package ldap

import (
	"encoding/json"
	"log"
	"net/http"
	"regexp"
	"strconv"

	auth "imuslab.com/arozos/mod/auth"
	"imuslab.com/arozos/mod/auth/ldap/ldapreader"
	reg "imuslab.com/arozos/mod/auth/register"
	"imuslab.com/arozos/mod/common"
	db "imuslab.com/arozos/mod/database"
	permission "imuslab.com/arozos/mod/permission"
	"imuslab.com/arozos/mod/user"
)

type ldapHandler struct {
	ag                *auth.AuthAgent
	ldapreader        *ldapreader.LdapReader
	reg               *reg.RegisterHandler
	coredb            *db.Database
	permissionHandler *permission.PermissionHandler
	userHandler       *user.UserHandler
}

type Config struct {
	Enabled      bool   `json:"enabled"`
	AutoRedirect bool   `json:"auto_redirect"`
	BindUsername string `json:"bind_username"`
	BindPassword string `json:"bind_password"`
	FQDN         string `json:"fqdn"`
	BaseDN       string `json:"base_dn"`
}

type UserAccount struct {
	Username   string   `json:"username"`
	Group      []string `json:"group"`
	EquivGroup []string `json:"equiv_group"`
}

/*
TODO: not sure why auto redirect will keep enable
TODO: stop user to syncorize if the current user will lost admin access
*/

//NewLdapHandler xxx
func NewLdapHandler(authAgent *auth.AuthAgent, register *reg.RegisterHandler, coreDb *db.Database, permissionHandler *permission.PermissionHandler, userHandler *user.UserHandler) *ldapHandler {
	//ldap handler init
	log.Println("Starting LDAP client...")
	err := coreDb.NewTable("ldap")
	if err != nil {
		log.Println("Failed to create LDAP database. Terminating.")
		panic(err)
	}

	//key value to be used for LDAP authentication
	BindUsername := readSingleConfig("BindUsername", coreDb)
	BindPassword := readSingleConfig("BindPassword", coreDb)
	FQDN := readSingleConfig("FQDN", coreDb)
	BaseDN := readSingleConfig("BaseDN", coreDb)

	LDAPHandler := ldapHandler{
		ag:                authAgent,
		ldapreader:        ldapreader.NewLDAPReader(BindUsername, BindPassword, FQDN, BaseDN),
		reg:               register,
		coredb:            coreDb,
		permissionHandler: permissionHandler,
		userHandler:       userHandler,
	}

	return &LDAPHandler
}

func (ldap *ldapHandler) ReadConfig(w http.ResponseWriter, r *http.Request) {
	//basic components
	enabled, err := strconv.ParseBool(ldap.readSingleConfig("enabled"))
	if err != nil {
		common.SendTextResponse(w, "Invalid config value [key=enabled].")
		return
	}
	autoredirect, err := strconv.ParseBool(ldap.readSingleConfig("autoredirect"))
	if err != nil {
		common.SendTextResponse(w, "Invalid config value [key=autoredirect].")
		return
	}
	//get the LDAP config from db
	BindUsername := ldap.readSingleConfig("BindUsername")
	BindPassword := ldap.readSingleConfig("BindPassword")
	FQDN := ldap.readSingleConfig("FQDN")
	BaseDN := ldap.readSingleConfig("BaseDN")

	//marshall it and return
	config, err := json.Marshal(Config{
		Enabled:      enabled,
		AutoRedirect: autoredirect,
		BindUsername: BindUsername,
		BindPassword: BindPassword,
		FQDN:         FQDN,
		BaseDN:       BaseDN,
	})
	if err != nil {
		empty, err := json.Marshal(Config{})
		if err != nil {
			common.SendErrorResponse(w, "Error while marshalling config")
		}
		common.SendJSONResponse(w, string(empty))
	}
	common.SendJSONResponse(w, string(config))
}

func (ldap *ldapHandler) WriteConfig(w http.ResponseWriter, r *http.Request) {
	enabled, err := common.Mv(r, "enabled", true)
	if err != nil {
		common.SendErrorResponse(w, "enabled field can't be empty")
		return
	}
	autoredirect, err := common.Mv(r, "autoredirect", true)
	if err != nil {
		common.SendErrorResponse(w, "enabled field can't be empty")
		return
	}

	//allow empty fields if enabled is false
	showError := true
	if enabled != "true" {
		showError = false
	}

	//four fields to store the LDAP authentication information
	BindUsername, err := common.Mv(r, "bind_username", true)
	if err != nil {
		if showError {
			common.SendErrorResponse(w, "bind_username field can't be empty")
			return
		}
	}
	BindPassword, err := common.Mv(r, "bind_password", true)
	if err != nil {
		if showError {
			common.SendErrorResponse(w, "bind_password field can't be empty")
			return
		}
	}
	FQDN, err := common.Mv(r, "fqdn", true)
	if err != nil {
		if showError {
			common.SendErrorResponse(w, "fqdn field can't be empty")
			return
		}
	}
	BaseDN, err := common.Mv(r, "base_dn", true)
	if err != nil {
		if showError {
			common.SendErrorResponse(w, "base_dn field can't be empty")
			return
		}
	}

	ldap.coredb.Write("ldap", "enabled", enabled)
	ldap.coredb.Write("ldap", "autoredirect", autoredirect)
	ldap.coredb.Write("ldap", "BindUsername", BindUsername)
	ldap.coredb.Write("ldap", "BindPassword", BindPassword)
	ldap.coredb.Write("ldap", "FQDN", FQDN)
	ldap.coredb.Write("ldap", "BaseDN", BaseDN)

