package jdr

import(
    "html/template"

    "log"
    "errors"
    "strings"
    "strconv"
    "regexp"
)

var regexp_d = regexp.MustCompile(`^[1-9][0-9]*d([468]|1[02]|20|100)$`)

type VariableType interface {
    Name() string
    Validate(value string) bool
    ToHTML(value string) (template.HTML, error)
    DefaultValue() string
}

type VariableType_badType struct {}

func (*VariableType_badType) Name() string {
    return "unknown type"
}

func (*VariableType_badType) Validate(s string) bool {
    return false
}

func (*VariableType_badType) ToHTML(value string) (template.HTML, error) {
    return template.HTML(""), errors.New("unknown type")
}

func (*VariableType_badType) DefaultValue() string {
    return ""
}

type VariableType_bool struct {}

func (*VariableType_bool) Name() string {
    return "bool"
}

func (*VariableType_bool) ToBool(value string) (bool, error) {
    switch strings.ToLower(value) {
    case "true":
        return true, nil
    case "false":
        return false, nil
    default:
        return false, errors.New("unknown bool value")
    }
}

func (self *VariableType_bool) Validate(value string) bool {
    _, err := self.ToBool(value)
    return err == nil
}

func (self *VariableType_bool) ToHTML(value string) (template.HTML, error) {
    val, err := self.ToBool(value)
    if err != nil {
        return template.HTML(""), err
    }

    ret := `<input type="checkbox"`
    if(val) {
        ret += ` checked`
    }
    ret += `/>`

    return template.HTML(ret), nil
}

func (self *VariableType_bool) DefaultValue() string {
    return "false"
}

type VariableType_int struct {}

func (*VariableType_int) Name() string {
    return "int"
}

func (self *VariableType_int) ToInt(value string) (int64, error) {
    return strconv.ParseInt(value, 10, 64)
}

func (self *VariableType_int) Validate(value string) bool {
    _, err := self.ToInt(value)
    return err == nil
}

func (self *VariableType_int) ToHTML(value string) (template.HTML, error) {
    val, err := self.ToInt(value)
    if err != nil {
        return template.HTML(""), err
    }

    ret := `<input type="number" step="1" value="` + strconv.FormatInt(val, 10) + `"/>`
    return template.HTML(ret), nil
}

func (self *VariableType_int) DefaultValue() string {
    return "0"
}

type VariableType_float struct {}

func (*VariableType_float) Name() string {
    return "float"
}

func (*VariableType_float) ToFloat(value string) (float64, error) {
    return strconv.ParseFloat(value, 64)
}

func (self *VariableType_float) Validate(value string) bool {
    _, err := self.ToFloat(value)
    return err == nil
}

func (self *VariableType_float) ToHTML(value string) (template.HTML, error) {
    val, err := self.ToFloat(value)
    if err != nil {
        return template.HTML(""), err
    }

    ret := `<input type="number" value="` + strconv.FormatFloat(val, 'g', -1, 64) + `"/>`

    return template.HTML(ret), nil
}

func (self *VariableType_float) DefaultValue() string {
    return "0.0"
}

type VariableType_string struct {}

func (*VariableType_string) Name() string {
    return "string"
}

func (*VariableType_string) Validate(s string) bool {
    return true
}

func (self *VariableType_string) ToHTML(value string) (template.HTML, error) {
    ret := `<input type="text" value="` + template.HTMLEscapeString(value) + `"/>`
    return template.HTML(ret), nil
}

func (self *VariableType_string) DefaultValue() string {
    return ""
}

type VariableType_d struct {}

func (*VariableType_d) Name() string {
    return "d"
}

func (*VariableType_d) Validate(s string) bool {
    return regexp_d.MatchString(s)
}

func (self *VariableType_d) ToHTML(value string) (template.HTML, error) {
    //FIXME: non-generic version
    ret := `<input type="text" value="` + template.HTMLEscapeString(value) +`"/>`

    return template.HTML(ret), nil
}

func (self *VariableType_d) DefaultValue() string {
    //FIXME: non-generic version
    return ""
}

func makeVariableType(s string) VariableType {
    switch(strings.ToLower(s)) {
    case "bool":
        return &VariableType_bool{}
    case "int":
        return &VariableType_int{}
    case "float":
        return &VariableType_float{}
    case "string":
        return &VariableType_string{}
    case "d":
        return &VariableType_d{}
    default:
        log.Println("Unknown type:", s)
        return &VariableType_badType{}
    }
}

