package owl

import (
	"fmt"
	"github.com/cjslep/activity/tools/exp/rdf"
)

const (
	owlSpec                = "http://www.w3.org/2002/07/owl#"
	membersSpec            = "members"
	disjointWithSpec       = "disjointWith"
	unionOfSpec            = "unionOf"
	importsSpec            = "imports"
	ontologySpec           = "Ontology"
	classSpec              = "Class"
	objectPropertySpec     = "ObjectProperty"
	functionalPropertySpec = "FunctionalProperty"
)

type OWLOntology struct {
	alias string
}

func (o *OWLOntology) SpecURI() string {
	return owlSpec
}

func (o *OWLOntology) Load() ([]rdf.RDFNode, error) {
	return o.LoadAsAlias("")
}

func (o *OWLOntology) LoadAsAlias(s string) ([]rdf.RDFNode, error) {
	o.alias = s
	return []rdf.RDFNode{
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     membersSpec,
			Delegate: &members{},
		},
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     disjointWithSpec,
			Delegate: &disjointWith{},
		},
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     unionOfSpec,
			Delegate: &unionOf{},
		},
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     importsSpec,
			Delegate: &imports{},
		},
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     ontologySpec,
			Delegate: &ontology{},
		},
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     classSpec,
			Delegate: &class{},
		},
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     objectPropertySpec,
			Delegate: &objectProperty{},
		},
		&rdf.AliasedDelegate{
			Spec:     owlSpec,
			Alias:    s,
			Name:     functionalPropertySpec,
			Delegate: &functionalProperty{},
		},
	}, nil
}

func (o *OWLOntology) LoadElement(name string, payload map[string]interface{}) ([]rdf.RDFNode, error) {
	// First, detect if an idValue exists
	var idValue interface{}
	var ok bool
	idValue, ok = payload[rdf.IdSpec]
	if !ok {
		idValue, ok = payload[rdf.IdActivityStreamsSpec]
	}
	if !ok {
		return nil, nil
	}
	vStr, ok := idValue.(string)
	if !ok {
		return nil, nil
	}
	// Now that we have a string idValue, handle the import use case
	if !rdf.IsKeyApplicable(vStr, owlSpec, o.alias, importsSpec) {
		return nil, nil
	}
	node := &rdf.AliasedDelegate{
		Spec:  "",
		Alias: "",
		Name:  name,
		// Need to set Delegate, based on below logic
	}
	for k, v := range payload {
		if k == rdf.IdSpec || k == rdf.IdActivityStreamsSpec {
			continue
		}
		switch k {
		case rdf.ContainerSpec:
			container := &rdf.ContainerLD{}
			node.Delegate = container
			// Ugly, maybe move out to its own function when needed
			if cValStr, ok := v.(string); !ok {
				return nil, fmt.Errorf("unhandled owl import @container to non-string type: %T", v)
			} else {
				switch cValStr {
				case rdf.IndexSpec:
					container.ContainsNode = &rdf.IndexLD{}
				default:
					return nil, fmt.Errorf("unhandled owl import @container to string type %s", cValStr)
				}
			}
		default:
			return nil, fmt.Errorf("unhandled owl import use case: %s", k)
		}
	}
	return []rdf.RDFNode{node}, nil
}

var _ rdf.RDFNode = &members{}

type members struct{}

func (m *members) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	if !ctx.IsReset() {
		return true, fmt.Errorf("owl members entered without reset context")
	}
	return true, nil
}

func (m *members) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	// Finish adding the Current item to the resulting vocabulary
	if ctx.Current == nil {
		return true, fmt.Errorf("owl members exiting with nil Current")
	}
	switch v := ctx.Current.(type) {
	case *rdf.VocabularyType:
		if err := ctx.Result.Vocab.SetType(ctx.Name, v); err != nil {
			return true, err
		}
	case *rdf.VocabularyProperty:
		if err := ctx.Result.Vocab.SetProperty(ctx.Name, v); err != nil {
			return true, err
		}
	case *rdf.VocabularyValue:
		if err := ctx.Result.Vocab.SetValue(ctx.Name, v); err != nil {
			return true, err
		}
	default:
		return true, fmt.Errorf("owl members exiting with unhandled type: %T", ctx.Current)
	}
	ctx.Reset()
	return true, nil
}

