// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package admin

import (
	"errors"
	"fmt"
	"regexp"

	"code.gitea.io/gitea/models"
	"code.gitea.io/gitea/modules/auth"
	"code.gitea.io/gitea/modules/auth/ldap"
	"code.gitea.io/gitea/modules/auth/oauth2"
	"code.gitea.io/gitea/modules/base"
	"code.gitea.io/gitea/modules/context"
	"code.gitea.io/gitea/modules/log"
	"code.gitea.io/gitea/modules/setting"
	"code.gitea.io/gitea/modules/util"

	"github.com/unknwon/com"
	"xorm.io/xorm/convert"
)

const (
	tplAuths    base.TplName = "admin/auth/list"
	tplAuthNew  base.TplName = "admin/auth/new"
	tplAuthEdit base.TplName = "admin/auth/edit"
)

var (
	separatorAntiPattern = regexp.MustCompile(`[^\w-\.]`)
	langCodePattern      = regexp.MustCompile(`^[a-z]{2}-[A-Z]{2}$`)
)

// Authentications show authentication config page
func Authentications(ctx *context.Context) {
	ctx.Data["Title"] = ctx.Tr("admin.authentication")
	ctx.Data["PageIsAdmin"] = true
	ctx.Data["PageIsAdminAuthentications"] = true

	var err error
	ctx.Data["Sources"], err = models.LoginSources()
	if err != nil {
		ctx.ServerError("LoginSources", err)
		return
	}

	ctx.Data["Total"] = models.CountLoginSources()
	ctx.HTML(200, tplAuths)
}

type dropdownItem struct {
	Name string
	Type interface{}
}

var (
	authSources = []dropdownItem{
		{models.LoginNames[models.LoginLDAP], models.LoginLDAP},
		{models.LoginNames[models.LoginDLDAP], models.LoginDLDAP},
		{models.LoginNames[models.LoginSMTP], models.LoginSMTP},
		{models.LoginNames[models.LoginPAM], models.LoginPAM},
		{models.LoginNames[models.LoginOAuth2], models.LoginOAuth2},
		{models.LoginNames[models.LoginSSPI], models.LoginSSPI},
	}
	securityProtocols = []dropdownItem{
		{models.SecurityProtocolNames[ldap.SecurityProtocolUnencrypted], ldap.SecurityProtocolUnencrypted},
		{models.SecurityProtocolNames[ldap.SecurityProtocolLDAPS], ldap.SecurityProtocolLDAPS},
		{models.SecurityProtocolNames[ldap.SecurityProtocolStartTLS], ldap.SecurityProtocolStartTLS},
	}
)

// NewAuthSource render adding a new auth source page
func NewAuthSource(ctx *context.Context) {
	ctx.Data["Title"] = ctx.Tr("admin.auths.new")
	ctx.Data["PageIsAdmin"] = true
	ctx.Data["PageIsAdminAuthentications"] = true

	ctx.Data["type"] = models.LoginLDAP
	ctx.Data["CurrentTypeName"] = models.LoginNames[models.LoginLDAP]
	ctx.Data["CurrentSecurityProtocol"] = models.SecurityProtocolNames[ldap.SecurityProtocolUnencrypted]
	ctx.Data["smtp_auth"] = "PLAIN"
	ctx.Data["is_active"] = true
	ctx.Data["is_sync_enabled"] = true
	ctx.Data["AuthSources"] = authSources
	ctx.Data["SecurityProtocols"] = securityProtocols
	ctx.Data["SMTPAuths"] = models.SMTPAuths
	ctx.Data["OAuth2Providers"] = models.OAuth2Providers
	ctx.Data["OAuth2DefaultCustomURLMappings"] = models.OAuth2DefaultCustomURLMappings

	ctx.Data["SSPIAutoCreateUsers"] = true
	ctx.Data["SSPIAutoActivateUsers"] = true
	ctx.Data["SSPIStripDomainNames"] = true
	ctx.Data["SSPISeparatorReplacement"] = "_"
	ctx.Data["SSPIDefaultLanguage"] = ""

