import Foundation

// Unicode comment: 你好世界 🌍🚀

// Unicode string literals
let unicode = "こんにちは世界"
print(unicode)

// Null byte in string
let nullStr = "hello\0world"
print("Null-str length: \(nullStr.count)")

// Deeply nested optionals
let deep: Int????? = 42
if let l1 = deep,
   let l2 = l1,
   let l3 = l2,
   let l4 = l3 {
    print("Deep optional: \(l4)")
}

// Very long string
let longStr = String(repeating: "x", count: 10000)
print("Long string length: \(longStr.count)")

// BOM bytes
let bom = Data([0xEF, 0xBB, 0xBF, 0x48, 0x69])
print(String(data: bom, encoding: .utf8) ?? "")

// Deep closure nesting
let f1: (Int) -> (Int) -> (Int) -> (Int) -> Int = { x in
    { y in
        { z in
            { w in x + y + z + w }
        }
    }
}
print("Nested closures: \(f1(1)(2)(3)(4))")

// Deep dictionary nesting
let deepDict: [String: Any] = [
    "a": [
        "b": [
            "c": [
                "d": [
                    "e": "deep"
                ]
            ]
        ]
    ]
]
if let a = deepDict["a"] as? [String: Any],
   let b = a["b"] as? [String: Any],
   let c = b["c"] as? [String: Any],
   let d = c["d"] as? [String: Any],
   let e = d["e"] as? String {
    print("Deep dict: \(e)")
}

// Deep error nesting
enum AppError: Error {
    case inner(String)
    case middle(String, Error)
    case outer(String, Error)
}

do {
    do {
        do {
            throw AppError.inner("oops")
        } catch {
            throw AppError.middle("wrapped", error)
        }
    } catch {
        throw AppError.outer("re-wrapped", error)
    }
} catch {
    print("Nested error: \(error)")
}