type CustomEnum struct {
    name        string
    BaseType    VariableType
    Values      []string
}

func (self *CustomEnum) Name() string {
    return self.name
}

func (self *CustomEnum) ToId(value string) (int, error) {
    if !self.BaseType.Validate(value) {
        return 0, errors.New("Invalid value")
    }

    for i := 0; i < len(self.Values); i++ {
        if self.Values[i] == value {
            return i, nil
        }
    }

    return 0, errors.New("No such element")
}

func (self *CustomEnum) Validate(value string) bool {
    _, err := self.ToId(value)
    return err == nil
}

func (self *CustomEnum) ToHTML(value string) (template.HTML, error) {
    selectItem := value != ""

    value_id := 0
    if selectItem {
        var err error
        value_id, err = self.ToId(value)
        if err != nil {
            return template.HTML(""), err
        }
    }

    ret := `<select>`
    for i, v := range(self.Values) {
        ret += `<option`
        if selectItem && i == value_id {
            ret += ` selected`
        }
        ret += `>`
        ret += template.HTMLEscapeString(v)
        ret += `</option>`
    }
    ret += `</select>`

    return template.HTML(ret), nil
}

func (self *CustomEnum) DefaultValue() string {
    return ""
}

type CustomStruct struct {
    name        string
    Variables   []Variable
}

func (self *CustomStruct) Name() string {
    return self.name
}

func (self *CustomStruct) Validate(s string) bool {
    //FIXME
    log.Println("Custom struct Validate is not (yet) implemented")
    return false
}

func (self *CustomStruct) ToHTML(value string) (template.HTML, error) {
    //FIXME: implement
    return template.HTML(""), nil
}

func (self *CustomStruct) DefaultValue() string {
    //FIXME: non-generic version
    return ""
}

func parseCustomEnum(root xmlNode) (*CustomEnum, error) {
    customEnum := CustomEnum {}

    nameOk := false;
    typeOk := false;
    for i := 0; i < len(root.Attrs); i++ {
        attrName := root.Attrs[i].Name.Local
        attrVal  := root.Attrs[i].Value

        switch attrName {
        case "name":
            nameOk = true
            customEnum.name = attrVal
        case "base-type":
            typeOk = true
            customEnum.BaseType = makeVariableType(attrVal)
            switch customEnum.BaseType.(type) {
            case *VariableType_badType:
                typeOk = false
            }
        }
    }

    if !nameOk {
        return nil, errors.New("Unnamed custom enum")
    }
    if !typeOk {
        return nil, errors.New("Bad base type for " + customEnum.Name())
    }

    for i := 0; i < len(root.Nodes); i++ {
        node := root.Nodes[i]

        switch node.XMLName.Local {
        case "value":
            value := string(node.Content)
            if customEnum.BaseType.Validate(value) {
                customEnum.Values = append(customEnum.Values, value)
            } else {
                log.Println("Cannot validate value enum \"" + value + "\" with type \"" +
                            customEnum.BaseType.Name() + "\". Discarded")
            }
        }
    }

    return &customEnum, nil
}

func parseCustomStruct(root xmlNode) (*CustomStruct, error) {
    customType := CustomStruct{}

    nameOk := false
    for i := 0; i < len(root.Attrs); i++ {
        attrName := root.Attrs[i].Name.Local
        attrVal  := root.Attrs[i].Value

        switch attrName {
        case "name":
            nameOk = true
            customType.name = attrVal
        }
    }
    if !nameOk {
        return nil, errors.New("Unnamed custom type")
    }

    return &customType, nil
}

func parseCustomTypes(root xmlNode) ([]VariableType, error) {
    types := []VariableType{}

    for i := 0; i < len(root.Nodes); i++ {
        node := root.Nodes[i]

        switch node.XMLName.Local {
        case "enum":
            customEnum, err := parseCustomEnum(node)
            if err != nil {
                return []VariableType{}, err
            }
            types = append(types, customEnum)
        case "type":
            customType, err := parseCustomStruct(node)
            if err != nil {
                return []VariableType{}, err
            }
            types = append(types, customType)
        default:
            return []VariableType{}, errors.New("Unknown CustomType: " + root.Nodes[i].XMLName.Local)
        }
    }

    return types, nil
}