package autostruct

import (
	"fmt"
	"os"
)

// Generates structures given json
//
// Can also be used to generate structures via go code
type AutoStruct struct {
	StructName  string   // Name to prefix to all structures generated
	PackageName string   // Package to assign the new go file
	FileName    string   // The name to assign the new go file
	File        *os.File // Access to the new go file (writer)
}

//
func (a *AutoStruct) Init(fname, packname, structname string) error {
	a.StructName = structname
	a.FileName = fname
	a.PackageName = packname
	if !FileExists(a.FileName + ".go") {
		var err error
		a.File, err = os.Create(a.FileName + ".go")
		if err != nil {
			return err
		}
	} else {
		return fmt.Errorf("file already exists, update mode is not yet implemented")
	}
	return nil
}

// Places the package name defined in the init
func (a *AutoStruct) PlacePackageName() {
	a.File.Write([]byte("package " + a.PackageName + "\n"))
}

// In cases where you use a specific type from another module
//
// Don't forget to call EndImports() to close this, go will be cranky
func (a *AutoStruct) StartImports() {
	a.File.Write([]byte("import (\n"))
}

// Adds a unambiguous import
//
// Use AddAliasImport() for 'alias "import"'
func (a *AutoStruct) AddImport(importname string) {
	a.File.Write([]byte("\t\"" + importname + "\"\n"))
}

// Adds an aliased import
//
// Ex  door "red-gree.com/door"
//
// Use AddImport() for a unambiguous import
func (a *AutoStruct) AddAliasImport(importalias, importname string) {
	a.File.Write([]byte("\t" + importalias + " \"" + importname + "\"\n"))
}

// Closes the import statement
func (a *AutoStruct) EndImports() {
	a.File.Write([]byte(")\n"))
}

// Begins a structure
func (a *AutoStruct) StartStruct(structname string) {
	a.File.Write([]byte("type " + a.StructName + structname + " struct {\n"))
}

// Adds a field to the structure
//
// Ex   Name string
//
// Use AddCommentField() to add a comment with the field
//
// Use AddJsonField() to add a json tag with the field
//
// Use AddJsonCommentField() to add a json tag and a comment
func (a *AutoStruct) AddField(fieldname, fieldtype string) {
	a.File.Write([]byte("\t" + fieldname + " " + fieldtype + "\n"))
}

// Adds a field to the structure (includes a comment about the field)
//
// Ex    Name string // The BBS user name
//
// Use AddField() to add a field without a comment or json tag
//
// Use AddJsonCommentField() to add a field with a comment and a json tag
//
// Use AddJsonField() to add a field with a json tag but no comment
func (a *AutoStruct) AddCommentField(fieldname, fieldtype, comment string) {
	a.File.Write([]byte("\t" + fieldname + " " + fieldtype + " // " + comment + "\n"))
}

// Adds a field to the structure (includes a json tag)
//
// Ex     Name string `json:"name"`
//
// Use json tag "-" to mark fields to not be in json's marshal or unmarshal process
//
// Use AddField() to add a field without a comment or json tag
//
// Use AddCommentField() to add a field without a json tag but with a comment
//
// Use AddJsonCommentField() to add a field with a json tag and a comment
func (a *AutoStruct) AddJsonField(fieldname, fieldtype, jsonname string) {
	a.File.Write([]byte("\t" + fieldname + " " + fieldtype + " `json:\"" + jsonname + "\"`\n"))
}

// Adds a field to the structure (includes both a json tag and a comment)
//
// Ex     Name string `json:"name"` // The BBS user name
//
// Use json tag "-" to mark fields to not be in json's marshal or unmarshal process
//
// Use AddJsonField() to add a field with a json tag but no comment
//
// Use AddField() to add a field without a comment or json tag
//
// Use AddCommentField() to add a field with a comment but no json tag
func (a *AutoStruct) AddJsonCommentField(fieldname, fieldtype, jsonname, comment string) {
	a.File.Write([]byte("\t" + fieldname + " " + fieldtype + " `json:\"" + jsonname + "\"` // " + comment + "\n"))
}

// Ends/Closes the structure
func (a *AutoStruct) EndStruct() {
	a.File.Write([]byte("}\n"))
}

// Adds some space between things
func (a *AutoStruct) Newline() {
	a.File.Write([]byte("\n"))
}

// Adds a single line comment
func (a *AutoStruct) Comment(comment string) {
	a.File.Write([]byte("// " + comment + "\n"))
}

// Closes the newly formed go file
func (a *AutoStruct) Close() {
	a.File.Close()
}