"""14a sim memory sync: mfu_dump_t builder, EML_MEMSET push, config-page safety.

Covers the P0 fix — loading a Type 2 (NTAG/Ultralight) model's memory into the
firmware emulator so the reader sees real page data (UID/CC/NDEF/PWD/PACK).
"""
import struct
from unittest.mock import MagicMock, patch

from pm3py.sim import NTAG213, NTAG216, ndef_uri
from pm3py.transponders.hf.iso14443a.ndef import (
    MFU_DUMP_PREFIX_LENGTH, CMD_HF_MIFARE_EML_MEMSET, PAGE_SIZE,
)


def test_mfu_dump_layout():
    t = NTAG213()
    t.set_ndef(ndef_uri("https://dngr.us/rick"))
    img = t._build_mfu_dump()

    assert len(img) == MFU_DUMP_PREFIX_LENGTH + t._total_pages * PAGE_SIZE
    assert img[0:8] == t._version_bytes                 # version[8]
    assert img[11] == t._total_pages - 1                # pages = last page index
    assert img[12:44] == bytes(t._signature)[:32].ljust(32, b"\x00")  # signature[32]
    # page data begins at offset 56 and mirrors _memory
    assert img[MFU_DUMP_PREFIX_LENGTH:] == bytes(t._memory)
    # NDEF TLV present at page 4
    assert img[MFU_DUMP_PREFIX_LENGTH + 4 * PAGE_SIZE] == 0x03


def test_set_ndef_preserves_config_pages():
    """set_ndef must not wipe the lock/config/PWD/PACK pages above the NDEF area."""
    t = NTAG213()
    assert t.get_page(0x2B) == b"\xff\xff\xff\xff"        # PWD default
    assert t.get_page(0x29)[3] == 0xFF                    # CFG0 AUTH0

    t.set_ndef(ndef_uri("https://dngr.us/rick"))

    assert t.get_page(0x2B) == b"\xff\xff\xff\xff"        # PWD survived
    assert t.get_page(0x29)[3] == 0xFF                    # AUTH0 survived
    assert t.get_page(4)[0] == 0x03                       # NDEF TLV written


def test_clear_ndef_preserves_config_pages():
    t = NTAG213()
    t.set_ndef(ndef_uri("https://dngr.us/rick"))
    t.clear_ndef()
    assert t.get_page(0x2B) == b"\xff\xff\xff\xff"        # PWD still intact
    assert t.get_page(4) == b"\x00\x00\x00\x00"           # NDEF area cleared


def _capture_eml_writes(tag):
    """Run tag.sync() with a mock serial; return list of (cmd, payload)."""
    captured = []

    def fake_encode(cmd, payload=b""):
        captured.append((cmd, payload))
        return b""

    tag._serial = MagicMock()
    with patch("pm3py.core.transport.encode_ng_frame", side_effect=fake_encode):
        tag.sync()
    return captured


def test_sync_pushes_full_image_via_eml_memset():
    t = NTAG213()
    t.set_ndef(ndef_uri("https://dngr.us/rick"))
    image = t._build_mfu_dump()

    frames = _capture_eml_writes(t)
    assert frames, "sync() wrote no frames"

    reassembled = bytearray()
    for cmd, payload in frames:
        assert cmd == CMD_HF_MIFARE_EML_MEMSET
        blockno, blockcnt, blockwidth = struct.unpack_from("<HBB", payload, 0)
        assert blockwidth == PAGE_SIZE
        data = payload[4:]
        assert len(data) == blockcnt * blockwidth
        assert blockno * blockwidth == len(reassembled)   # contiguous, in order
        reassembled += data

    assert bytes(reassembled) == image


def test_sync_chunks_large_tag():
    """NTAG216 (~231 pages) exceeds one 512-byte frame -> multiple EML_MEMSET."""
    t = NTAG216()
    frames = _capture_eml_writes(t)
    assert len(frames) >= 2
    # every chunk stays within the NG payload cap
    for _cmd, payload in frames:
        assert len(payload) <= 512


def test_sync_requires_live_session():
    import pytest
    t = NTAG213()
    t._serial = None
    with pytest.raises(RuntimeError, match="live session"):
        t.sync()