package main

import (
	"fmt"
	"io"
	"log"
	"os"
	"regexp"
	"strings"

	"gopkg.in/yaml.v3"
)

const (
	PRIVILEGE_OPT   = "no-new-privileges=true"
	ROOT_USER_GROUP = "1000:1000"
	ROOT_USER       = "1000"
	ROOT_GROUP      = "1000"
	IM_SO_SORRY     = `^(\${{\s*(vars|secrets)\..*}}|[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}):(\${{\s*(vars|secrets)\..*}}|[0-9]+):(\${{\s*(vars|secrets)\..*}}|[0-9]+)`

	FATAL   IssueLevel = "FATAL"
	WARNING IssueLevel = "WARNING"
	PASSED  IssueLevel = "PASSED"
)

type IssueLevel string

type Issue struct {
	Level    IssueLevel
	Safe     bool
	Messages []string
}

func (i *Issue) Passed() {
	i.Level = PASSED
	i.Safe = true
}

func (i *Issue) Warning() {
	i.Level = WARNING
	i.Safe = true
}

func (i *Issue) Fatal() {
	i.Level = FATAL
	i.Safe = false
}

type RestartConfig struct {
	Condition   *string `yaml:"condition"`
	Delay       *string `yaml:"delay"`
	MaxAttempts *int    `yaml:"max_attempts"`
	Window      *string `yaml:"window"`
}

type DeployConfig struct {
	Policy *RestartConfig `yaml:"restart_policy"`
}

type ServiceConfig struct {
	MemLimit   *string       `yaml:"mem_limit"`
	Cpus       *float64      `yaml:"cpus"`
	Ports      *[]string     `yaml:"ports"`
	User       *string       `yaml:"user"`
	Deploy     *DeployConfig `yaml:"deploy"`
	SecOpts    *[]string     `yaml:"security_opt"`
	Privileged *bool         `yaml:"privileged"`
}

type Compose struct {
	Services map[string]ServiceConfig `yaml:"services"`
}

func main() {
	filePath := os.Getenv("COMPOSE_FILE_PATH")
	if filePath == "" {
		filePath = "compose.yaml"
	}
	f, err := os.Open(filePath)
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	fd, err := io.ReadAll(f)
	if err != nil {
		log.Fatal(err)
	}

	var data Compose
	err = yaml.Unmarshal(fd, &data)
	if err != nil {
		log.Fatal(err)
	}

	// type report struct {
	// 	Name string //service name

	// 	//restart policy
	// 	PolicyPresent bool       //is it present
	// 	PolicyLevel   IssueLevel //how serious
	// 	PolicyIssues  []string
	// 	//are ports behind a proxy?
	// 	PortSafe   bool
	// 	PortIssues []string
	// 	PortLevel  IssueLevel
	// 	//memory limits and cpu
	// 	ResourceSafe   bool
	// 	ResourceIssues []string
	// 	ResourceLevel  IssueLevel
	// 	//proper security options
	// 	SecurityOptSafe   bool
	// 	SecurityOptLevel  IssueLevel
	// 	SecurityOptIssues []string
	// 	//are users nonroot
	// 	UserSafe       bool
	// 	UserIssues     []string
	// 	UserIssueLevel IssueLevel
	// }

	type NewReport struct {
		Name   string
		Issues []*Issue
	}

	var issues []NewReport
	for name, serviceConf := range data.Services {
		rprt := NewReport{
			Name: name,
		}

		i := ResourceCheck(serviceConf)
		if i != nil {
			rprt.Issues = append(rprt.Issues, i)
		}

		j := SecurityOptCheck(serviceConf)
		if j != nil {
			rprt.Issues = append(rprt.Issues, j)
		}

		k, err := UserCheck(serviceConf)
		if err != nil {
			log.Fatal(err)
		}
		if k != nil {
			rprt.Issues = append(rprt.Issues, k)
		}

		l, err := PortCheck(serviceConf)
		if err != nil {
			log.Fatal(err)
		}
		if len(l) > 0 {
			rprt.Issues = append(rprt.Issues, l...)
		}

		m := PolicyCheck(serviceConf)
		if m != nil {
			rprt.Issues = append(rprt.Issues, m)
		}

		issues = append(issues, rprt)
	}

	for _, p := range issues {
		fmt.Println(p.Name)
		for _, x := range p.Issues {
			fmt.Println(*x)
		}
	}
}

func ResourceCheck(srv ServiceConfig) *Issue {
	i := &Issue{}
	if srv.Cpus == nil {
		i.Warning()
		i.Messages = append(i.Messages, "there is no cpu limit set for the service")
	}

	if srv.MemLimit == nil {
		i.Warning()
		i.Messages = append(i.Messages, "there is no memory limit set for the service")
	}

	if srv.Cpus == nil && srv.MemLimit == nil {
		i.Fatal()
		i.Messages = append(i.Messages, "there are no resource limits set for the service")
	}

	i.Passed()
	i.Messages = append(i.Messages, "resource limits configuration is safe")
	return i
}

func PrivilegedCheck(srv ServiceConfig) *Issue {
	i := &Issue{}
	if srv.Privileged == nil {
		i.Passed()
		i.Messages = append(i.Messages, "no privileged flag set")
		return i
	}

