feat: add messages tab

AGENTS.md

@@ -0,0 +1,208 @@
+# DevBits Agent Guidelines
+
+This document provides essential information for AI coding agents working on the DevBits codebase.
+
+## Project Overview
+
+DevBits is a social media mobile application for developers, built with:
+- **Backend**: Go 1.24 + Gin framework + PostgreSQL/SQLite
+- **Frontend**: React Native 0.81.5 + Expo SDK 54 + TypeScript 5.3
+- **Architecture**: Monorepo with separate `/backend` and `/frontend` directories
+
+## Build, Lint, and Test Commands
+
+### Frontend (run from `/frontend` directory)
+
+```bash
+# Development
+npm run frontend              # Start Expo dev server
+npm run android              # Start on Android device/emulator
+npm run ios                  # Start on iOS device/simulator
+
+# Testing
+npm test                     # Run Jest tests
+npm test -- ComponentName    # Run tests for specific component
+
+# Linting
+npm run lint                 # Run ESLint with Expo config
+
+# Building
+npx eas build -p android --profile production    # Build Android APK/AAB
+npx eas build -p ios --profile production        # Build iOS app
+```
+
+### Backend (run from `/backend` directory)
+
+```bash
+# Development
+go run ./api                 # Start API server locally
+
+# Testing
+cd backend
+go test ./api/internal/tests/              # Run all tests
+go test ./api/internal/tests/ -v           # Run with verbose output
+go test ./api/internal/tests/ -run TestUsers  # Run specific test
+
+# Building
+go build -o bin/api ./api    # Build binary
+
+# Docker
+docker compose up -d          # Start all services (Postgres, API, Nginx)
+docker compose up -d --build  # Rebuild and restart
+docker compose logs -f backend # View backend logs
+```
+
+## Code Style Guidelines
+
+### TypeScript/React Native (Frontend)
+
+#### File Organization
+- Use PascalCase for component files: `Post.tsx`, `UserCard.tsx`
+- Use camelCase for utility/hook files: `useAppColors.ts`, `api.ts`
+- Components go in `/frontend/components/`
+- Pages use Expo Router file-based routing in `/frontend/app/`
+- Custom hooks in `/frontend/hooks/`
+- API services in `/frontend/services/`
+
+#### Imports
+- Group imports: React/React Native → third-party → local
+- Use path alias `@/` for imports: `import { useAppColors } from "@/hooks/useAppColors"`
+- Order: components, hooks, contexts, services, types, constants
+
+```typescript
+import React, { useCallback, useEffect, useState } from "react";
+import { View, StyleSheet, Pressable } from "react-native";
+import { useRouter } from "expo-router";
+import { ThemedText } from "@/components/ThemedText";
+import { useAppColors } from "@/hooks/useAppColors";
+import { getPostsFeed } from "@/services/api";
+import { UiPost } from "@/constants/Types";
+```
+
+#### TypeScript Types
+- Define interfaces in `/frontend/constants/Types.ts` for API models
+- Use type inference where obvious: `const [count, setCount] = useState(0)`
+- Explicit types for function parameters and returns:
+  ```typescript
+  const mapPostToUi = (post: PostProps): UiPost => { ... }
+  ```
+- Use `interface` for object shapes, `type` for unions/intersections
+
+#### Component Style
+- Functional components with hooks
+- Export default for page components, named exports for reusable components
+- Use `useMemo` and `useCallback` for performance optimization
+- Prefer StyleSheet.create() for styles at bottom of file
+- Use Reanimated for complex animations, Animated API for simple ones
+
+#### Naming Conventions
+- Components: PascalCase (`Post`, `UserCard`)
+- Hooks: camelCase with `use` prefix (`useAppColors`, `useMotionConfig`)
+- Functions/variables: camelCase (`getCachedCommentCount`, `postData`)
+- Constants: UPPER_SNAKE_CASE or camelCase for config objects
+- Event handlers: `onPress`, `handleSubmit`, etc.
