// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.

package resource

import (
	"context"
	"fmt"
	"gopkg.in/yaml.v3"
	"log/slog"
	"net/url"
_	"os"
	"os/exec"
	"os/user"
	"io"
	"strconv"
	"strings"
)

type User struct {
	Name       string   `json:"name" yaml:"name"`
	UID        int      `json:"uid,omitempty" yaml:"uid,omitempty"`
	Group      string   `json:"group,omitempty" yaml:"group,omitempty"`
	Groups     []string `json:"groups,omitempty" yaml:"groups,omitempty"`
	Gecos      string   `json:"gecos,omitempty" yaml:"gecos,omitempty"`
	Home       string   `json:"home" yaml:"home"`
	CreateHome bool     `json:"createhome,omitempty" yaml:"createhome,omitempty"`
	Shell      string   `json:"shell,omitempty" yaml:"shell,omitempty"`

	State string `json:"state" yaml:"state"`
}

func NewUser() *User {
	return &User{}
}

func init() {
	ResourceTypes.Register("user", func(u *url.URL) Resource {
		user := NewUser()
		user.Name = u.Path
		user.UID, _ = LookupUID(u.Path)
		return user
	})
}

func (u *User) URI() string {
	return fmt.Sprintf("user://%s", u.Name)
}

func (u *User) ResolveId(ctx context.Context) string {
	return LookupUIDString(u.Name)
}

func (u *User) Apply() error {
	switch u.State {
	case "present":
		_, NoUserExists := LookupUID(u.Name)
		if NoUserExists != nil {
			var userCommandName string = "useradd"
			args := make([]string, 0, 7)
			if u.UID >= 0 {
				args = append(args, "-u", fmt.Sprintf("%d", u.UID))
			}

			if _, pathErr := exec.LookPath("useradd"); pathErr != nil {
				if _, addUserPathErr := exec.LookPath("adduser"); addUserPathErr == nil {
					userCommandName = "adduser"
					if addUserCommandErr := u.AddUserCommand(&args); addUserCommandErr != nil {
						return addUserCommandErr
					}
				}
			} else {
				if userAddCommandErr := u.UserAddCommand(&args); userAddCommandErr != nil {
					return userAddCommandErr
				}
			}
			args = append(args, u.Name)
			cmd := exec.Command(userCommandName, args...)
			cmdOutput, cmdErr := cmd.CombinedOutput()
			slog.Info("user command", "command", cmd.String(), "output", string(cmdOutput))
			return cmdErr
		}
	case "absent":
		var userDelCommandName string = "userdel"
		args := make([]string, 0, 7)

		if _, pathErr := exec.LookPath("userdel"); pathErr != nil {
			if _, delUserPathErr := exec.LookPath("deluser"); delUserPathErr == nil {
				userDelCommandName = "deluser"
			}
		}
		args = append(args, u.Name)
		cmd := exec.Command(userDelCommandName, args...)
		cmdOutput, cmdErr := cmd.CombinedOutput()
		slog.Info("user command", "command", cmd.String(), "output", string(cmdOutput))
		return cmdErr
	}
	return nil
}

func (u *User) Load(r io.Reader) error {
	c := NewYAMLDecoder(r)
	return c.Decode(u)
}

func (u *User) LoadDecl(yamlResourceDeclaration string) error {
	c := NewYAMLStringDecoder(yamlResourceDeclaration)
	return c.Decode(u)
}

func (u *User) AddUserCommand(args *[]string) error {
	*args = append(*args, "-D")
	if u.Group != "" {
		*args = append(*args, "-G", u.Group)
	}
	if u.Home != "" {
		*args = append(*args, "-h", u.Home)
	}
	return nil
}

func (u *User) UserAddCommand(args *[]string) error {
	if u.Group != "" {
		*args = append(*args, "-g", u.Group)
	}
	if len(u.Groups) > 0 {
		*args = append(*args, "-G", strings.Join(u.Groups, ","))
	}
	if u.Home != "" {
		*args = append(*args, "-d", u.Home)
	}
	if u.CreateHome {
		*args = append(*args, "-m")
	}
	return nil
}

func (u *User) Type() string { return "user" }

func (u *User) Read(ctx context.Context) ([]byte, error) {
	var readUser *user.User
	var e error
	if u.Name != "" {
		readUser, e = user.Lookup(u.Name)
	}
	if u.UID >= 0 {
		readUser, e = user.LookupId(strconv.Itoa(u.UID))
	}

	if e != nil {
		panic(e)
	}

	u.Name = readUser.Username
	u.UID, _ = strconv.Atoi(readUser.Uid)
	if readGroup, groupErr := user.LookupGroupId(readUser.Gid); groupErr == nil {
		u.Group = readGroup.Name
	} else {
		panic(groupErr)
	}
	u.Home = readUser.HomeDir
	u.Gecos = readUser.Name

	return yaml.Marshal(u)
}