How to Clone Nextdoor

Create a Nextdoor-style hyperlocal social network called BlockTalk using Next.js (App Router), Tailwind, Prisma + SQLite (store polygons and points as GeoJSON/lat-lng fields). Niche: renters in a single city.

## What to build
A neighborhood-scoped social feed gated by address verification. Users verify an address, get assigned to a neighborhood polygon, and see posts only from their area and nearby ones.

## Screens
- Onboarding: address input -> map shows assigned neighborhood -> mock SMS verification -> profile
- Home feed: category-tagged posts (General/Recommendation/Lost+Found/For Sale/Safety) from the user's neighborhood + nearby (radius toggle), each with verified-neighbor badge, reactions, comment count; compose box with category picker
- Post detail: threaded comments, reactions, report
- Map: neighborhood boundary outline, pins for safety alerts and for-sale items
- Directory: neighbor-recommended local businesses with ratings
- Profile: posts, recommendations, verified badge
- Moderator: flagged-post queue, manage neighborhoods/members

## Prisma schema
Neighborhood (id, name, polygon Json, city, memberCount), User (id, name, email, address, lat, lng, neighborhoodId, isVerified), Post (id, userId, neighborhoodId, category, title, body, images Json, createdAt), Comment (id, postId, userId, body, createdAt), Reaction (id, postId, userId, type), Business (id, name, category, neighborhoodId, recommendedBy Json, ratingAvg)

## Logic (must actually work)
- Point-in-polygon assignment: a geocoded (lat,lng) is matched to the neighborhood whose polygon contains it (use a small turf.js-style helper server-side)
- Feed query returns posts from neighborhoodId plus neighborhoods within the chosen radius (haversine on centroids); never global
- Only verified users can post; gate the compose endpoint server-side
- Safety posts pin to the top and trigger a (mock) neighborhood notification
- API responses never expose another user's exact address - return neighborhood + verified badge only
- Reactions are one per user per post; flagged posts move to a moderation queue

## Style
Friendly, trustworthy: warm green #00A676 primary, clean cards, prominent verified-neighbor badges, soft map look, category color-tags. Mobile-first.

## Seed data
4 adjacent neighborhood polygons in one city, 20 verified neighbors with addresses inside them, 30 posts across all categories (including 3 safety alerts), 10 recommended businesses, and threaded comments with reactions.

Build a production-quality Nextdoor-style hyperlocal network. The geo-scoping and address verification are the core - get the boundary logic and the privacy model right, everything else is a normal social feed.

## Stack
- Next.js 14 App Router + TypeScript + Tailwind + shadcn/ui; React Native (Expo) client later sharing the API
- PostgreSQL with PostGIS via Prisma (raw SQL for spatial); NextAuth (email + phone)
- Mapbox GL for maps and boundary rendering; a geocoding API for address -> coordinates
- Twilio for SMS verification codes; Zod for all input validation

## Core design: geo as a first-class concern
- Neighborhoods stored as PostGIS geometry(Polygon). Address assignment is ST_Contains(neighborhood.geom, user_point) run in the DB - one query, authoritative
- The 'nearby' ring uses ST_DWithin on neighborhood centroids, radius user-adjustable but capped
- Feed query is scoped to (user's neighborhood) UNION (neighborhoods in ring); there is no code path that returns a global feed - enforce it at the data layer
- Privacy: never expose exact lat/lng of other users; the API returns neighborhood, not address

## Verification & integrity (server-authoritative)
- Verification flow: geocode address -> point-in-polygon -> send SMS code -> on confirm set is_verified and neighborhood_id. Posting endpoints reject unverified users
- Rate-limit verification attempts per phone/IP to stop fake-address farming
- Safety posts get priority ranking and fan out notifications, but still only within scope

## Schema
neighborhoods (geom geometry(Polygon,4326), gist index), users (point geometry, neighborhood_id, is_verified, phone), posts (category enum, neighborhood_id), comments, reactions, businesses, reports, notifications. GIST index on neighborhoods.geom; btree on posts(neighborhood_id, created_at desc).

## Implementation order
1. Schema + PostGIS setup + auth + seed (4 polygons + 20 users placed inside them)
2. Verification flow: geocode + ST_Contains assignment + SMS code (Twilio test mode)
3. Scoped feed query (neighborhood + ring) with category filter; compose gated to verified
4. Post detail, threaded comments, reactions, reporting
5. Mapbox map: boundary polygon, safety/for-sale pins, member count
6. Local business directory + recommendations
7. Moderation queue + safety-post priority + notifications

## Quality bar
- No endpoint can leak another user's exact address; verified by a test
- Feed scoping enforced in SQL, not just the UI
- Spatial queries use GIST indexes; assignment is a single point-in-polygon query

Start with step 1; show me the PostGIS schema and the ST_Contains assignment query before continuing.

