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

package services

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

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

// OpenRouterService handles interactions with the OpenRouter API
type OpenRouterService struct {
	pool       *pgxpool.Pool
	httpClient *http.Client
	apiKey     string

	// Cached model list
	modelCache     []OpenRouterModel
	modelCacheMu   sync.RWMutex
	modelCacheTime time.Time
}

// OpenRouterModel represents a model available on OpenRouter
type OpenRouterModel struct {
	ID               string            `json:"id"`
	Name             string            `json:"name"`
	Description      string            `json:"description,omitempty"`
	Pricing          OpenRouterPricing `json:"pricing"`
	ContextLength    int               `json:"context_length"`
	Architecture     map[string]any    `json:"architecture,omitempty"`
	TopProvider      map[string]any    `json:"top_provider,omitempty"`
	PerRequestLimits map[string]any    `json:"per_request_limits,omitempty"`
}

type OpenRouterPricing struct {
	Prompt     string `json:"prompt"`
	Completion string `json:"completion"`
	Image      string `json:"image,omitempty"`
	Request    string `json:"request,omitempty"`
}

// ModerationConfigEntry represents a row in ai_moderation_config
type ModerationConfigEntry struct {
	ID             string    `json:"id"`
	ModerationType string    `json:"moderation_type"`
	ModelID        string    `json:"model_id"`
	ModelName      string    `json:"model_name"`
	SystemPrompt   string    `json:"system_prompt"`
	Enabled        bool      `json:"enabled"`
	Engines        []string  `json:"engines"`
	UpdatedAt      time.Time `json:"updated_at"`
	UpdatedBy      *string   `json:"updated_by,omitempty"`
}

// HasEngine returns true if the given engine is in the config's engines list.
func (c *ModerationConfigEntry) HasEngine(engine string) bool {
	for _, e := range c.Engines {
		if e == engine {
			return true
		}
	}
	return false
}

// OpenRouterChatMessage represents a message in a chat completion request
type OpenRouterChatMessage struct {
	Role    string `json:"role"`
	Content any    `json:"content"`
}

// OpenRouterChatRequest represents a chat completion request
type OpenRouterChatRequest struct {
	Model       string                  `json:"model"`
	Messages    []OpenRouterChatMessage `json:"messages"`
	Temperature *float64                `json:"temperature,omitempty"`
	MaxTokens   *int                    `json:"max_tokens,omitempty"`
}

func floatPtr(f float64) *float64 { return &f }
func intPtr(i int) *int           { return &i }

// OpenRouterChatResponse represents a chat completion response
type OpenRouterChatResponse struct {
	ID      string `json:"id"`
	Choices []struct {
		Message struct {
			Role    string `json:"role"`
			Content string `json:"content"`
		} `json:"message"`
		FinishReason string `json:"finish_reason"`
	} `json:"choices"`
	Usage struct {
		PromptTokens     int `json:"prompt_tokens"`
		CompletionTokens int `json:"completion_tokens"`
		TotalTokens      int `json:"total_tokens"`
	} `json:"usage"`
}

func NewOpenRouterService(pool *pgxpool.Pool, apiKey string) *OpenRouterService {
	return &OpenRouterService{
		pool:   pool,
		apiKey: apiKey,
		httpClient: &http.Client{
			Timeout: 60 * time.Second,
		},
	}
}

// ListModels fetches available models from OpenRouter, with 1-hour cache
func (s *OpenRouterService) ListModels(ctx context.Context) ([]OpenRouterModel, error) {
	s.modelCacheMu.RLock()
	if len(s.modelCache) > 0 && time.Since(s.modelCacheTime) < time.Hour {
		cached := s.modelCache
		s.modelCacheMu.RUnlock()
		return cached, nil
	}
	s.modelCacheMu.RUnlock()

	req, err := http.NewRequestWithContext(ctx, "GET", "https://openrouter.ai/api/v1/models", nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}
	if s.apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+s.apiKey)
	}