	if *srv.Privileged == true {
		i.Fatal()
		i.Messages = append(i.Messages, "privileged flag is set to true")
		return i
	}

	i.Passed()
	i.Messages = append(i.Messages, "privileged flag is set to false")
	return i
}

func SecurityOptCheck(srv ServiceConfig) *Issue {
	i := &Issue{}
	if srv.SecOpts == nil {
		i.Fatal()
		i.Messages = append(i.Messages, "set no-new-privileges=true on the service security_opts")
		return i
	}

	for _, opt := range *srv.SecOpts {
		if strings.EqualFold(opt, PRIVILEGE_OPT) {
			i.Passed()
			i.Messages = append(i.Messages, "security option are safe")
			return i
		}
	}

	i.Fatal()
	i.Messages = append(i.Messages, "set no-new-privileges=true on the container security_opts")
	return i
}

func PortCheck(srv ServiceConfig) ([]*Issue, error) {
	il := []*Issue{}
	if srv.Ports == nil {
		i := &Issue{}
		i.Passed()
		i.Messages = append(i.Messages, "no ports exposed")
		il = append(il, i)
		return il, nil
	}

	for _, prt := range *srv.Ports {
		i := &Issue{}
		m, err := regexp.Match(`^[0-9]*:[0-9]*`, []byte(prt))
		if err != nil {
			return nil, err
		}

		if m {
			i.Fatal()
			i.Messages = append(i.Messages, fmt.Sprintf("%s is fully exposed", prt))
			il = append(il, i)
			continue
		}

		m2, err := regexp.Match(IM_SO_SORRY, []byte(prt))
		if err != nil {
			return nil, err
		}

		if m2 {
			i.Passed()
			i.Messages = append(i.Messages, fmt.Sprintf("%s is safe", prt))
			il = append(il, i)
			continue
		} else {
			i.Warning()
			i.Messages = append(i.Messages, fmt.Sprintf("unable to parse port configuration for %s", prt))
			il = append(il, i)
			continue
		}
	}

	return il, nil
}

func UserCheck(srv ServiceConfig) (*Issue, error) {
	i := &Issue{}
	if srv.User == nil {
		i.Warning()
		i.Messages = append(i.Messages, "no user is specified in the compose file")
		return i, nil
	}

	mtch, err := regexp.Match("[0-9]*:[0-9]*", []byte(*srv.User))
	if err != nil {
		return nil, err
	}

	if mtch {
		if strings.EqualFold(ROOT_USER_GROUP, *srv.User) {
			i.Fatal()
			i.Messages = append(i.Messages, "a root user set in the compose file")
		} else {
			i.Passed()
			i.Messages = append(i.Messages, "user configuration is safe")
		}
		return i, nil
	} else {
		users := strings.Split(*srv.User, ":")
		if len(users) != 2 {
			i.Fatal()
			i.Messages = append(i.Messages, "user value seems misconfigured, check compose file")
			return i, nil
		}
		//shoutouts and/or blame should go to: https://regex101.com/ -- seems like a cool tool, but time will tell
		leftUser, err := regexp.Match(`(?m)\${{\s*(vars|secrets)\..*}}`, []byte(users[0]))
		if err != nil {
			return nil, err
		}
		rightUser, err := regexp.Match(`(?m)\${{\s*(vars|secrets)\..*}}`, []byte(users[1]))
		if err != nil {
			return nil, err
		}

		if leftUser && rightUser {
			i.Passed()
			i.Messages = append(i.Messages, "user configuration is safe")
			return i, nil
		}

		if leftUser {
			if strings.EqualFold(users[1], ROOT_GROUP) {
				i.Warning()
				i.Messages = append(i.Messages, "a root user is present in configuration")
			} else {
				i.Passed()
				i.Messages = append(i.Messages, "user configuration is safe")
			}
			return i, nil
		}

		if rightUser {
			if strings.EqualFold(users[0], ROOT_USER) {
				i.Warning()
				i.Messages = append(i.Messages, "a root user is present in configuration")
			} else {
				i.Passed()
				i.Messages = append(i.Messages, "user configuration is safe")
			}
			return i, nil
		}
	}

	i.Fatal()
	i.Messages = append(i.Messages, "unable to parse user configuration")
	return i, nil
}

func PolicyCheck(srv ServiceConfig) *Issue {
	i := &Issue{}
	if srv.Deploy != nil {
		if srv.Deploy.Policy != nil {
			if srv.Deploy.Policy.Condition != nil {
				if srv.Deploy.Policy.MaxAttempts != nil {
					i.Passed()
					i.Messages = append(i.Messages, "restart policy configuration is safe")
					return i
				} else {
					i.Warning()
					i.Messages = append(i.Messages, "no max_attempts value set on restart policy container could death loop")
					return i
				}
			} else {
				i.Fatal()
				i.Messages = append(i.Messages, "no restart condition is set on the container")
				return i
			}
		} else {
			i.Fatal()
			i.Messages = append(i.Messages, "no restart policy is set on the container")
			return i
		}
	}

	i.Fatal()
	i.Messages = append(i.Messages, "no restart policy is set on the container")
	return i
}