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

package folio

import (
_	"errors"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"gopkg.in/yaml.v3"
	"log/slog"
_	"gitea.rosskeen.house/rosskeen.house/machine"
	"gitea.rosskeen.house/pylon/luaruntime"
	"decl/internal/codec"
	"decl/internal/data"
	"decl/internal/schema"
	"errors"
)

var (
	ErrUnknownStateTransition error = errors.New("Unknown state transition")
)

type ConfigName string

type DeclarationType struct {
	Type TypeName `json:"type" yaml:"type"`
	Transition string `json:"transition,omitempty" yaml:"transition,omitempty"`
	Config ConfigName `json:"config,omitempty" yaml:"config,omitempty"`
	OnError OnError   `json:"onerror,omitempty" yaml:"onerror,omitempty"`
	Error   string    `json:"error,omitempty" yaml:"error,omitempty"`
	Requires Dependencies `json:"requires,omitempty" yaml:"requires,omitempty"`
	On *Events `json:"on,omitempty" yaml:"on,omitempty"`
}

type Declaration struct {
	Type TypeName `json:"type" yaml:"type"`
	Transition string `json:"transition,omitempty" yaml:"transition,omitempty"`
	Attributes data.Resource `json:"attributes" yaml:"attributes"`
	Config ConfigName `json:"config,omitempty" yaml:"config,omitempty"`
	OnError OnError   `json:"onerror,omitempty" yaml:"onerror,omitempty"`
	Error   string    `json:"error,omitempty" yaml:"error,omitempty"`
	Requires Dependencies `json:"requires,omitempty" yaml:"requires,omitempty"`
	On *Events `json:"on,omitempty" yaml:"on,omitempty"`
	runtime luaruntime.LuaRunner
	document *Document
	configBlock data.Block
	ResourceTypes data.TypesRegistry[data.Resource] `json:"-" yaml:"-"`
}

func NewDeclaration() *Declaration {
	return &Declaration{ ResourceTypes: DocumentRegistry.ResourceTypes, runtime: luaruntime.New() }
}

func NewDeclarationFromDocument(document *Document) *Declaration {
	return &Declaration{ document: document, ResourceTypes: document.Types() }
}

func (n *ConfigName) Exists() bool {
	return DocumentRegistry.ConfigNameMap.Has(string(*n))
}

func (n *ConfigName) GetBlock() *Block {
	if v, ok := DocumentRegistry.ConfigNameMap.Get(string(*n)); ok {
		return v
	}
	return nil
}

func (d *Declaration) SetDocument(newDocument *Document) {
	slog.Info("Declaration.SetDocument()", "declaration", d)
	d.document = newDocument
	d.SetConfig(d.document.config)
	d.ResourceTypes = d.document.Types()
	d.Attributes.SetResourceMapper(d.document.uris)
}

func (d *Declaration) ResolveId(ctx context.Context) string {
	defer func() {
		if r := recover(); r != nil {
			slog.Info("Declaration.ResolveId() - panic", "recover", r, "state", d.Attributes.StateMachine())
			if triggerErr := d.Attributes.StateMachine().Trigger("notexists"); triggerErr != nil {
				panic(triggerErr)
			}
		}
	}()
	slog.Info("Declaration.ResolveId()")
	id := d.Attributes.ResolveId(ctx)
	return id
}

func (d *Declaration) Clone() data.Declaration {
	return &Declaration {
		Type: d.Type,
		Transition: d.Transition,
		Attributes: d.Attributes.Clone(),
		//runtime: luaruntime.New(),
		Config: d.Config,
		Requires: d.Requires,
		On: d.On,
	}
}

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

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

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

func (d *Declaration) ResourceType() data.TypeName {
	return data.TypeName(d.Type)
}

func (d *Declaration) URI() string {
	return d.Attributes.URI()
}

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

func (d *Declaration) Validate() (err error) {
	var declarationJson []byte
	if declarationJson, err = d.JSON(); err == nil {
		s := schema.New(fmt.Sprintf("%s-declaration", d.Type), schemaFiles)
		err = s.Validate(string(declarationJson))
	}
	return err
}

func (d *Declaration) NewResourceFromParsedURI(u data.URIParser) (err error) {
	if u == nil {
		d.Attributes, err = d.ResourceTypes.NewFromType(string(d.Type))
	} else {
		parsed := u.URL()
		if d.Attributes, err = d.ResourceTypes.NewFromParsedURI(parsed); err == nil {
			err = d.Attributes.SetParsedURI(u)
		}
	}
	return
}

func (d *Declaration) NewResource(uri *string) (err error) {
	slog.Info("Declaration.NewResource()")
	if d.ResourceTypes == nil {
		panic(fmt.Errorf("Undefined type registry: unable to create new resource %s", *uri))
	}