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

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

	var result struct {
		Data []OpenRouterModel `json:"data"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("failed to decode models: %w", err)
	}

	s.modelCacheMu.Lock()
	s.modelCache = result.Data
	s.modelCacheTime = time.Now()
	s.modelCacheMu.Unlock()

	return result.Data, nil
}

// GetModerationConfigs returns all moderation type configurations
func (s *OpenRouterService) GetModerationConfigs(ctx context.Context) ([]ModerationConfigEntry, error) {
	rows, err := s.pool.Query(ctx, `
		SELECT id, moderation_type, model_id, model_name, system_prompt, enabled, engines, updated_at, updated_by
		FROM ai_moderation_config
		ORDER BY moderation_type
	`)
	if err != nil {
		return nil, fmt.Errorf("failed to query configs: %w", err)
	}
	defer rows.Close()

	var configs []ModerationConfigEntry
	for rows.Next() {
		var c ModerationConfigEntry
		if err := rows.Scan(&c.ID, &c.ModerationType, &c.ModelID, &c.ModelName, &c.SystemPrompt, &c.Enabled, &c.Engines, &c.UpdatedAt, &c.UpdatedBy); err != nil {
			return nil, err
		}
		configs = append(configs, c)
	}
	return configs, nil
}

// GetModerationConfig returns config for a specific moderation type
func (s *OpenRouterService) GetModerationConfig(ctx context.Context, moderationType string) (*ModerationConfigEntry, error) {
	var c ModerationConfigEntry
	err := s.pool.QueryRow(ctx, `
		SELECT id, moderation_type, model_id, model_name, system_prompt, enabled, engines, updated_at, updated_by
		FROM ai_moderation_config WHERE moderation_type = $1
	`, moderationType).Scan(&c.ID, &c.ModerationType, &c.ModelID, &c.ModelName, &c.SystemPrompt, &c.Enabled, &c.Engines, &c.UpdatedAt, &c.UpdatedBy)
	if err != nil {
		return nil, err
	}
	return &c, nil
}

// SetModerationConfig upserts a moderation config
func (s *OpenRouterService) SetModerationConfig(ctx context.Context, moderationType, modelID, modelName, systemPrompt string, enabled bool, engines []string, updatedBy string) error {
	if len(engines) == 0 {
		engines = []string{"local_ai", "openrouter", "openai"}
	}
	_, err := s.pool.Exec(ctx, `
		INSERT INTO ai_moderation_config (moderation_type, model_id, model_name, system_prompt, enabled, engines, updated_by, updated_at)
		VALUES ($1, $2, $3, $4, $5, $7, $6, NOW())
		ON CONFLICT (moderation_type)
		DO UPDATE SET model_id = $2, model_name = $3, system_prompt = $4, enabled = $5, engines = $7, updated_by = $6, updated_at = NOW()
	`, moderationType, modelID, modelName, systemPrompt, enabled, updatedBy, engines)
	return err
}

// ModerateText sends text content to the configured model for moderation
func (s *OpenRouterService) ModerateText(ctx context.Context, content string) (*ModerationResult, error) {
	config, err := s.GetModerationConfig(ctx, "text")
	if err != nil || !config.Enabled || config.ModelID == "" {
		return nil, fmt.Errorf("text moderation not configured")
	}
	return s.callModel(ctx, config.ModelID, config.SystemPrompt, content, nil)
}

// ModerateImage sends an image URL to a vision model for moderation
func (s *OpenRouterService) ModerateImage(ctx context.Context, imageURL string) (*ModerationResult, error) {
	config, err := s.GetModerationConfig(ctx, "image")
	if err != nil || !config.Enabled || config.ModelID == "" {
		return nil, fmt.Errorf("image moderation not configured")
	}
	return s.callModel(ctx, config.ModelID, config.SystemPrompt, "", []string{imageURL})
}

// ModerateWithType sends content to a specific moderation type config (e.g. "group_text", "beacon_image").
// Returns nil if the config doesn't exist or isn't enabled — caller should fall back to generic.
func (s *OpenRouterService) ModerateWithType(ctx context.Context, moderationType string, textContent string, imageURLs []string) (*ModerationResult, error) {
	config, err := s.GetModerationConfig(ctx, moderationType)
	if err != nil || !config.Enabled || config.ModelID == "" {
		return nil, fmt.Errorf("%s moderation not configured", moderationType)
	}
	return s.callModel(ctx, config.ModelID, config.SystemPrompt, textContent, imageURLs)
}