	// only the first as default
	for key := range models.OAuth2Providers {
		ctx.Data["oauth2_provider"] = key
		break
	}

	ctx.HTML(200, tplAuthNew)
}

func parseLDAPConfig(form auth.AuthenticationForm) *models.LDAPConfig {
	var pageSize uint32
	if form.UsePagedSearch {
		pageSize = uint32(form.SearchPageSize)
	}
	return &models.LDAPConfig{
		Source: &ldap.Source{
			Name:                  form.Name,
			Host:                  form.Host,
			Port:                  form.Port,
			SecurityProtocol:      ldap.SecurityProtocol(form.SecurityProtocol),
			SkipVerify:            form.SkipVerify,
			BindDN:                form.BindDN,
			UserDN:                form.UserDN,
			BindPassword:          form.BindPassword,
			UserBase:              form.UserBase,
			AttributeUsername:     form.AttributeUsername,
			AttributeName:         form.AttributeName,
			AttributeSurname:      form.AttributeSurname,
			AttributeMail:         form.AttributeMail,
			AttributesInBind:      form.AttributesInBind,
			AttributeSSHPublicKey: form.AttributeSSHPublicKey,
			SearchPageSize:        pageSize,
			Filter:                form.Filter,
			AdminFilter:           form.AdminFilter,
			RestrictedFilter:      form.RestrictedFilter,
			AllowDeactivateAll:    form.AllowDeactivateAll,
			Enabled:               true,
		},
	}
}

func parseSMTPConfig(form auth.AuthenticationForm) *models.SMTPConfig {
	return &models.SMTPConfig{
		Auth:           form.SMTPAuth,
		Host:           form.SMTPHost,
		Port:           form.SMTPPort,
		AllowedDomains: form.AllowedDomains,
		TLS:            form.TLS,
		SkipVerify:     form.SkipVerify,
	}
}

func parseOAuth2Config(form auth.AuthenticationForm) *models.OAuth2Config {
	var customURLMapping *oauth2.CustomURLMapping
	if form.Oauth2UseCustomURL {
		customURLMapping = &oauth2.CustomURLMapping{
			TokenURL:   form.Oauth2TokenURL,
			AuthURL:    form.Oauth2AuthURL,
			ProfileURL: form.Oauth2ProfileURL,
			EmailURL:   form.Oauth2EmailURL,
		}
	} else {
		customURLMapping = nil
	}
	return &models.OAuth2Config{
		Provider:                      form.Oauth2Provider,
		ClientID:                      form.Oauth2Key,
		ClientSecret:                  form.Oauth2Secret,
		OpenIDConnectAutoDiscoveryURL: form.OpenIDConnectAutoDiscoveryURL,
		CustomURLMapping:              customURLMapping,
	}
}

func parseSSPIConfig(ctx *context.Context, form auth.AuthenticationForm) (*models.SSPIConfig, error) {
	if util.IsEmptyString(form.SSPISeparatorReplacement) {
		ctx.Data["Err_SSPISeparatorReplacement"] = true
		return nil, errors.New(ctx.Tr("form.SSPISeparatorReplacement") + ctx.Tr("form.require_error"))
	}
	if separatorAntiPattern.MatchString(form.SSPISeparatorReplacement) {
		ctx.Data["Err_SSPISeparatorReplacement"] = true
		return nil, errors.New(ctx.Tr("form.SSPISeparatorReplacement") + ctx.Tr("form.alpha_dash_dot_error"))
	}

	if form.SSPIDefaultLanguage != "" && !langCodePattern.MatchString(form.SSPIDefaultLanguage) {
		ctx.Data["Err_SSPIDefaultLanguage"] = true
		return nil, errors.New(ctx.Tr("form.lang_select_error"))
	}

	return &models.SSPIConfig{
		AutoCreateUsers:      form.SSPIAutoCreateUsers,
		AutoActivateUsers:    form.SSPIAutoActivateUsers,
		StripDomainNames:     form.SSPIStripDomainNames,
		SeparatorReplacement: form.SSPISeparatorReplacement,
		DefaultLanguage:      form.SSPIDefaultLanguage,
	}, nil
}