	//update the new authencation infromation
	ldap.ldapreader = ldapreader.NewLDAPReader(BindUsername, BindPassword, FQDN, BaseDN)

	common.SendOK(w)
}

//@para limit: -1 means unlimited
func (ldap *ldapHandler) getAllUser(limit int) []UserAccount {
	var accounts []UserAccount
	result, _ := ldap.ldapreader.GetAllUser()
	//loop through the result
	for i, v := range result {
		//check the group belongs
		var Group []string
		var EquivGroup []string
		regexSyntax := regexp.MustCompile("cn=([^,]+),")
		for _, v := range v.GetAttributeValues("memberOf") {
			groups := regexSyntax.FindStringSubmatch(v)
			if len(groups) > 0 {
				//check if the LDAP group is already exists in ArOZOS system
				if ldap.permissionHandler.GroupExists(groups[1]) {
					EquivGroup = append(EquivGroup, groups[1])
				}
				//LDAP list
				Group = append(Group, groups[1])
			}
		}
		if len(EquivGroup) < 1 {
			EquivGroup = append(EquivGroup, ldap.reg.DefaultUserGroup)
		}
		account := UserAccount{
			Username:   v.GetAttributeValue("uid"),
			Group:      Group,
			EquivGroup: EquivGroup,
		}
		accounts = append(accounts, account)
		if i > limit && limit != -1 {
			break
		}
	}
	if len(accounts) > 0 {
		return accounts[1:]
	} else {
		return []UserAccount{}
	}
}

func (ldap *ldapHandler) TestConnection(w http.ResponseWriter, r *http.Request) {
	//marshall it and return
	accountJSON, err := json.Marshal(ldap.getAllUser(10))
	if err != nil {
		empty, err := json.Marshal(UserAccount{})
		if err != nil {
			common.SendErrorResponse(w, "Error while marshalling information")
		}
		common.SendJSONResponse(w, string(empty))
	}
	common.SendJSONResponse(w, string(accountJSON))
}

func (ldap *ldapHandler) checkCurrUserAdmin(w http.ResponseWriter, r *http.Request) bool {
	//check current user is admin and new update will remove it or not
	currentLoggedInUser, err := ldap.userHandler.GetUserInfoFromRequest(w, r)
	if err != nil {
		common.SendErrorResponse(w, "Error while getting user info")
		return false
	}
	ldapCurrUserInfo, err := ldap.ldapreader.GetUser(currentLoggedInUser.Username)
	if err != nil {
		common.SendErrorResponse(w, "Error while getting user info from LDAP")
		return false
	}
	isAdmin := false
	regexSyntax := regexp.MustCompile("cn=([^,]+),")
	for _, v := range ldapCurrUserInfo.GetAttributeValues("memberOf") {
		groups := regexSyntax.FindStringSubmatch(v)
		if len(groups) > 0 {
			//check if the LDAP group is already exists in ArOZOS system
			if ldap.permissionHandler.GroupExists(groups[1]) {
				if ldap.permissionHandler.GetPermissionGroupByName(groups[1]).IsAdmin {
					isAdmin = true
				}
			}
		}
	}
	return isAdmin
}

func (ldap *ldapHandler) SynchronizeUser(w http.ResponseWriter, r *http.Request) {
	consistencyCheck := ldap.checkCurrUserAdmin(w, r)
	if !consistencyCheck {
		common.SendErrorResponse(w, "You will no longer become the admin after synchronizing, synchronize terminated")
		return
	}

	ldapUsersList := ldap.getAllUser(-1)
	for _, ldapUser := range ldapUsersList {
		//check if user does not exist in system
		if !ldap.ag.UserExists(ldapUser.Username) {
			//TODO change password
			ldap.ag.CreateUserAccount(ldapUser.Username, "P@ssw0rd", ldapUser.EquivGroup)
		} else {
			//if exists, then check if the user group is the same with ldap's setting
			//Get the permission groups by their ids
			userinfo, err := ldap.userHandler.GetUserInfoFromUsername(ldapUser.Username)
			if err != nil {
				common.SendErrorResponse(w, "Error while getting user info")
				return
			}
			newPermissionGroups := ldap.permissionHandler.GetPermissionGroupByNameList(ldapUser.EquivGroup)
			//Set the user's permission to these groups
			userinfo.SetUserPermissionGroup(newPermissionGroups)
		}
	}
	common.SendOK(w)
}