package storage

import (
	"context"
	"io"
	"os"
	"strings"
	"testing"
)

func TestSaveAndOpen(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStorage(dir)
	if err != nil {
		t.Fatalf("NewLocalStorage: %v", err)
	}
	ctx := context.Background()

	content := "hello, mygo storage"
	written, err := store.SaveStaged(ctx, "staging/test/hello.txt", strings.NewReader(content))
	if err != nil {
		t.Fatalf("SaveStaged: %v", err)
	}
	if written != int64(len(content)) {
		t.Errorf("written = %d, want %d", written, len(content))
	}

	if err := store.PromoteStaged(ctx, "staging/test/hello.txt", "data/test/hello.txt"); err != nil {
		t.Fatalf("PromoteStaged: %v", err)
	}

	reader, err := store.Open(ctx, "data/test/hello.txt")
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	defer reader.Close()

	got, err := io.ReadAll(reader)
	if err != nil {
		t.Fatalf("ReadAll: %v", err)
	}
	if string(got) != content {
		t.Errorf("content = %q, want %q", string(got), content)
	}

	// Verify the file exists on disk under the base path.
	expectedPath := dir + "/data/test/hello.txt"
	if _, err := os.Stat(expectedPath); err != nil {
		t.Errorf("file not found on disk at %s: %v", expectedPath, err)
	}
}

func TestDelete(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStorage(dir)
	if err != nil {
		t.Fatalf("NewLocalStorage: %v", err)
	}
	ctx := context.Background()

	_, err = store.SaveStaged(ctx, "staging/to_delete.txt", strings.NewReader("delete me"))
	if err != nil {
		t.Fatalf("SaveStaged: %v", err)
	}
	if err := store.PromoteStaged(ctx, "staging/to_delete.txt", "data/to_delete.txt"); err != nil {
		t.Fatalf("PromoteStaged: %v", err)
	}

	if err := store.Delete(ctx, "data/to_delete.txt"); err != nil {
		t.Fatalf("Delete: %v", err)
	}

	_, err = store.Open(ctx, "data/to_delete.txt")
	if err == nil {
		t.Error("Open should fail after delete")
	}
}

func TestDeleteIdempotent(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStorage(dir)
	if err != nil {
		t.Fatalf("NewLocalStorage: %v", err)
	}
	ctx := context.Background()

	// Deleting a non-existent file should not error.
	if err := store.Delete(ctx, "nonexistent.txt"); err != nil {
		t.Errorf("Delete nonexistent should be idempotent, got: %v", err)
	}
}

func TestPathTraversalRejected(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStorage(dir)
	if err != nil {
		t.Fatalf("NewLocalStorage: %v", err)
	}
	ctx := context.Background()

	_, err = store.SaveStaged(ctx, "../escape.txt", strings.NewReader("malicious"))
	if err == nil {
		t.Error("SaveStaged should reject path traversal")
	} else if !strings.Contains(err.Error(), "path traversal") {
		t.Errorf("expected path traversal error, got: %v", err)
	}

	err = store.PromoteStaged(ctx, "../escape.txt", "data/escape.txt")
	if err == nil {
		t.Error("PromoteStaged should reject staged path traversal")
	} else if !strings.Contains(err.Error(), "path traversal") {
		t.Errorf("expected path traversal error, got: %v", err)
	}

	err = store.PromoteStaged(ctx, "staging/escape.txt", "../escape.txt")
	if err == nil {
		t.Error("PromoteStaged should reject final path traversal")
	} else if !strings.Contains(err.Error(), "path traversal") {
		t.Errorf("expected path traversal error, got: %v", err)
	}

	_, err = store.Open(ctx, "../escape.txt")
	if err == nil {
		t.Error("Open should reject path traversal")
	} else if !strings.Contains(err.Error(), "path traversal") {
		t.Errorf("expected path traversal error, got: %v", err)
	}

	err = store.Delete(ctx, "../escape.txt")
	if err == nil {
		t.Error("Delete should reject path traversal")
	} else if !strings.Contains(err.Error(), "path traversal") {
		t.Errorf("expected path traversal error, got: %v", err)
	}

	err = store.DeleteStaged(ctx, "../escape.txt")
	if err == nil {
		t.Error("DeleteStaged should reject path traversal")
	} else if !strings.Contains(err.Error(), "path traversal") {
		t.Errorf("expected path traversal error, got: %v", err)
	}
}

func TestStagedPathsRequireStagingPrefix(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStorage(dir)
	if err != nil {
		t.Fatalf("NewLocalStorage: %v", err)
	}
	ctx := context.Background()

	_, err = store.SaveStaged(ctx, "data/not-staged.txt", strings.NewReader("bad"))
	if err == nil {
		t.Fatal("SaveStaged should reject non-staging path")
	}

	err = store.DeleteStaged(ctx, "data/not-staged.txt")
	if err == nil {
		t.Fatal("DeleteStaged should reject non-staging path")
	}
}

func TestPromoteRequiresDataFinalPrefix(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStorage(dir)
	if err != nil {
		t.Fatalf("NewLocalStorage: %v", err)
	}
	ctx := context.Background()

	_, err = store.SaveStaged(ctx, "staging/promote.txt", strings.NewReader("content"))
	if err != nil {
		t.Fatalf("SaveStaged: %v", err)
	}

	err = store.PromoteStaged(ctx, "staging/promote.txt", "other/promote.txt")
	if err == nil {
		t.Fatal("PromoteStaged should reject non-data final path")
	}
}

func TestOpenMissingFile(t *testing.T) {
	dir := t.TempDir()
	store, err := NewLocalStorage(dir)
	if err != nil {
		t.Fatalf("NewLocalStorage: %v", err)
	}
	ctx := context.Background()

	_, err = store.Open(ctx, "no/such/file.txt")
	if err == nil {
		t.Error("Open should error for missing file")
	} else if !strings.Contains(err.Error(), "not found on disk") {
		t.Errorf("expected 'not found on disk' error, got: %v", err)
	}
}

func TestIsSubPath_SameDirectory(t *testing.T) {
	if !isSubPath("/base", "/base") {
		t.Error("isSubPath should return true when base == target")
	}
}

func TestIsSubPath_ShortChildName(t *testing.T) {
	if !isSubPath("/base", "/base/a") {
		t.Error("isSubPath should return true for single-char child path")
	}
}

func TestIsSubPath_DotDotPrefixFilename(t *testing.T) {
	if !isSubPath("/base", "/base/..foo") {
		t.Error("isSubPath should return true for filename starting with ..")
	}
}