package docker

import (
	"crypto/tls"
	"fmt"
	"log"
	"net"
	"net/http"
	"strings"
	"time"

	drc "github.com/rusenask/docker-registry-client/registry"
)

type LogfCallback func(format string, args ...interface{})

type Registry struct {
	URL    string
	Client *http.Client
	Logf   LogfCallback
}

/*
 * Pass log messages along to Go's "log" module.
 */
func Log(format string, args ...interface{}) {
	log.Printf(format, args...)
}

/*
 * Create a new Registry with the given URL and credentials, then Ping()s it
 * before returning it to verify that the registry is available.
 *
 * You can, alternately, construct a Registry manually by populating the fields.
 * This passes http.DefaultTransport to WrapTransport when creating the
 * http.Client.
 */
func New(registryURL, username, password string) *Registry {
	transport := &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: (&net.Dialer{
			Timeout:   10 * time.Second,
			KeepAlive: 30 * time.Second,
			DualStack: true,
		}).DialContext,
		MaxIdleConns:          10,
		IdleConnTimeout:       90 * time.Second,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
	}

	return newFromTransport(registryURL, username, password, transport, Log)
}

/*
 * Create a new Registry, as with New, using an http.Transport that disables
 * SSL certificate verification.
 */
func NewInsecure(registryURL, username, password string) *Registry {
	transport := &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: (&net.Dialer{
			Timeout:   10 * time.Second,
			KeepAlive: 30 * time.Second,
			DualStack: true,
		}).DialContext,
		TLSClientConfig: &tls.Config{
			InsecureSkipVerify: true,
		},
		MaxIdleConns:          10,
		IdleConnTimeout:       90 * time.Second,
		TLSHandshakeTimeout:   10 * time.Second,
		ExpectContinueTimeout: 1 * time.Second,
	}

	return newFromTransport(registryURL, username, password, transport, Log)
}

func newFromTransport(registryURL, username, password string, transport *http.Transport, logf LogfCallback) *Registry {
	url := strings.TrimSuffix(registryURL, "/")
	registry := &Registry{
		URL: url,
		Client: &http.Client{
			Transport: drc.WrapTransport(transport, url, username, password),
		},
		Logf: logf,
	}

	return registry
}

func (r *Registry) Ping() error {
	url := r.url("/v2/")
	r.Logf("registry.ping url=%s", url)
	resp, err := r.Client.Get(url)
	if resp != nil {
		defer resp.Body.Close()
	}
	return err
}

type tagsResponse struct {
	Tags []string `json:"tags"`
}

func (r *Registry) url(pathTemplate string, args ...interface{}) string {
	pathSuffix := fmt.Sprintf(pathTemplate, args...)
	url := fmt.Sprintf("%s%s", r.URL, pathSuffix)

	return url
}