package http

import (
	"embed"
	"errors"
	"net/http"
	"strings"

	"github.com/mudler/LocalAI/pkg/utils"

	"github.com/mudler/LocalAI/core/http/endpoints/localai"
	"github.com/mudler/LocalAI/core/http/endpoints/openai"
	"github.com/mudler/LocalAI/core/http/routes"

	"github.com/mudler/LocalAI/core/config"
	"github.com/mudler/LocalAI/core/schema"
	"github.com/mudler/LocalAI/core/services"
	"github.com/mudler/LocalAI/pkg/model"

	"github.com/gofiber/contrib/fiberzerolog"
	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/fiber/v2/middleware/cors"
	"github.com/gofiber/fiber/v2/middleware/csrf"
	"github.com/gofiber/fiber/v2/middleware/favicon"
	"github.com/gofiber/fiber/v2/middleware/filesystem"
	"github.com/gofiber/fiber/v2/middleware/recover"

	// swagger handler
	"github.com/rs/zerolog/log"
)

func readAuthHeader(c *fiber.Ctx) string {
	authHeader := c.Get("Authorization")

	// elevenlabs
	xApiKey := c.Get("xi-api-key")
	if xApiKey != "" {
		authHeader = "Bearer " + xApiKey
	}

	// anthropic
	xApiKey = c.Get("x-api-key")
	if xApiKey != "" {
		authHeader = "Bearer " + xApiKey
	}

	return authHeader
}

// Embed a directory
//
//go:embed static/*
var embedDirStatic embed.FS

// @title LocalAI API
// @version 2.0.0
// @description The LocalAI Rest API.
// @termsOfService
// @contact.name LocalAI
// @contact.url https://localai.io
// @license.name MIT
// @license.url https://raw.githubusercontent.com/mudler/LocalAI/master/LICENSE
// @BasePath /
// @securityDefinitions.apikey BearerAuth
// @in header
// @name Authorization

func App(cl *config.BackendConfigLoader, ml *model.ModelLoader, appConfig *config.ApplicationConfig) (*fiber.App, error) {

	fiberCfg := fiber.Config{
		Views:     renderEngine(),
		BodyLimit: appConfig.UploadLimitMB * 1024 * 1024, // this is the default limit of 4MB
		// We disable the Fiber startup message as it does not conform to structured logging.
		// We register a startup log line with connection information in the OnListen hook to keep things user friendly though
		DisableStartupMessage: true,
		// Override default error handler
	}

	if !appConfig.OpaqueErrors {
		// Normally, return errors as JSON responses
		fiberCfg.ErrorHandler = func(ctx *fiber.Ctx, err error) error {
			// Status code defaults to 500
			code := fiber.StatusInternalServerError

			// Retrieve the custom status code if it's a *fiber.Error
			var e *fiber.Error
			if errors.As(err, &e) {
				code = e.Code
			}

			// Send custom error page
			return ctx.Status(code).JSON(
				schema.ErrorResponse{
					Error: &schema.APIError{Message: err.Error(), Code: code},
				},
			)
		}
	} else {
		// If OpaqueErrors are required, replace everything with a blank 500.
		fiberCfg.ErrorHandler = func(ctx *fiber.Ctx, _ error) error {
			return ctx.Status(500).SendString("")
		}
	}

	app := fiber.New(fiberCfg)

	app.Hooks().OnListen(func(listenData fiber.ListenData) error {
		scheme := "http"
		if listenData.TLS {
			scheme = "https"
		}
		log.Info().Str("endpoint", scheme+"://"+listenData.Host+":"+listenData.Port).Msg("LocalAI API is listening! Please connect to the endpoint for API documentation.")
		return nil
	})

	// Have Fiber use zerolog like the rest of the application rather than it's built-in logger
	logger := log.Logger
	app.Use(fiberzerolog.New(fiberzerolog.Config{
		Logger: &logger,
	}))

	// Default middleware config

	if !appConfig.Debug {
		app.Use(recover.New())
	}

	metricsService, err := services.NewLocalAIMetricsService()
	if err != nil {
		return nil, err
	}

	if metricsService != nil {
		app.Use(localai.LocalAIMetricsAPIMiddleware(metricsService))
		app.Hooks().OnShutdown(func() error {
			return metricsService.Shutdown()
		})
	}

	// Auth middleware checking if API key is valid. If no API key is set, no auth is required.
	auth := func(c *fiber.Ctx) error {
		if len(appConfig.ApiKeys) == 0 {
			return c.Next()
		}

		if len(appConfig.ApiKeys) == 0 {
			return c.Next()
		}

		authHeader := readAuthHeader(c)
		if authHeader == "" {
			return c.Status(fiber.StatusUnauthorized).JSON(fiber.Map{"message": "Authorization header missing"})
		}

		// If it's a bearer token
		authHeaderParts := strings.Split(authHeader, " ")
		if len(authHeaderParts) != 2 || authHeaderParts[0] != "Bearer" {
			return c.Status(fiber.StatusUnauthorized).JSON(fiber.Map{"message": "Invalid Authorization header format"})
		}

		apiKey := authHeaderParts[1]
		for _, key := range appConfig.ApiKeys {
			if apiKey == key {
				return c.Next()
			}
		}

		return c.Status(fiber.StatusUnauthorized).JSON(fiber.Map{"message": "Invalid API key"})
	}

	if appConfig.CORS {
		var c func(ctx *fiber.Ctx) error
		if appConfig.CORSAllowOrigins == "" {
			c = cors.New()
		} else {
			c = cors.New(cors.Config{AllowOrigins: appConfig.CORSAllowOrigins})
		}

		app.Use(c)
	}

	if appConfig.CSRF {
		log.Debug().Msg("Enabling CSRF middleware. Tokens are now required for state-modifying requests")
		app.Use(csrf.New())
	}

	// Load config jsons
	utils.LoadConfig(appConfig.UploadDir, openai.UploadedFilesFile, &openai.UploadedFiles)
	utils.LoadConfig(appConfig.ConfigsDir, openai.AssistantsConfigFile, &openai.Assistants)
	utils.LoadConfig(appConfig.ConfigsDir, openai.AssistantsFileConfigFile, &openai.AssistantFiles)

	galleryService := services.NewGalleryService(appConfig)
	galleryService.Start(appConfig.Context, cl)

	routes.RegisterElevenLabsRoutes(app, cl, ml, appConfig, auth)
	routes.RegisterLocalAIRoutes(app, cl, ml, appConfig, galleryService, auth)
	routes.RegisterOpenAIRoutes(app, cl, ml, appConfig, auth)
	if !appConfig.DisableWebUI {
		routes.RegisterUIRoutes(app, cl, ml, appConfig, galleryService, auth)
	}
	routes.RegisterJINARoutes(app, cl, ml, appConfig, auth)

	httpFS := http.FS(embedDirStatic)

	app.Use(favicon.New(favicon.Config{
		URL:        "/favicon.ico",
		FileSystem: httpFS,
		File:       "static/favicon.ico",
	}))

	app.Use("/static", filesystem.New(filesystem.Config{
		Root:       httpFS,
		PathPrefix: "static",
		Browse:     true,
	}))

	// Define a custom 404 handler
	// Note: keep this at the bottom!
	app.Use(notFoundHandler)

	return app, nil
}