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

// Service resource
package resource

import (
	"context"
	"fmt"
_	"log/slog"
	"net/url"
	"path/filepath"
	"io"
	"gopkg.in/yaml.v3"
	"gitea.rosskeen.house/rosskeen.house/machine"
	"decl/internal/codec"
	"encoding/json"
	"strings"
)

type ServiceManagerType string

const (
	ServiceManagerTypeSystemd ServiceManagerType = "systemd"
	ServiceManagerTypeSysV ServiceManagerType = "sysv"
)

type Service struct {
	stater	machine.Stater `yaml:"-" json:"-"`
	Name	string	`json:"name" yaml:"name"`
	ServiceManagerType ServiceManagerType `json:"servicemanager,omitempty" yaml:"servicemanager,omitempty"`

	CreateCommand *Command `yaml:"-" json:"-"`
	ReadCommand   *Command `yaml:"-" json:"-"`
	UpdateCommand *Command `yaml:"-" json:"-"`
	DeleteCommand *Command `yaml:"-" json:"-"`

	State string `yaml:"state,omitempty" json:"state,omitempty"`
	config ConfigurationValueGetter
	Resources ResourceMapper `yaml:"-" json:"-"`
}

func init() {
	ResourceTypes.Register([]string{"service"}, func(u *url.URL) Resource {
		s := NewService()
		s.Name = filepath.Join(u.Hostname(), u.Path)
		s.CreateCommand, s.ReadCommand, s.UpdateCommand, s.DeleteCommand = s.ServiceManagerType.NewCRUD()
		return s
	})
}

func NewService() *Service {
	return &Service{ ServiceManagerType: ServiceManagerTypeSystemd }
}

func (s *Service) StateMachine() machine.Stater {
	if s.stater == nil {
		s.stater = ProcessMachine(s)
	}
	return s.stater
}

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

func (s *Service) URI() string {
	return fmt.Sprintf("service://%s", s.Name)
}

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

func (s *Service) UseConfig(config ConfigurationValueGetter) {
	s.config = config
}

func (s *Service) JSON() ([]byte, error) {
	return json.Marshal(s)
}

func (s *Service) Validate() error {
	return nil
}

func (s *Service) SetResourceMapper(resources ResourceMapper) {
	s.Resources = resources
}

func (s *Service) Clone() Resource {
	news := &Service{
		Name: s.Name,
		ServiceManagerType: s.ServiceManagerType,
	}
	news.CreateCommand, news.ReadCommand, news.UpdateCommand, news.DeleteCommand = s.ServiceManagerType.NewCRUD()
	return news
}

func (s *Service) Apply() error {
	return nil
}

func (s *Service) Load(r io.Reader) error {
	return codec.NewYAMLDecoder(r).Decode(s)
}

func (s *Service) LoadDecl(yamlResourceDeclaration string) error {
	return codec.NewYAMLStringDecoder(yamlResourceDeclaration).Decode(s)
}

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

func (s *Service) UnmarshalYAML(value *yaml.Node) error {
	type decodeService Service
	if unmarshalErr := value.Decode((*decodeService)(s)); unmarshalErr != nil {
		return unmarshalErr
	}
	s.CreateCommand, s.ReadCommand, s.UpdateCommand, s.DeleteCommand = s.ServiceManagerType.NewCRUD()
	return nil
}

func (s *ServiceManagerType) NewCRUD() (create *Command, read *Command, update *Command, del *Command) {
	switch *s {
	case ServiceManagerTypeSystemd:
		return NewSystemdCreateCommand(), NewSystemdReadCommand(), NewSystemdUpdateCommand(), NewSystemdDeleteCommand()
	case ServiceManagerTypeSysV:
		return NewSysVCreateCommand(), NewSysVReadCommand(), NewSysVUpdateCommand(), NewSysVDeleteCommand()
	default:
	}
	return nil, nil, nil, nil
}


func (s *Service) Create(ctx context.Context) error {
	return nil
}

func (s *Service) Read(ctx context.Context) ([]byte, error) {
	
	return yaml.Marshal(s)
}

func (s *Service) Delete(ctx context.Context) error {
	return nil
}

func (s *Service) Type() string { return "service" }

func (s *Service) ResolveId(ctx context.Context) string {
	return ""
}

func NewSystemdCreateCommand() *Command {
	c := NewCommand()
	c.Path = "systemctl"
	c.Args = []CommandArg{
		CommandArg("enable"),
		CommandArg("{{ .Name }}"),
	}
	return c
}

func NewSystemdReadCommand() *Command {
	c := NewCommand()
	c.Path = "systemctl"
	c.Args = []CommandArg{
		CommandArg("show"),
		CommandArg("{{ .Name }}"),
	}
	c.Extractor = func(out []byte, target any) error {
		s := target.(*Service)
		serviceStatus := strings.Split(string(out), "\n")
		for _, statusLine := range(serviceStatus) {
			if len(statusLine) > 1 {
				statusKeyValue := strings.Split(statusLine, "=")
				key := statusKeyValue[0]
				value := strings.TrimSpace(strings.Join(statusKeyValue[1:], "="))
				switch key {
				case "Id":
				case "ActiveState":
					switch value {
					case "active":
						if stateCreatedErr := s.stater.Trigger("created"); stateCreatedErr != nil {
							return stateCreatedErr
						}
					case "inactive":
					}
				case "SubState":
					switch value {
					case "running":
						if stateRunningErr := s.stater.Trigger("running"); stateRunningErr != nil {
							return stateRunningErr
						}
					case "dead":
					}
				}
			}
		}
		return nil
	}
	return c
}

func NewSystemdUpdateCommand() *Command {
	return nil
}

func NewSystemdDeleteCommand() *Command {
	return nil
}

func NewSysVCreateCommand() *Command {
	return nil
}

func NewSysVReadCommand() *Command {
	return nil
}

func NewSysVUpdateCommand() *Command {
	return nil
}

func NewSysVDeleteCommand() *Command {
	return nil
}