// NewAuthSourcePost response for adding an auth source
func NewAuthSourcePost(ctx *context.Context, form auth.AuthenticationForm) {
	ctx.Data["Title"] = ctx.Tr("admin.auths.new")
	ctx.Data["PageIsAdmin"] = true
	ctx.Data["PageIsAdminAuthentications"] = true

	ctx.Data["CurrentTypeName"] = models.LoginNames[models.LoginType(form.Type)]
	ctx.Data["CurrentSecurityProtocol"] = models.SecurityProtocolNames[ldap.SecurityProtocol(form.SecurityProtocol)]
	ctx.Data["AuthSources"] = authSources
	ctx.Data["SecurityProtocols"] = securityProtocols
	ctx.Data["SMTPAuths"] = models.SMTPAuths
	ctx.Data["OAuth2Providers"] = models.OAuth2Providers
	ctx.Data["OAuth2DefaultCustomURLMappings"] = models.OAuth2DefaultCustomURLMappings

	ctx.Data["SSPIAutoCreateUsers"] = true
	ctx.Data["SSPIAutoActivateUsers"] = true
	ctx.Data["SSPIStripDomainNames"] = true
	ctx.Data["SSPISeparatorReplacement"] = "_"
	ctx.Data["SSPIDefaultLanguage"] = ""

	hasTLS := false
	var config convert.Conversion
	switch models.LoginType(form.Type) {
	case models.LoginLDAP, models.LoginDLDAP:
		config = parseLDAPConfig(form)
		hasTLS = ldap.SecurityProtocol(form.SecurityProtocol) > ldap.SecurityProtocolUnencrypted
	case models.LoginSMTP:
		config = parseSMTPConfig(form)
		hasTLS = true
	case models.LoginPAM:
		config = &models.PAMConfig{
			ServiceName: form.PAMServiceName,
		}
	case models.LoginOAuth2:
		config = parseOAuth2Config(form)
	case models.LoginSSPI:
		var err error
		config, err = parseSSPIConfig(ctx, form)
		if err != nil {
			ctx.RenderWithErr(err.Error(), tplAuthNew, form)
			return
		}
		existing, err := models.LoginSourcesByType(models.LoginSSPI)
		if err != nil || len(existing) > 0 {
			ctx.Data["Err_Type"] = true
			ctx.RenderWithErr(ctx.Tr("admin.auths.login_source_of_type_exist"), tplAuthNew, form)
			return
		}
	default:
		ctx.Error(400)
		return
	}
	ctx.Data["HasTLS"] = hasTLS

	if ctx.HasError() {
		ctx.HTML(200, tplAuthNew)
		return
	}

	if err := models.CreateLoginSource(&models.LoginSource{
		Type:          models.LoginType(form.Type),
		Name:          form.Name,
		IsActived:     form.IsActive,
		IsSyncEnabled: form.IsSyncEnabled,
		Cfg:           config,
	}); err != nil {
		if models.IsErrLoginSourceAlreadyExist(err) {
			ctx.Data["Err_Name"] = true
			ctx.RenderWithErr(ctx.Tr("admin.auths.login_source_exist", err.(models.ErrLoginSourceAlreadyExist).Name), tplAuthNew, form)
		} else {
			ctx.ServerError("CreateSource", err)
		}
		return
	}

	log.Trace("Authentication created by admin(%s): %s", ctx.User.Name, form.Name)

	ctx.Flash.Success(ctx.Tr("admin.auths.new_success", form.Name))
	ctx.Redirect(setting.AppSubURL + "/admin/auths")
}

