package main

import (
	"bufio"
	"context"
	"database/sql"
	"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/llm"
	"github.com/gooseek/backend/internal/usage"
	"github.com/gooseek/backend/pkg/config"
	"github.com/gooseek/backend/pkg/middleware"
	"github.com/gooseek/backend/pkg/ndjson"
	_ "github.com/lib/pq"
)

type GenerateRequest struct {
	ProviderID string `json:"providerId"`
	ModelKey   string `json:"key"`
	Messages   []struct {
		Role    string `json:"role"`
		Content string `json:"content"`
	} `json:"messages"`
	Options struct {
		MaxTokens   int     `json:"maxTokens"`
		Temperature float64 `json:"temperature"`
		Stream      bool    `json:"stream"`
	} `json:"options"`
}

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

	var usageRepo *usage.Repository
	if cfg.DatabaseURL != "" {
		db, err := sql.Open("postgres", cfg.DatabaseURL)
		if err != nil {
			log.Printf("Usage tracking unavailable: %v", err)
		} else {
			db.SetMaxOpenConns(5)
			db.SetMaxIdleConns(2)
			defer db.Close()

			usageRepo = usage.NewRepository(db)
			ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
			if err := usageRepo.RunMigrations(ctx); err != nil {
				log.Printf("Usage migrations warning: %v", err)
			}
			cancel()
			log.Println("Usage tracking enabled")
		}
	}

	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.Get("/api/v1/providers", func(c *fiber.Ctx) error {
		providers := []fiber.Map{}

		if cfg.OpenAIAPIKey != "" {
			providers = append(providers, fiber.Map{
				"id":     "openai",
				"name":   "OpenAI",
				"models": []string{"gpt-4o", "gpt-4o-mini", "gpt-4-turbo", "gpt-3.5-turbo"},
			})
		}

		if cfg.AnthropicAPIKey != "" {
			providers = append(providers, fiber.Map{
				"id":     "anthropic",
				"name":   "Anthropic",
				"models": []string{"claude-3-5-sonnet-20241022", "claude-3-opus-20240229", "claude-3-haiku-20240307"},
			})
		}

		if cfg.GeminiAPIKey != "" {
			providers = append(providers, fiber.Map{
				"id":     "gemini",
				"name":   "Google Gemini",
				"models": []string{"gemini-1.5-pro", "gemini-1.5-flash", "gemini-2.0-flash-exp"},
			})
		}

		return c.JSON(fiber.Map{
			"providers":   providers,
			"envOnlyMode": true,
		})
	})

	app.Get("/api/v1/providers/ui-config", func(c *fiber.Ctx) error {
		return c.JSON(fiber.Map{
			"sections": []interface{}{},
		})
	})

	llmAPI := app.Group("/api/v1", middleware.JWT(middleware.JWTConfig{
		Secret:     cfg.JWTSecret,
		AuthSvcURL: cfg.AuthSvcURL,
		AllowGuest: false,
	}), middleware.LLMLimits(middleware.LLMLimitsConfig{
		UsageRepo: usageRepo,
	}))

	llmAPI.Post("/generate", func(c *fiber.Ctx) error {
		userID := middleware.GetUserID(c)
		tier := middleware.GetUserTier(c)
		if tier == "" {
			tier = "free"
		}
		var req GenerateRequest
		if err := c.BodyParser(&req); err != nil {
			return c.Status(400).JSON(fiber.Map{"error": "Invalid request body"})
		}

		if len(req.Messages) == 0 {
			return c.Status(400).JSON(fiber.Map{"error": "Messages required"})
		}

		limits := usage.GetLimits(tier)
		if req.Options.MaxTokens == 0 || req.Options.MaxTokens > limits.MaxTokensPerReq {
			req.Options.MaxTokens = limits.MaxTokensPerReq
		}

		client, err := llm.NewClient(llm.ProviderConfig{
			ProviderID: req.ProviderID,
			ModelKey:   req.ModelKey,
			APIKey:     getAPIKey(cfg, req.ProviderID),
		})
		if err != nil {
			return c.Status(500).JSON(fiber.Map{"error": err.Error()})
		}

		messages := make([]llm.Message, len(req.Messages))
		for i, m := range req.Messages {
			messages[i] = llm.Message{
				Role:    llm.Role(m.Role),
				Content: m.Content,
			}
		}

		ctx, cancel := context.WithTimeout(context.Background(), cfg.LLMTimeout)
		defer cancel()

		if req.Options.Stream {
			stream, err := client.StreamText(ctx, llm.StreamRequest{
				Messages: messages,
				Options: llm.StreamOptions{
					MaxTokens:   req.Options.MaxTokens,
					Temperature: req.Options.Temperature,
				},
			})
			if err != nil {
				return c.Status(500).JSON(fiber.Map{"error": err.Error()})
			}

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

			c.Context().SetBodyStreamWriter(func(w *bufio.Writer) {
				writer := ndjson.NewWriter(w)
				for chunk := range stream {
					writer.Write(fiber.Map{
						"type":  "chunk",
						"chunk": chunk.ContentChunk,
					})
					w.Flush()
				}
				writer.Write(fiber.Map{"type": "done"})
			})

			return nil
		}

		response, err := client.GenerateText(ctx, llm.StreamRequest{
			Messages: messages,
			Options: llm.StreamOptions{
				MaxTokens:   req.Options.MaxTokens,
				Temperature: req.Options.Temperature,
			},
		})
		if err != nil {
			return c.Status(500).JSON(fiber.Map{"error": err.Error()})
		}

		if usageRepo != nil {
			go usageRepo.IncrementLLMUsage(context.Background(), userID, tier, len(response)/4)
		}

		return c.JSON(fiber.Map{
			"content": response,
		})
	})

	llmAPI.Post("/embed", func(c *fiber.Ctx) error {
		return c.Status(501).JSON(fiber.Map{"error": "Not implemented"})
	})

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

func getAPIKey(cfg *config.Config, providerID string) string {
	switch providerID {
	case "openai", "timeweb":
		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", "3020")
	}
}