Design the complete UI for a Nextdoor-style hyperlocal neighborhood network app called BlockTalk. React + Tailwind + shadcn/ui + lucide-react. Aesthetic: friendly, trustworthy, community-warm - warm green #00A676 primary, soft cards, prominent 'Verified neighbor' badges, a gentle map look, clear category color-tags. Mobile-first.

## Screens

### 1. Onboarding / address verification
- Step 1: address input with autocomplete; a map below drops a pin and outlines the assigned neighborhood polygon
- Step 2: 'We found your neighborhood: Riverside East' confirmation card with member count
- Step 3: phone verification - 6-digit code input, 'Verify to join'
- Welcome screen with a 'Verified neighbor' badge reveal

### 2. Home feed (main screen)
- Sticky top: neighborhood name + radius toggle ('Riverside East + nearby'), search, notifications bell
- Category filter chips with colors (General gray, Recommendation blue, Lost+Found amber, For Sale green, Safety red)
- Post cards: author with verified badge + neighborhood, category tag, title, body excerpt, optional image, reaction row and comment count
- Compose card pinned near top with a category picker
- Safety posts visually elevated (red left border, pinned)
- Mobile bottom tabs (Feed, Map, Post, Directory, Me)

### 3. Map
- Full map with the neighborhood boundary outlined and shaded; colored pins for safety alerts and for-sale items; a bottom sheet listing nearby posts; member-count chip

### 4. Local directory
- Search + category filter; business cards with name, category, star rating, 'recommended by 8 neighbors', and a 'Recommend' button

### 5. Profile & post detail
- Profile: avatar, name, neighborhood, verified badge, tabs for Posts and Recommendations
- Post detail: full post, threaded comments with reactions, a report action in an overflow menu

### 6. Moderator queue (desktop)
- A list of flagged posts with reason, reporter count, and Approve / Remove actions; a panel to edit neighborhood boundaries and view member counts

Fully responsive, mobile-first. Fill everything with realistic neighborhood content across all categories, ~20 verified neighbors, a few safety alerts pinned to the top, and 10 recommended local businesses with ratings.

Build a hyperlocal neighborhood social network app (Nextdoor model) called BlockTalk for a niche: renters in a single city.

## Entities
- Neighborhood: name, polygon (GeoJSON), city, memberCount
- User: name, email, address, lat, lng, neighborhood reference, isVerified
- Post: user, neighborhood reference, category (general/recommendation/lost_found/for_sale/safety), title, body, images (JSON), createdAt
- Comment: post reference, user, body, createdAt
- Reaction: post reference, user, type
- Business: name, category, neighborhood reference, recommendedBy (JSON of user ids), ratingAvg

## Roles
- Neighbor: verifies their address, posts and comments within their neighborhood, recommends businesses
- Moderator: reviews flagged posts, manages neighborhood boundaries and members, dashboard with active members and posts

## Pages
1. Onboarding: enter address -> map shows assigned neighborhood -> verify by code -> profile
2. Home feed: category-tagged posts from the user's neighborhood plus nearby (radius toggle), each with a verified-neighbor badge, reactions and comments; compose box with category picker
3. Post detail: threaded comments, reactions, report
4. Map: neighborhood boundary outline with pins for safety alerts and for-sale items
5. Directory: neighbor-recommended businesses with ratings and a recommend action
6. Profile: posts, recommendations, verified badge
7. Moderator: flagged-post queue and neighborhood management

## Rules
- A user is assigned to the neighborhood whose polygon contains their geocoded address (point-in-polygon)
- The feed is scoped to the user's neighborhood and ones within a chosen radius - never global
- Only verified users can post; unverified users get a limited preview
- Safety posts are pinned and notify the whole neighborhood

## Look & feel
Friendly and trustworthy: warm green #00A676 primary, clean cards, prominent verified-neighbor badges, soft map aesthetic, category color-tags. Mobile-first.

Seed: 4 adjacent neighborhood polygons in one city, 20 verified neighbors placed inside them, 30 posts across all categories, 10 recommended businesses, and threaded comments.