package main

import (
	"bytes"
	"unsafe"
)

var fileHandles []*File

func allocFileHandle(f *File) int32 {
	for i, h := range fileHandles {
		if h == nil {
			fileHandles[i] = f
			return int32(i)
		}
	}
	fileHandles = append(fileHandles, f)
	return int32(len(fileHandles) - 1)
}

func getFile(h int32) *File {
	if h < 0 || int(h) >= len(fileHandles) {
		return nil
	}
	return fileHandles[h]
}

func copyOut(dst unsafe.Pointer, cap int32, src string) int32 {
	n := int32(len(src))
	if n > cap {
		n = cap
	}
	if n > 0 {
		buf := unsafe.Slice((*byte)(dst), n)
		copy(buf, src[:n])
	}
	return n
}

//export moxie_parse_file
func moxie_parse_file(pathPtr unsafe.Pointer, pathLen int32) int32 {
	path := string(unsafe.Slice((*byte)(pathPtr), pathLen))
	f, err := ParseFile(path, nil, nil, 0)
	if err != nil || f == nil {
		return -1
	}
	return allocFileHandle(f)
}

//export moxie_parse_bytes
func moxie_parse_bytes(srcPtr unsafe.Pointer, srcLen int32, namePtr unsafe.Pointer, nameLen int32) int32 {
	src := unsafe.Slice((*byte)(srcPtr), srcLen)
	name := string(unsafe.Slice((*byte)(namePtr), nameLen))
	r := bytes.NewReader(src)
	f, err := Parse(NewFileBase(name), r, nil, nil, 0)
	if err != nil || f == nil {
		return -1
	}
	return allocFileHandle(f)
}

//export moxie_file_pkg_name
func moxie_file_pkg_name(h int32, out unsafe.Pointer, cap int32) int32 {
	f := getFile(h)
	if f == nil || f.PkgName == nil {
		return 0
	}
	return copyOut(out, cap, f.PkgName.Value)
}

//export moxie_file_decl_count
func moxie_file_decl_count(h int32) int32 {
	f := getFile(h)
	if f == nil {
		return 0
	}
	return int32(len(f.DeclList))
}

//export moxie_file_decl_kind
func moxie_file_decl_kind(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	switch f.DeclList[idx].(type) {
	case *ImportDecl:
		return 1
	case *ConstDecl:
		return 2
	case *TypeDecl:
		return 3
	case *VarDecl:
		return 4
	case *FuncDecl:
		return 5
	}
	return 0
}

//export moxie_file_import_path
func moxie_file_import_path(h int32, idx int32, out unsafe.Pointer, cap int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*ImportDecl)
	if !ok || d.Path == nil {
		return 0
	}
	return copyOut(out, cap, d.Path.Value)
}

//export moxie_file_func_name
func moxie_file_func_name(h int32, idx int32, out unsafe.Pointer, cap int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*FuncDecl)
	if !ok || d.Name == nil {
		return 0
	}
	return copyOut(out, cap, d.Name.Value)
}

//export moxie_file_func_has_body
func moxie_file_func_has_body(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*FuncDecl)
	if !ok {
		return 0
	}
	if d.Body != nil {
		return 1
	}
	return 0
}

//export moxie_file_func_param_count
func moxie_file_func_param_count(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*FuncDecl)
	if !ok || d.Type == nil {
		return 0
	}
	return int32(len(d.Type.ParamList))
}

//export moxie_file_func_result_count
func moxie_file_func_result_count(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*FuncDecl)
	if !ok || d.Type == nil {
		return 0
	}
	return int32(len(d.Type.ResultList))
}

//export moxie_file_func_body_stmt_count
func moxie_file_func_body_stmt_count(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*FuncDecl)
	if !ok || d.Body == nil {
		return 0
	}
	return int32(len(d.Body.List))
}

//export moxie_file_func_has_recv
func moxie_file_func_has_recv(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*FuncDecl)
	if !ok {
		return 0
	}
	if d.Recv != nil {
		return 1
	}
	return 0
}

//export moxie_file_type_name
func moxie_file_type_name(h int32, idx int32, out unsafe.Pointer, cap int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*TypeDecl)
	if !ok || d.Name == nil {
		return 0
	}
	return copyOut(out, cap, d.Name.Value)
}

//export moxie_file_type_is_alias
func moxie_file_type_is_alias(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*TypeDecl)
	if !ok {
		return 0
	}
	if d.Alias {
		return 1
	}
	return 0
}

//export moxie_file_var_name_count
func moxie_file_var_name_count(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*VarDecl)
	if !ok {
		return 0
	}
	return int32(len(d.NameList))
}

//export moxie_file_const_name_count
func moxie_file_const_name_count(h int32, idx int32) int32 {
	f := getFile(h)
	if f == nil || idx < 0 || int(idx) >= len(f.DeclList) {
		return 0
	}
	d, ok := f.DeclList[idx].(*ConstDecl)
	if !ok {
		return 0
	}
	return int32(len(d.NameList))
}

//export moxie_file_go_version
func moxie_file_go_version(h int32, out unsafe.Pointer, cap int32) int32 {
	f := getFile(h)
	if f == nil {
		return 0
	}
	return copyOut(out, cap, f.GoVersion)
}

//export moxie_file_free
func moxie_file_free(h int32) {
	if h >= 0 && int(h) < len(fileHandles) {
		fileHandles[h] = nil
	}
}

func main() {}