sojorn/go-backend/internal/services/moderation_service.go

package services

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgxpool"
)

type ModerationService struct {
	pool       *pgxpool.Pool
	httpClient *http.Client
	openAIKey  string
	googleKey  string
}

func NewModerationService(pool *pgxpool.Pool, openAIKey, googleKey string) *ModerationService {
	return &ModerationService{
		pool: pool,
		httpClient: &http.Client{
			Timeout: 30 * time.Second,
		},
		openAIKey: openAIKey,
		googleKey: googleKey,
	}
}

type ThreePoisonsScore struct {
	Hate     float64 `json:"hate"`
	Greed    float64 `json:"greed"`
	Delusion float64 `json:"delusion"`
}

// OpenAIModerationResponse represents the response from OpenAI Moderation API
type OpenAIModerationResponse struct {
	Results []struct {
		Categories struct {
			Hate                 float64 `json:"hate"`
			HateThreatening      float64 `json:"hate/threatening"`
			SelfHarm             float64 `json:"self-harm"`
			SelfHarmIntent       float64 `json:"self-harm/intent"`
			SelfHarmInstructions float64 `json:"self-harm/instructions"`
			Sexual               float64 `json:"sexual"`
			SexualMinors         float64 `json:"sexual/minors"`
			Violence             float64 `json:"violence"`
			ViolenceGraphic      float64 `json:"violence/graphic"`
		} `json:"categories"`
		CategoryScores struct {
			Hate                 float64 `json:"hate"`
			HateThreatening      float64 `json:"hate/threatening"`
			SelfHarm             float64 `json:"self-harm"`
			SelfHarmIntent       float64 `json:"self-harm/intent"`
			SelfHarmInstructions float64 `json:"self-harm/instructions"`
			Sexual               float64 `json:"sexual"`
			SexualMinors         float64 `json:"sexual/minors"`
			Violence             float64 `json:"violence"`
			ViolenceGraphic      float64 `json:"violence/graphic"`
		} `json:"category_scores"`
		Flagged bool `json:"flagged"`
	} `json:"results"`
}

// GoogleVisionSafeSearch represents SafeSearch detection results
type GoogleVisionSafeSearch struct {
	Adult    string `json:"adult"`
	Spoof    string `json:"spoof"`
	Medical  string `json:"medical"`
	Violence string `json:"violence"`
	Racy     string `json:"racy"`
}

// GoogleVisionResponse represents the response from Google Vision API
type GoogleVisionResponse struct {
	Responses []struct {
		SafeSearchAnnotation GoogleVisionSafeSearch `json:"safeSearchAnnotation"`
	} `json:"responses"`
}

func (s *ModerationService) AnalyzeContent(ctx context.Context, body string, mediaURLs []string) (*ThreePoisonsScore, string, error) {
	score := &ThreePoisonsScore{
		Hate:     0.0,
		Greed:    0.0,
		Delusion: 0.0,
	}

	// Analyze text with OpenAI Moderation API
	if s.openAIKey != "" && body != "" {
		openAIScore, err := s.analyzeWithOpenAI(ctx, body)
		if err != nil {
			// Log error but continue with fallback
			fmt.Printf("OpenAI moderation error: %v\n", err)
		} else {
			score = openAIScore
		}
	}

	// Analyze media with Google Vision API if provided
	if s.googleKey != "" && len(mediaURLs) > 0 {
		visionScore, err := s.analyzeWithGoogleVision(ctx, mediaURLs)
		if err != nil {
			fmt.Printf("Google Vision analysis error: %v\n", err)
		} else {
			// Merge vision scores with existing scores
			if visionScore.Hate > score.Hate {
				score.Hate = visionScore.Hate
			}
			if visionScore.Delusion > score.Delusion {
				score.Delusion = visionScore.Delusion
			}
		}
	}

	// Fallback to keyword-based analysis for greed/spam detection
	if score.Greed == 0.0 {
		greedKeywords := []string{
			"buy", "crypto", "rich", "scam", "investment", "profit",
			"money", "cash", "bitcoin", "ethereum", "trading", "forex",
			"get rich", "quick money", "guaranteed returns", "multiplier",
		}
		if containsAny(body, greedKeywords) {
			score.Greed = 0.7
		}
	}

	// Determine primary flag reason
	flagReason := ""
	if score.Hate > 0.5 {
		flagReason = "hate"
	} else if score.Greed > 0.5 {
		flagReason = "greed"
	} else if score.Delusion > 0.5 {
		flagReason = "delusion"
	}

	return score, flagReason, nil
}

// analyzeWithOpenAI sends content to OpenAI Moderation API
func (s *ModerationService) analyzeWithOpenAI(ctx context.Context, content string) (*ThreePoisonsScore, error) {
	if s.openAIKey == "" {
		return nil, fmt.Errorf("OpenAI API key not configured")
	}

	requestBody := map[string]interface{}{
		"input": content,
		"model": "text-moderation-latest",
	}

	jsonBody, err := json.Marshal(requestBody)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal request: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, "POST", "https://api.openai.com/v1/moderations", bytes.NewBuffer(jsonBody))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer "+s.openAIKey)

