package middleware

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

const (
	ApiKey = ContextKey("apikey")
)

func NewApiKey() *ApiKeyMiddleware {
	return &ApiKeyMiddleware{}
}

type ApiKeyMiddleware struct{}

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 ApiKeyFromContext(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 "", nil
}