package ginoidc

import (
	"fmt"
	"net/http"

	"git.icod.de/dalu/ginoidc/ginerror"
	"git.icod.de/dalu/oidc"
	"git.icod.de/dalu/oidc/options"
	"github.com/gin-gonic/gin"
)

// New returns an OpenID Connect (OIDC) discovery handler (middleware)
// to be used with `gin`.
func New(setters ...options.Option) gin.HandlerFunc {
	oidcHandler, err := oidc.NewHandler(setters...)
	if err != nil {
		panic(fmt.Sprintf("oidc discovery: %v", err))
	}
	return toGinHandler(oidcHandler.ParseToken, setters...)
}

// onError is called when there's an error.
func onError(c *gin.Context, errorHandler options.ErrorHandler, statusCode int, description options.ErrorDescription, err error) {
	c.AbortWithStatusJSON(statusCode, gin.H{"error": err.Error()})
}

// toGinHandler creates a gin.HandlerFunc so the stdlib handler can be used as a gin middleware.
func toGinHandler(parseToken oidc.ParseTokenFunc, setters ...options.Option) gin.HandlerFunc {
	opts := options.New(setters...)

	var errs []ginerror.Error

	return func(c *gin.Context) {
		tokenString, err := oidc.GetTokenString(c.Request.Header.Get, opts.TokenString)
		if err != nil {
			if !opts.Permissive {
				onError(c, opts.ErrorHandler, http.StatusBadRequest, options.GetTokenErrorDescription, err)
				return
			} else {
				errs = append(errs, ginerror.Error{
					Description: string(options.GetTokenErrorDescription),
					Error:       err,
				})
				c.Set(string(opts.ErrorsContextKeyName), errs)
				c.Next()
				return
			}
		}

		token, err := parseToken(c, tokenString)
		if err != nil {
			onError(c, opts.ErrorHandler, http.StatusUnauthorized, options.ParseTokenErrorDescription, err)
			return
		}

		tokenClaims, err := token.AsMap(c)
		if err != nil {
			onError(c, opts.ErrorHandler, http.StatusUnauthorized, options.ConvertTokenErrorDescription, err)
			return
		}

		c.Set(string(opts.ClaimsContextKeyName), tokenClaims)

		c.Next()
	}
}