package archive

import (
	"archive/tar"
	"bytes"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"

	"github.com/klauspost/compress/zstd"
)

func TestBuildSourceArchive_RoundTrip(t *testing.T) {
	dir := t.TempDir()
	run := func(name string, args ...string) {
		t.Helper()
		cmd := exec.Command(name, args...)
		cmd.Dir = dir
		cmd.Env = append(os.Environ(),
			"GIT_AUTHOR_NAME=t",
			"GIT_AUTHOR_EMAIL=t@t",
			"GIT_COMMITTER_NAME=t",
			"GIT_COMMITTER_EMAIL=t@t",
		)
		out, err := cmd.CombinedOutput()
		if err != nil {
			t.Fatalf("%s %v: %v\n%s", name, args, err, out)
		}
	}
	run("git", "init", "-q")
	if err := os.WriteFile(filepath.Join(dir, "plugin.mod"),
		[]byte("[plugin]\nname=\"x\"\nscope=\"@s\"\nversion=\"0.1.0\"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "ignored.log"), []byte("nope"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, ".gitignore"), []byte("ignored.log\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	run("git", "add", "plugin.mod", ".gitignore")
	run("git", "commit", "-qm", "init")

	zstdBytes, err := BuildSourceArchive(dir)
	if err != nil {
		t.Fatalf("BuildSourceArchive: %v", err)
	}
	if len(zstdBytes) == 0 {
		t.Fatal("empty archive")
	}

	dec, err := zstd.NewReader(bytes.NewReader(zstdBytes))
	if err != nil {
		t.Fatal(err)
	}
	defer dec.Close()
	tr := tar.NewReader(dec)
	got := map[string]string{}
	for {
		hdr, err := tr.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			t.Fatal(err)
		}
		buf, err := io.ReadAll(tr)
		if err != nil {
			t.Fatal(err)
		}
		got[hdr.Name] = string(buf)
	}
	if _, ok := got["plugin.mod"]; !ok {
		t.Errorf("expected plugin.mod in archive, got %v", keys(got))
	}
	if _, ok := got["ignored.log"]; ok {
		t.Errorf("ignored.log should not be in archive (gitignored + untracked)")
	}
}

func keys(m map[string]string) []string {
	out := make([]string, 0, len(m))
	for k := range m {
		out = append(out, k)
	}
	return out
}

func TestBuildSourceArchive_DirtyTreeShipsWorkingCopy(t *testing.T) {
	dir := t.TempDir()
	runGitArchive(t, dir, "init", "-q")
	modPath := filepath.Join(dir, "plugin.mod")
	if err := os.WriteFile(modPath,
		[]byte("[plugin]\nname=\"x\"\nscope=\"@s\"\nversion=\"0.1.0\"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	runGitArchive(t, dir, "add", "plugin.mod")
	runGitArchive(t, dir, "commit", "-qm", "init")

	dirtyContents := []byte("[plugin]\nname=\"x\"\nscope=\"@s\"\nversion=\"0.1.1\"\n")
	if err := os.WriteFile(modPath, dirtyContents, 0o644); err != nil {
		t.Fatal(err)
	}

	zstdBytes, err := BuildSourceArchive(dir)
	if err != nil {
		t.Fatalf("BuildSourceArchive: %v", err)
	}

	got := readArchive(t, zstdBytes)
	contents, ok := got["plugin.mod"]
	if !ok {
		t.Fatalf("expected plugin.mod in archive, got %v", keys(got))
	}
	if !strings.Contains(contents, `version="0.1.1"`) {
		t.Errorf("archived plugin.mod should have dirty version 0.1.1, got: %q", contents)
	}
	if strings.Contains(contents, `version="0.1.0"`) {
		t.Errorf("archived plugin.mod should NOT have HEAD version 0.1.0, got: %q", contents)
	}

	// Working tree should be unchanged after stash-create.
	postContents, err := os.ReadFile(modPath)
	if err != nil {
		t.Fatal(err)
	}
	if string(postContents) != string(dirtyContents) {
		t.Errorf("working tree mutated after BuildSourceArchive\nwant: %q\ngot:  %q",
			string(dirtyContents), string(postContents))
	}
}

func TestBuildSourceArchive_DirtyTreeOmitsUntracked(t *testing.T) {
	dir := t.TempDir()
	runGitArchive(t, dir, "init", "-q")
	modPath := filepath.Join(dir, "plugin.mod")
	if err := os.WriteFile(modPath,
		[]byte("[plugin]\nname=\"x\"\nscope=\"@s\"\nversion=\"0.1.0\"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	runGitArchive(t, dir, "add", "plugin.mod")
	runGitArchive(t, dir, "commit", "-qm", "init")

	// Dirty the tracked file.
	if err := os.WriteFile(modPath,
		[]byte("[plugin]\nname=\"x\"\nscope=\"@s\"\nversion=\"0.1.1\"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	// Add an untracked file (no git add).
	if err := os.WriteFile(filepath.Join(dir, "extra.txt"), []byte("not tracked"), 0o644); err != nil {
		t.Fatal(err)
	}

	zstdBytes, err := BuildSourceArchive(dir)
	if err != nil {
		t.Fatalf("BuildSourceArchive: %v", err)
	}

	got := readArchive(t, zstdBytes)
	if _, ok := got["extra.txt"]; ok {
		t.Errorf("untracked extra.txt should not be in archive, got %v", keys(got))
	}
}

func runGitArchive(t *testing.T, dir string, args ...string) {
	t.Helper()
	cmd := exec.Command("git", args...)
	cmd.Dir = dir
	cmd.Env = append(os.Environ(),
		"GIT_AUTHOR_NAME=t",
		"GIT_AUTHOR_EMAIL=t@t",
		"GIT_COMMITTER_NAME=t",
		"GIT_COMMITTER_EMAIL=t@t",
	)
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("git %v: %v\n%s", args, err, out)
	}
}

func readArchive(t *testing.T, zstdBytes []byte) map[string]string {
	t.Helper()
	dec, err := zstd.NewReader(bytes.NewReader(zstdBytes))
	if err != nil {
		t.Fatal(err)
	}
	defer dec.Close()
	tr := tar.NewReader(dec)
	got := map[string]string{}
	for {
		hdr, err := tr.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			t.Fatal(err)
		}
		buf, err := io.ReadAll(tr)
		if err != nil {
			t.Fatal(err)
		}
		got[hdr.Name] = string(buf)
	}
	return got
}