// EditAuthSource render editing auth source page
func EditAuthSource(ctx *context.Context) {
	ctx.Data["Title"] = ctx.Tr("admin.auths.edit")
	ctx.Data["PageIsAdmin"] = true
	ctx.Data["PageIsAdminAuthentications"] = true

	ctx.Data["SecurityProtocols"] = securityProtocols
	ctx.Data["SMTPAuths"] = models.SMTPAuths
	ctx.Data["OAuth2Providers"] = models.OAuth2Providers
	ctx.Data["OAuth2DefaultCustomURLMappings"] = models.OAuth2DefaultCustomURLMappings

	source, err := models.GetLoginSourceByID(ctx.ParamsInt64(":authid"))
	if err != nil {
		ctx.ServerError("GetLoginSourceByID", err)
		return
	}
	ctx.Data["Source"] = source
	ctx.Data["HasTLS"] = source.HasTLS()

	if source.IsOAuth2() {
		ctx.Data["CurrentOAuth2Provider"] = models.OAuth2Providers[source.OAuth2().Provider]
	}
	ctx.HTML(200, tplAuthEdit)
}

// EditAuthSourcePost response for editing auth source
func EditAuthSourcePost(ctx *context.Context, form auth.AuthenticationForm) {
	ctx.Data["Title"] = ctx.Tr("admin.auths.edit")
	ctx.Data["PageIsAdmin"] = true
	ctx.Data["PageIsAdminAuthentications"] = true

	ctx.Data["SMTPAuths"] = models.SMTPAuths
	ctx.Data["OAuth2Providers"] = models.OAuth2Providers
	ctx.Data["OAuth2DefaultCustomURLMappings"] = models.OAuth2DefaultCustomURLMappings

	source, err := models.GetLoginSourceByID(ctx.ParamsInt64(":authid"))
	if err != nil {
		ctx.ServerError("GetLoginSourceByID", err)
		return
	}
	ctx.Data["Source"] = source
	ctx.Data["HasTLS"] = source.HasTLS()

	if ctx.HasError() {
		ctx.HTML(200, tplAuthEdit)
		return
	}

	var config convert.Conversion
	switch models.LoginType(form.Type) {
	case models.LoginLDAP, models.LoginDLDAP:
		config = parseLDAPConfig(form)
	case models.LoginSMTP:
		config = parseSMTPConfig(form)
	case models.LoginPAM:
		config = &models.PAMConfig{
			ServiceName: form.PAMServiceName,
		}
	case models.LoginOAuth2:
		config = parseOAuth2Config(form)
	case models.LoginSSPI:
		config, err = parseSSPIConfig(ctx, form)
		if err != nil {
			ctx.RenderWithErr(err.Error(), tplAuthEdit, form)
			return
		}
	default:
		ctx.Error(400)
		return
	}

	source.Name = form.Name
	source.IsActived = form.IsActive
	source.IsSyncEnabled = form.IsSyncEnabled
	source.Cfg = config
	if err := models.UpdateSource(source); err != nil {
		if models.IsErrOpenIDConnectInitialize(err) {
			ctx.Flash.Error(err.Error(), true)
			ctx.HTML(200, tplAuthEdit)
		} else {
			ctx.ServerError("UpdateSource", err)
		}
		return
	}
	log.Trace("Authentication changed by admin(%s): %d", ctx.User.Name, source.ID)

	ctx.Flash.Success(ctx.Tr("admin.auths.update_success"))
	ctx.Redirect(setting.AppSubURL + "/admin/auths/" + com.ToStr(form.ID))
}

// DeleteAuthSource response for deleting an auth source
func DeleteAuthSource(ctx *context.Context) {
	source, err := models.GetLoginSourceByID(ctx.ParamsInt64(":authid"))
	if err != nil {
		ctx.ServerError("GetLoginSourceByID", err)
		return
	}

	if err = models.DeleteSource(source); err != nil {
		if models.IsErrLoginSourceInUse(err) {
			ctx.Flash.Error(ctx.Tr("admin.auths.still_in_used"))
		} else {
			ctx.Flash.Error(fmt.Sprintf("DeleteSource: %v", err))
		}
		ctx.JSON(200, map[string]interface{}{
			"redirect": setting.AppSubURL + "/admin/auths/" + ctx.Params(":authid"),
		})
		return
	}
	log.Trace("Authentication deleted by admin(%s): %d", ctx.User.Name, source.ID)

	ctx.Flash.Success(ctx.Tr("admin.auths.deletion_success"))
	ctx.JSON(200, map[string]interface{}{
		"redirect": setting.AppSubURL + "/admin/auths",
	})
}