/*
   Copyright 2020 Docker, 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 ecs

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/aws/aws-sdk-go/aws"
	ecsapi "github.com/aws/aws-sdk-go/service/ecs"
	"github.com/awslabs/goformation/v4/cloudformation"
	"github.com/awslabs/goformation/v4/cloudformation/ecs"
	"github.com/compose-spec/compose-go/types"
	"github.com/docker/cli/opts"
	"github.com/joho/godotenv"

	"github.com/docker/api/ecs/secrets"
)

const secretsInitContainerImage = "docker/ecs-secrets-sidecar"

func convert(project *types.Project, service types.ServiceConfig) (*ecs.TaskDefinition, error) {
	cpu, mem, err := toLimits(service)
	if err != nil {
		return nil, err
	}
	_, memReservation, err := toContainerReservation(service)
	if err != nil {
		return nil, err
	}
	credential := getRepoCredentials(service)

	// override resolve.conf search directive to also search <project>.local
	// TODO remove once ECS support hostname-only service discovery
	service.Environment["LOCALDOMAIN"] = aws.String(
		cloudformation.Join("", []string{
			cloudformation.Ref("AWS::Region"),
			".compute.internal",
			fmt.Sprintf(" %s.local", project.Name),
		}))

	logConfiguration := getLogConfiguration(service, project)

	var (
		containers     []ecs.TaskDefinition_ContainerDefinition
		volumes        []ecs.TaskDefinition_Volume
		mounts         []ecs.TaskDefinition_MountPoint
		initContainers []ecs.TaskDefinition_ContainerDependency
	)
	if len(service.Secrets) > 0 {
		initContainerName := fmt.Sprintf("%s_Secrets_InitContainer", normalizeResourceName(service.Name))
		volumes = append(volumes, ecs.TaskDefinition_Volume{
			Name: "secrets",
		})
		mounts = append(mounts, ecs.TaskDefinition_MountPoint{
			ContainerPath: "/run/secrets/",
			ReadOnly:      true,
			SourceVolume:  "secrets",
		})
		initContainers = append(initContainers, ecs.TaskDefinition_ContainerDependency{
			Condition:     ecsapi.ContainerConditionSuccess,
			ContainerName: initContainerName,
		})

		var (
			args        []secrets.Secret
			taskSecrets []ecs.TaskDefinition_Secret
		)
		for _, s := range service.Secrets {
			secretConfig := project.Secrets[s.Source]
			if s.Target == "" {
				s.Target = s.Source
			}
			taskSecrets = append(taskSecrets, ecs.TaskDefinition_Secret{
				Name:      s.Target,
				ValueFrom: secretConfig.Name,
			})
			var keys []string
			if ext, ok := secretConfig.Extensions[ExtensionKeys]; ok {
				if key, ok := ext.(string); ok {
					keys = append(keys, key)
				} else {
					for _, k := range ext.([]interface{}) {
						keys = append(keys, k.(string))
					}
				}
			}
			args = append(args, secrets.Secret{
				Name: s.Target,
				Keys: keys,
			})
		}
		command, err := json.Marshal(args)
		if err != nil {
			return nil, err
		}
		containers = append(containers, ecs.TaskDefinition_ContainerDefinition{
			Name:             initContainerName,
			Image:            secretsInitContainerImage,
			Command:          []string{string(command)},
			Essential:        false, // FIXME this will be ignored, see https://github.com/awslabs/goformation/issues/61#issuecomment-625139607
			LogConfiguration: logConfiguration,
			MountPoints: []ecs.TaskDefinition_MountPoint{
				{
					ContainerPath: "/run/secrets/",
					ReadOnly:      false,
					SourceVolume:  "secrets",
				},
			},
			Secrets: taskSecrets,
		})
	}

	pairs, err := createEnvironment(project, service)
	if err != nil {
		return nil, err
	}

	containers = append(containers, ecs.TaskDefinition_ContainerDefinition{
		Command:                service.Command,
		DisableNetworking:      service.NetworkMode == "none",
		DependsOnProp:          initContainers,
		DnsSearchDomains:       service.DNSSearch,
		DnsServers:             service.DNS,
		DockerSecurityOptions:  service.SecurityOpt,
		EntryPoint:             service.Entrypoint,
		Environment:            pairs,
		Essential:              true,
		ExtraHosts:             toHostEntryPtr(service.ExtraHosts),
		FirelensConfiguration:  nil,
		HealthCheck:            toHealthCheck(service.HealthCheck),
		Hostname:               service.Hostname,
		Image:                  service.Image,
		Interactive:            false,
		Links:                  nil,
		LinuxParameters:        toLinuxParameters(service),
		LogConfiguration:       logConfiguration,
		MemoryReservation:      memReservation,
		MountPoints:            mounts,
		Name:                   service.Name,
		PortMappings:           toPortMappings(service.Ports),
		Privileged:             service.Privileged,
		PseudoTerminal:         service.Tty,
		ReadonlyRootFilesystem: service.ReadOnly,
		RepositoryCredentials:  credential,
		ResourceRequirements:   nil,
		StartTimeout:           0,
		StopTimeout:            durationToInt(service.StopGracePeriod),
		SystemControls:         toSystemControls(service.Sysctls),
		Ulimits:                toUlimits(service.Ulimits),
		User:                   service.User,
		VolumesFrom:            nil,
		WorkingDirectory:       service.WorkingDir,
	})

