import XCTest
@testable import MontanaApp

final class MnemonicTests: XCTestCase {
    /// spec, раздел "Test vectors (binding) → M-1 Vector 1"
    /// entropy = [0x00; 32]
    /// mnemonic = "abandon abandon ... abandon art"
    /// master_seed = 38a1421ac3ce191fbdc46b1cca266a9d72d22320fb38bda6a3df90a1ead664a7
    ///               8951703197be882ace38e0f557a492a8e9ff5e3c02290a8eecf5939468708edb
    func testM1Vector1_ZeroEntropy() throws {
        let entropy = Data(count: 32)
        let mnemonic = try Mnemonic.encode(entropy: entropy)
        XCTAssertEqual(mnemonic.split(whereSeparator: { $0.isWhitespace }).count, 24)
        XCTAssertTrue(mnemonic.hasSuffix(" art"), "BIP-39 standard: zero entropy + checksum 0x66 → word 'art'")

        let masterSeed = try Mnemonic.decodeAndDerive(mnemonic: mnemonic)
        let hex = masterSeed.map { String(format: "%02x", $0) }.joined()
        XCTAssertEqual(hex,
            "38a1421ac3ce191fbdc46b1cca266a9d72d22320fb38bda6a3df90a1ead664a7" +
            "8951703197be882ace38e0f557a492a8e9ff5e3c02290a8eecf5939468708edb"
        )
    }

    /// spec, раздел "Test vectors (binding) → M-1 Vector 2"
    /// entropy = [0xFF; 32]
    /// master_seed = a5925c51583447a0abe43b65dbc591f3780a91c7d44c6b333975a211096039f3
    ///               d1d0ca9e125aa4e756f0a35b0006378ac69450e8254e32f16409a350f3ca9104
    func testM1Vector2_MaxEntropy() throws {
        let entropy = Data(repeating: 0xFF, count: 32)
        let mnemonic = try Mnemonic.encode(entropy: entropy)
        XCTAssertTrue(mnemonic.hasSuffix(" vote"))

        let masterSeed = try Mnemonic.decodeAndDerive(mnemonic: mnemonic)
        let hex = masterSeed.map { String(format: "%02x", $0) }.joined()
        XCTAssertEqual(hex,
            "a5925c51583447a0abe43b65dbc591f3780a91c7d44c6b333975a211096039f3" +
            "d1d0ca9e125aa4e756f0a35b0006378ac69450e8254e32f16409a350f3ca9104"
        )
    }

    func testWordlistFingerprint() {
        XCTAssertTrue(Wordlist.verifyBindingFingerprint(),
                     "wordlist.txt SHA-256 должен соответствовать spec binding fingerprint")
    }

    func testGenerateProduces24Words() {
        let m = Mnemonic.generate()
        XCTAssertEqual(m.split(whereSeparator: { $0.isWhitespace }).count, 24)
    }

    func testRoundtrip() throws {
        let entropy = Data((0..<32).map { _ in UInt8.random(in: 0...255) })
        let mnemonic = try Mnemonic.encode(entropy: entropy)
        let seed1 = try Mnemonic.decodeAndDerive(mnemonic: mnemonic)
        let seed2 = try Mnemonic.decodeAndDerive(mnemonic: mnemonic)
        XCTAssertEqual(seed1, seed2, "Determinism")
    }

    func testInvalidWordCount() {
        XCTAssertThrowsError(try Mnemonic.decodeAndDerive(mnemonic: "abandon abandon")) { err in
            if case Mnemonic.MnemonicError.wordCount(let n) = err {
                XCTAssertEqual(n, 2)
            } else {
                XCTFail("expected wordCount error")
            }
        }
    }

    func testInvalidWord() {
        let bad = Array(repeating: "abandon", count: 23).joined(separator: " ") + " bogusword"
        XCTAssertThrowsError(try Mnemonic.decodeAndDerive(mnemonic: bad)) { err in
            if case Mnemonic.MnemonicError.unknownWord(let pos) = err {
                XCTAssertEqual(pos, 23)
            } else {
                XCTFail("expected unknownWord error")
            }
        }
    }

    func testInvalidChecksum() {
        let m = Array(repeating: "abandon", count: 24).joined(separator: " ")
        XCTAssertThrowsError(try Mnemonic.decodeAndDerive(mnemonic: m)) { err in
            XCTAssertEqual(err as? Mnemonic.MnemonicError, .checksumMismatch)
        }
    }
}