// SPDX-License-Identifier: AGPL-3.0-only

package main

import (
	"archive/zip"
	"crypto/sha256"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"time"
)

var skillFiles = []string{
	"LICENSE",
	"SKILL.md",
	"agents/openai.yaml",
	"references/authoring.md",
	"references/workflows.md",
}

func main() {
	root, err := filepath.Abs(filepath.Join("skills", "sandwich-hime"))
	must(err)
	artifactDir := "artifacts"
	must(os.MkdirAll(artifactDir, 0o755))
	outputPath := filepath.Join(artifactDir, "sandwich-hime-skill-v0.1.0.zip")
	file, err := os.OpenFile(outputPath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o644)
	must(err)
	archive := zip.NewWriter(file)
	fixed := time.Date(1980, 1, 1, 0, 0, 0, 0, time.UTC)
	sort.Strings(skillFiles)
	for _, relative := range skillFiles {
		path := filepath.Join(root, filepath.FromSlash(relative))
		info, err := os.Lstat(path)
		must(err)
		if !info.Mode().IsRegular() || info.Mode()&os.ModeSymlink != 0 {
			panic("skill archive input is not a regular file: " + relative)
		}
		header := &zip.FileHeader{Name: "sandwich-hime/" + relative, Method: zip.Deflate}
		header.SetModTime(fixed)
		header.SetMode(0o644)
		writer, err := archive.CreateHeader(header)
		must(err)
		source, err := os.Open(path)
		must(err)
		_, copyErr := io.Copy(writer, source)
		closeErr := source.Close()
		must(copyErr)
		must(closeErr)
	}
	must(archive.Close())
	must(file.Close())

	verifyExactTree(root)
	content, err := os.ReadFile(outputPath)
	must(err)
	digest := fmt.Sprintf("%x", sha256.Sum256(content))
	must(os.WriteFile(filepath.Join(artifactDir, "sandwich-hime-skill-v0.1.0.zip.sha256"), []byte(digest+"  "+filepath.Base(outputPath)+"\n"), 0o644))
	fmt.Printf("%s  %s\n", digest, outputPath)
}

func verifyExactTree(root string) {
	want := make(map[string]bool, len(skillFiles))
	for _, file := range skillFiles {
		want[file] = true
	}
	var actual []string
	must(filepath.WalkDir(root, func(path string, entry os.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if entry.IsDir() {
			return nil
		}
		relative, err := filepath.Rel(root, path)
		if err != nil {
			return err
		}
		relative = filepath.ToSlash(relative)
		actual = append(actual, relative)
		if !want[relative] {
			return fmt.Errorf("unexpected skill file: %s", relative)
		}
		return nil
	}))
	if len(actual) != len(want) {
		panic(fmt.Sprintf("skill file count = %d, want %d", len(actual), len(want)))
	}
	for _, file := range actual {
		if strings.TrimSpace(file) == "" {
			panic("empty skill filename")
		}
	}
}

func must(err error) {
	if err != nil {
		panic(err)
	}
}