#!/usr/bin/env python3
"""Execute the production ESP32 UART begin/end and bridge state checks."""
from pathlib import Path
import shutil
import subprocess
import tempfile
import unittest

from test_replay_reset_integration import extract_braced

ROOT = Path(__file__).resolve().parents[1]

FIXTURE = r'''
#include <cassert>
#include <cstdint>
#define ESP32 1
#define BRIDGE_DEBUG_PRINTLN(...) ((void)0)
struct NodePrefs { uint32_t bridge_baud = 57600; };
struct Stream { virtual ~Stream() = default; };
struct HardwareSerial : Stream {
  bool pins_ok = true, begin_ok = true, installed = false;
  unsigned pin_calls = 0, begin_calls = 0, end_calls = 0;
  int16_t rx = -1, tx = -1;
  uint32_t baud = 0;
  bool setPins(int16_t selected_rx, int16_t selected_tx) {
    ++pin_calls; rx = selected_rx; tx = selected_tx; return pins_ok;
  }
  void begin(uint32_t selected_baud) { ++begin_calls; baud = selected_baud; installed = begin_ok; }
  explicit operator bool() const { return installed; }
  void end() { ++end_calls; installed = false; }
};
struct BridgeBase {
  bool _initialized = false;
  @RUNNING@
};
struct RS232Bridge : BridgeBase {
  NodePrefs* _prefs;
  Stream* _serial;
  int16_t _rx_pin, _tx_pin;
  uint16_t _rx_buffer_pos = 37;
  bool _rx_packet_ready = true;
  uint16_t _tx_size = 19, _tx_pos = 3;
  bool _tx_wire_pending = true, _tx_is_ping = true;
  uint32_t _tx_ping_challenge = 4, _outstanding_challenge = 5;
  uint64_t _pong_target = 6;
  uint32_t _pong_challenge = 7;
  bool _ping_due = false, _partial_suspend_grace = true;
  RS232Bridge(NodePrefs& prefs, HardwareSerial& serial)
      : _prefs(&prefs), _serial(&serial), _rx_pin(5), _tx_pin(6) {}
  void begin();
  void end();
  void resetTransportState();
};
@RESET@
@BEGIN@
@END@
int main() {
  NodePrefs prefs;
  HardwareSerial serial;
  RS232Bridge bridge(prefs, serial);
  auto dirty_parser = [&]() {
    bridge._rx_buffer_pos = 37; bridge._rx_packet_ready = true;
    bridge._tx_size = 19; bridge._tx_pos = 3;
    bridge._tx_wire_pending = bridge._tx_is_ping = true;
    bridge._tx_ping_challenge = 4; bridge._outstanding_challenge = 5;
    bridge._pong_target = 6; bridge._pong_challenge = 7;
    bridge._ping_due = false; bridge._partial_suspend_grace = true;
  };
  auto assert_parser_reset = [&]() {
    assert(bridge._rx_buffer_pos == 0 && !bridge._rx_packet_ready);
    assert(bridge._tx_size == 0 && bridge._tx_pos == 0);
    assert(!bridge._tx_wire_pending && !bridge._tx_is_ping);
    assert(bridge._tx_ping_challenge == 0 && bridge._outstanding_challenge == 0);
    assert(bridge._pong_target == 0 && bridge._pong_challenge == 0);
    assert(bridge._ping_due && !bridge._partial_suspend_grace);
  };
  assert(!bridge.isRunning());
  serial.pins_ok = false;
  bridge.begin();
  assert(!bridge.isRunning() && serial.pin_calls == 1 && serial.begin_calls == 0);
  assert_parser_reset();
  serial.pins_ok = true; serial.begin_ok = false;
  dirty_parser();
  bridge.begin();
  assert(!bridge.isRunning() && !serial.installed && serial.begin_calls == 1);
  assert_parser_reset();
  serial.begin_ok = true;
  dirty_parser();
  bridge.begin();
  assert(bridge.isRunning() && serial.installed && serial.begin_calls == 2);
  assert_parser_reset();
  assert(serial.rx == 5 && serial.tx == 6 && serial.baud == 57600);
  dirty_parser();
  bridge.end();
  assert(!bridge.isRunning() && !serial.installed && serial.end_calls == 1);
  assert_parser_reset();
  // A failed restart must clear its former state, and a later retry can recover.
  dirty_parser(); bridge.begin(); assert(bridge.isRunning()); assert_parser_reset();
  serial.pins_ok = false;
  dirty_parser(); bridge.begin(); assert(!bridge.isRunning()); assert_parser_reset();
  dirty_parser(); bridge.end(); assert_parser_reset();
  serial.pins_ok = true; prefs.bridge_baud = 19200;
  dirty_parser(); bridge.begin(); assert(bridge.isRunning() && serial.baud == 19200); assert_parser_reset();
  for (unsigned cycle = 0; cycle < 100; ++cycle) {
    dirty_parser(); bridge.end(); assert(!bridge.isRunning()); assert_parser_reset();
    dirty_parser(); bridge.begin(); assert(bridge.isRunning()); assert_parser_reset();
  }
  dirty_parser(); bridge.end(); assert(!bridge.isRunning()); assert_parser_reset();
}
'''


class RS232DriverLifecycleTests(unittest.TestCase):
    def test_failed_pins_or_driver_start_never_report_running_and_retry_recovers(self):
        compiler = shutil.which("g++") or shutil.which("clang++")
        self.assertIsNotNone(compiler, "a host C++ compiler is required")
        driver = (ROOT / "src/helpers/bridges/RS232Bridge.cpp").read_text(encoding="ascii")
        base = (ROOT / "src/helpers/bridges/BridgeBase.cpp").read_text(encoding="ascii")
        code = FIXTURE.replace("@RUNNING@", extract_braced(base, "bool BridgeBase::isRunning() const")
                               .replace("BridgeBase::", "").replace(" override", ""))
        code = code.replace("@BEGIN@", extract_braced(driver, "void RS232Bridge::begin()"))
        code = code.replace("@END@", extract_braced(driver, "void RS232Bridge::end()"))
        code = code.replace("@RESET@", extract_braced(driver, "void RS232Bridge::resetTransportState()"))
        with tempfile.TemporaryDirectory(prefix="rs232-driver-lifecycle-") as directory:
            work = Path(directory)
            source, binary = work / "main.cpp", work / "test"
            source.write_text(code, encoding="ascii")
            built = subprocess.run([compiler, "-std=c++17", "-Wall", "-Wextra", "-Werror",
                "-fsanitize=address,undefined", "-fno-sanitize-recover=all", "-fno-pie", "-no-pie",
                str(source), "-o", str(binary)], capture_output=True, text=True, timeout=60)
            self.assertEqual(built.returncode, 0, built.stdout + built.stderr)
            checked = subprocess.run([str(binary)], capture_output=True, text=True, timeout=10)
            self.assertEqual(checked.returncode, 0, checked.stdout + checked.stderr)


if __name__ == "__main__":
    unittest.main()