package auth

import (
	"errors"
	"fmt"

	"github.com/go-ldap/ldap"
	"github.com/grafana/grafana/pkg/log"
	"github.com/grafana/grafana/pkg/setting"
)

func init() {
	setting.LdapServers = []*setting.LdapServerConf{
		&setting.LdapServerConf{
			UseSSL:        false,
			Host:          "127.0.0.1",
			Port:          "389",
			BindDN:        "cn=%s,dc=grafana,dc=org",
			AttrName:      "givenName",
			AttrSurname:   "sn",
			AttrUsername:  "cn",
			AttrMemberOf:  "memberOf",
			AttrEmail:     "email",
			SearchFilter:  "(cn=%s)",
			SearchBaseDNs: []string{"dc=grafana,dc=org"},
		},
	}
}

type ldapAuther struct {
	server *setting.LdapServerConf
	conn   *ldap.Conn
}

type ldapUserInfo struct {
	FirstName string
	LastName  string
	Username  string
	Email     string
	MemberOf  []string
}

func NewLdapAuthenticator(server *setting.LdapServerConf) *ldapAuther {
	return &ldapAuther{
		server: server,
	}
}

func (a *ldapAuther) Dial() error {
	address := fmt.Sprintf("%s:%s", a.server.Host, a.server.Port)
	var err error
	if a.server.UseSSL {
		a.conn, err = ldap.DialTLS("tcp", address, nil)
	} else {
		a.conn, err = ldap.Dial("tcp", address)
	}

	return err
}

func (a *ldapAuther) login(query *AuthenticateUserQuery) error {
	if err := a.Dial(); err != nil {
		return err
	}
	defer a.conn.Close()

	// perform initial authentication
	if err := a.initialBind(query.Username, query.Password); err != nil {
		return err
	}

	// find user entry & attributes
	if user, err := a.searchForUser(query.Username); err != nil {
		return err
	} else {
		log.Info("Surname: %s", user.LastName)
		log.Info("givenName: %s", user.FirstName)
		log.Info("email: %s", user.Email)
		log.Info("memberOf: %s", user.MemberOf)
	}

	return errors.New("Aasd")
}

func (a *ldapAuther) initialBind(username, userPassword string) error {
	if a.server.BindPassword != "" {
		userPassword = a.server.BindPassword
	}

	bindPath := fmt.Sprintf(a.server.BindDN, username)

	if err := a.conn.Bind(bindPath, userPassword); err != nil {
		if ldapErr, ok := err.(*ldap.Error); ok {
			if ldapErr.ResultCode == 49 {
				return ErrInvalidCredentials
			}
		}
		return err
	}

	return nil
}

func (a *ldapAuther) searchForUser(username string) (*ldapUserInfo, error) {
	var searchResult *ldap.SearchResult
	var err error

	for _, searchBase := range a.server.SearchBaseDNs {
		searchReq := ldap.SearchRequest{
			BaseDN:       searchBase,
			Scope:        ldap.ScopeWholeSubtree,
			DerefAliases: ldap.NeverDerefAliases,
			Attributes: []string{
				a.server.AttrUsername,
				a.server.AttrSurname,
				a.server.AttrEmail,
				a.server.AttrName,
				a.server.AttrMemberOf,
			},
			Filter: fmt.Sprintf(a.server.SearchFilter, username),
		}

		searchResult, err = a.conn.Search(&searchReq)
		if err != nil {
			return nil, err
		}

		if len(searchResult.Entries) > 0 {
			break
		}
	}

	if len(searchResult.Entries) == 0 {
		return nil, errors.New("Ldap search matched no entry, please review your filter setting.")
	}

	if len(searchResult.Entries) > 1 {
		return nil, errors.New("Ldap search matched mopre than one entry, please review your filter setting")
	}

	return &ldapUserInfo{
		LastName:  getLdapAttr(a.server.AttrSurname, searchResult),
		FirstName: getLdapAttr(a.server.AttrName, searchResult),
		Username:  getLdapAttr(a.server.AttrUsername, searchResult),
		Email:     getLdapAttr(a.server.AttrEmail, searchResult),
		MemberOf:  getLdapAttrArray(a.server.AttrMemberOf, searchResult),
	}, nil
}

func getLdapAttr(name string, result *ldap.SearchResult) string {
	for _, attr := range result.Entries[0].Attributes {
		if attr.Name == name {
			if len(attr.Values) > 0 {
				return attr.Values[0]
			}
		}
	}
	return ""
}

func getLdapAttrArray(name string, result *ldap.SearchResult) []string {
	for _, attr := range result.Entries[0].Attributes {
		if attr.Name == name {
			return attr.Values
		}
	}
	return []string{}
}

func createUserFromLdapInfo() error {
	return nil

}