	resp, err := s.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("OpenAI API error: %d - %s", resp.StatusCode, string(body))
	}

	var moderationResp OpenAIModerationResponse
	if err := json.NewDecoder(resp.Body).Decode(&moderationResp); err != nil {
		return nil, fmt.Errorf("failed to decode response: %w", err)
	}

	if len(moderationResp.Results) == 0 {
		return &ThreePoisonsScore{Hate: 0, Greed: 0, Delusion: 0}, nil
	}

	result := moderationResp.Results[0]
	score := &ThreePoisonsScore{
		// Map OpenAI categories to Three Poisons
		Hate: max(
			result.Categories.Hate,
			result.Categories.HateThreatening,
			result.Categories.Violence,
			result.Categories.ViolenceGraphic,
		),
		Greed: 0, // OpenAI doesn't detect greed/spam well
		Delusion: max(
			result.Categories.SelfHarm,
			result.Categories.SelfHarmIntent,
			result.Categories.SelfHarmInstructions,
		),
	}

	return score, nil
}

// analyzeWithGoogleVision analyzes images for inappropriate content
func (s *ModerationService) analyzeWithGoogleVision(ctx context.Context, mediaURLs []string) (*ThreePoisonsScore, error) {
	if s.googleKey == "" {
		return nil, fmt.Errorf("Google Vision API key not configured")
	}

	score := &ThreePoisonsScore{
		Hate:     0.0,
		Greed:    0.0,
		Delusion: 0.0,
	}

	for _, mediaURL := range mediaURLs {
		// Only process image URLs
		if !isImageURL(mediaURL) {
			continue
		}

		requestBody := map[string]interface{}{
			"requests": []map[string]interface{}{
				{
					"image": map[string]interface{}{
						"source": map[string]interface{}{
							"imageUri": mediaURL,
						},
					},
					"features": []map[string]interface{}{
						{
							"type":       "SAFE_SEARCH_DETECTION",
							"maxResults": 1,
						},
					},
				},
			},
		}

		jsonBody, err := json.Marshal(requestBody)
		if err != nil {
			continue
		}

		req, err := http.NewRequestWithContext(ctx, "POST", "https://vision.googleapis.com/v1/images:annotate", bytes.NewBuffer(jsonBody))
		if err != nil {
			continue
		}

		req.Header.Set("Content-Type", "application/json")
		req.URL.RawQuery = "key=" + s.googleKey

		resp, err := s.httpClient.Do(req)
		if err != nil {
			continue
		}
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK {
			continue
		}

		var visionResp GoogleVisionResponse
		if err := json.NewDecoder(resp.Body).Decode(&visionResp); err != nil {
			continue
		}

		if len(visionResp.Responses) > 0 {
			imageScore := s.convertVisionScore(visionResp.Responses[0].SafeSearchAnnotation)
			// Merge with overall score (take maximum)
			if imageScore.Hate > score.Hate {
				score.Hate = imageScore.Hate
			}
			if imageScore.Delusion > score.Delusion {
				score.Delusion = imageScore.Delusion
			}
		}
	}

	return score, nil
}

// convertVisionScore converts Google Vision SafeSearch results to ThreePoisonsScore
func (s *ModerationService) convertVisionScore(safeSearch GoogleVisionSafeSearch) *ThreePoisonsScore {
	score := &ThreePoisonsScore{
		Hate:     0.0,
		Greed:    0.0,
		Delusion: 0.0,
	}

	// Convert string likelihoods to numeric scores
	likelihoodToScore := map[string]float64{
		"UNKNOWN":       0.0,
		"VERY_UNLIKELY": 0.1,
		"UNLIKELY":      0.3,
		"POSSIBLE":      0.5,
		"LIKELY":        0.7,
		"VERY_LIKELY":   0.9,
	}

	// Map Vision categories to Three Poisons
	if hateScore, ok := likelihoodToScore[safeSearch.Violence]; ok {
		score.Hate = hateScore
	}
	if adultScore, ok := likelihoodToScore[safeSearch.Adult]; ok && adultScore > score.Hate {
		score.Hate = adultScore
	}
	if racyScore, ok := likelihoodToScore[safeSearch.Racy]; ok && racyScore > score.Delusion {
		score.Delusion = racyScore
	}

	return score
}

// Helper function to get maximum of multiple floats
func max(values ...float64) float64 {
	maxVal := 0.0
	for _, v := range values {
		if v > maxVal {
			maxVal = v
		}
	}
	return maxVal
}

