package middleware

import (
	"context"
	"net/http"
)

type headerKey int

const hdrKey headerKey = iota

// GetHeaders fetches http headers from the request context.
func GetHeaders(ctx context.Context) (http.Header, bool) {
	h, ok := ctx.Value(hdrKey).(http.Header)
	if !ok {
		return http.Header{}, false
	}

	return h, true
}

// SaveHeaders adds the needed values to the request context for twirp services.
func SaveHeaders(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		ctx := r.Context()

		if ctx == nil {
			panic("context is nil")
		}

		ctx = context.WithValue(ctx, hdrKey, r.Header)

		next.ServeHTTP(w, r.WithContext(ctx))
	})
}