	if uri == nil {
		d.Attributes, err = d.ResourceTypes.NewFromType(string(d.Type))
	} else {
		slog.Info("Declaration.NewResource()", "uri", *uri)
		parsedURI := URI(*uri).Parse()
		d.Attributes, err = d.ResourceTypes.NewFromParsedURI(parsedURI.URL())
	}
	return
}

func (d *Declaration) Resource() data.Resource {
	return d.Attributes
}

func (d *Declaration) Apply(stateTransition string) (result error) {
	defer func() {
		if r := recover(); r != nil {
			slog.Info("Declaration.Apply()", "error", r, "resourceerror", d.Error)
			if d.Error != "" {
				result = fmt.Errorf("%s - %s", r, d.Error)
			} else {
				result = fmt.Errorf("%s", r)
			}
		}
		if result != nil {
			d.Error = result.Error()
		}
	}()

	if stateTransition == "" {
		stateTransition = d.Transition
	}

	stater := d.Attributes.StateMachine()
	slog.Info("Declaration.Apply()", "stateTransition", stateTransition, "machine", stater, "machine.state", stater.CurrentState(), "uri", d.Attributes.URI())
	switch stateTransition {
	case "construct":
		if doc, ok := DocumentRegistry.DeclarationMap[d]; ok {
			d.SetDocument(doc)
		}
	case "stat":
		result = stater.Trigger("stat")
	case "read":
		result = stater.Trigger("read")
	case "delete", "absent":
		if stater.CurrentState() == "present" {
			result = stater.Trigger("delete")
		}
	case "update":
		if result = stater.Trigger("update"); result != nil {
			return result
		}
		result = stater.Trigger("read")
	default:
		return fmt.Errorf("%w: %s on %s", ErrUnknownStateTransition, stateTransition, d.Attributes.URI())
	case "create", "present":
		if stater.CurrentState() == "absent" || stater.CurrentState() == "unknown" {
			if result = stater.Trigger("create"); result != nil {
				slog.Info("Declaration.Apply()", "trigger", "create", "state", stater.CurrentState(), "error", result, "declaration", d)
				return result
			}
		}

		slog.Info("Declaration.Apply() - read", "state", stater.CurrentState(), "declaration", d)
		result = stater.Trigger("read")
		currentState := stater.CurrentState()
		switch currentState {
		case "create", "present":
		default:
			return fmt.Errorf("Failed to create resource: %s - state: %s, err: %s", d.URI(), currentState, d.Error)
		}
	}
	return result
}

func (d *Declaration) SetConfig(configDoc data.Document) {
	slog.Info("Declaration.SetConfig()", "config", configDoc)
	if configDoc != nil {
		if configDoc.Has(string(d.Config)) {
			if v, ok := configDoc.Get(string(d.Config)); ok {
				d.configBlock = v.(data.Block)
				d.Attributes.UseConfig(d.configBlock)
				return
			}
		}
	}

	if v, ok := DocumentRegistry.ConfigNameMap.Get(string(d.Config)); ok {
		d.configBlock = v
		d.Attributes.UseConfig(d.configBlock)
		return
	}
	if d.Config != "" { // XXX
		panic(fmt.Sprintf("failed setting config: %s", d.Config))
	}
}

func (d *Declaration) SetURI(uri string) (err error) {
	slog.Info("Declaration.SetURI()", "uri", uri, "declaration", d)
	if d.Attributes == nil {
		err = d.NewResource(&uri)
	} else {
		err = d.Attributes.SetParsedURI(URI(uri).Parse())
	}
	if err != nil {
		return err
	}
	if d.Attributes == nil {
		return fmt.Errorf("%w: %s", ErrUnknownResourceType, uri)
	}
	d.Type = TypeName(d.Attributes.Type())
	_, err = d.Attributes.Read(context.Background()) // fix context
	slog.Info("Declaration.SetURI() - read", "error", err)
	return
}

func (d *Declaration) SetParsedURI(uri data.URIParser) (err error) {
	slog.Info("Declaration.SetParsedURI()", "uri", uri, "declaration", d)
	if d.Attributes == nil {
		err = d.NewResourceFromParsedURI(uri)
	} else {
		err = d.Attributes.SetParsedURI(uri)
	}
	if err != nil {
		return err
	}
	if d.Attributes == nil {
		return fmt.Errorf("%w: %s", ErrUnknownResourceType, uri)
	}
	d.Type = TypeName(d.Attributes.Type())
	_, err = d.Attributes.Read(context.Background()) // fix context
	slog.Info("Declaration.SetURI() - read", "error", err)
	return
}

