package main

import (
	"runtime"
	"unsafe"
)

var loaderHandles []*LoaderProgram

func allocLoaderHandle(p *LoaderProgram) int32 {
	for i, h := range loaderHandles {
		if h == nil {
			loaderHandles[i] = p
			return int32(i)
		}
	}
	loaderHandles = append(loaderHandles, p)
	return int32(len(loaderHandles) - 1)
}

func getLoader(h int32) *LoaderProgram {
	if h < 0 || int(h) >= len(loaderHandles) {
		return nil
	}
	return loaderHandles[h]
}

func loaderCopyOut(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_loader_load
func moxie_loader_load(rootDirPtr unsafe.Pointer, rootDirLen int32, inputPkgPtr unsafe.Pointer, inputPkgLen int32, gorootPtr unsafe.Pointer, gorootLen int32) int32 {
	runtime.InitCShared()
	rootDir := string(unsafe.Slice((*byte)(rootDirPtr), rootDirLen))
	inputPkg := string(unsafe.Slice((*byte)(inputPkgPtr), inputPkgLen))
	goroot := string(unsafe.Slice((*byte)(gorootPtr), gorootLen))

	prog, err := LoadPackages(rootDir, inputPkg, goroot)
	if err != nil || prog == nil {
		return -1
	}
	return allocLoaderHandle(prog)
}

//export moxie_loader_pkg_count
func moxie_loader_pkg_count(h int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil {
		return 0
	}
	return int32(len(p.Packages))
}

//export moxie_loader_mod_path
func moxie_loader_mod_path(h int32, out unsafe.Pointer, cap int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil {
		return 0
	}
	return loaderCopyOut(out, cap, p.ModPath)
}

//export moxie_loader_pkg_path
func moxie_loader_pkg_path(h int32, idx int32, out unsafe.Pointer, cap int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil || idx < 0 || int(idx) >= len(p.Packages) {
		return 0
	}
	return loaderCopyOut(out, cap, p.Packages[idx].ImportPath)
}

//export moxie_loader_pkg_dir
func moxie_loader_pkg_dir(h int32, idx int32, out unsafe.Pointer, cap int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil || idx < 0 || int(idx) >= len(p.Packages) {
		return 0
	}
	return loaderCopyOut(out, cap, p.Packages[idx].Dir)
}

//export moxie_loader_pkg_name
func moxie_loader_pkg_name(h int32, idx int32, out unsafe.Pointer, cap int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil || idx < 0 || int(idx) >= len(p.Packages) {
		return 0
	}
	return loaderCopyOut(out, cap, p.Packages[idx].PkgName)
}

//export moxie_loader_pkg_file_count
func moxie_loader_pkg_file_count(h int32, idx int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil || idx < 0 || int(idx) >= len(p.Packages) {
		return 0
	}
	return int32(len(p.Packages[idx].Files))
}

//export moxie_loader_pkg_import_count
func moxie_loader_pkg_import_count(h int32, idx int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil || idx < 0 || int(idx) >= len(p.Packages) {
		return 0
	}
	return int32(len(p.Packages[idx].Imports))
}

//export moxie_loader_pkg_import
func moxie_loader_pkg_import(h int32, idx int32, impIdx int32, out unsafe.Pointer, cap int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil || idx < 0 || int(idx) >= len(p.Packages) {
		return 0
	}
	pkg := p.Packages[idx]
	if impIdx < 0 || int(impIdx) >= len(pkg.Imports) {
		return 0
	}
	return loaderCopyOut(out, cap, pkg.Imports[impIdx])
}

//export moxie_loader_pkg_is_mxh
func moxie_loader_pkg_is_mxh(h int32, idx int32) int32 {
	runtime.InitCShared()
	p := getLoader(h)
	if p == nil || idx < 0 || int(idx) >= len(p.Packages) {
		return 0
	}
	if p.Packages[idx].IsMXH {
		return 1
	}
	return 0
}

//export moxie_loader_free
func moxie_loader_free(h int32) {
	runtime.InitCShared()
	if h >= 0 && int(h) < len(loaderHandles) {
		loaderHandles[h] = nil
	}
}

func main() {}