/*
   Copyright 2020 Docker Compose CLI authors

   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 formatter

import (
	"fmt"
	"sort"
	"strconv"
	"strings"

	"github.com/docker/compose-cli/api/containers"
)

type portGroup struct {
	first uint32
	last  uint32
}

// PortsToStrings returns a human readable published ports
func PortsToStrings(ports []containers.Port, fqdn string) []string {
	groupMap := make(map[string]*portGroup)
	result := []string{}
	var (
		hostMappings []string
		groupMapKeys []string
	)

	sort.Slice(ports, func(i int, j int) bool {
		return comparePorts(ports[i], ports[j])
	})

	for _, port := range ports {
		// Simple case: HOST_IP:PORT1:PORT2
		hostIP := "0.0.0.0"
		if port.HostIP != "" {
			hostIP = port.HostIP
		}
		if fqdn != "" {
			hostIP = fqdn
		}

		if port.HostPort != port.ContainerPort {
			hostMappings = append(hostMappings, fmt.Sprintf("%s:%d->%d/%s", hostIP, port.HostPort, port.ContainerPort, port.Protocol))
			continue
		}

		current := port.ContainerPort
		portKey := fmt.Sprintf("%s/%s", hostIP, port.Protocol)
		group := groupMap[portKey]

		if group == nil {
			groupMap[portKey] = &portGroup{first: current, last: current}
			// record order that groupMap keys are created
			groupMapKeys = append(groupMapKeys, portKey)
			continue
		}

		if current == (group.last + 1) {
			group.last = current
			continue
		}

		result = append(result, formGroup(portKey, group.first, group.last))
		groupMap[portKey] = &portGroup{first: current, last: current}
	}

	for _, portKey := range groupMapKeys {
		g := groupMap[portKey]
		result = append(result, formGroup(portKey, g.first, g.last))
	}

	result = append(result, hostMappings...)

	return result
}

func formGroup(key string, start uint32, last uint32) string {
	parts := strings.Split(key, "/")
	protocol := parts[0]
	var ip string
	if len(parts) > 1 {
		ip = parts[0]
		protocol = parts[1]
	}
	group := strconv.Itoa(int(start))

	// add range
	if start != last {
		group = fmt.Sprintf("%s-%d", group, last)
	}

	// add host ip
	if ip != "" {
		group = fmt.Sprintf("%s:%s->%s", ip, group, group)
	}

	// add protocol
	return fmt.Sprintf("%s/%s", group, protocol)
}

func comparePorts(i containers.Port, j containers.Port) bool {
	if i.ContainerPort != j.ContainerPort {
		return i.ContainerPort < j.ContainerPort
	}

	if i.HostIP != j.HostIP {
		return i.HostIP < j.HostIP
	}

	if i.HostPort != j.HostPort {
		return i.HostPort < j.HostPort
	}

	return i.Protocol < j.Protocol
}