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"`
	UpdatedAt       time.Time `json:"updated_at"`
	UpdatedBy       *string   `json:"updated_by,omitempty"`
}

// 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"`
}

// 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, 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.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, 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.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, updatedBy string) error {
	_, err := s.pool.Exec(ctx, `
		INSERT INTO ai_moderation_config (moderation_type, model_id, model_name, system_prompt, enabled, updated_by, updated_at)
		VALUES ($1, $2, $3, $4, $5, $6, NOW())
		ON CONFLICT (moderation_type)
		DO UPDATE SET model_id = $2, model_name = $3, system_prompt = $4, enabled = $5, updated_by = $6, updated_at = NOW()
	`, moderationType, modelID, modelName, systemPrompt, enabled, updatedBy)
	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})
}

// 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"`
	Reason     string  `json:"reason"`
	Hate       float64 `json:"hate"`
	Greed      float64 `json:"greed"`
	Delusion   float64 `json:"delusion"`
	RawContent string  `json:"raw_content"`
}

// 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 — text only or multimodal (text + images)
	if len(imageURLs) > 0 {
		// Multimodal content array
		parts := []map[string]any{}
		if textContent != "" {
			parts = append(parts, map[string]any{"type": "text", "text": textContent})
		}
		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 {
		messages = append(messages, OpenRouterChatMessage{Role: "user", Content: textContent})
	}

	reqBody := OpenRouterChatRequest{
		Model:    modelID,
		Messages: messages,
	}

	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}

	// Try to parse JSON from the response
	// Models may wrap JSON in markdown code blocks
	cleaned := raw
	if idx := strings.Index(cleaned, "```json"); idx >= 0 {
		cleaned = cleaned[idx+7:]
		if end := strings.Index(cleaned, "```"); end >= 0 {
			cleaned = cleaned[:end]
		}
	} else if idx := strings.Index(cleaned, "```"); idx >= 0 {
		cleaned = cleaned[idx+3:]
		if end := strings.Index(cleaned, "```"); end >= 0 {
			cleaned = cleaned[:end]
		}
	}
	cleaned = strings.TrimSpace(cleaned)

	var parsed struct {
		Flagged  bool    `json:"flagged"`
		Reason   string  `json:"reason"`
		Hate     float64 `json:"hate"`
		Greed    float64 `json:"greed"`
		Delusion float64 `json:"delusion"`
	}
	if err := json.Unmarshal([]byte(cleaned), &parsed); err == nil {
		result.Flagged = parsed.Flagged
		result.Reason = parsed.Reason
		result.Hate = parsed.Hate
		result.Greed = parsed.Greed
		result.Delusion = parsed.Delusion
		return result
	}

	// Fallback: check for keywords in raw text
	lower := strings.ToLower(raw)
	if strings.Contains(lower, "violation") || strings.Contains(lower, "inappropriate") || strings.Contains(lower, "flagged") {
		result.Flagged = true
		result.Reason = "Content flagged by AI moderation"
	}

	return result
}

const defaultModerationSystemPrompt = `You are a content moderation AI for Sojorn, a social media platform. 
Analyze the provided content for policy violations.

Respond ONLY with a JSON object in this exact format:
{
  "flagged": true/false,
  "reason": "brief reason if flagged, empty string if not",
  "hate": 0.0-1.0,
  "greed": 0.0-1.0,
  "delusion": 0.0-1.0
}

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

Score 0.0 = no concern, 1.0 = extreme violation. Flag if any score > 0.5.
Only respond with the JSON, no other text.`