package fileio

import (
	"io/fs"
	"os"
	"path/filepath"
	"reflect"
	"testing"
)

func TestCopyFiles(t *testing.T) {
	// Create a temporary directory for testing
	srcDir, err := os.MkdirTemp("", "src")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(srcDir)

	// Create a source file
	srcFile := filepath.Join(srcDir, "source.txt")
	err = os.WriteFile(srcFile, []byte("test data"), 0644)
	if err != nil {
		t.Fatal(err)
	}

	// Specify the destination directory
	dstDir, err := os.MkdirTemp("", "dst")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dstDir)

	// Call the CopyFiles function
	const perm = fs.FileMode(0444)
	pattern := filepath.Join(srcDir, "*.txt")
	err = CopyFiles(pattern, dstDir, perm)
	if err != nil {
		t.Fatal(err)
	}

	// Verify that the file was copied correctly
	dstFile := filepath.Join(dstDir, "source.txt")
	fileInfo, err := os.Stat(dstFile)
	if err != nil {
		t.Fatalf("file not copied: %s", err)
	}
	if fileInfo.Mode() != perm {
		t.Errorf("unexpected file permissions: got %v, want %v", fileInfo.Mode(), perm)
	}

	// Read the contents of the copied file
	data, err := os.ReadFile(dstFile)
	if err != nil {
		t.Fatal(err)
	}

	// Verify the contents of the copied file
	expected := []byte("test data")
	if string(data) != string(expected) {
		t.Errorf("unexpected file content: got %q, want %q", data, expected)
	}
}

func TestReadJson(t *testing.T) {
	type Person struct{ Name string }

	t.Run("valid", func(t *testing.T) {
		got, err := ReadJson[Person](filepath.Join("testdata", "valid.json"))
		if err != nil {
			t.Fatalf("unexpected error %v", err)
		}
		want := Person{"alice"}
		if !reflect.DeepEqual(got, want) {
			t.Errorf("expected %v, got %v", want, got)
		}
	})
	t.Run("invalid", func(t *testing.T) {
		_, err := ReadJson[Person](filepath.Join("testdata", "invalid.json"))
		if err == nil {
			t.Fatal("expected error, got nil")
		}
	})
	t.Run("does not exist", func(t *testing.T) {
		_, err := ReadJson[Person](filepath.Join("testdata", "missing.json"))
		if err == nil {
			t.Fatal("expected error, got nil")
		}
	})
}

func TestWriteFile(t *testing.T) {
	dir, err := os.MkdirTemp("", "files")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(dir)

	t.Run("text", func(t *testing.T) {
		path := filepath.Join(dir, "data.txt")
		err = WriteFile(path, "hello", 0444)
		if err != nil {
			t.Fatalf("expected nil err, got %v", err)
		}
		got, err := os.ReadFile(path)
		if err != nil {
			t.Fatalf("read file: expected nil err, got %v", err)
		}
		want := []byte("hello")
		if !reflect.DeepEqual(got, want) {
			t.Errorf("read file: expected %v, got %v", want, got)
		}
	})

	t.Run("binary", func(t *testing.T) {
		path := filepath.Join(dir, "data.bin")
		err = WriteFile(path, "data:application/octet-stream;base64,MTIz", 0444)
		if err != nil {
			t.Fatalf("expected nil err, got %v", err)
		}
		got, err := os.ReadFile(path)
		if err != nil {
			t.Fatalf("read file: expected nil err, got %v", err)
		}
		want := []byte("123")
		if !reflect.DeepEqual(got, want) {
			t.Errorf("read file: expected %v, got %v", want, got)
		}
	})

	t.Run("perm", func(t *testing.T) {
		const perm = fs.FileMode(0444)
		path := filepath.Join(dir, "perm.txt")
		err = WriteFile(path, "hello", perm)
		if err != nil {
			t.Fatalf("expected nil err, got %v", err)
		}
		fileInfo, err := os.Stat(path)
		if err != nil {
			t.Fatalf("file not created: %s", err)
		}
		if fileInfo.Mode() != perm {
			t.Errorf("unexpected file permissions: got %v, want %v", fileInfo.Mode(), perm)
		}
	})

	t.Run("missing data-url separator", func(t *testing.T) {
		path := filepath.Join(dir, "data.bin")
		err = WriteFile(path, "data:application/octet-stream:MTIz", 0444)
		if err == nil {
			t.Fatal("expected error, got nil")
		}
	})

	t.Run("invalid binary value", func(t *testing.T) {
		path := filepath.Join(dir, "data.bin")
		err = WriteFile(path, "data:application/octet-stream;base64,12345", 0444)
		if err == nil {
			t.Fatal("expected error, got nil")
		}
	})
}