package sync

import (
	"bytes"
	"crypto/tls"
	"fmt"
	"log"
	"strings"

	"github.com/remogatto/slicediff"
	"github.com/sethvargo/go-password/password"

	gomail "gopkg.in/gomail.v2"
	ldap "gopkg.in/ldap.v2"

	"text/template"

	karmen_client "gogs.carduccidante.edu.it/karmen/core/client"
	"gogs.carduccidante.edu.it/karmen/core/config"
	karmen_ldap "gogs.carduccidante.edu.it/karmen/core/ldap"
	"gogs.carduccidante.edu.it/karmen/core/orm"

	tpl_util "gogs.carduccidante.edu.it/karmen/core/util/template"
)

type entriesToDN []*ldap.Entry

func (entries entriesToDN) Convert() (result []string) {
	for _, entry := range entries {
		result = append(
			result,
			entry.DN,
		)
	}
	return
}

type usersToDNConverter []orm.User

func (users usersToDNConverter) Convert() (result []string) {
	for _, user := range users {
		result = append(
			result,
			user.DN(),
		)
	}
	return
}

type usersToUsernamesConverter []orm.User

func (users usersToUsernamesConverter) Convert() (result []string) {
	for _, user := range users {
		result = append(
			result,
			user.Username(),
		)
	}
	return
}

type SliceToStringSlicer []string

func (slice SliceToStringSlicer) Convert() (result []string) {
	return slice
}

type Result struct {
	Description string

	Added   []orm.User
	Updated []orm.User
	Removed []string
}

func (result *Result) String() string {
	output := fmt.Sprintf("\n%s\n", result.Description)
	if len(result.Added) > 0 {
		output += "\n== ADDED ==\n\n"
		for _, user := range result.Added {
			output += fmt.Sprintf("* %s\n", user.CompleteName())
		}
	}
	if len(result.Updated) > 0 {
		output += "\n== UPDATED ==\n\n"
		for _, user := range result.Updated {
			output += fmt.Sprintf("* %s\n", user.CompleteName())
		}
	}
	if len(result.Removed) > 0 {
		output += "\n== REMOVED ==\n\n"
		for _, user := range result.Removed {
			output += fmt.Sprintf("* %s\n", user)
		}
	}

	if len(result.Added)*len(result.Updated)*len(result.Removed) > 0 {
		output += "\n"
	}

	output += fmt.Sprintf("[%d added, %d updated, %d removed]", len(result.Added), len(result.Updated), len(result.Removed))

	return output
}

type SyncJob struct {
	conf *config.ConfigT
}

func NewSyncJob(conf *config.ConfigT) *SyncJob {
	return &SyncJob{conf}
}

func logf(fmt string, args ...interface{}) {
	if config.Config.Sync.Verbose {
		log.Printf(fmt, args...)
	}
}

func (syncJob *SyncJob) sendMail(user orm.User, tpl *template.Template) error {
	var buf bytes.Buffer

	err := tpl.Execute(&buf, user)
	if err != nil {
		return err
	}

	if !syncJob.conf.Sync.SafeRun {
		logf("SEND user credential to %s...", user.GetAltEmail())
		m := gomail.NewMessage()
		m.SetHeader("From", syncJob.conf.Smtp.From)
		m.SetHeader("To", user.GetAltEmail())
		m.SetHeader("Cc", syncJob.conf.Smtp.Cc)
		m.SetHeader("Subject", fmt.Sprintf("Attivazione dell'utenza %s per l'accesso ai servizi informatici del Liceo \"Carducci-Dante\" di Trieste", user.CompleteName()))
		m.SetBody("text/plain", buf.String())

		d := gomail.NewDialer(syncJob.conf.Smtp.Host, syncJob.conf.Smtp.Port, syncJob.conf.Smtp.Username, syncJob.conf.Smtp.Password)
		d.TLSConfig = &tls.Config{InsecureSkipVerify: true}

		if err := d.DialAndSend(m); err != nil {
			return err
		}
	} else {
		logf("Credentials would be sent to %s, new password is %s", user.GetAltEmail(), user.GetPlainPassword())
	}

	return nil
}

func (syncJob *SyncJob) SyncUsers(ldapClient *karmen_ldap.Client, karmenClient *karmen_client.Client, entries []*ldap.Entry, users []orm.User) (*Result, error) {

	var mailTpl *template.Template

	actions := slicediff.Diff(entriesToDN(entries).Convert, usersToDNConverter(users).Convert)

	result := new(Result)

	result.Description = "Sync users..."

