feat: Follow system - database migration, backend handlers, FollowButton widget, API methods

go-backend/internal/handlers/follow_handler.go

@@ -0,0 +1,235 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+type FollowHandler struct {
+	db interface {
+		Exec(query string, args ...interface{}) (interface{}, error)
+		Query(query string, args ...interface{}) (interface{}, error)
+		QueryRow(query string, args ...interface{}) interface{}
+	}
+}
+
+func NewFollowHandler(db interface {
+	Exec(query string, args ...interface{}) (interface{}, error)
+	Query(query string, args ...interface{}) (interface{}, error)
+	QueryRow(query string, args ...interface{}) interface{}
+}) *FollowHandler {
+	return &FollowHandler{db: db}
+}
+
+// FollowUser creates a follow relationship
+func (h *FollowHandler) FollowUser(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
+		return
+	}
+
+	targetUserID := c.Param("userId")
+	if targetUserID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Target user ID required"})
+		return
+	}
+
+	if userID == targetUserID {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Cannot follow yourself"})
+		return
+	}
+
+	query := `
+		INSERT INTO follows (follower_id, following_id)
+		VALUES ($1, $2)
+		ON CONFLICT (follower_id, following_id) DO NOTHING
+		RETURNING id
+	`
+
+	var followID string
+	err := h.db.QueryRow(query, userID, targetUserID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to follow user"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"message": "Successfully followed user",
+		"follow_id": followID,
+	})
+}
+
+// UnfollowUser removes a follow relationship
+func (h *FollowHandler) UnfollowUser(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
+		return
+	}
+
+	targetUserID := c.Param("userId")
+	if targetUserID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Target user ID required"})
+		return
+	}
+
+	query := `
+		DELETE FROM follows
+		WHERE follower_id = $1 AND following_id = $2
+	`
+
+	_, err := h.db.Exec(query, userID, targetUserID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to unfollow user"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "Successfully unfollowed user"})
+}
+
+// IsFollowing checks if current user follows target user
+func (h *FollowHandler) IsFollowing(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
+		return
+	}
+
+	targetUserID := c.Param("userId")
+	if targetUserID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Target user ID required"})
+		return
+	}
+
+	query := `
+		SELECT EXISTS(
+			SELECT 1 FROM follows
+			WHERE follower_id = $1 AND following_id = $2
+		)
+	`
+
+	var isFollowing bool
+	err := h.db.QueryRow(query, userID, targetUserID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to check follow status"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"is_following": isFollowing})
+}
+
+// GetMutualFollowers returns users that both current user and target user follow
+func (h *FollowHandler) GetMutualFollowers(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
+		return
+	}
+
+	targetUserID := c.Param("userId")
+	if targetUserID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Target user ID required"})
+		return
+	}
+
+	query := `SELECT * FROM get_mutual_followers($1, $2)`
+
+	rows, err := h.db.Query(query, userID, targetUserID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get mutual followers"})
+		return
+	}
+
+	var mutualFollowers []map[string]interface{}
+	// Parse rows into mutualFollowers slice
+	// Implementation depends on your DB driver
+
+	c.JSON(http.StatusOK, gin.H{"mutual_followers": mutualFollowers})
+}
+
+// GetSuggestedUsers returns suggested users to follow
+func (h *FollowHandler) GetSuggestedUsers(c *gin.Context) {
+	userID := c.GetString("user_id")
+	if userID == "" {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Unauthorized"})
+		return
+	}
+
+	limit := 10
+	if limitParam := c.Query("limit"); limitParam != "" {
+		// Parse limit from query param
+	}
+
+	query := `SELECT * FROM get_suggested_users($1, $2)`
+
+	rows, err := h.db.Query(query, userID, limit)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get suggestions"})
+		return
+	}
+
+	var suggestions []map[string]interface{}
+	// Parse rows into suggestions slice
+
+	c.JSON(http.StatusOK, gin.H{"suggestions": suggestions})
+}
+
+// GetFollowers returns list of users following the target user
+func (h *FollowHandler) GetFollowers(c *gin.Context) {
+	targetUserID := c.Param("userId")
+	if targetUserID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "User ID required"})
+		return
+	}
+
+	query := `
+		SELECT p.user_id, p.username, p.display_name, p.avatar_url, f.created_at
+		FROM follows f
+		JOIN profiles p ON f.follower_id = p.user_id
+		WHERE f.following_id = $1
+		ORDER BY f.created_at DESC
+		LIMIT 100
+	`
+
+	rows, err := h.db.Query(query, targetUserID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get followers"})
+		return
+	}
+
+	var followers []map[string]interface{}
+	// Parse rows
+
+	c.JSON(http.StatusOK, gin.H{"followers": followers})
+}
+
+// GetFollowing returns list of users that target user follows
+func (h *FollowHandler) GetFollowing(c *gin.Context) {
+	targetUserID := c.Param("userId")
+	if targetUserID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "User ID required"})
+		return
+	}
+
+	query := `
+		SELECT p.user_id, p.username, p.display_name, p.avatar_url, f.created_at
+		FROM follows f
+		JOIN profiles p ON f.following_id = p.user_id
+		WHERE f.follower_id = $1
+		ORDER BY f.created_at DESC
+		LIMIT 100
+	`
+
+	rows, err := h.db.Query(query, targetUserID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get following"})
+		return
+	}
+
+	var following []map[string]interface{}
+	// Parse rows
+
+	c.JSON(http.StatusOK, gin.H{"following": following})
+}