func (d *Declaration) UnmarshalValue(value *DeclarationType) error {
	slog.Info("Declaration.UnmarshalValue", "declaration", d, "value", value, "addr", d)
	if d.ResourceTypes == nil {
		panic(fmt.Errorf("Undefined type registry: unable to create new resource %s", value.Type))
	}
	d.Type = value.Type
	d.Transition = value.Transition
	d.Config = value.Config
	d.OnError = value.OnError
	d.Error = value.Error
	d.Requires = value.Requires
	d.On = value.On
	newResource, resourceErr := d.ResourceTypes.NewFromType(string(value.Type))

	slog.Info("Declaration.UnmarshalValue", "value", value, "error", resourceErr, "type", value.Type, "resource", newResource, "resourcetypes", d.ResourceTypes)
	if resourceErr != nil {
		slog.Info("Declaration.UnmarshalValue", "value", value, "error", resourceErr)
		return resourceErr
	}
	d.Attributes = newResource
	d.configBlock = d.Config.GetBlock()

	if d.On != nil {
		if handler, ok := (*d.On)[EventTypeLoad]; ok {
			stackSize := d.runtime.Api().GetTop()
			if e := d.runtime.LoadScriptFromString(string(handler)); e != nil {
				d.Error = e.Error()
			}
			returnsCount := d.runtime.Api().GetTop() - stackSize
			if ! d.runtime.Api().IsNil(-1) {
		 		if returnsCount == 0 {
					// return nil
				} else {
					if lr,le := d.runtime.CopyReturnValuesFromCall(int(returnsCount)); le == nil {
						slog.Info("Event.Load", "result", lr, "error", le)
					}
				}
			}
		}
	}

	return nil
}

func (d *Declaration) UnmarshalYAML(value *yaml.Node) (err error) {
	if d.ResourceTypes == nil {
		d.ResourceTypes = DocumentRegistry.ResourceTypes
	}
	t := &DeclarationType{}
	if unmarshalResourceTypeErr := value.Decode(t); unmarshalResourceTypeErr != nil {
		return unmarshalResourceTypeErr
	}

	if err := d.UnmarshalValue(t); err != nil {
		return err
	}

	resourceAttrs := struct {
		Attributes yaml.Node `json:"attributes"`
	}{}
	if unmarshalAttributesErr := value.Decode(&resourceAttrs); unmarshalAttributesErr != nil {
		return unmarshalAttributesErr
	}
	if unmarshalResourceErr := resourceAttrs.Attributes.Decode(d.Attributes); unmarshalResourceErr != nil {
		return unmarshalResourceErr
	}

	if i, ok := d.Attributes.(data.ResourceInitializer); ok {
		err = i.Init(nil)
	} else {
		err = fmt.Errorf("failed to execute init")
	}

	return
}

func (d *Declaration) UnmarshalJSON(jsonData []byte) (err error) {
	if d.ResourceTypes == nil {
		d.ResourceTypes = DocumentRegistry.ResourceTypes
	}
	t := &DeclarationType{}
	if unmarshalResourceTypeErr := json.Unmarshal(jsonData, t); unmarshalResourceTypeErr != nil {
		return unmarshalResourceTypeErr
	}

	if err := d.UnmarshalValue(t); err != nil {
		return err
	}

	resourceAttrs := struct {
		Attributes data.Resource `json:"attributes"`
	}{Attributes: d.Attributes}
	if unmarshalAttributesErr := json.Unmarshal(jsonData, &resourceAttrs); unmarshalAttributesErr != nil {
		return unmarshalAttributesErr
	}

	if i, ok := d.Attributes.(data.ResourceInitializer); ok {
		err = i.Init(nil)
	} else {
		err = fmt.Errorf("failed to execute init")
	}

	return
}

/*
func (l *LuaWorker) Receive(m message.Envelope) {
  s := m.Sender()
  switch b := m.Body().(type) {
  case *message.Error:
  //  case *worker.Terminated:
  case *CodeExecute:
    stackSize := l.runtime.Api().GetTop()
    if e := l.runtime.LoadScriptFromString(b.Code); e != nil {
      s.Send(message.New(&message.Error{ E: e }, l))
    }
    returnsCount := l.runtime.Api().GetTop() - stackSize
    if len(b.Entrypoint) == 0 {
      if ! l.runtime.Api().IsNil(-1) {
        if returnsCount == 0 {
            s.Send(message.New(&CodeResult{ Result: []interface{}{ 0 } }, l))
        } else {
          lr,le := l.runtime.CopyReturnValuesFromCall(int(returnsCount))
          if le != nil {
            s.Send(message.New(&message.Error{ E: le }, l))
          } else {
            s.Send(message.New(&CodeResult{ Result: lr }, l))
          }
        }
      }
    } else {
      r,ce := l.runtime.CallFunction(b.Entrypoint, b.Args)
      if ce != nil {
        s.Send(message.New(&message.Error{ E: ce }, l))
      }
      s.Send(message.New(&CodeResult{ Result: r }, l))
    }
  }
}
*/