package safeio

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"testing"

	"github.com/aritmolab/thothii/tools/tht/internal/testsupport"
)

func TestReadCanonicalRegularRejectsFinalAndParentSymlinks(t *testing.T) {
	temporaryRoot, err := filepath.EvalSymlinks(os.TempDir())
	if err != nil {
		t.Fatal(err)
	}
	root, err := os.MkdirTemp(temporaryRoot, "tht-safeio-")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = os.RemoveAll(root) })

	realDirectory := filepath.Join(root, "real")
	if err := os.Mkdir(realDirectory, 0o700); err != nil {
		t.Fatal(err)
	}
	realFile := filepath.Join(realDirectory, "secret")
	if err := os.WriteFile(realFile, []byte("secret"), 0o600); err != nil {
		t.Fatal(err)
	}

	parentLink := filepath.Join(root, "parent-link")
	testsupport.SymlinkOrSkip(t, realDirectory, parentLink)
	if _, err := ReadCanonicalRegular(filepath.Join(parentLink, "secret"), 1024); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("parent symlink error = %v, want ErrUnsafeFile", err)
	}

	finalLink := filepath.Join(root, "final-link")
	testsupport.SymlinkOrSkip(t, realFile, finalLink)
	if _, err := ReadCanonicalRegular(finalLink, 1024); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("final symlink error = %v, want ErrUnsafeFile", err)
	}
}

func TestReadCanonicalUTF8RejectsNonUTF8AndHardlinks(t *testing.T) {
	temporaryRoot, err := filepath.EvalSymlinks(os.TempDir())
	if err != nil {
		t.Fatal(err)
	}
	root, err := os.MkdirTemp(temporaryRoot, "tht-safeio-")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = os.RemoveAll(root) })

	nonUTF8 := filepath.Join(root, "annotations.yaml")
	if err := os.WriteFile(nonUTF8, []byte{0xff, 0xfe, 0xfd}, 0o600); err != nil {
		t.Fatal(err)
	}
	if _, err := ReadCanonicalUTF8(nonUTF8, 1024); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("ReadCanonicalUTF8(nonUTF8) error = %v, want ErrUnsafeFile", err)
	}

	target := filepath.Join(root, "regular.txt")
	if err := os.WriteFile(target, []byte("linked"), 0o600); err != nil {
		t.Fatal(err)
	}
	link := filepath.Join(root, "hardlink.txt")
	if err := os.Link(target, link); err != nil {
		t.Fatal(err)
	}
	if _, err := ReadCanonicalUTF8(link, 1024); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("ReadCanonicalUTF8(hardlink) error = %v, want ErrUnsafeFile", err)
	}
}

func TestWriteCanonicalNewFileRejectsExistingTargets(t *testing.T) {
	temporaryRoot, err := filepath.EvalSymlinks(os.TempDir())
	if err != nil {
		t.Fatal(err)
	}
	root, err := os.MkdirTemp(temporaryRoot, "tht-safeio-")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = os.RemoveAll(root) })

	path := filepath.Join(root, "artifact.yaml")
	if err := os.WriteFile(path, []byte("existing"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := WriteCanonicalNewFile(path, []byte("new"), 0o600); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("WriteCanonicalNewFile(existing) error = %v, want ErrUnsafeFile", err)
	}
}

func TestListCanonicalPrivateDirectoryBoundsAndSortsValidatedEntries(t *testing.T) {
	temporaryRoot, err := filepath.EvalSymlinks(os.TempDir())
	if err != nil {
		t.Fatal(err)
	}
	root, err := os.MkdirTemp(temporaryRoot, "tht-safeio-list-")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = os.RemoveAll(root) })
	if err := ProtectPrivateDirectory(root); err != nil {
		t.Fatal(err)
	}
	for index := 255; index >= 0; index-- {
		path := filepath.Join(root, fmt.Sprintf("%064x.json", index))
		if err := WriteCanonicalNewFile(path, []byte("record"), 0o600); err != nil {
			t.Fatalf("WriteCanonicalNewFile(%d) error = %v", index, err)
		}
	}
	entries, err := ListCanonicalPrivateDirectory(root, 256)
	if err != nil || len(entries) != 256 || entries[0].Name != fmt.Sprintf("%064x.json", 0) || entries[255].Name != fmt.Sprintf("%064x.json", 255) {
		t.Fatalf("bounded ordered entries = %#v error = %v", entries, err)
	}
	if err := WriteCanonicalNewFile(filepath.Join(root, fmt.Sprintf("%064x.json", 256)), []byte("record"), 0o600); err != nil {
		t.Fatal(err)
	}
	if _, err := ListCanonicalPrivateDirectory(root, 256); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("257-entry listing error = %v, want ErrUnsafeFile", err)
	}
}