// 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"
	"encoding/json"
	"errors"
	"strings"
	"gitea.rosskeen.house/rosskeen.house/machine"
	"decl/internal/codec"
	"decl/internal/command"
	"decl/internal/data"
	"decl/internal/folio"
)

type decodeGroup Group

type GroupType string

const (
	GroupTypeAddGroup = "addgroup"
	GroupTypeGroupAdd = "groupadd"
)

var ErrUnsupportedGroupType error = errors.New("The GroupType is not supported on this system")
var ErrInvalidGroupType error = errors.New("invalid GroupType value")

var SystemGroupType GroupType = FindSystemGroupType()

type Group struct {
	*Common	`json:"-" yaml:"-"`
	stater		machine.Stater	`json:"-" yaml:"-"`
	Name       string   `json:"name" yaml:"name"`
	GID        string   `json:"gid,omitempty" yaml:"gid,omitempty"`
	GroupType  GroupType `json:"-" yaml:"-"`

	CreateCommand *command.Command `json:"-" yaml:"-"`
	ReadCommand *command.Command   `json:"-" yaml:"-"`
	UpdateCommand *command.Command `json:"-" yaml:"-"`
	DeleteCommand *command.Command `json:"-" yaml:"-"`
	State string           `json:"state,omitempty" yaml:"state,omitempty"`
	config data.ConfigurationValueGetter
	Resources data.ResourceMapper `json:"-" yaml:"-"`
}

func NewGroup() *Group {
	return &Group{}
}

func init() {
	folio.DocumentRegistry.ResourceTypes.Register([]string{"group"}, func(u *url.URL) data.Resource {
		group := NewGroup()
		group.Name = u.Hostname()
		group.GID = LookupGIDString(u.Hostname())
		if _, addGroupPathErr := exec.LookPath("addgroup"); addGroupPathErr == nil {
			group.GroupType = GroupTypeAddGroup
		}
		if _, pathErr := exec.LookPath("groupadd"); pathErr == nil {
			group.GroupType = GroupTypeGroupAdd
		}
		group.CreateCommand, group.ReadCommand, group.UpdateCommand, group.DeleteCommand = group.GroupType.NewCRUD()
		return group
	})
}

func FindSystemGroupType() GroupType {
	for _, groupType := range []GroupType{GroupTypeAddGroup, GroupTypeGroupAdd} {
		c := groupType.NewCreateCommand()
		if c.Exists() {
			return groupType
		}
	}
	return GroupTypeAddGroup
}

func (g *Group) SetResourceMapper(resources data.ResourceMapper) {
	g.Resources = resources
}

func (g *Group) Clone() data.Resource {
	newg := &Group {
		Name: g.Name,
		GID: g.GID,
		State: g.State,
		GroupType: g.GroupType,
	}
	newg.CreateCommand, newg.ReadCommand, newg.UpdateCommand, newg.DeleteCommand = g.GroupType.NewCRUD()
	return newg
}

func (g *Group) StateMachine() machine.Stater {
	if g.stater == nil {
		g.stater = StorageMachine(g)
	}
	return g.stater
}

func (g *Group) Notify(m *machine.EventMessage) {
	ctx := context.Background()
	switch m.On {
	case machine.ENTERSTATEEVENT:
		switch m.Dest {
		case "start_create":
			if e := g.Create(ctx); e == nil {
				if triggerErr := g.stater.Trigger("created"); triggerErr == nil {
					return
				}
			}
			g.State = "absent"
		case "present":
			g.State = "present"
		}
	case machine.EXITSTATEEVENT:
	}
}

func (g *Group) SetURI(uri string) error {
	resourceUri, e := url.Parse(uri)
	if e == nil {
		if resourceUri.Scheme == "group" {
			g.Name = resourceUri.Hostname()
		} else {
			e = fmt.Errorf("%w: %s is not a group", ErrInvalidResourceURI, uri)
		}
	}
	return e
}

func (g *Group) URI() string {
	return fmt.Sprintf("group://%s", g.Name)
}

func (g *Group) UseConfig(config data.ConfigurationValueGetter) {
	g.config = config
}

func (g *Group) ResolveId(ctx context.Context) string {
	return LookupUIDString(g.Name)
}

