package main

import (
	"bufio"
	"context"
	"fmt"
	"log"
	"os"
	"time"

	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/fiber/v2/middleware/cors"
	"github.com/gofiber/fiber/v2/middleware/logger"
	"github.com/gooseek/backend/internal/agent"
	"github.com/gooseek/backend/internal/llm"
	"github.com/gooseek/backend/internal/search"
	"github.com/gooseek/backend/internal/session"
	"github.com/gooseek/backend/pkg/config"
	"github.com/gooseek/backend/pkg/ndjson"
)

type SearchRequest struct {
	Message struct {
		MessageID string `json:"messageId"`
		ChatID    string `json:"chatId"`
		Content   string `json:"content"`
	} `json:"message"`
	OptimizationMode   string     `json:"optimizationMode"`
	Sources            []string   `json:"sources"`
	History            [][]string `json:"history"`
	Files              []string   `json:"files"`
	ChatModel          ChatModel  `json:"chatModel"`
	SystemInstructions string     `json:"systemInstructions"`
	Locale             string     `json:"locale"`
	AnswerMode         string     `json:"answerMode"`
	ResponsePrefs      *struct {
		Format string `json:"format"`
		Length string `json:"length"`
		Tone   string `json:"tone"`
	} `json:"responsePrefs"`
	LearningMode bool `json:"learningMode"`
}

type ChatModel struct {
	ProviderID string `json:"providerId"`
	Key        string `json:"key"`
}

func main() {
	cfg, err := config.Load()
	if err != nil {
		log.Fatal("Failed to load config:", err)
	}

	searchClient := search.NewSearXNGClient(cfg)

	app := fiber.New(fiber.Config{
		StreamRequestBody: true,
		BodyLimit:         10 * 1024 * 1024,
		ReadTimeout:       time.Minute,
		WriteTimeout:      5 * time.Minute,
		IdleTimeout:       2 * time.Minute,
	})

	app.Use(logger.New())
	app.Use(cors.New())

	app.Get("/health", func(c *fiber.Ctx) error {
		return c.JSON(fiber.Map{"status": "ok"})
	})

	app.Post("/api/v1/agents/search", func(c *fiber.Ctx) error {
		var req SearchRequest
		if err := c.BodyParser(&req); err != nil {
			return c.Status(400).JSON(fiber.Map{"error": "Invalid request body"})
		}

		if req.Message.Content == "" {
			return c.Status(400).JSON(fiber.Map{"error": "Message content required"})
		}

		providerID := req.ChatModel.ProviderID
		modelKey := req.ChatModel.Key
		
		if providerID == "" && cfg.TimewebAPIKey != "" {
			providerID = "timeweb"
			modelKey = "gpt-4o"
		} else if providerID == "" {
			providerID = "openai"
			modelKey = "gpt-4o-mini"
		}

		llmClient, err := llm.NewClient(llm.ProviderConfig{
			ProviderID:    providerID,
			ModelKey:      modelKey,
			APIKey:        getAPIKey(cfg, providerID),
			BaseURL:       cfg.TimewebAPIBaseURL,
			AgentAccessID: cfg.TimewebAgentAccessID,
		})
		if err != nil {
			return c.Status(500).JSON(fiber.Map{"error": "Failed to create LLM client: " + err.Error()})
		}

		chatHistory := make([]llm.Message, 0, len(req.History))
		for _, h := range req.History {
			if len(h) >= 2 {
				role := llm.RoleUser
				if h[0] == "ai" || h[0] == "assistant" {
					role = llm.RoleAssistant
				}
				chatHistory = append(chatHistory, llm.Message{
					Role:    role,
					Content: h[1],
				})
			}
		}

		mode := agent.ModeBalanced
		switch req.OptimizationMode {
		case "speed":
			mode = agent.ModeSpeed
		case "quality":
			mode = agent.ModeQuality
		}

		var responsePrefs *agent.ResponsePrefs
		if req.ResponsePrefs != nil {
			responsePrefs = &agent.ResponsePrefs{
				Format: req.ResponsePrefs.Format,
				Length: req.ResponsePrefs.Length,
				Tone:   req.ResponsePrefs.Tone,
			}
		}

		input := agent.OrchestratorInput{
			ChatHistory: chatHistory,
			FollowUp:    req.Message.Content,
			Config: agent.OrchestratorConfig{
				LLM:                llmClient,
				SearchClient:       searchClient,
				Mode:               mode,
				Sources:            req.Sources,
				FileIDs:            req.Files,
				SystemInstructions: req.SystemInstructions,
				Locale:             req.Locale,
				AnswerMode:         req.AnswerMode,
				ResponsePrefs:      responsePrefs,
				LearningMode:       req.LearningMode,
				DiscoverSvcURL:     cfg.DiscoverSvcURL,
				Crawl4AIURL:        cfg.Crawl4AIURL,
			},
		}

		sess := session.NewSession()

		c.Set("Content-Type", "application/x-ndjson")
		c.Set("Cache-Control", "no-cache")
		c.Set("Transfer-Encoding", "chunked")

		c.Context().SetBodyStreamWriter(func(w *bufio.Writer) {
			ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
			defer cancel()
			
			writer := ndjson.NewWriter(w)

			unsubscribe := sess.Subscribe(func(eventType session.EventType, data interface{}) {
				if eventType == session.EventData {
					if dataMap, ok := data.(map[string]interface{}); ok {
						writer.Write(dataMap)
						w.Flush()
					}
				}
			})
			defer unsubscribe()

			err := agent.RunOrchestrator(ctx, sess, input)
			if err != nil {
				ndjson.WriteError(writer, err)
			}
		})

		return nil
	})

	port := cfg.AgentSvcPort
	log.Printf("agent-svc listening on :%d", port)
	log.Fatal(app.Listen(fmt.Sprintf(":%d", port)))
}

func getAPIKey(cfg *config.Config, providerID string) string {
	switch providerID {
	case "timeweb":
		return cfg.TimewebAPIKey
	case "openai":
		return cfg.OpenAIAPIKey
	case "anthropic":
		return cfg.AnthropicAPIKey
	case "gemini", "google":
		return cfg.GeminiAPIKey
	default:
		return ""
	}
}

func init() {
	if os.Getenv("PORT") == "" {
		os.Setenv("PORT", "3018")
	}
}