import re
import threading
import time
from typing import Callable, Optional

import serial


class GSMGateway:
    def __init__(
        self,
        port: str,
        baudrate: int,
        message_callback: Optional[Callable[[str, str], None]] = None,
    ):
        self.port = port
        self.baudrate = baudrate
        self.message_callback = message_callback
        self.serial_conn = None
        self.is_running = False
        self.read_thread = None
        self.lock = threading.Lock()

    @property
    def is_connected(self) -> bool:
        return bool(self.serial_conn and self.serial_conn.is_open)

    def connect(self) -> bool:
        try:
            self.serial_conn = serial.Serial(
                port=self.port,
                baudrate=self.baudrate,
                timeout=1,
            )
            self.is_running = True
            self.send_at_cmd("AT")
            self.send_at_cmd("AT+CMGF=1")
            self.send_at_cmd('AT+CNMI=2,1,0,0,0')
            self.read_thread = threading.Thread(target=self._read_loop, daemon=True)
            self.read_thread.start()
            return True
        except Exception:
            self.serial_conn = None
            self.is_running = False
            return False

    def disconnect(self):
        self.is_running = False
        if self.serial_conn and self.serial_conn.is_open:
            self.serial_conn.close()
        if self.read_thread:
            self.read_thread.join(timeout=1.5)

    def send_at_cmd(self, command: str, expected_response: str = "OK", timeout: float = 2.0) -> tuple[bool, list[str]]:
        with self.lock:
            if not self.is_connected:
                return False, ["offline"]
            self.serial_conn.reset_input_buffer()
            self.serial_conn.write((command + "\r\n").encode("ascii"))
            start = time.time()
            lines = []
            while time.time() - start < timeout:
                if self.serial_conn.in_waiting:
                    line = self.serial_conn.readline().decode("ascii", errors="ignore").strip()
                    if line:
                        lines.append(line)
                        if expected_response in line or "ERROR" in line:
                            break
                else:
                    time.sleep(0.05)
            return expected_response in "\n".join(lines), lines

    def send_frames(self, phone: str, frames: list[str]) -> bool:
        if not self.is_connected:
            return False
        for frame in frames:
            if not self._send_single_sms(phone, frame):
                return False
            time.sleep(0.8)
        return True

    def _send_single_sms(self, phone: str, body: str) -> bool:
        with self.lock:
            try:
                self.serial_conn.reset_input_buffer()
                self.serial_conn.write(f'AT+CMGS="{phone}"\r\n'.encode("ascii"))
                start = time.time()
                prompt_ready = False
                while time.time() - start < 2:
                    if self.serial_conn.in_waiting:
                        char = self.serial_conn.read().decode("ascii", errors="ignore")
                        if char == ">":
                            prompt_ready = True
                            break
                    time.sleep(0.05)
                if not prompt_ready:
                    self.serial_conn.write(chr(27).encode("ascii"))
                    return False
                self.serial_conn.write(body.encode("ascii") + chr(26).encode("ascii"))
                start = time.time()
                while time.time() - start < 10:
                    if self.serial_conn.in_waiting:
                        line = self.serial_conn.readline().decode("ascii", errors="ignore").strip()
                        if "OK" in line:
                            return True
                        if "ERROR" in line:
                            return False
                    else:
                        time.sleep(0.1)
            except Exception:
                return False
            return False

    def _read_loop(self):
        while self.is_running:
            try:
                if self.is_connected and self.serial_conn.in_waiting and self.lock.acquire(blocking=False):
                    try:
                        line = self.serial_conn.readline().decode("ascii", errors="ignore").strip()
                        if line.startswith("+CMTI:"):
                            match = re.search(r'\+CMTI:\s*".*?",(\d+)', line)
                            if match:
                                index = int(match.group(1))
                                threading.Thread(
                                    target=self._process_incoming_sms,
                                    args=(index,),
                                    daemon=True,
                                ).start()
                    finally:
                        self.lock.release()
            except Exception:
                pass
            time.sleep(0.1)

    def _process_incoming_sms(self, index: int):
        time.sleep(0.7)
        ok, lines = self.send_at_cmd(f"AT+CMGR={index}", expected_response="OK", timeout=3)
        if not ok:
            return
        sender = "ناشناس"
        body_lines = []
        reading_body = False
        for line in lines:
            if line.startswith("+CMGR:"):
                parts = line.split(",")
                if len(parts) >= 2:
                    sender = parts[1].strip('"')
                reading_body = True
                continue
            if reading_body and line not in {"OK", "ERROR"}:
                body_lines.append(line)
        if self.message_callback:
            self.message_callback(sender, "\n".join(body_lines))
        self.send_at_cmd(f"AT+CMGD={index}")