import platform
import shutil
import socket
from pathlib import Path


APP_NAME = "Car UI"
VERSION = "0.1.0-dev"
BUILD_DATE = "dev"
GIT_HASH = "dev"
DEVICE_MODEL = "Raspberry Pi"
DEFAULT_SOUND_VOLUME = 100
DEFAULT_PREMUTE_VOLUME = 10
DEFAULT_DUCKING_VOLUME = 35
DEV_MODE_ENABLE = (Path(__file__).resolve().parent / "dev_mode_enable").exists()


def get_device_model() -> str:
    for path in ("/proc/device-tree/model", "/sys/firmware/devicetree/base/model"):
        try:
            with open(path, "rb") as f:
                raw = f.read().strip(b"\x00").strip()
            if raw:
                return raw.decode("utf-8", errors="replace")
        except OSError:
            continue
    return DEVICE_MODEL


def get_os_pretty_name() -> str:
    for path in ("/etc/os-release", "/usr/lib/os-release"):
        try:
            with open(path, "r", encoding="utf-8") as f:
                for line in f:
                    if line.startswith("PRETTY_NAME="):
                        value = line.split("=", 1)[1].strip().strip('"')
                        return value or "—"
        except OSError:
            continue
    return platform.system() or "—"


def get_kernel_version() -> str:
    return platform.release() or "—"


def _read_meminfo() -> dict[str, int]:
    info: dict[str, int] = {}
    try:
        with open("/proc/meminfo", "r", encoding="utf-8") as f:
            for line in f:
                if ":" not in line:
                    continue
                key, rest = line.split(":", 1)
                parts = rest.strip().split()
                if not parts:
                    continue
                try:
                    value_kb = int(parts[0])
                except ValueError:
                    continue
                info[key] = value_kb * 1024
    except OSError:
        return {}
    return info


def _format_bytes(num_bytes: int) -> str:
    if num_bytes <= 0:
        return "—"
    gib = num_bytes / (1024 ** 3)
    if gib >= 1:
        return f"{gib:.1f} GB"
    mib = num_bytes / (1024 ** 2)
    return f"{mib:.0f} MB"


def get_ram_info() -> str:
    info = _read_meminfo()
    total = info.get("MemTotal", 0)
    free = info.get("MemFree", 0)
    if total <= 0:
        return "—"
    return f"{_format_bytes(free)} / {_format_bytes(total)}"


def get_disk_info() -> str:
    try:
        usage = shutil.disk_usage("/")
    except OSError:
        return "—"
    return f"{_format_bytes(usage.used)} / {_format_bytes(usage.total)}"


def get_serial_number() -> str:
    for path in ("/proc/device-tree/serial-number",):
        try:
            with open(path, "rb") as f:
                raw = f.read().strip(b"\x00").strip()
            if raw:
                return raw.decode("utf-8", errors="replace")
        except OSError:
            continue
    try:
        with open("/proc/cpuinfo", "r", encoding="utf-8") as f:
            for line in f:
                if line.lower().startswith("serial"):
                    return line.split(":", 1)[1].strip() or "—"
    except OSError:
        pass
    return "—"


def get_ip_address() -> str:
    try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        try:
            sock.connect(("8.8.8.8", 80))
            ip = sock.getsockname()[0]
        finally:
            sock.close()
        if ip and not ip.startswith("127."):
            return ip
    except OSError:
        pass
    try:
        ip = socket.gethostbyname(socket.gethostname())
        if ip and not ip.startswith("127."):
            return ip
    except OSError:
        pass
    return "—"


def get_cpu_temp() -> str:
    for path in ("/sys/class/thermal/thermal_zone0/temp",):
        try:
            with open(path, "r", encoding="utf-8") as f:
                raw = f.read().strip()
            if raw:
                temp_c = float(raw) / 1000.0
                return f"{temp_c:.1f} C"
        except (OSError, ValueError):
            continue
    return "—"


def get_display_resolution() -> str:
    for path in ("/sys/class/graphics/fb0/virtual_size", "/sys/class/graphics/fb0/modes"):
        try:
            with open(path, "r", encoding="utf-8") as f:
                raw = f.read().strip()
            if not raw:
                continue
            if "x" in raw:
                first_line = raw.splitlines()[0]
                return first_line.split(" ", 1)[0]
            if "," in raw:
                width, height = raw.split(",", 1)
                return f"{width.strip()}x{height.strip()}"
        except OSError:
            continue
    return "—"