"""Tests for identity mapping."""

import tempfile
from pathlib import Path

import pytest
from radicle_reticulum.identity import (
    RadicleIdentity,
    _base58btc_encode,
    _base58btc_decode,
)


class TestBase58:
    """Test base58btc encoding/decoding."""

    def test_encode_decode_roundtrip(self):
        """Test that encode/decode are inverses."""
        test_data = b"\x00\x01\x02\x03\x04\x05"
        encoded = _base58btc_encode(test_data)
        decoded = _base58btc_decode(encoded)
        assert decoded == test_data

    def test_encode_known_value(self):
        """Test encoding against known value."""
        # "Hello" in base58btc
        data = b"Hello"
        encoded = _base58btc_encode(data)
        assert encoded == "9Ajdvzr"

    def test_preserves_leading_zeros(self):
        """Test that leading zeros are preserved."""
        data = b"\x00\x00\x00test"
        encoded = _base58btc_encode(data)
        decoded = _base58btc_decode(encoded)
        assert decoded == data


class TestRadicleIdentity:
    """Test RadicleIdentity class."""

    def test_generate_creates_valid_identity(self):
        """Test that generate() creates a valid identity."""
        identity = RadicleIdentity.generate()

        assert identity.private_key is not None
        assert identity.public_key is not None
        assert identity.rns_identity is not None
        assert len(identity.public_key_bytes) == 32
        assert len(identity.rns_hash) == 16

    def test_did_format(self):
        """Test that DID has correct format."""
        identity = RadicleIdentity.generate()
        did = identity.did

        assert did.startswith("did:key:z6Mk")
        assert identity.node_id == did

    def test_did_roundtrip(self):
        """Test DID encoding/decoding roundtrip."""
        identity = RadicleIdentity.generate()
        original_did = identity.did

        # Create identity from DID (public key only)
        restored = RadicleIdentity.from_did(original_did)

        assert restored.did == original_did
        assert restored.public_key_bytes == identity.public_key_bytes
        assert restored.private_key is None  # DID import is public-only
        assert restored.rns_identity is None  # DID doesn't have X25519 key

    def test_sign_and_verify(self):
        """Test signing and verification."""
        identity = RadicleIdentity.generate()
        message = b"test message"

        signature = identity.sign(message)
        assert len(signature) == 64  # Ed25519 signature size

        assert identity.verify(signature, message)
        assert not identity.verify(signature, b"wrong message")

    def test_cannot_sign_without_private_key(self):
        """Test that signing fails without private key."""
        identity = RadicleIdentity.generate()
        public_only = RadicleIdentity.from_did(identity.did)

        with pytest.raises(ValueError, match="Cannot sign without private key"):
            public_only.sign(b"test")

    def test_invalid_did_format(self):
        """Test that invalid DIDs are rejected."""
        with pytest.raises(ValueError, match="Invalid DID format"):
            RadicleIdentity.from_did("not:a:valid:did")

    def test_rns_hash_is_stable(self):
        """Test that RNS hash is deterministic for same key."""
        identity = RadicleIdentity.generate()
        hash1 = identity.rns_hash_hex

        # The hash should be consistent
        assert identity.rns_hash_hex == hash1
        assert len(hash1) == 32  # 16 bytes = 32 hex chars

    def test_repr(self):
        """Test string representation."""
        identity = RadicleIdentity.generate()
        repr_str = repr(identity)

        assert "RadicleIdentity" in repr_str
        assert "with private key" in repr_str

        public_only = RadicleIdentity.from_did(identity.did)
        assert "public only" in repr(public_only)


class TestIdentityPersistence:
    """Test identity save/load."""

    def test_save_and_load_roundtrip(self):
        """Saved identity reloads with same DID and RNS hash."""
        with tempfile.TemporaryDirectory() as tmpdir:
            path = Path(tmpdir) / "identity"
            original = RadicleIdentity.generate()
            original.save(path)

            loaded = RadicleIdentity.load(path)
            assert loaded.did == original.did
            assert loaded.rns_identity_hash_hex == original.rns_identity_hash_hex
            assert loaded.private_key is not None

    def test_save_creates_parent_dirs(self):
        """save() creates intermediate directories."""
        with tempfile.TemporaryDirectory() as tmpdir:
            path = Path(tmpdir) / "subdir" / "nested" / "identity"
            identity = RadicleIdentity.generate()
            identity.save(path)
            assert path.exists()

    def test_load_missing_file_raises(self):
        """load() raises FileNotFoundError for missing path."""
        with pytest.raises(FileNotFoundError):
            RadicleIdentity.load("/nonexistent/path/identity")

    def test_load_or_generate_creates_on_first_run(self):
        """load_or_generate() creates and saves a new identity when absent."""
        with tempfile.TemporaryDirectory() as tmpdir:
            path = Path(tmpdir) / "identity"
            assert not path.exists()
            identity = RadicleIdentity.load_or_generate(path)
            assert path.exists()
            assert identity.did.startswith("did:key:z6Mk")

    def test_load_or_generate_stable_across_calls(self):
        """load_or_generate() returns the same identity on subsequent calls."""
        with tempfile.TemporaryDirectory() as tmpdir:
            path = Path(tmpdir) / "identity"
            first = RadicleIdentity.load_or_generate(path)
            second = RadicleIdentity.load_or_generate(path)
            assert first.did == second.did
            assert first.rns_identity_hash_hex == second.rns_identity_hash_hex

    def test_save_public_only_raises(self):
        """save() raises ValueError for public-key-only identities."""
        identity = RadicleIdentity.from_did(
            "did:key:z6MkhaXgBZDvotDkL5257faiztiGiC2QtKLGpbnnEGta2doK"
        )
        with tempfile.TemporaryDirectory() as tmpdir:
            with pytest.raises(ValueError, match="public-key-only"):
                identity.save(Path(tmpdir) / "identity")