// 测试 pack 的固定目标源码选择器；产品只运行签名 pack 提供的对应工具。
package main

import (
	"encoding/json"
	"fmt"
	"go/build"
	"io/fs"
	"os"
	"path/filepath"
	"sort"
	"strings"
)

func main() {
	if err := selectPackage(); err != nil { fmt.Fprintln(os.Stderr, err); os.Exit(1) }
}

func selectPackage() error {
	if len(os.Args) != 4 { return fmt.Errorf("expected OS architecture directory") }
	context := build.Default
	context.GOOS, context.GOARCH = os.Args[1], os.Args[2]
	context.GOROOT, context.GOPATH = "", ""
	context.CgoEnabled = true
	directory := os.Args[3]
	selected, err := context.ImportDir(directory, 0)
	if err != nil { return err }
	if len(selected.CgoFiles)+len(selected.CFiles)+len(selected.CXXFiles)+len(selected.SFiles)+len(selected.SysoFiles) != 0 {
		return fmt.Errorf("cgo/assembly/native objects are unsupported")
	}
	embed := map[string][]string{}
	for _, pattern := range selected.EmbedPatterns {
		glob := strings.TrimPrefix(pattern, "all:")
		if filepath.IsAbs(glob) || strings.Contains(glob, "..") { return fmt.Errorf("invalid embed pattern") }
		matches, err := filepath.Glob(filepath.Join(directory, glob))
		if err != nil || len(matches) == 0 { return fmt.Errorf("unmatched embed pattern") }
		for _, match := range matches {
			err = filepath.WalkDir(match, func(path string, entry fs.DirEntry, failure error) error {
				if failure != nil { return failure }
				if entry.Type()&os.ModeSymlink != 0 { return fmt.Errorf("embed link") }
				if entry.IsDir() { return nil }
				relative, err := filepath.Rel(directory, path)
				if err != nil { return err }
				embed[pattern] = append(embed[pattern], filepath.ToSlash(relative))
				return nil
			})
			if err != nil { return err }
		}
		sort.Strings(embed[pattern])
	}
	imports := selected.Imports
	if imports == nil { imports = []string{} }
	return json.NewEncoder(os.Stdout).Encode(map[string]any{"name":selected.Name,"files":selected.GoFiles,"imports":imports,"embed":embed})
}