package middleware

import (
	"context"
	"fmt"
	"net/http"

	"github.com/99designs/gqlgen/graphql"
	"github.com/apex/log"
)

type ContextKey string

const (
	ApiKey = ContextKey("apikey")
)

func NewApiKey(apiKey string, logger log.Interface) *ApiKeyMiddleware {
	return &ApiKeyMiddleware{
		apiKey: apiKey,
	}
}

type ApiKeyMiddleware struct {
	apiKey string
}

func (m *ApiKeyMiddleware) Handler(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		header := r.Header.Get("x-api-key")
		if len(header) == 0 {
			next.ServeHTTP(w, r)
		} else {
			ctx := context.WithValue(r.Context(), ApiKey, header)
			next.ServeHTTP(w, r.WithContext(ctx))
		}
	})
}

func (m *ApiKeyMiddleware) Directive(ctx context.Context, obj interface{}, next graphql.Resolver) (res interface{}, err error) {
	key, err := m.fromContext(ctx)
	if err != nil {
		return nil, err
	}
	if key != m.apiKey {
		return nil, fmt.Errorf("invalid API-key")
	}
	return next(ctx)
}

func (m *ApiKeyMiddleware) fromContext(ctx context.Context) (string, error) {
	if value := ctx.Value(ApiKey); value != nil {
		if u, ok := value.(string); ok {
			return u, nil
		}
		return "", fmt.Errorf("current API-key is in wrong format")
	}
	return "", fmt.Errorf("no API-key found")
}