// Helper function to check if URL is an image
func isImageURL(url string) bool {
	imageExtensions := []string{".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp"}
	lowerURL := strings.ToLower(url)
	for _, ext := range imageExtensions {
		if strings.HasSuffix(lowerURL, ext) {
			return true
		}
	}
	return false
}

func (s *ModerationService) FlagPost(ctx context.Context, postID uuid.UUID, scores *ThreePoisonsScore, reason string) error {
	scoresJSON, err := json.Marshal(scores)
	if err != nil {
		return fmt.Errorf("failed to marshal scores: %w", err)
	}

	query := `
		INSERT INTO moderation_flags (post_id, flag_reason, scores, status)
		VALUES ($1, $2, $3, 'pending')
		RETURNING id, created_at
	`

	var flagID uuid.UUID
	var createdAt time.Time
	err = s.pool.QueryRow(ctx, query, postID, reason, scoresJSON).Scan(&flagID, &createdAt)
	if err != nil {
		return fmt.Errorf("failed to insert moderation flag: %w", err)
	}

	return nil
}

func (s *ModerationService) FlagComment(ctx context.Context, commentID uuid.UUID, scores *ThreePoisonsScore, reason string) error {
	scoresJSON, err := json.Marshal(scores)
	if err != nil {
		return fmt.Errorf("failed to marshal scores: %w", err)
	}

	query := `
		INSERT INTO moderation_flags (comment_id, flag_reason, scores, status)
		VALUES ($1, $2, $3, 'pending')
		RETURNING id, created_at
	`

	var flagID uuid.UUID
	var createdAt time.Time
	err = s.pool.QueryRow(ctx, query, commentID, reason, scoresJSON).Scan(&flagID, &createdAt)
	if err != nil {
		return fmt.Errorf("failed to insert comment moderation flag: %w", err)
	}

	return nil
}

// GetPendingFlags retrieves all pending moderation flags
func (s *ModerationService) GetPendingFlags(ctx context.Context, limit, offset int) ([]map[string]interface{}, error) {
	query := `
		SELECT 
			mf.id, mf.post_id, mf.comment_id, mf.flag_reason, mf.scores, 
			mf.status, mf.created_at,
			p.content as post_content,
			c.content as comment_content,
			u.handle as author_handle
		FROM moderation_flags mf
		LEFT JOIN posts p ON mf.post_id = p.id
		LEFT JOIN comments c ON mf.comment_id = c.id
		LEFT JOIN users u ON (p.user_id = u.id OR c.user_id = u.id)
		WHERE mf.status = 'pending'
		ORDER BY mf.created_at ASC
		LIMIT $1 OFFSET $2
	`

	rows, err := s.pool.Query(ctx, query, limit, offset)
	if err != nil {
		return nil, fmt.Errorf("failed to query pending flags: %w", err)
	}
	defer rows.Close()

	var flags []map[string]interface{}
	for rows.Next() {
		var id, postID, commentID uuid.UUID
		var flagReason, status string
		var scoresJSON []byte
		var createdAt time.Time
		var postContent, commentContent, authorHandle *string

		err := rows.Scan(&id, &postID, &commentID, &flagReason, &scoresJSON, &status, &createdAt, &postContent, &commentContent, &authorHandle)
		if err != nil {
			return nil, fmt.Errorf("failed to scan flag row: %w", err)
		}

		var scores map[string]float64
		if err := json.Unmarshal(scoresJSON, &scores); err != nil {
			return nil, fmt.Errorf("failed to unmarshal scores: %w", err)
		}

		flag := map[string]interface{}{
			"id":              id,
			"post_id":         postID,
			"comment_id":      commentID,
			"flag_reason":     flagReason,
			"scores":          scores,
			"status":          status,
			"created_at":      createdAt,
			"post_content":    postContent,
			"comment_content": commentContent,
			"author_handle":   authorHandle,
		}

		flags = append(flags, flag)
	}

	return flags, nil
}

// UpdateFlagStatus updates the status of a moderation flag
func (s *ModerationService) UpdateFlagStatus(ctx context.Context, flagID uuid.UUID, status string, reviewedBy uuid.UUID) error {
	query := `
		UPDATE moderation_flags 
		SET status = $1, reviewed_by = $2, reviewed_at = NOW()
		WHERE id = $3
	`

	_, err := s.pool.Exec(ctx, query, status, reviewedBy, flagID)
	if err != nil {
		return fmt.Errorf("failed to update flag status: %w", err)
	}

	return nil
}

// UpdateUserStatus updates a user's moderation status
func (s *ModerationService) UpdateUserStatus(ctx context.Context, userID uuid.UUID, status string, changedBy uuid.UUID, reason string) error {
	query := `
		UPDATE users 
		SET status = $1
		WHERE id = $2
	`

	_, err := s.pool.Exec(ctx, query, status, userID)
	if err != nil {
		return fmt.Errorf("failed to update user status: %w", err)
	}

	// Log the status change
	historyQuery := `
		INSERT INTO user_status_history (user_id, old_status, new_status, reason, changed_by)
		SELECT $1, status, $2, $3, $4
		FROM users 
		WHERE id = $1
	`

	_, err = s.pool.Exec(ctx, historyQuery, userID, status, reason, changedBy)
	if err != nil {
		// Log error but don't fail the main operation
		fmt.Printf("Failed to log user status change: %v\n", err)
	}

	return nil
}

func containsAny(body string, terms []string) bool {
	// Case insensitive check
	lower := bytes.ToLower([]byte(body))
	for _, term := range terms {
		if bytes.Contains(lower, []byte(term)) {
			return true
		}
	}
	return false
}