// 2018 Rackspace, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.

package shutdown

import (
	"errors"
	"fmt"
	"net"
	"regexp"
)

type f5 struct {
	Opts          Options
	RawConfig     string
	StartupConfig string
	UpdatedConfig string
}

func (d *f5) modify() string {
	d.UpdatedConfig = d.RawConfig
	d.modifyMgmtInfo()
	d.modifyVlans()
	return d.UpdatedConfig
}

func (d *f5) modifyMgmtInfo() {
	if d.Opts.MgmtInfo == nil {
		return
	}

	matched, _ := regexp.MatchString("sys management-ip", d.UpdatedConfig)
	if matched { // 11.x+ code versions
		re := regexp.MustCompile(
			fmt.Sprintf(
				`sys management-ip %s/%d(\b)`,
				d.Opts.MgmtInfo.IP.Old,
				d.netmaskToCidr(d.Opts.MgmtInfo.Netmask.Old),
			))
		d.UpdatedConfig = re.ReplaceAllString(
			d.UpdatedConfig,
			fmt.Sprintf(
				`sys management-ip %s/%d${1}`,
				d.Opts.MgmtInfo.IP.New,
				d.netmaskToCidr(d.Opts.MgmtInfo.Netmask.New),
			),
		)

		re = regexp.MustCompile(
			fmt.Sprintf(`(?s)(sys management-route.*?gateway) %s(\b)`, d.Opts.MgmtInfo.Gateway.Old),
		)
		d.UpdatedConfig = re.ReplaceAllString(
			d.UpdatedConfig,
			fmt.Sprintf(`${1} %s${2}`, d.Opts.MgmtInfo.Gateway.New),
		)

		re = regexp.MustCompile(
			fmt.Sprintf(`(?s)(cm device .*?) management-ip %s(\b)`, d.Opts.MgmtInfo.IP.Old),
		)
		d.UpdatedConfig = re.ReplaceAllString(
			d.UpdatedConfig,
			fmt.Sprintf(`${1} management-ip %s${2}`, d.Opts.MgmtInfo.IP.New),
		)

		re = regexp.MustCompile(
			fmt.Sprintf(
				`(?s)(unicast-address .*?) effective-ip %s(\b.*?) ip %s(\b)`,
				d.Opts.MgmtInfo.IP.Old,
				d.Opts.MgmtInfo.IP.Old,
			),
		)
		d.UpdatedConfig = re.ReplaceAllString(
			d.UpdatedConfig,
			fmt.Sprintf(`${1} effective-ip %s${2} ip %s${3}`, d.Opts.MgmtInfo.IP.New, d.Opts.MgmtInfo.IP.New),
		)
	} else { // 10.x code versions
		re := regexp.MustCompile(
			fmt.Sprintf(
				`(?s)mgmt %s (.*?) netmask %s(\b)`,
				d.Opts.MgmtInfo.IP.Old,
				d.Opts.MgmtInfo.Netmask.Old,
			),
		)
		d.UpdatedConfig = re.ReplaceAllString(
			d.UpdatedConfig,
			fmt.Sprintf(
				`mgmt %s ${1} netmask %s${2}`,
				d.Opts.MgmtInfo.IP.New,
				d.Opts.MgmtInfo.Netmask.New,
			),
		)

		re = regexp.MustCompile(
			fmt.Sprintf(`(?s)(mgmt route .*? gateway) %s(\b)`, d.Opts.MgmtInfo.Gateway.Old),
		)
		d.UpdatedConfig = re.ReplaceAllString(
			d.UpdatedConfig,
			fmt.Sprintf(`${1} %s${2}`, d.Opts.MgmtInfo.Gateway.New),
		)
	}
}

func (d *f5) modifyVlans() {
	if d.Opts.VlanMap == nil {
		return
	}

	for o, n := range d.Opts.VlanMap {
		re := regexp.MustCompile(fmt.Sprintf(`(?s)((?:net )?vlan.*?) tag %s(\b)`, o))
		d.UpdatedConfig = re.ReplaceAllString(
			d.UpdatedConfig,
			fmt.Sprintf(`${1} tag %s${2}`, n),
		)
	}
}

func (d *f5) netmaskToCidr(netmask string) int {
	nm := net.ParseIP(netmask).To4()
	size, _ := net.IPv4Mask(nm[0], nm[1], nm[2], nm[3]).Size()
	return size
}

func (d *f5) verify() error {
	if err := d.verifyMgmtInfo(); err != nil {
		return err
	}

	if err := d.verifyVlans(); err != nil {
		return err
	}

	return nil
}

func (d *f5) verifyMgmtInfo() error {
	if d.Opts.MgmtInfo == nil {
		return nil
	}

	matched, _ := regexp.MatchString("sys management-ip", d.UpdatedConfig)
	//nolint
	re := new(regexp.Regexp)
	if matched { // 11.x+ code versions
		re = regexp.MustCompile(
			fmt.Sprintf(
				`sys management-ip %s/%d(\b)`,
				d.Opts.MgmtInfo.IP.New,
				d.netmaskToCidr(d.Opts.MgmtInfo.Netmask.New),
			))
	} else { // 10.x code versions
		re = regexp.MustCompile(
			fmt.Sprintf(
				`(?s)mgmt %s (.*?) netmask %s(\b)`,
				d.Opts.MgmtInfo.IP.New,
				d.Opts.MgmtInfo.Netmask.New,
			),
		)
	}
	if !re.MatchString(d.StartupConfig) {
		return errors.New("verify(): failure matching on updated mgmt IP")
	}

	return nil
}

func (d *f5) verifyVlans() error {
	if d.Opts.VlanMap == nil {
		return nil
	}
	vlans := make([]string, 0)
	for o := range d.Opts.VlanMap {
		re := regexp.MustCompile(fmt.Sprintf(`(?s)(?:net )?vlan.*? tag %s\b`, o))
		if re.MatchString(d.RawConfig) {
			vlans = append(vlans, o)
		}
	}

	for _, oldVlan := range vlans {
		re := regexp.MustCompile(fmt.Sprintf(`(?s)(?:net )?vlan.*? tag %s\b`, d.Opts.VlanMap[oldVlan]))
		if !re.MatchString(d.StartupConfig) {
			return fmt.Errorf("verify(): failure matching on vlan %s", d.Opts.VlanMap[oldVlan])
		}
	}
	return nil
}