package handlers

import (
	"context"
	"net/http"
	"sync/atomic"

	log "github.com/sirupsen/logrus"
)

type key int

const (
	requestIdKey key = iota
)

type statusCodeInterceptor struct {
	http.ResponseWriter
	code  int
	count int
}

func (sci *statusCodeInterceptor) WriteHeader(code int) {
	sci.code = code
	sci.ResponseWriter.WriteHeader(code)
}

func (sci *statusCodeInterceptor) Write(content []byte) (int, error) {
	count, err := sci.ResponseWriter.Write(content)
	sci.count += count
	return count, err
}

func Logging(logger *log.Logger) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			interceptor := &statusCodeInterceptor{w, http.StatusOK, 0}
			defer func() {
				requestId, ok := r.Context().Value(requestIdKey).(string)
				if !ok {
					requestId = "unknown"
				}
				logger.Infof(
					"%s %s \"%s %s\" %d %d \"%s\"",
					requestId,
					r.RemoteAddr,
					r.Method,
					r.URL.Path,
					interceptor.code,
					interceptor.count,
					r.UserAgent(),
				)
			}()
			next.ServeHTTP(interceptor, r)
		})
	}
}

func Tracing(nextRequestId func() string) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			requestId := r.Header.Get("X-Request-Id")
			if requestId == "" {
				requestId = nextRequestId()
			}
			ctx := context.WithValue(r.Context(), requestIdKey, requestId)
			w.Header().Set("X-Request-Id", requestId)
			next.ServeHTTP(w, r.WithContext(ctx))
		})
	}
}

var Healthy int32

func NewHealthHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if atomic.LoadInt32(&Healthy) == 1 {
			w.WriteHeader(http.StatusNoContent)
			return
		}
		w.WriteHeader(http.StatusServiceUnavailable)
	})
}