package schema

import (
	"fmt"
	"sort"
	"strconv"
	"strings"

	"github.com/deiu/rdf2go"
	"github.com/pkg/errors"
)

type RDFParser interface {
	Validate(document string) (bool, error)
}

type TurtleRDFParser struct {
}

type Field struct {
	Name       string
	Type       string
	Size       uint32
	Comment    string
	Annotation string
	RdfType    string
	Order      int
	ClassUrl   rdf2go.Term
}

const RdfNS = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
const RdfsNS = "http://www.w3.org/2000/01/rdf-schema#"
const SchemaRepositoryNS = "https://types.quilibrium.com/schema-repository/"
const QCLNS = "https://types.quilibrium.com/qcl/"
const Prefix = "<%s>"
const TupleString = "%s%s"
const NTupleString = "<%s%s>"

var rdfTypeN = fmt.Sprintf(NTupleString, RdfNS, "type")
var rdfsClassN = fmt.Sprintf(NTupleString, RdfsNS, "Class")
var rdfsPropertyN = fmt.Sprintf(NTupleString, RdfsNS, "Property")
var rdfsDomainN = fmt.Sprintf(NTupleString, RdfsNS, "domain")
var rdfsRangeN = fmt.Sprintf(NTupleString, RdfsNS, "range")
var rdfsCommentN = fmt.Sprintf(NTupleString, RdfsNS, "comment")

var rdfType = fmt.Sprintf(TupleString, RdfNS, "type")
var rdfsClass = fmt.Sprintf(TupleString, RdfsNS, "Class")
var rdfsProperty = fmt.Sprintf(TupleString, RdfsNS, "Property")
var rdfsDomain = fmt.Sprintf(TupleString, RdfsNS, "domain")
var rdfsRange = fmt.Sprintf(TupleString, RdfsNS, "range")
var qclSize = fmt.Sprintf(TupleString, QCLNS, "size")
var qclOrder = fmt.Sprintf(TupleString, QCLNS, "order")
var rdfsComment = fmt.Sprintf(TupleString, RdfsNS, "comment")

var qclRdfTypeMap = map[string]string{
	"Uint":      "uint%d",
	"Int":       "int%d",
	"ByteArray": "[%d]byte",
	"Bool":      "bool",
	"Float":     "float%d",
	"String":    "string",
	"Struct":    "struct",
}

func (t *TurtleRDFParser) Validate(document string) (bool, error) {
	g := rdf2go.NewGraph("https://types.quilibrium.com/schema-repository/")
	reader := strings.NewReader(document)
	err := g.Parse(reader, "text/turtle")
	if err != nil {
		return false, errors.Wrap(err, "validate")
	}

	return true, nil
}

func (t *TurtleRDFParser) GenerateQCL(document string) (string, error) {
	g := rdf2go.NewGraph("https://types.quilibrium.com/schema-repository/")
	reader := strings.NewReader(document)
	err := g.Parse(reader, "text/turtle")
	if err != nil {
		return "", errors.Wrap(err, "validate")
	}

	prefixMap := make(map[string]string)

	for _, line := range strings.Split(document, "\n") {
		parts := strings.Split(line, " ")
		switch parts[0] {
		case "PREFIX":
			if len(parts) != 3 {
				return "", errors.Wrap(err, "invalid PREFIX line")
			}

			prefixMap[strings.Trim(parts[2], "<>")] = parts[1]
		}
	}

	iter := g.IterTriples()
	classes := []string{}
	classTerms := []rdf2go.Term{}
	classUrls := []string{}
	fields := make(map[string]map[string]*Field)
	for a := range iter {
		if a.Predicate.String() == rdfTypeN &&
			a.Object.String() == rdfsClassN {
			subj := a.Subject.RawValue()
			parts := strings.Split(subj, "#")
			className := parts[len(parts)-1]
			parts = strings.Split(className, "/")
			className = parts[len(parts)-1]
			classUrl := subj[:len(subj)-len(className)]
			classes = append(classes, className)
			classUrls = append(classUrls, classUrl)
			classTerms = append(classTerms, a.Subject)
		}
	}

	for i, c := range classTerms {
		for _, prop := range g.All(nil, rdf2go.NewResource(rdfsRange), c) {
			subj := prop.Subject.RawValue()
			parts := strings.Split(subj, "#")
			className := parts[len(parts)-1]
			parts = strings.Split(className, "/")
			className = parts[len(parts)-1]
			classUrl := subj[:len(subj)-len(className)]
			if _, ok := fields[classes[i]]; !ok {
				fields[classes[i]] = make(map[string]*Field)
			}