func (g *Group) Validate() error {
	return fmt.Errorf("failed")
}

func (g *Group) Apply() error {
	ctx := context.Background()
	switch g.State {
	case "present":
		_, NoGroupExists := LookupGID(g.Name)
		if NoGroupExists != nil {
			cmdErr := g.Create(ctx)
			return cmdErr
		}
	case "absent":
		cmdErr := g.Delete(ctx)
		return cmdErr
	}
	return nil
}

func (g *Group) Load(docData []byte, f codec.Format) (err error) {
	err = f.StringDecoder(string(docData)).Decode(g)
	return
}

func (g *Group) LoadReader(r io.ReadCloser, f codec.Format) (err error) {
	err = f.Decoder(r).Decode(g)
	return
}

func (g *Group) LoadString(docData string, f codec.Format) (err error) {
	err = f.StringDecoder(docData).Decode(g)
	return
}

func (g *Group) LoadDecl(yamlResourceDeclaration string) error {
	return g.LoadString(yamlResourceDeclaration, codec.FormatYaml)
}

func (g *Group) Type() string { return "group" }

func (g *Group) Create(ctx context.Context) (error) {
	_, err := g.CreateCommand.Execute(g)
	if err != nil {
		return err
	}

	_,e := g.Read(ctx)
	return e
}

func (g *Group) Read(ctx context.Context) ([]byte, error) {
	exErr := g.ReadCommand.Extractor(nil, g)
	if exErr != nil {
		g.State = "absent"
	}
	if yaml, yamlErr := yaml.Marshal(g); yamlErr != nil {
		return yaml, yamlErr
	} else {
		return yaml, exErr
	}
}

func (g *Group) Update(ctx context.Context) (error) {
	return g.Create(ctx)
}

func (g *Group) Delete(ctx context.Context) (error) {
	_, err := g.DeleteCommand.Execute(g)
	if err != nil {
		return err
	}

	return err
}

func (g *Group) UnmarshalJSON(data []byte) error {
	if unmarshalErr := json.Unmarshal(data, (*decodeGroup)(g)); unmarshalErr != nil {
		return unmarshalErr
	}
	g.CreateCommand, g.ReadCommand, g.UpdateCommand, g.DeleteCommand = g.GroupType.NewCRUD()
	return nil
}

func (g *Group) UnmarshalYAML(value *yaml.Node) error {
	if unmarshalErr := value.Decode((*decodeGroup)(g)); unmarshalErr != nil {
		return unmarshalErr
	}
	g.CreateCommand, g.ReadCommand, g.UpdateCommand, g.DeleteCommand = g.GroupType.NewCRUD()
	return nil
}

func (g *GroupType) NewCRUD() (create *command.Command, read *command.Command, update *command.Command, del *command.Command) {
	switch *g {
	case GroupTypeGroupAdd:
		return NewGroupAddCreateCommand(), NewGroupReadCommand(), NewGroupUpdateCommand(), NewGroupDelDeleteCommand()
	case GroupTypeAddGroup:
		return NewAddGroupCreateCommand(), NewGroupReadCommand(), NewGroupUpdateCommand(), NewDelGroupDeleteCommand()
	default:
		if _, addGroupPathErr := exec.LookPath("addgroup"); addGroupPathErr == nil {
			*g = GroupTypeAddGroup
			return NewAddGroupCreateCommand(), NewGroupReadCommand(), NewGroupUpdateCommand(), NewDelGroupDeleteCommand()
		}
		if _, pathErr := exec.LookPath("groupadd"); pathErr == nil {
			*g = GroupTypeGroupAdd
			return NewGroupAddCreateCommand(), NewGroupReadCommand(), NewGroupUpdateCommand(), NewGroupDelDeleteCommand()
		}
		return NewGroupAddCreateCommand(), NewGroupReadCommand(), NewGroupUpdateCommand(), NewGroupDelDeleteCommand()
	}
}

func (g *GroupType) NewCreateCommand() (create *command.Command) {
	switch *g {
	case GroupTypeGroupAdd:
		return NewGroupAddCreateCommand()
	case GroupTypeAddGroup:
		return NewAddGroupCreateCommand()
	default:
	}
	return nil
}