+
+#### Error Handling
+- Use try/catch for async operations
+- Show user-friendly error messages via Alert.alert()
+- Log errors for debugging: `console.error("Failed to fetch:", error)`
+- Handle loading and error states in UI
+
+### Go (Backend)
+
+#### File Organization
+- Package per feature: `handlers/`, `database/`, `auth/`, `logger/`
+- Route handlers in `/backend/api/internal/handlers/*_routes.go`
+- Database queries in `/backend/api/internal/database/*_queries.go`
+- Test files in `/backend/api/internal/tests/`
+
+#### Imports
+- Group: standard library → third-party → local
+- Use explicit package names for local imports:
+  ```go
+  import (
+      "database/sql"
+      "fmt"
+      "net/http"
+
+      "github.com/gin-gonic/gin"
+
+      "backend/api/internal/database"
+      "backend/api/internal/logger"
+  )
+  ```
+
+#### Naming Conventions
+- Exported functions/types: PascalCase (`GetUserById`, `ApiUser`)
+- Unexported: camelCase (`setupTestRouter`, `respondWithError`)
+- Interfaces: PascalCase, often with `-er` suffix (`Handler`, `Querier`)
+- Constants: PascalCase or ALL_CAPS for package-level
+
+#### Error Handling
+- Return errors explicitly: `func GetUser(id int) (*User, error)`
+- Use `fmt.Errorf` with `%w` for error wrapping: `fmt.Errorf("failed to parse: %w", err)`
+- Check errors immediately: `if err != nil { return err }`
+- Use `RespondWithError(context, status, message)` in handlers
+- Log errors using the logger package
+
+#### Types and Structs
+- Use struct tags for JSON/DB mapping:
+  ```go
+  type ApiUser struct {
+      Id       int    `json:"id"`
+      Username string `json:"username" binding:"required"`
+  }
+  ```
+- Pointer receivers for methods that modify state
+- Value receivers for read-only methods
+
+#### Database
+- Use parameterized queries with `$1, $2, ...` placeholders (PostgreSQL style)
+- Always check `sql.ErrNoRows` when expecting single results
+- Use `json.Marshal/Unmarshal` for JSON columns (links, settings)
+- Transaction handling for multi-step operations
+
+#### Testing
+- Use table-driven tests with `TestCase` structs
+- Test setup: create in-memory SQLite DB, initialize tables
+- Use `httptest.NewServer` for HTTP testing (no external network)
+- Use `testify/assert` for assertions: `assert.Equal(t, expected, actual)`
+- Sequential test execution to avoid race conditions
+
+## Common Patterns
+
+### Frontend
+- Context for global state (Auth, Notifications, Preferences, Saved)
+- Custom hooks for reusable logic (colors, motion, auto-refresh)
+- Event emitters for real-time updates (`postEvents.ts`, `projectEvents.ts`)
+- Caching strategies for performance (comment counts, media URLs)
+
+### Backend
+- JWT middleware: `handlers.RequireAuth()` protects routes
+- CORS configured for local and production origins
+- File uploads to `/uploads` directory with media ingestion
+- WebSocket support for real-time features
+- Health check endpoint: `/health`
+
+## Testing Guidelines
+
+- **Write tests** for new API endpoints and database queries
+- **Frontend**: Test components with Jest + React Test Renderer
+- **Backend**: Use table-driven tests, test both success and error cases
+- **Run tests** before committing significant changes
+- Test file naming: `*_test.go` (Go), `*-test.tsx` (TypeScript)
+
+## Important Notes
+
+- **Never commit** `.env` files or credentials
+- **Database migrations**: Schema in `create_tables.sql`
+- **Media files**: Images/videos go to `/backend/uploads/`
+- **API base URL**: Production uses `https://devbits.ddns.net`
+- **Deep linking**: Custom scheme `devbits://`
+- **Version**: Frontend v1.0.2, Android versionCode 14
+
+## Documentation
+
+- Main instructions: `/INSTRUCTIONS.md`
+- Database scripts: `/backend/scripts/README.md`
+- Publishing guide: `/README_PUBLISHING.md`