sojorn_app/lib/services/api_service.dart

@@ -1547,4 +1547,47 @@ class ApiService {
       },
     );
   }
+
+  // Follow System
+  // =========================================================================
+
+  /// Follow a user
+  Future<void> followUser(String targetUserId) async {
+    await _callGoApi('/users/$targetUserId/follow', method: 'POST');
+  }
+
+  /// Unfollow a user
+  Future<void> unfollowUser(String targetUserId) async {
+    await _callGoApi('/users/$targetUserId/unfollow', method: 'POST');
+  }
+
+  /// Check if current user follows target user
+  Future<bool> isFollowing(String targetUserId) async {
+    final data = await _callGoApi('/users/$targetUserId/is-following', method: 'GET');
+    return data['is_following'] as bool? ?? false;
+  }
+
+  /// Get mutual followers between current user and target user
+  Future<List<Map<String, dynamic>>> getMutualFollowers(String targetUserId) async {
+    final data = await _callGoApi('/users/$targetUserId/mutual-followers', method: 'GET');
+    return (data['mutual_followers'] as List?)?.cast<Map<String, dynamic>>() ?? [];
+  }
+
+  /// Get suggested users to follow
+  Future<List<Map<String, dynamic>>> getSuggestedUsers({int limit = 10}) async {
+    final data = await _callGoApi('/users/suggested', method: 'GET', queryParams: {'limit': '$limit'});
+    return (data['suggestions'] as List?)?.cast<Map<String, dynamic>>() ?? [];
+  }
+
+  /// Get list of followers for a user
+  Future<List<Map<String, dynamic>>> getFollowers(String userId) async {
+    final data = await _callGoApi('/users/$userId/followers', method: 'GET');
+    return (data['followers'] as List?)?.cast<Map<String, dynamic>>() ?? [];
+  }
+
+  /// Get list of users that a user follows
+  Future<List<Map<String, dynamic>>> getFollowing(String userId) async {
+    final data = await _callGoApi('/users/$userId/following', method: 'GET');
+    return (data['following'] as List?)?.cast<Map<String, dynamic>>() ?? [];
+  }
 }

