package rest

import (
	"encoding/json"
	"errors"
	"net/http"

	"gitea.dwysokinski.me/twhelp/sessions/internal/domain"
	"gitea.dwysokinski.me/twhelp/sessions/internal/router/rest/internal/docs"
	"gitea.dwysokinski.me/twhelp/sessions/internal/router/rest/internal/model"
	"github.com/go-chi/chi/v5"
	"github.com/go-chi/cors"
	httpSwagger "github.com/swaggo/http-swagger"
)

//go:generate counterfeiter -generate

type CORSConfig struct {
	Enabled          bool
	AllowedOrigins   []string
	AllowedMethods   []string
	AllowCredentials bool
	MaxAge           int
}

type SwaggerConfig struct {
	Enabled bool
	Host    string
	Schemes []string
}

type RouterConfig struct {
	APIKeyVerifier APIKeyVerifier
	SessionService SessionService
	CORS           CORSConfig
	Swagger        SwaggerConfig
}

func NewRouter(cfg RouterConfig) *chi.Mux {
	// handlers
	uh := userHandler{}
	sh := sessionHandler{
		svc: cfg.SessionService,
	}

	router := chi.NewRouter()

	if cfg.CORS.Enabled {
		router.Use(cors.Handler(cors.Options{
			AllowedOrigins:   cfg.CORS.AllowedOrigins,
			AllowCredentials: cfg.CORS.AllowCredentials,
			AllowedMethods:   cfg.CORS.AllowedMethods,
			AllowedHeaders:   []string{"Origin", "Content-Length", "Content-Type", "X-API-Key"},
			MaxAge:           cfg.CORS.MaxAge,
		}))
	}

	router.NotFound(routeNotFoundHandler)
	router.MethodNotAllowed(methodNotAllowedHandler)

	router.Route("/v1", func(r chi.Router) {
		if cfg.Swagger.Enabled {
			if cfg.Swagger.Host != "" {
				docs.SwaggerInfo.Host = cfg.Swagger.Host
			}
			if len(cfg.Swagger.Schemes) > 0 {
				docs.SwaggerInfo.Schemes = cfg.Swagger.Schemes
			}
			r.Get("/swagger/*", httpSwagger.Handler())
		}

		authMw := authMiddleware(cfg.APIKeyVerifier)

		r.With(authMw).Get("/user", uh.getCurrent)
		r.With(authMw).Put("/user/sessions/{serverKey}", sh.createOrUpdate)
		r.With(authMw).Get("/user/sessions/{serverKey}", sh.getCurrentUser)
	})

	return router
}

func routeNotFoundHandler(w http.ResponseWriter, _ *http.Request) {
	renderJSON(w, http.StatusNotFound, model.ErrorResp{
		Error: model.APIError{
			Code:    "route-not-found",
			Message: "route not found",
		},
	})
}

func methodNotAllowedHandler(w http.ResponseWriter, _ *http.Request) {
	renderJSON(w, http.StatusMethodNotAllowed, model.ErrorResp{
		Error: model.APIError{
			Code:    "method-not-allowed",
			Message: "method not allowed",
		},
	})
}

type internalServerError struct {
	err error
}

func (e internalServerError) Error() string {
	return e.err.Error()
}

func (e internalServerError) UserError() string {
	return "internal server error"
}

func (e internalServerError) Code() domain.ErrorCode {
	return domain.ErrorCodeUnknown
}

func (e internalServerError) Unwrap() error {
	return e.err
}

func renderErr(w http.ResponseWriter, err error) {
	var domainErr domain.Error
	if !errors.As(err, &domainErr) {
		domainErr = internalServerError{err: err}
	}
	renderJSON(w, errorCodeToHTTPStatus(domainErr.Code()), model.ErrorResp{
		Error: model.APIError{
			Code:    domainErr.Code().String(),
			Message: domainErr.UserError(),
		},
	})
}

func errorCodeToHTTPStatus(code domain.ErrorCode) int {
	switch code {
	case domain.ErrorCodeValidationError:
		return http.StatusBadRequest
	case domain.ErrorCodeEntityNotFound:
		return http.StatusNotFound
	case domain.ErrorCodeAlreadyExists:
		return http.StatusConflict
	case domain.ErrorCodeUnknown:
		fallthrough
	default:
		return http.StatusInternalServerError
	}
}

func renderJSON(w http.ResponseWriter, status int, data any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(data)
}