package main

import (
	"bytes"
	"crypto/sha256"
	"encoding/hex"
	"os"
	"path/filepath"
	"sync"
	"testing"

	"github.com/stretchr/testify/require"
)

func TestImagesArePrivateSharedAndWrittenOnce(t *testing.T) {
	root, err := openAgent(filepath.Join(t.TempDir(), "agent"))
	require.NoError(t, err)

	child := &Agent{
		dir:    filepath.Join(root.dir, "children", "House"),
		config: AgentConfig{Parent: root.config.Name},
	}
	require.Equal(t, root.Images().dir, child.Images().dir)

	data := imageTestPNG(t, 3, 2)
	sum := sha256.Sum256(data)
	expected := hex.EncodeToString(sum[:]) + ".png"
	store := root.Images()
	name, err := store.Save(data)
	require.NoError(t, err)
	require.Equal(t, expected, name)

	info, err := os.Stat(filepath.Join(store.dir, name))
	require.NoError(t, err)
	require.Equal(t, os.FileMode(0o600), info.Mode().Perm())

	var workers sync.WaitGroup

	for range 8 {
		workers.Go(func() {
			saved, saveErr := child.Images().Save(data)
			require.NoError(t, saveErr)
			require.Equal(t, name, saved)
		})
	}

	workers.Wait()

	again, err := os.Stat(filepath.Join(store.dir, name))
	require.NoError(t, err)
	require.True(t, os.SameFile(info, again))

	files, err := os.ReadDir(store.dir)
	require.NoError(t, err)
	require.Len(t, files, 1)

	actual, err := store.Read(name)
	require.NoError(t, err)
	require.Equal(t, data, actual)
}

func TestImageStoreRejectsLargeUnsupportedAndUnsafeImages(t *testing.T) {
	store := &ImageStore{dir: filepath.Join(t.TempDir(), imageDirName)}
	_, err := store.Save(bytes.Repeat([]byte{0}, imageMaxBytes+1))
	require.ErrorContains(t, err, "exceeds 20 MB")

	_, err = store.Save([]byte("not an image"))
	require.ErrorContains(t, err, "JPEG, PNG, or WebP")

	_, err = store.Read("../secret.png")
	require.ErrorContains(t, err, "invalid image name")

	_, err = os.Stat(store.dir)
	require.ErrorIs(t, err, os.ErrNotExist)
}

func TestBackupKeepsImagesAndTheirModes(t *testing.T) {
	dir := t.TempDir()
	store := &ImageStore{dir: filepath.Join(dir, imageDirName)}
	data := imageTestPNG(t, 2, 2)
	name, err := store.Save(data)
	require.NoError(t, err)
	require.NoError(t, os.WriteFile(filepath.Join(store.dir, ".image-incomplete"), []byte("partial"), 0o600))

	stage := t.TempDir()
	archive := filepath.Join(t.TempDir(), "images.tar.gz")
	require.NoError(t, backupCopy(t.Context(), dir, stage, archive))

	_, err = backupArchive(t.Context(), stage, archive)
	require.NoError(t, err)

	restored := t.TempDir()
	require.NoError(t, backupRestore(t.Context(), archive, restored))

	actual, err := (&ImageStore{dir: filepath.Join(restored, imageDirName)}).Read(name)
	require.NoError(t, err)
	require.Equal(t, data, actual)

	info, err := os.Stat(filepath.Join(restored, imageDirName, name))
	require.NoError(t, err)
	require.Equal(t, os.FileMode(0o600), info.Mode().Perm())

	_, err = os.Stat(filepath.Join(restored, imageDirName, ".image-incomplete"))
	require.ErrorIs(t, err, os.ErrNotExist)
}

func TestImageMarkersKeepCaptionAndOnlySafeNames(t *testing.T) {
	name := "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.png"
	text := imageText([]string{name}, "Read the label.")
	require.Equal(t, "[image "+name+"]\nRead the label.", text)
	require.Equal(t, []string{name}, imageFiles(text+"\n[image ../secret.png]\ntext [image "+name+"]"))
}