backend/api/internal/database/direct_message_queries.go

@@ -19,6 +19,7 @@ type DirectMessage struct {
 
 type DirectMessageThread struct {
 	PeerUsername string    `json:"peer_username"`
+	PeerPicture  string    `json:"peer_picture"`
 	LastContent  string    `json:"last_content"`
 	LastAt       time.Time `json:"last_at"`
 }
@@ -209,7 +210,7 @@ func QueryDirectMessageThreads(username string, start int, count int) ([]DirectM
 		FROM directmessages dm
 		WHERE dm.sender_id = $1 OR dm.recipient_id = $1
 	)
-	SELECT u.username, rt.content, rt.creation_date
+	SELECT u.username, COALESCE(u.picture, ''), rt.content, rt.creation_date
 	FROM ranked_threads rt
 	JOIN users u ON u.id = rt.peer_id
 	WHERE rt.rank_in_thread = 1
@@ -225,7 +226,7 @@ func QueryDirectMessageThreads(username string, start int, count int) ([]DirectM
 	threads := make([]DirectMessageThread, 0)
 	for rows.Next() {
 		var thread DirectMessageThread
-		if err := rows.Scan(&thread.PeerUsername, &thread.LastContent, &thread.LastAt); err != nil {
+		if err := rows.Scan(&thread.PeerUsername, &thread.PeerPicture, &thread.LastContent, &thread.LastAt); err != nil {
 			return nil, http.StatusInternalServerError, fmt.Errorf("failed to scan direct message thread: %w", err)
 		}
 		threads = append(threads, thread)

backend/api/internal/database/user_queries.go

@@ -228,6 +228,51 @@ func DeleteUser(username string) error {
 	return nil
 }
 
+// SearchUsers retrieves users whose username starts with the given prefix (case-insensitive), limited to the specified limit.
+func SearchUsers(prefix string, limit int) ([]*ApiUser, error) {
+	query := `
+		SELECT id, username, picture, bio, links, settings, creation_date
+		FROM users
+		WHERE LOWER(username) LIKE LOWER($1) AND id > 0
+		ORDER BY username ASC
+		LIMIT $2;
+	`
+	rows, err := DB.Query(query, prefix+"%", limit)
+	if err != nil {
+		return nil, fmt.Errorf("failed to search users: %w", err)
+	}
+	defer rows.Close()
+
+	var users []*ApiUser
+	for rows.Next() {
+		user := &ApiUser{}
+		var links, settings []byte
+		if err := rows.Scan(
+			&user.Id,
+			&user.Username,
+			&user.Picture,
+			&user.Bio,
+			&links,
+			&settings,
+			&user.CreationDate,
+		); err != nil {
+			return nil, fmt.Errorf("failed to scan user row: %w", err)
+		}
+		if err := json.Unmarshal(links, &user.Links); err != nil {
+			log.Printf("WARN: could not unmarshal user links: %v", err)
+		}
+		if err := json.Unmarshal(settings, &user.Settings); err != nil {
+			log.Printf("WARN: could not unmarshal user settings: %v", err)
+		}
+		users = append(users, user)
+	}
+
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("failed to iterate over user search results: %w", err)
+	}
+	return users, nil
+}
+
 // GetUsers retrieves a list of all users
 func GetUsers() ([]*ApiUser, error) {
 	query := `

backend/api/internal/handlers/user_routes.go

@@ -18,6 +18,38 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+// SearchUsers handles GET /users/search?q=<prefix>&count=<n>
+// Returns up to `count` users (max 20, default 10) whose username starts with `q`.
+func SearchUsers(context *gin.Context) {
+	q := strings.TrimSpace(context.Query("q"))
+	if q == "" {
+		context.JSON(http.StatusOK, []*database.ApiUser{})
+		return
+	}
+
+	limit := 10
+	if strCount := context.Query("count"); strCount != "" {
+		if parsed, err := strconv.Atoi(strCount); err == nil && parsed > 0 {
+			if parsed > 20 {
+				parsed = 20
+			}
+			limit = parsed
+		}
+	}
+
+	users, err := database.SearchUsers(q, limit)
+	if err != nil {
+		RespondWithError(context, http.StatusInternalServerError, fmt.Sprintf("Failed to search users: %v", err))
+		return
+	}
+
+	if users == nil {
+		users = []*database.ApiUser{}
+	}
+
+	context.JSON(http.StatusOK, users)
+}
+
 // GetUsernameById handles GET requests to fetch a user by their username.
 // It expects the `username` parameter in the URL.
 // Returns:

