import XCTest
@testable import LChatCore

// 🤖 The safe-filename derivation for downloading/previewing attachments: the
// sender's name is untrusted, and the extension (which Quick Look and the Files
// app route on) may be missing. These pin the sanitisation + MIME fallback.
final class AttachmentDownloadTests: XCTestCase {
    func testKeepsGoodNameAndExtension() {
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: "report.pdf", mime: "application/pdf"),
            "report.pdf")
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: "photo.jpeg", mime: "image/jpeg"),
            "photo.jpeg")
    }

    func testDerivesExtensionFromMIMEWhenNameHasNone() {
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: "report", mime: "application/pdf"),
            "report.pdf")
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: "notes", mime: "text/plain"),
            "notes.txt")
    }

    func testFallsBackToFileWhenNameMissingOrEmpty() {
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: nil, mime: "application/pdf"),
            "file.pdf")
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: "   ", mime: "image/png"),
            "file.png")
    }

    func testStripsDirectoryPathFromSenderName() {
        // lastPathComponent defuses a path-traversal-shaped name.
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: "../../etc/passwd", mime: nil),
            "passwd")
        XCTAssertEqual(
            AttachmentDownload.safeFilename(name: "a/b/c/secret.docx", mime: nil),
            "secret.docx")
    }

    func testNoExtensionWhenNeitherNameNorMIMEProvidesOne() {
        // No name extension and no usable MIME → leave it bare rather than invent one.
        XCTAssertEqual(AttachmentDownload.safeFilename(name: "notes", mime: nil), "notes")
        XCTAssertEqual(AttachmentDownload.safeFilename(name: "notes", mime: ""), "notes")
        XCTAssertEqual(AttachmentDownload.safeFilename(name: nil, mime: nil), "file")
    }
}