// ModerateVideo sends video frame URLs to a vision model for moderation
func (s *OpenRouterService) ModerateVideo(ctx context.Context, frameURLs []string) (*ModerationResult, error) {
	config, err := s.GetModerationConfig(ctx, "video")
	if err != nil || !config.Enabled || config.ModelID == "" {
		return nil, fmt.Errorf("video moderation not configured")
	}
	return s.callModel(ctx, config.ModelID, config.SystemPrompt, "These are 3 frames extracted from a short video. Analyze all frames for policy violations.", frameURLs)
}

// ModerationResult is the parsed response from OpenRouter moderation
type ModerationResult struct {
	Flagged        bool    `json:"flagged"`
	Action         string  `json:"action"`      // "clean", "nsfw", "flag"
	NSFWReason     string  `json:"nsfw_reason"` // e.g. "violence", "nudity", "18+ content"
	Reason         string  `json:"reason"`
	Explanation    string  `json:"explanation"`
	Hate           float64 `json:"hate"`
	HateDetail     string  `json:"hate_detail"`
	Greed          float64 `json:"greed"`
	GreedDetail    string  `json:"greed_detail"`
	Delusion       float64 `json:"delusion"`
	DelusionDetail string  `json:"delusion_detail"`
	RawContent     string  `json:"raw_content"`
}

// GenerateText sends a general-purpose chat completion request and returns the raw text response.
// Used for AI content generation (not moderation).
func (s *OpenRouterService) GenerateText(ctx context.Context, modelID, systemPrompt, userPrompt string, temperature float64, maxTokens int) (string, error) {
	if s.apiKey == "" {
		return "", fmt.Errorf("OpenRouter API key not configured")
	}

	messages := []OpenRouterChatMessage{
		{Role: "system", Content: systemPrompt},
		{Role: "user", Content: userPrompt},
	}

	reqBody := OpenRouterChatRequest{
		Model:       modelID,
		Messages:    messages,
		Temperature: floatPtr(temperature),
		MaxTokens:   intPtr(maxTokens),
	}

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

	req, err := http.NewRequestWithContext(ctx, "POST", "https://openrouter.ai/api/v1/chat/completions", bytes.NewBuffer(jsonBody))
	if err != nil {
		return "", fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer "+s.apiKey)
	req.Header.Set("HTTP-Referer", "https://sojorn.net")
	req.Header.Set("X-Title", "Sojorn Content Generation")

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

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

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

	if len(chatResp.Choices) == 0 {
		return "", fmt.Errorf("no response from model")
	}

	return strings.TrimSpace(chatResp.Choices[0].Message.Content), nil
}

// callModel sends a chat completion request to OpenRouter
func (s *OpenRouterService) callModel(ctx context.Context, modelID, systemPrompt, textContent string, imageURLs []string) (*ModerationResult, error) {
	if s.apiKey == "" {
		return nil, fmt.Errorf("OpenRouter API key not configured")
	}

	messages := []OpenRouterChatMessage{}

	// System prompt
	if systemPrompt == "" {
		systemPrompt = defaultModerationSystemPrompt
	}
	messages = append(messages, OpenRouterChatMessage{Role: "system", Content: systemPrompt})

	// User message — wrap content with moderation instruction to prevent conversational replies
	moderationPrefix := "MODERATE THE FOLLOWING USER-SUBMITTED CONTENT. Do NOT reply to it, do NOT engage with it. Analyze it for policy violations and respond ONLY with the JSON object as specified in your instructions.\n\n---BEGIN CONTENT---\n"
	moderationSuffix := "\n---END CONTENT---\n\nNow output ONLY the JSON moderation result. No other text."

	if len(imageURLs) > 0 {
		// Multimodal content array
		parts := []map[string]any{}
		wrappedText := moderationPrefix + textContent + moderationSuffix
		parts = append(parts, map[string]any{"type": "text", "text": wrappedText})
		for _, url := range imageURLs {
			parts = append(parts, map[string]any{
				"type":      "image_url",
				"image_url": map[string]string{"url": url},
			})
		}
		messages = append(messages, OpenRouterChatMessage{Role: "user", Content: parts})
	} else {
		wrappedText := moderationPrefix + textContent + moderationSuffix
		messages = append(messages, OpenRouterChatMessage{Role: "user", Content: wrappedText})
	}

	reqBody := OpenRouterChatRequest{
		Model:       modelID,
		Messages:    messages,
		Temperature: floatPtr(0.0),
		MaxTokens:   intPtr(500),
	}