	return &ecs.TaskDefinition{
		ContainerDefinitions:    containers,
		Cpu:                     cpu,
		Family:                  fmt.Sprintf("%s-%s", project.Name, service.Name),
		IpcMode:                 service.Ipc,
		Memory:                  mem,
		NetworkMode:             ecsapi.NetworkModeAwsvpc, // FIXME could be set by service.NetworkMode, Fargate only supports network mode ‘awsvpc’.
		PidMode:                 service.Pid,
		PlacementConstraints:    toPlacementConstraints(service.Deploy),
		ProxyConfiguration:      nil,
		RequiresCompatibilities: []string{ecsapi.LaunchTypeFargate},
		Volumes:                 volumes,
	}, nil
}

func createEnvironment(project *types.Project, service types.ServiceConfig) ([]ecs.TaskDefinition_KeyValuePair, error) {
	environment := map[string]*string{}
	for _, f := range service.EnvFile {
		if !filepath.IsAbs(f) {
			f = filepath.Join(project.WorkingDir, f)
		}
		if _, err := os.Stat(f); os.IsNotExist(err) {
			return nil, err
		}
		file, err := os.Open(f)
		if err != nil {
			return nil, err
		}
		defer file.Close() // nolint:errcheck

		env, err := godotenv.Parse(file)
		if err != nil {
			return nil, err
		}
		for k, v := range env {
			environment[k] = &v
		}
	}
	for k, v := range service.Environment {
		environment[k] = v
	}

	var pairs []ecs.TaskDefinition_KeyValuePair
	for k, v := range environment {
		name := k
		var value string
		if v != nil {
			value = *v
		}
		pairs = append(pairs, ecs.TaskDefinition_KeyValuePair{
			Name:  name,
			Value: value,
		})
	}
	return pairs, nil
}

func getLogConfiguration(service types.ServiceConfig, project *types.Project) *ecs.TaskDefinition_LogConfiguration {
	options := map[string]string{
		"awslogs-region":        cloudformation.Ref("AWS::Region"),
		"awslogs-group":         cloudformation.Ref("LogGroup"),
		"awslogs-stream-prefix": project.Name,
	}
	if service.Logging != nil {
		for k, v := range service.Logging.Options {
			if strings.HasPrefix(k, "awslogs-") {
				options[k] = v
			}
		}
	}
	logConfiguration := &ecs.TaskDefinition_LogConfiguration{
		LogDriver: ecsapi.LogDriverAwslogs,
		Options:   options,
	}
	return logConfiguration
}

func toSystemControls(sysctls types.Mapping) []ecs.TaskDefinition_SystemControl {
	sys := []ecs.TaskDefinition_SystemControl{}
	for k, v := range sysctls {
		sys = append(sys, ecs.TaskDefinition_SystemControl{
			Namespace: k,
			Value:     v,
		})
	}
	return sys
}

const MiB = 1024 * 1024

func toLimits(service types.ServiceConfig) (string, string, error) {
	// All possible cpu/mem values for Fargate
	cpuToMem := map[int64][]types.UnitBytes{
		256:  {512, 1024, 2048},
		512:  {1024, 2048, 3072, 4096},
		1024: {2048, 3072, 4096, 5120, 6144, 7168, 8192},
		2048: {4096, 5120, 6144, 7168, 8192, 9216, 10240, 11264, 12288, 13312, 14336, 15360, 16384},
		4096: {8192, 9216, 10240, 11264, 12288, 13312, 14336, 15360, 16384, 17408, 18432, 19456, 20480, 21504, 22528, 23552, 24576, 25600, 26624, 27648, 28672, 29696, 30720},
	}
	cpuLimit := "256"
	memLimit := "512"

	if service.Deploy == nil {
		return cpuLimit, memLimit, nil
	}

	limits := service.Deploy.Resources.Limits
	if limits == nil {
		return cpuLimit, memLimit, nil
	}

	if limits.NanoCPUs == "" {
		return cpuLimit, memLimit, nil
	}

	v, err := opts.ParseCPUs(limits.NanoCPUs)
	if err != nil {
		return "", "", err
	}

	var cpus []int64
	for k := range cpuToMem {
		cpus = append(cpus, k)
	}
	sort.Slice(cpus, func(i, j int) bool { return cpus[i] < cpus[j] })

	for _, cpu := range cpus {
		mem := cpuToMem[cpu]
		if v <= cpu*MiB {
			for _, m := range mem {
				if limits.MemoryBytes <= m*MiB {
					cpuLimit = strconv.FormatInt(cpu, 10)
					memLimit = strconv.FormatInt(int64(m), 10)
					return cpuLimit, memLimit, nil
				}
			}
		}
	}
	return "", "", fmt.Errorf("the resources requested are not supported by ECS/Fargate")
}