			fields[classes[i]][className] = &Field{
				Name:       className,
				ClassUrl:   prop.Subject,
				Annotation: prefixMap[classUrl] + className,
				Order:      -1,
			}
		}
	}

	for _, class := range fields {
		for fieldName, field := range class {
			// scan the types
			for _, prop := range g.All(field.ClassUrl, rdf2go.NewResource(
				rdfsDomain,
			), nil) {
				obj := prop.Object.RawValue()
				parts := strings.Split(obj, "#")
				className := parts[len(parts)-1]
				parts = strings.Split(className, "/")
				className = parts[len(parts)-1]
				classUrl := obj[:len(obj)-len(className)]
				switch classUrl {
				case QCLNS:
					field.Type = qclRdfTypeMap[className]
					for _, sprop := range g.All(field.ClassUrl, rdf2go.NewResource(
						qclSize,
					), nil) {
						sobj := sprop.Object.RawValue()
						parts := strings.Split(sobj, "#")
						size := parts[len(parts)-1]
						parts = strings.Split(size, "/")
						size = parts[len(parts)-1]
						s, err := strconv.Atoi(size)
						fieldSize := s
						if className != "String" && className != "ByteArray" && className != "Struct" {
							fieldSize *= 8
						}
						if err != nil || s < 1 {
							return "", errors.Wrap(
								fmt.Errorf(
									"invalid size for %s: %s",
									fieldName,
									size,
								),
								"generate qcl",
							)
						}
						if strings.Contains(field.Type, "%") {
							field.Type = fmt.Sprintf(field.Type, fieldSize)
						}
						field.RdfType = className
						field.Size = uint32(s)
					}
					if strings.Contains(field.Type, "%d") {
						return "", errors.Wrap(
							fmt.Errorf(
								"size unspecified for %s, add a qcl:size predicate",
								fieldName,
							),
							"generate qcl",
						)
					}
				case RdfsNS:
					if className != "Literal" {
						return "", errors.Wrap(
							fmt.Errorf(
								"invalid property type for %s: %s",
								fieldName,
								className,
							),
							"generate qcl",
						)
					}
					field.Type = className
				default:
					field.Type = "hypergraph.Extrinsic"
					field.Annotation += ",extrinsic=" + prefixMap[classUrl] + className
					field.Size = 32
					field.RdfType = "Struct"
				}
				break
			}

			for _, sprop := range g.All(field.ClassUrl, rdf2go.NewResource(
				qclOrder,
			), nil) {
				sobj := sprop.Object.RawValue()
				parts := strings.Split(sobj, "#")
				order := parts[len(parts)-1]
				parts = strings.Split(order, "/")
				order = parts[len(parts)-1]
				o, err := strconv.Atoi(order)
				fieldOrder := o
				if err != nil || o < 0 {
					return "", errors.Wrap(
						fmt.Errorf(
							"invalid order for %s: %s",
							fieldName,
							order,
						),
						"generate qcl",
					)
				}
				field.Order = fieldOrder
			}
			if field.Order < 0 {
				return "", errors.Wrap(
					fmt.Errorf(
						"field order unspecified for %s, add a qcl:order predicate",
						fieldName,
					),
					"generate qcl",
				)
			}

			for _, prop := range g.All(field.ClassUrl, rdf2go.NewResource(
				rdfsComment,
			), nil) {
				field.Comment = prop.Object.String()
			}
		}
	}

	output := "package main\n\n"

	sort.Slice(classes, func(i, j int) bool {
		return strings.Compare(classes[i], classes[j]) < 0
	})

	for _, class := range classes {
		output += fmt.Sprintf("type %s struct {\n", class)

		sortedFields := []*Field{}
		for _, field := range fields[class] {
			sortedFields = append(sortedFields, field)
		}
		sort.Slice(sortedFields, func(i, j int) bool {
			return sortedFields[i].Order < sortedFields[j].Order
		})
		for _, field := range sortedFields {
			if field.Comment != "" {
				output += fmt.Sprintf("  // %s\n", field.Comment)
			}
			output += fmt.Sprintf(
				"  %s %s `rdf:\"%s\"`\n",
				field.Name,
				field.Type,
				field.Annotation,
			)
		}
		output += "}\n\n"
	}

