app. Test a missed scheduled day, time-zone change, duplicate taps, denied notifications, archived reminder cleanup, and malformed imports. Build in Xcode and exercise VoiceOver and large text in a simulator/device. Exclude automatic HealthKit tracking, copied icons, cloud sync, watches, subscriptions, and claims that streaks prove lasting behavior change.

## Originality and assets
The named product is a reference for general workflows only. Use an original product name, visual identity, wording, layout, and assets. Do not copy proprietary code, branded logos, distinctive screens, private APIs, paid templates, or protected media. Use original or appropriately licensed sample data and assets. Build from this brief rather than scraping the reference service. Do not imply affiliation with the referenced company.

## Implementation quality
- Make every visible control work, with clear loading, success, empty, validation, and failure states. Remove controls for unimplemented features.
- Support the target platform and responsive or resizable layouts where appropriate. Use platform-appropriate accessibility semantics, labels, keyboard operation, visible focus, sufficient contrast, and reduced-motion preferences. Provide alternatives for drag-only interactions.
- Validate inputs at the relevant boundary. Treat imported or user-generated content as untrusted; render it safely. Confirm destructive actions or offer undo.
- Keep state changes reliable across navigation and reloads. Never silently lose edits. Handle persistence and network errors with an actionable message.
- Keep the scope realistic. Prioritize the complete primary journey. If a custom Features section differs from the baseline, update the data model, design, and acceptance checks to match it; explicit custom requirements take precedence over baseline assumptions.
- Provide realistic original sample content and a useful empty state. Keep sample data clearly separate from user-created data.

## Delivery and verification
1. Inspect the repository and outline the implementation in a few sentences.
2. Implement the app and connect its actual data flow. Continue until the primary journey works.
3. Run appropriate checks and test the acceptance cases above on the target platform. Verify responsive layouts and keyboard navigation when browser tools are available. For native projects, build with the available SDK and test an emulator or device when possible; report any missing native verification honestly. For games, verify the rules and gameplay loop, not only the menus.
4. Fix observed failures, then provide the runnable result, setup/run instructions, a brief explanation of what is implemented, and any specific configuration or verification limits.

This is a focused MVP. Do not add billing, AI services, or unrelated features unless explicitly requested in the brief. Start building now.