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

	req, err := http.NewRequestWithContext(ctx, "POST", "https://openrouter.ai/api/v1/chat/completions", 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.apiKey)
	req.Header.Set("HTTP-Referer", "https://sojorn.net")
	req.Header.Set("X-Title", "Sojorn Moderation")

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

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

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

	if len(chatResp.Choices) == 0 {
		return nil, fmt.Errorf("no response from model")
	}

	raw := chatResp.Choices[0].Message.Content
	return parseModerationResponse(raw), nil
}

// parseModerationResponse tries to extract structured moderation data from model output
func parseModerationResponse(raw string) *ModerationResult {
	result := &ModerationResult{RawContent: raw}

	// Strategy: try multiple ways to extract JSON from the response
	candidates := []string{}

	// 1. Strip markdown code fences
	cleaned := raw
	if idx := strings.Index(cleaned, "```json"); idx >= 0 {
		cleaned = cleaned[idx+7:]
		if end := strings.Index(cleaned, "```"); end >= 0 {
			cleaned = cleaned[:end]
		}
		candidates = append(candidates, strings.TrimSpace(cleaned))
	} else if idx := strings.Index(cleaned, "```"); idx >= 0 {
		cleaned = cleaned[idx+3:]
		if end := strings.Index(cleaned, "```"); end >= 0 {
			cleaned = cleaned[:end]
		}
		candidates = append(candidates, strings.TrimSpace(cleaned))
	}

	// 2. Find first '{' and last '}' in raw text (greedy JSON extraction)
	if start := strings.Index(raw, "{"); start >= 0 {
		if end := strings.LastIndex(raw, "}"); end > start {
			candidates = append(candidates, raw[start:end+1])
		}
	}

	// 3. Try the raw text as-is
	candidates = append(candidates, strings.TrimSpace(raw))

	var parsed struct {
		Flagged        bool    `json:"flagged"`
		Action         string  `json:"action"`
		NSFWReason     string  `json:"nsfw_reason"`
		Reason         string  `json:"reason"`
		Explanation    string  `json:"explanation"`
		Hate           float64 `json:"hate"`
		HateDetail     string  `json:"hate_detail"`
		Greed          float64 `json:"greed"`
		GreedDetail    string  `json:"greed_detail"`
		Delusion       float64 `json:"delusion"`
		DelusionDetail string  `json:"delusion_detail"`
	}

	for _, candidate := range candidates {
		if err := json.Unmarshal([]byte(candidate), &parsed); err == nil {
			result.Reason = parsed.Reason
			result.Explanation = parsed.Explanation
			result.Hate = parsed.Hate
			result.HateDetail = parsed.HateDetail
			result.Greed = parsed.Greed
			result.GreedDetail = parsed.GreedDetail
			result.Delusion = parsed.Delusion
			result.DelusionDetail = parsed.DelusionDetail
			result.NSFWReason = parsed.NSFWReason

			// Use the action field if present, otherwise derive from scores
			action := strings.ToLower(strings.TrimSpace(parsed.Action))
			if action == "nsfw" || action == "flag" || action == "clean" {
				result.Action = action
			} else {
				// Fallback: derive from scores
				maxScore := max(parsed.Hate, max(parsed.Greed, parsed.Delusion))
				if maxScore > 0.5 {
					result.Action = "flag"
				} else if maxScore > 0.25 {
					result.Action = "nsfw"
				} else {
					result.Action = "clean"
				}
			}

			result.Flagged = result.Action == "flag"

			// Safety override: if any score > 0.7, always flag regardless of what model said
			if parsed.Hate > 0.7 || parsed.Greed > 0.7 || parsed.Delusion > 0.7 {
				result.Action = "flag"
				result.Flagged = true
				if result.Reason == "" {
					result.Reason = "Flagged: score exceeded 0.7 threshold"
				}
			}

			return result
		}
	}

	// All parsing failed — mark as error so admin can see the raw output
	result.Explanation = "Failed to parse model response as JSON. Check raw response below."
	return result
}

const defaultModerationSystemPrompt = `You are a content moderation AI for Sojorn, a social media platform.
Analyze the provided content and decide one of three actions:

1. "clean" — Content is appropriate for all users. No issues.
2. "nsfw" — Content is mature/sensitive but ALLOWED on the platform. It will be blurred behind a warning label for users who have opted in. Think "Cinemax late night" — permissive but not extreme.
3. "flag" — Content is NOT ALLOWED and will be removed. The user will receive an appeal notice.