	for _, a := range actions {
		switch a.Type {
		case slicediff.Remove:
			entry := entries[a.Id]
			result.Removed = append(result.Removed, entry.DN)

		case slicediff.Add:
			user := users[a.Id]
			if !user.GetExclude() {
				result.Added = append(result.Added, user)
			}

		case slicediff.Update:
			user := users[a.Id]
			if !user.GetExclude() && user.GetRegenerate() {
				result.Updated = append(result.Updated, user)
			}
			if user.GetExclude() {
				result.Removed = append(result.Removed, user.DN())
			}

		}
	}

	if syncJob.conf.Sync.SendMail {
		var err error

		mailTpl, err = tpl_util.LoadTextTemplate("cron/sync/mail.tpl")
		if err != nil {
			return nil, err
		}
	}

	if !syncJob.conf.Sync.SafeRun {

		// Add

		for _, user := range result.Added {
			password, err := password.Generate(8, 2, 0, false, true)
			if err != nil {
				return nil, err
			}

			user.SetPlainPassword(password)

			err = ldapClient.AddUser(user)
			if err != nil {
				return nil, fmt.Errorf("An error occurred for user %s: %v", user.CompleteName(), err)
			}

			if user.GetRegenerate() {
				if syncJob.conf.Sync.SendMail && user.GetAltEmail() != "" {
					err = syncJob.sendMail(user, mailTpl)
					if err != nil {
						return nil, fmt.Errorf("An error occurred for user %s: %v", user.CompleteName(), err)
					}
				}

				user.SetRegenerate(false)

				err = karmenClient.UpdateUser(user)
				if err != nil {
					return nil, fmt.Errorf("An error occurred for user %s: %v", user.CompleteName(), err)
				}

			}

		}

		// Remove

		for _, entry := range result.Removed {
			err := ldapClient.DeleteByDN(entry)
			if err != nil {
				return nil, fmt.Errorf("An error occurred for entry %s: %v", entry, err)
			}
		}

		// Update

		for _, user := range result.Updated {
			if user.GetRegenerate() {
				password, err := password.Generate(8, 2, 0, false, true)
				if err != nil {
					return nil, fmt.Errorf("An error occurred for user %s: %v", user.CompleteName(), err)
				}

				user.SetPlainPassword(password)

				if syncJob.conf.Sync.SendMail && user.GetAltEmail() != "" {
					err = syncJob.sendMail(user, mailTpl)
					if err != nil {
						return nil, fmt.Errorf("An error occurred for user %s: %v", user.CompleteName(), err)
					}
				}

				user.SetRegenerate(false)

				err = karmenClient.UpdateUser(user)
				if err != nil {
					return nil, fmt.Errorf("An error occurred for user %s: %v", user.CompleteName(), err)
				}
				err = ldapClient.UpdateUserPassword(user)
				if err != nil {
					return nil, fmt.Errorf("An error occurred for user %s: %v", user.CompleteName(), err)

				}
			}
		}

	}

	return result, nil
}

func (syncJob *SyncJob) SyncGroup(ldapClient *karmen_ldap.Client, users []orm.User, groupDN string) (*Result, error) {
	var ml bool

	result := new(Result)

	result.Description = fmt.Sprintf("Sync group %s", groupDN)

	actions := make(map[string]*slicediff.Action)
	entries, err := ldapClient.GroupMembers(groupDN)
	if err != nil {
		return nil, err
	}

	values := make([]string, 0)

	if len(entries) > 0 {
		values = entries[0].Attributes[0].Values
	}

	if strings.Contains(groupDN, "Mailing Lists") {
		ml = true
		actions = slicediff.Diff(SliceToStringSlicer(values).Convert, usersToDNConverter(users).Convert)
	} else {
		actions = slicediff.Diff(SliceToStringSlicer(values).Convert, usersToUsernamesConverter(users).Convert)
	}

	for _, a := range actions {
		switch a.Type {
		case slicediff.Remove:
			result.Removed = append(result.Removed, values[a.Id])

		case slicediff.Add:
			user := users[a.Id]
			if !user.GetExclude() {
				result.Added = append(result.Added, user)
			}
		case slicediff.Update:
			user := users[a.Id]
			if user.GetExclude() && !ml {
				result.Removed = append(result.Removed, user.Username())
			}

