import XCTest
@testable import Receiver

final class LineAssemblerTests: XCTestCase {
    private func bytes(_ s: String) -> [UInt8] { Array(s.utf8) }

    func testSingleLine() {
        let a = LineAssembler()
        XCTAssertEqual(a.feed(bytes("hello")), [])
        XCTAssertEqual(a.feed(bytes("\n")), ["hello"])
    }

    func testMultipleLinesInOneChunk() {
        let a = LineAssembler()
        XCTAssertEqual(a.feed(bytes("one\ntwo\nthree\n")), ["one", "two", "three"])
    }

    func testDropsCR() {
        let a = LineAssembler()
        XCTAssertEqual(a.feed(bytes("line\r\n")), ["line"])
    }

    func testIgnoresEmptyLine() {
        let a = LineAssembler()
        XCTAssertEqual(a.feed(bytes("\n")), [])
    }

    func testSplitAcrossChunks() {
        let a = LineAssembler()
        let payload = "{\"session_id\":\"x\"}"
        var lines: [String] = []
        lines += a.feed(Array(payload.prefix(5)))
        lines += a.feed(Array(payload.suffix(from: 5)))
        lines += a.feed(["\n".utf8.first!])
        XCTAssertEqual(lines, [payload])
    }

    func testDropsOversizedLine() {
        let a = LineAssembler()
        let big = String(repeating: "a", count: SignalingMessage.maxMessageBytes + 1)
        _ = a.feed(Array(big.utf8))
        XCTAssertEqual(a.feed(bytes("\n")), [])
    }
}