	for _, class := range classes {
		totalSize := uint32(0)
		for _, field := range fields[class] {
			totalSize += field.Size
		}
		output += fmt.Sprintf(
			"func Unmarshal%s(payload [%d]byte) %s {\n  result := %s{}\n",
			class,
			totalSize,
			class,
			class,
		)
		s := uint32(0)
		sortedFields := []*Field{}
		for _, field := range fields[class] {
			sortedFields = append(sortedFields, field)
		}
		sort.Slice(sortedFields, func(i, j int) bool {
			return sortedFields[i].Order < sortedFields[j].Order
		})
		for _, field := range sortedFields {
			sizedType := ""
			switch field.RdfType {
			case "Uint":
				sizedType = fmt.Sprintf(
					"binary.GetUint(payload[%d:%d])",
					s,
					s+field.Size,
				)
				s += field.Size
			case "Int":
				sizedType = fmt.Sprintf(
					"int%d(binary.GetUint(payload[%d:%d]))",
					field.Size,
					s,
					s+field.Size,
				)
				s += field.Size
			case "ByteArray":
				sizedType = fmt.Sprintf(
					"payload[%d:%d]",
					s,
					s+field.Size,
				)
				s += field.Size
			case "Bool":
				sizedType = "bool"
				s++
			case "Float":
				sizedType = fmt.Sprintf(
					"payload[%d:%d]",
					s,
					s+field.Size,
				)
				s += field.Size
			case "String":
				sizedType = fmt.Sprintf(
					"string(payload[%d:%d])",
					s,
					s+field.Size,
				)
				s += field.Size
			case "Struct":
				sizedType = fmt.Sprintf(
					"hypergraph.Extrinsic{}\n  result.%s.Ref = payload[%d:%d]",
					field.Name,
					s,
					s+field.Size,
				)
				s += field.Size
			}
			output += fmt.Sprintf(
				"  result.%s = %s\n",
				field.Name,
				sizedType,
			)
		}
		output += "  return result\n}\n\n"
	}

	for _, class := range classes {
		totalSize := uint32(0)
		for _, field := range fields[class] {
			totalSize += field.Size
		}
		output += fmt.Sprintf(
			"func Marshal%s(obj %s) [%d]byte {\n",
			class,
			class,
			totalSize,
		)
		s := uint32(0)
		sortedFields := []*Field{}
		for _, field := range fields[class] {
			sortedFields = append(sortedFields, field)
		}
		sort.Slice(sortedFields, func(i, j int) bool {
			return sortedFields[i].Order < sortedFields[j].Order
		})
		output += fmt.Sprintf("  buf := make([]byte, %d)\n", totalSize)

		for _, field := range sortedFields {
			sizedType := ""
			switch field.RdfType {
			case "Uint":
				sizedType = fmt.Sprintf(
					"binary.PutUint(buf, %d, obj.%s)",
					s,
					field.Name,
				)
				s += field.Size
			case "Int":
				sizedType = fmt.Sprintf(
					"binary.PutInt(buf, %d, obj.%s)",
					s,
					field.Name,
				)
				s += field.Size
			case "ByteArray":
				sizedType = fmt.Sprintf(
					"copy(buf[%d:%d], obj.%s)",
					s,
					s+field.Size,
					field.Name,
				)
				s += field.Size
			case "Bool":
				sizedType = fmt.Sprintf(
					"if obj.%s { buf[%d] = 0xff } else { buf[%d] = 0x00 }",
					field.Name,
					s,
					s,
				)
				s++
			case "Float":
				sizedType = fmt.Sprintf(
					"copy(buf[%d:%d], obj.%s)",
					s,
					s+field.Size,
					field.Name,
				)
				s += field.Size
			case "String":
				sizedType = fmt.Sprintf(
					"copy(buf[%d:%d], []byte(obj.%s))",
					s,
					s+field.Size,
					field.Name,
				)
				s += field.Size
			case "Struct":
				sizedType = fmt.Sprintf(
					"copy(buf[%d:%d], obj.%s.Ref)",
					s,
					s+field.Size,
					field.Name,
				)
				s += field.Size
			}
			output += fmt.Sprintf(
				"  %s\n",
				sizedType,
			)
		}
		output += "  return buf\n}\n\n"
	}

	return output, nil
}