func toContainerReservation(service types.ServiceConfig) (string, int, error) {
	cpuReservation := ".0"
	memReservation := 0

	if service.Deploy == nil {
		return cpuReservation, memReservation, nil
	}

	reservations := service.Deploy.Resources.Reservations
	if reservations == nil {
		return cpuReservation, memReservation, nil
	}
	return reservations.NanoCPUs, int(reservations.MemoryBytes / MiB), nil
}

func toPlacementConstraints(deploy *types.DeployConfig) []ecs.TaskDefinition_TaskDefinitionPlacementConstraint {
	if deploy == nil || deploy.Placement.Constraints == nil || len(deploy.Placement.Constraints) == 0 {
		return nil
	}
	pl := []ecs.TaskDefinition_TaskDefinitionPlacementConstraint{}
	for _, c := range deploy.Placement.Constraints {
		pl = append(pl, ecs.TaskDefinition_TaskDefinitionPlacementConstraint{
			Expression: c,
			Type:       "",
		})
	}
	return pl
}

func toPortMappings(ports []types.ServicePortConfig) []ecs.TaskDefinition_PortMapping {
	if len(ports) == 0 {
		return nil
	}
	m := []ecs.TaskDefinition_PortMapping{}
	for _, p := range ports {
		m = append(m, ecs.TaskDefinition_PortMapping{
			ContainerPort: int(p.Target),
			HostPort:      int(p.Published),
			Protocol:      p.Protocol,
		})
	}
	return m
}

func toUlimits(ulimits map[string]*types.UlimitsConfig) []ecs.TaskDefinition_Ulimit {
	if len(ulimits) == 0 {
		return nil
	}
	u := []ecs.TaskDefinition_Ulimit{}
	for k, v := range ulimits {
		u = append(u, ecs.TaskDefinition_Ulimit{
			Name:      k,
			SoftLimit: v.Soft,
			HardLimit: v.Hard,
		})
	}
	return u
}

func toLinuxParameters(service types.ServiceConfig) *ecs.TaskDefinition_LinuxParameters {
	return &ecs.TaskDefinition_LinuxParameters{
		Capabilities:       toKernelCapabilities(service.CapAdd, service.CapDrop),
		Devices:            nil,
		InitProcessEnabled: service.Init != nil && *service.Init,
		MaxSwap:            0,
		// FIXME SharedMemorySize:   service.ShmSize,
		Swappiness: 0,
		Tmpfs:      toTmpfs(service.Tmpfs),
	}
}

func toTmpfs(tmpfs types.StringList) []ecs.TaskDefinition_Tmpfs {
	if tmpfs == nil || len(tmpfs) == 0 {
		return nil
	}
	o := []ecs.TaskDefinition_Tmpfs{}
	for _, path := range tmpfs {
		o = append(o, ecs.TaskDefinition_Tmpfs{
			ContainerPath: path,
			Size:          100, // size is required on ECS, unlimited by the compose spec
		})
	}
	return o
}

func toKernelCapabilities(add []string, drop []string) *ecs.TaskDefinition_KernelCapabilities {
	if len(add) == 0 && len(drop) == 0 {
		return nil
	}
	return &ecs.TaskDefinition_KernelCapabilities{
		Add:  add,
		Drop: drop,
	}

}

func toHealthCheck(check *types.HealthCheckConfig) *ecs.TaskDefinition_HealthCheck {
	if check == nil {
		return nil
	}
	retries := 0
	if check.Retries != nil {
		retries = int(*check.Retries)
	}
	return &ecs.TaskDefinition_HealthCheck{
		Command:     check.Test,
		Interval:    durationToInt(check.Interval),
		Retries:     retries,
		StartPeriod: durationToInt(check.StartPeriod),
		Timeout:     durationToInt(check.Timeout),
	}
}

func durationToInt(interval *types.Duration) int {
	if interval == nil {
		return 0
	}
	v := int(time.Duration(*interval).Seconds())
	return v
}

func toHostEntryPtr(hosts types.HostsList) []ecs.TaskDefinition_HostEntry {
	if hosts == nil || len(hosts) == 0 {
		return nil
	}
	e := []ecs.TaskDefinition_HostEntry{}
	for _, h := range hosts {
		parts := strings.SplitN(h, ":", 2) // FIXME this should be handled by compose-go
		e = append(e, ecs.TaskDefinition_HostEntry{
			Hostname:  parts[0],
			IpAddress: parts[1],
		})
	}
	return e
}

func getRepoCredentials(service types.ServiceConfig) *ecs.TaskDefinition_RepositoryCredentials {
	// extract registry and namespace string from image name
	for key, value := range service.Extensions {
		if key == ExtensionPullCredentials {
			return &ecs.TaskDefinition_RepositoryCredentials{CredentialsParameter: value.(string)}
		}
	}
	return nil
}