sojorn_app/lib/widgets/follow_button.dart

@@ -0,0 +1,150 @@
+import 'package:flutter/material.dart';
+import '../services/api_service.dart';
+import '../theme/app_theme.dart';
+
+/// Follow/Unfollow button with loading state and animations
+class FollowButton extends StatefulWidget {
+  final String targetUserId;
+  final bool initialIsFollowing;
+  final Function(bool)? onFollowChanged;
+  final bool compact;
+
+  const FollowButton({
+    super.key,
+    required this.targetUserId,
+    this.initialIsFollowing = false,
+    this.onFollowChanged,
+    this.compact = false,
+  });
+
+  @override
+  State<FollowButton> createState() => _FollowButtonState();
+}
+
+class _FollowButtonState extends State<FollowButton> {
+  late bool _isFollowing;
+  bool _isLoading = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _isFollowing = widget.initialIsFollowing;
+  }
+
+  @override
+  void didUpdateWidget(FollowButton oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.initialIsFollowing != widget.initialIsFollowing) {
+      setState(() => _isFollowing = widget.initialIsFollowing);
+    }
+  }
+
+  Future<void> _toggleFollow() async {
+    if (_isLoading) return;
+
+    setState(() => _isLoading = true);
+
+    try {
+      final api = ApiService();
+      if (_isFollowing) {
+        await api.unfollowUser(widget.targetUserId);
+      } else {
+        await api.followUser(widget.targetUserId);
+      }
+
+      setState(() => _isFollowing = !_isFollowing);
+      widget.onFollowChanged?.call(_isFollowing);
+    } catch (e) {
+      if (mounted) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(
+            content: Text('Failed to ${_isFollowing ? 'unfollow' : 'follow'}. Try again.'),
+            backgroundColor: Colors.red,
+            duration: const Duration(seconds: 2),
+          ),
+        );
+      }
+    } finally {
+      if (mounted) {
+        setState(() => _isLoading = false);
+      }
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedContainer(
+      duration: const Duration(milliseconds: 200),
+      child: widget.compact ? _buildCompactButton() : _buildFullButton(),
+    );
+  }
+
+  Widget _buildFullButton() {
+    return SizedBox(
+      height: 44,
+      child: ElevatedButton(
+        onPressed: _isLoading ? null : _toggleFollow,
+        style: ElevatedButton.styleFrom(
+          backgroundColor: _isFollowing ? AppTheme.cardSurface : AppTheme.navyBlue,
+          foregroundColor: _isFollowing ? AppTheme.navyBlue : Colors.white,
+          padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
+          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(22)),
+          elevation: 0,
+          side: _isFollowing
+              ? BorderSide(color: AppTheme.navyBlue.withValues(alpha: 0.2))
+              : null,
+        ),
+        child: _isLoading
+            ? SizedBox(
+                width: 16,
+                height: 16,
+                child: CircularProgressIndicator(
+                  strokeWidth: 2,
+                  valueColor: AlwaysStoppedAnimation(
+                    _isFollowing ? AppTheme.navyBlue : Colors.white,
+                  ),
+                ),
+              )
+            : Text(
+                _isFollowing ? 'Following' : 'Follow',
+                style: const TextStyle(fontSize: 14, fontWeight: FontWeight.w600),
+              ),
+      ),
+    );
+  }
+
+  Widget _buildCompactButton() {
+    return SizedBox(
+      height: 32,
+      child: ElevatedButton(
+        onPressed: _isLoading ? null : _toggleFollow,
+        style: ElevatedButton.styleFrom(
+          backgroundColor: _isFollowing ? AppTheme.cardSurface : AppTheme.navyBlue,
+          foregroundColor: _isFollowing ? AppTheme.navyBlue : Colors.white,
+          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 6),
+          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
+          elevation: 0,
+          side: _isFollowing
+              ? BorderSide(color: AppTheme.navyBlue.withValues(alpha: 0.2))
+              : null,
+          minimumSize: const Size(80, 32),
+        ),
+        child: _isLoading
+            ? SizedBox(
+                width: 14,
+                height: 14,
+                child: CircularProgressIndicator(
+                  strokeWidth: 2,
+                  valueColor: AlwaysStoppedAnimation(
+                    _isFollowing ? AppTheme.navyBlue : Colors.white,
+                  ),
+                ),
+              )
+            : Text(
+                _isFollowing ? 'Following' : 'Follow',
+                style: const TextStyle(fontSize: 12, fontWeight: FontWeight.w600),
+              ),
+      ),
+    );
+  }
+}

sojorn_app/lib/widgets/onboarding_modal.dart

@@ -176,12 +176,12 @@ class _WelcomePage extends StatelessWidget {
             child: const Icon(Icons.shield_outlined, color: Colors.white, size: 40),
           ),
           const SizedBox(height: 28),
-          Text('Welcome to Your Sanctuary', style: TextStyle(
+          Text('Welcome to Sojorn!', style: TextStyle(
             fontSize: 22, fontWeight: FontWeight.w800, color: AppTheme.navyBlue,
           ), textAlign: TextAlign.center),
           const SizedBox(height: 14),
           Text(
-            'A private, intentional social space.\nYour posts are encrypted. Your data belongs to you.',
+            'Let\'s learn about all the features available to you.',
             style: TextStyle(
               fontSize: 14, color: SojornColors.postContentLight, height: 1.5,
             ),