═══════════════════════════════════════════
NUDITY & SEXUAL CONTENT RULES (Cinemax Rule)
═══════════════════════════════════════════
NSFW (allowed, blurred):
- Partial or full nudity (breasts, buttocks, genitalia visible)
- Suggestive or sensual poses, lingerie, implied sexual situations
- Artistic nude photography, figure drawing, body-positive content
- Breastfeeding, non-sexual nudity in natural contexts

NOT ALLOWED (flag):
- Explicit sexual intercourse (penetration, oral sex, any sex acts)
- Hardcore pornography of any kind
- Any sexual content involving minors (ZERO TOLERANCE — always flag)
- Non-consensual sexual content, revenge porn
- Bestiality

═══════════════════════════════════════════
VIOLENCE RULES (1-10 Scale)
═══════════════════════════════════════════
Rate the violence level on a 1-10 scale in your explanation:
  1-3: Mild (arguments, shoving, cartoon violence) → "clean"
  4-5: Moderate (blood from injuries, protest footage with blood, boxing/MMA, hunting) → "nsfw"
  6-7: Graphic (open wounds, significant bloodshed, war footage) → "flag"
  8-10: Extreme (torture, dismemberment, gore, execution) → "flag"

Only violence rated 5 or below is allowed. 6+ is always flagged and removed.
Protest footage showing blood or injuries = NSFW (4-5), NOT flagged.

═══════════════════════════════════════════
OTHER CONTENT RULES
═══════════════════════════════════════════
NSFW (allowed, blurred):
- Dark humor, edgy memes, intense themes
- Horror content, gore in fiction/movies (≤5 on violence scale)
- Drug/alcohol references, smoking imagery
- Heated political speech, strong profanity
- Depictions of self-harm recovery (educational/supportive context)

NOT ALLOWED (flag):
- Credible threats of violence against real people
- Doxxing (sharing private info to harass)
- Illegal activity instructions (bomb-making, drug synthesis)
- Extreme hate speech targeting protected groups
- Spam/scam content designed to defraud users
- Dangerous medical misinformation that could cause harm
- Deepfakes designed to deceive or defame

When unsure between clean and nsfw, prefer "nsfw" (better safe, user sees it blurred).
When unsure between nsfw and flag, prefer "nsfw" — only flag content that clearly crosses the lines above.

Respond ONLY with a JSON object in this exact format:
{
  "action": "clean" or "nsfw" or "flag",
  "nsfw_reason": "If action is nsfw, a short label: e.g. 'Nudity', 'Violence', 'Suggestive Content', '18+ Themes', 'Gore', 'Drug References'. Empty string if clean or flag.",
  "flagged": true/false,
  "reason": "one-line summary if flagged or nsfw, empty string if clean",
  "explanation": "Detailed paragraph explaining your analysis. For violence, include your 1-10 rating. For nudity, explain what is shown and why it does or does not cross the intercourse line.",
  "hate": 0.0-1.0,
  "hate_detail": "What you found or didn't find related to hate/violence/sexual content.",
  "greed": 0.0-1.0,
  "greed_detail": "What you found or didn't find related to spam/scams/manipulation.",
  "delusion": 0.0-1.0,
  "delusion_detail": "What you found or didn't find related to misinformation/self-harm."
}

Scoring guide (Three Poisons framework):
- hate: harassment, threats, violence, sexual content, nudity, hate speech, discrimination, graphic imagery
- greed: spam, scams, crypto schemes, misleading promotions, get-rich-quick, MLM recruitment
- delusion: misinformation, self-harm content, conspiracy theories, dangerous medical advice, deepfakes

Score 0.0 = no concern, 1.0 = extreme violation.
ALWAYS provide detailed explanations even when content is clean — explain what you checked and why it passed.
Only respond with the JSON, no other text.`