func (g *GroupType) NewReadGroupsCommand() *command.Command {
	return NewReadGroupsCommand()
}

func (g *GroupType) UnmarshalValue(value string) error {
	switch value {
	case string(GroupTypeGroupAdd), string(GroupTypeAddGroup):
		*g = GroupType(value)
	return nil
	default:
		return errors.New("invalid GroupType value")
	}
}

func (g *GroupType) UnmarshalJSON(data []byte) error {
	var s string
	if unmarshalGroupTypeErr := json.Unmarshal(data, &s); unmarshalGroupTypeErr != nil {
		return unmarshalGroupTypeErr
	}
	return g.UnmarshalValue(s)
}

func (g *GroupType) UnmarshalYAML(value *yaml.Node) error {
	var s string
	if err := value.Decode(&s); err != nil {
		return err
	}
	return g.UnmarshalValue(s)
}

func NewGroupAddCreateCommand() *command.Command {
	c := command.NewCommand()
	c.Path = "groupadd"
	c.Args = []command.CommandArg{
		command.CommandArg("{{ if .GID }}-g {{ .GID }}{{ end }}"),
		command.CommandArg("{{ .Name }}"),
	}
	c.Extractor = func(out []byte, target any) error {
		return nil
/*
		for _,line := range strings.Split(string(out), "\n") {
			if line == "iptables: Chain already exists." {
				return nil
			}
		}
		return fmt.Errorf(string(out))
*/
	}
	return c
}

func NewAddGroupCreateCommand() *command.Command {
	c := command.NewCommand()
	c.Path = "addgroup"
	c.Args = []command.CommandArg{
		command.CommandArg("{{ if .GID }}-g {{ .GID }}{{ end }}"),
		command.CommandArg("{{ .Name }}"),
	}
	c.Extractor = func(out []byte, target any) error {
		return nil
/*
		for _,line := range strings.Split(string(out), "\n") {
			if line == "iptables: Chain already exists." {
				return nil
			}
		}
		return fmt.Errorf(string(out))
*/
	}
	return c
}

func NewGroupReadCommand() *command.Command {
	c := command.NewCommand()
	c.Extractor = func(out []byte, target any) error {
		g := target.(*Group)
		g.State = "absent"
		var readGroup *user.Group
		var e error
		if g.Name != "" {
			readGroup, e = user.LookupGroup(g.Name)
		} else {
			if g.GID != "" {
				readGroup, e = user.LookupGroupId(g.GID)
			}
		}

		if e == nil {
			g.Name = readGroup.Name
			g.GID = readGroup.Gid
			if g.GID != "" {
				g.State = "present"
			}
		}
		return e
	}
	return c
}

func NewGroupUpdateCommand() *command.Command {
	return nil
}

func NewGroupDelDeleteCommand() *command.Command {
	c := command.NewCommand()
	c.Path = "groupdel"
	c.Args = []command.CommandArg{
		command.CommandArg("{{ .Name }}"),
	}
	c.Extractor = func(out []byte, target any) error {
		return nil
	}
	return c
}

func NewDelGroupDeleteCommand() *command.Command {
	c := command.NewCommand()
	c.Path = "delgroup"
	c.Args = []command.CommandArg{
		command.CommandArg("{{ .Name }}"),
	}
	c.Extractor = func(out []byte, target any) error {
		return nil
	}
	return c
}


func NewReadGroupsCommand() *command.Command {
	c := command.NewCommand()
	c.Path = "getent"
	c.Args = []command.CommandArg{
		command.CommandArg("passwd"),
	}

	c.Extractor = func(out []byte, target any) error {
		Groups := target.(*[]*Group)
		lines := strings.Split(strings.TrimSpace(string(out)), "\n")
		lineIndex := 0
		for _, line := range lines {
			groupRecord := strings.Split(strings.TrimSpace(line), ":")
			if len(*Groups) <= lineIndex + 1 {
				*Groups = append(*Groups, NewGroup())
			}
			g := (*Groups)[lineIndex]
			g.Name = groupRecord[0]
			g.GID = groupRecord[2]
			g.State = "present"
			g.GroupType = SystemGroupType
			lineIndex++
		}
		return nil
	}
	return c
}