backend/api/internal/tests/main_test.go

@@ -80,6 +80,7 @@ func setupTestRouter() *gin.Engine {
 	router.GET("/auth/me", handlers.RequireAuth(), handlers.GetMe)
 
 	router.GET("/users", handlers.GetUsers)
+	router.GET("/users/search", handlers.SearchUsers)
 	router.GET("/users/:username", handlers.GetUserByUsername)
 	router.GET("/users/id/:user_id", handlers.GetUserById)
 	router.POST("/users", handlers.RequireAuth(), handlers.CreateUser)

backend/api/internal/tests/user_test.go

@@ -199,4 +199,26 @@ var user_tests = []TestCase{
 		ExpectedStatus: http.StatusOK,
 		ExpectedBody:   `null`,
 	},
+
+	// search users – empty q returns empty array
+	{
+		Method:         http.MethodGet,
+		Endpoint:       "/users/search?q=",
+		ExpectedStatus: http.StatusOK,
+		ExpectedBody:   `[]`,
+	},
+	// search users – prefix match returns matching users
+	{
+		Method:         http.MethodGet,
+		Endpoint:       "/users/search?q=dev",
+		ExpectedStatus: http.StatusOK,
+		ExpectedBody:   `[{"bio":"Updated developer bio.","creation_date":"2023-12-13T00:00:00Z","id":1,"links":["https://github.com/dev_user1","https://devuser1.com"],"picture":"https://example.com/dev_user1.jpg","settings":{"accentColor":"","backgroundRefreshEnabled":false,"compactMode":false,"refreshIntervalMs":120000,"zenMode":false},"username":"dev_user1"}]`,
+	},
+	// search users – count is capped at 20
+	{
+		Method:         http.MethodGet,
+		Endpoint:       "/users/search?q=d&count=100",
+		ExpectedStatus: http.StatusOK,
+		ExpectedBody:   `[{"bio":"Data scientist with a passion for machine learning.","creation_date":"2023-06-13T00:00:00Z","id":3,"links":["https://github.com/data_scientist3","https://datascientist3.com"],"picture":"https://example.com/data_scientist3.jpg","settings":{"accentColor":"","backgroundRefreshEnabled":false,"compactMode":false,"refreshIntervalMs":120000,"zenMode":false},"username":"data_scientist3"},{"bio":"Updated developer bio.","creation_date":"2023-12-13T00:00:00Z","id":1,"links":["https://github.com/dev_user1","https://devuser1.com"],"picture":"https://example.com/dev_user1.jpg","settings":{"accentColor":"","backgroundRefreshEnabled":false,"compactMode":false,"refreshIntervalMs":120000,"zenMode":false},"username":"dev_user1"}]`,
+	},
 }

backend/api/main.go

@@ -119,6 +119,7 @@ func main() {
 	router.POST("/media/upload", handlers.RequireAuth(), handlers.UploadMedia)
 
 	router.GET("/users", handlers.GetUsers)
+	router.GET("/users/search", handlers.SearchUsers)
 	router.GET("/users/:username", handlers.GetUserByUsername)
 	router.GET("/users/id/:user_id", handlers.GetUserById)
 	router.POST("/users", handlers.RequireAuth(), handlers.CreateUser)

frontend/app/(tabs)/_layout.tsx

@@ -57,6 +57,15 @@ export default function TabLayout() {
           ),
         }}
       />
+      <Tabs.Screen
+        name="message"
+        options={{
+          title: "Messages",
+          tabBarIcon: ({ color }) => (
+            <IconSymbol size={28} name="terminal.fill" color={color} />
+          ),
+        }}
+      />
       <Tabs.Screen
         name="profile"
         options={{

frontend/app/(tabs)/index.tsx

@@ -138,7 +138,6 @@ export default function HomeScreen() {
     const task = InteractionManager.runAfterInteractions(() => {
       router.prefetch("/streams");
       router.prefetch("/bytes");
-      router.prefetch("/terminal");
     });
 
     return () => {