		}
	}

	if !syncJob.conf.Sync.SafeRun {
		for _, user := range result.Added {
			err = ldapClient.AddUserToGroup(user, groupDN)
			if err != nil {
				return nil, err
			}
		}

		for _, value := range result.Removed {
			ldapClient.RemoveUserFromGroupByMemberValue(value, groupDN)
		}
	}

	return result, nil
}

func (syncJob *SyncJob) Run() {
	if syncJob.conf.Sync.SafeRun {
		log.Println("Running in SAFE MODE...")
	}

	logf("Connecting to karmen at %s...", syncJob.conf.Url)
	karmenClient, err := karmen_client.Dial(syncJob.conf.Url, syncJob.conf.Admin.Username, syncJob.conf.Admin.Password)
	if err != nil {
		log.Println(err)
	}

	teachers, err := karmenClient.GetTeachers()
	if err != nil {
		log.Println(err)
	}

	logf("Connecting to LDAP at %s...", syncJob.conf.Ldap.Host)
	ldapClient, err := karmen_ldap.NewClient(syncJob.conf.Ldap.Host, syncJob.conf)
	if err != nil {
		log.Println(err)
	}

	log.Println("Retrieving teachers from LDAP...")
	entries, err := ldapClient.Users(syncJob.conf.Sync.TeachersSearchBase)
	if err != nil {
		log.Println(err)
	}

	log.Println("Retrieving Departments...")
	departments, err := karmenClient.GetDepartments()
	if err != nil {
		log.Println(err)
	}

	log.Println("Retrieving Offices...")
	offices, err := karmenClient.GetOffices()
	if err != nil {
		log.Println(err)
	}

	users := make([]orm.User, 0)
	for _, teacher := range teachers {
		users = append(users, teacher)
	}
	log.Println("Sync teachers...")
	if result, err := syncJob.SyncUsers(ldapClient, karmenClient, entries, users); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}
	if result, err := syncJob.SyncGroup(ldapClient, users, syncJob.conf.Sync.TeachersGroup); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	if result, err := syncJob.SyncGroup(ldapClient, users, syncJob.conf.Sync.TeachersML); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	departmentsCoordinators := make([]orm.User, 0)

	for _, department := range departments {
	        if department.Coordinator != nil {
			departmentsCoordinators = append(departmentsCoordinators, department.Coordinator)
		}
		users := make([]orm.User, 0)
		for _, teacher := range department.Teachers {
			users = append(users, teacher)
		}
		group := fmt.Sprintf("cn=%s,ou=Mailing Lists", department.Name)
		if result, err := syncJob.SyncGroup(ldapClient, users, group); err != nil {
			panic(err)
		} else {
			log.Println(result)
		}
		group = fmt.Sprintf("cn=%s,ou=Dipartimenti", department.Name)
		if result, err := syncJob.SyncGroup(ldapClient, users, group); err != nil {
			panic(err)
		} else {
			log.Println(result)
		}
	}

	// Class coordinators

	classCoordinators := make([]orm.User, 0)
	classes, err := karmenClient.GetClasses()
	if err != nil {
		panic(err)
	}

	for _, class := range classes {
	        if class.Coordinator != nil {
		    classCoordinators = append(classCoordinators, class.Coordinator)
		}
	}

	if result, err := syncJob.SyncGroup(ldapClient, classCoordinators, syncJob.conf.Sync.ClassCoordinatorsGroup); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	if result, err := syncJob.SyncGroup(ldapClient, classCoordinators, syncJob.conf.Sync.ClassCoordinatorsML); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	// Departments Coordinator

	log.Println("Sync Departments Coordinators...")

	for _, c := range departmentsCoordinators {
		log.Println("Coordinatore dipartimento", c.CompleteName())
	}

	if result, err := syncJob.SyncGroup(ldapClient, departmentsCoordinators, syncJob.conf.Sync.DepartmentsCoordinatorsGroup); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	if result, err := syncJob.SyncGroup(ldapClient, departmentsCoordinators, syncJob.conf.Sync.DepartmentsCoordinatorsML); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	administratives, err := karmenClient.GetAdministratives()
	if err != nil {
		log.Println(err)
	}

	log.Println("Getting administratives from LDAP...")
	entries, err = ldapClient.Users(syncJob.conf.Sync.AdministrativesSearchBase)
	if err != nil {
		log.Println(err)
	}

	users = make([]orm.User, 0)
	for _, administrative := range administratives {
		users = append(users, administrative)
	}
	log.Println("Sync administratives...")
	if result, err := syncJob.SyncUsers(ldapClient, karmenClient, entries, users); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	if result, err := syncJob.SyncGroup(ldapClient, users, syncJob.conf.Sync.AdministrativesGroup); err != nil {
		panic(err)
	} else {
		log.Println(result)
	}

	for _, office := range offices {
		users := make([]orm.User, 0)
		for _, administrative := range office.Administratives {
			users = append(users, administrative)
		}
		group := fmt.Sprintf("cn=%s,ou=Segreterie", office.Name)
		if result, err := syncJob.SyncGroup(ldapClient, users, group); err != nil {
			panic(err)
		} else {
			log.Println(result)
		}
	}

}