func (m *members) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl members cannot be applied")
}

var _ rdf.RDFNode = &disjointWith{}

type disjointWith struct{}

func (d *disjointWith) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	// Push the Current type aside, to build a Reference.
	if ctx.Current == nil {
		return true, fmt.Errorf("owl disjointWith enter given a nil Current")
	} else if _, ok := ctx.Current.(*rdf.VocabularyType); !ok {
		return true, fmt.Errorf("owl disjointWith enter not given a *rdf.VocabularyType")
	}
	ctx.Push()
	ctx.Current = &rdf.VocabularyReference{}
	return true, nil
}

func (d *disjointWith) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	// Pop the Reference, put into the type.
	ref, ok := ctx.Current.(*rdf.VocabularyReference)
	if !ok {
		return true, fmt.Errorf("owl disjointWith exit not given a *rdf.VocabularyReference")
	}
	ctx.Pop()
	vType, ok := ctx.Current.(*rdf.VocabularyType)
	if !ok {
		return true, fmt.Errorf("owl disjointWith exit not given a *rdf.VocabularyType")
	}
	vType.DisjointWith = append(vType.DisjointWith, *ref)
	return true, nil
}

func (d *disjointWith) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl disjointWith cannot be applied")
}

var _ rdf.RDFNode = &unionOf{}

type unionOf struct{}

func (u *unionOf) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

func (u *unionOf) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

func (u *unionOf) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

var _ rdf.RDFNode = &imports{}

type imports struct{}

func (i *imports) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

func (i *imports) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

func (i *imports) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

var _ rdf.RDFNode = &ontology{}

type ontology struct{}

func (o *ontology) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

func (o *ontology) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return true, nil
}

func (o *ontology) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	// TODO
	return false, nil
}

var _ rdf.RDFNode = &class{}

type class struct{}

func (c *class) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl class cannot be entered")
}

func (c *class) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl class cannot be exited")
}

func (c *class) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	// Prepare a new VocabularyType in the context
	if !ctx.IsReset() {
		return true, fmt.Errorf("owl class applied with non-reset ParsingContext")
	}
	ctx.Current = &rdf.VocabularyType{}
	return true, nil
}

var _ rdf.RDFNode = &objectProperty{}

type objectProperty struct{}

func (o *objectProperty) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl objectProperty cannot be entered")
}

func (o *objectProperty) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl objectProperty cannot be exited")
}

func (o *objectProperty) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	// Prepare a new VocabularyProperty in the context
	if !ctx.IsReset() {
		return true, fmt.Errorf("owl objectProperty applied with non-reset ParsingContext")
	}
	ctx.Current = &rdf.VocabularyProperty{}
	return true, nil
}

var _ rdf.RDFNode = &functionalProperty{}

type functionalProperty struct{}

func (f *functionalProperty) Enter(key string, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl functionalProperty cannot be entered")
}

func (f *functionalProperty) Exit(key string, ctx *rdf.ParsingContext) (bool, error) {
	return true, fmt.Errorf("owl functionalProperty cannot be exited")
}

func (f *functionalProperty) Apply(key string, value interface{}, ctx *rdf.ParsingContext) (bool, error) {
	if ctx.Current == nil {
		return true, fmt.Errorf("owl functionalProperty given nil Current in context")
	}
	prop, ok := ctx.Current.(*rdf.VocabularyProperty)
	if !ok {
		return true, fmt.Errorf("owl functionalProperty given Current that is not *rdf.VocabularyProperty")
	}
	prop.Functional = true
	return true, nil
}