#!/usr/bin/env python3
"""
Discover WLED devices in local networks and flash them sequentially via OTA.
"""

from __future__ import annotations

import argparse
import ipaddress
import os
import re
import subprocess
import time
from concurrent.futures import ThreadPoolExecutor, as_completed
from dataclasses import dataclass
from pathlib import Path
from typing import Iterable

import requests


DEFAULT_OUTPUT_FILE = "tools/discovered_wled_hosts.txt"


@dataclass
class WledHost:
    ip: str
    name: str
    version: str
    arch: str


@dataclass
class WledInfo(WledHost):
    uptime_s: int


def _run(cmd: list[str]) -> str:
    proc = subprocess.run(cmd, check=True, capture_output=True, text=True)
    return proc.stdout


def local_networks() -> list[ipaddress.IPv4Network]:
    """
    Read active IPv4 interfaces from `ip` and return private subnets.
    """
    out = _run(["ip", "-o", "-4", "addr", "show", "scope", "global"])
    nets: list[ipaddress.IPv4Network] = []
    seen: set[str] = set()
    for line in out.splitlines():
        match = re.search(r"\binet\s+(\d+\.\d+\.\d+\.\d+/\d+)\b", line)
        if not match:
            continue
        iface_cidr = match.group(1)
        iface_ip = ipaddress.ip_interface(iface_cidr)
        net = iface_ip.network
        if not iface_ip.ip.is_private:
            continue
        if net.num_addresses > 2048:
            # avoid accidentally scanning very large ranges by default
            net = ipaddress.ip_network(f"{iface_ip.ip}/24", strict=False)
        key = str(net)
        if key in seen:
            continue
        seen.add(key)
        nets.append(net)
    return nets


def parse_networks(raw: Iterable[str] | None) -> list[ipaddress.IPv4Network]:
    if raw:
        nets: list[ipaddress.IPv4Network] = []
        for item in raw:
            nets.append(ipaddress.ip_network(item, strict=False))
        return nets
    return local_networks()


def probe_wled_info(ip: str, timeout_s: float) -> WledInfo | None:
    url = f"http://{ip}/json/info"
    try:
        resp = requests.get(url, timeout=timeout_s)
        if resp.status_code != 200:
            return None
        data = resp.json()
    except (requests.RequestException, ValueError):
        return None

    # WLED info endpoint typically includes "name", "ver", and "arch"
    ver = str(data.get("ver", "")).strip()
    name = str(data.get("name", "")).strip()
    arch = str(data.get("arch", "")).strip()
    if not ver:
        return None

    if not name:
        name = "WLED"
    if not arch:
        arch = "-"

    uptime_s = int(data.get("uptime", 0) or 0)
    return WledInfo(ip=ip, name=name, version=ver, arch=arch, uptime_s=uptime_s)


def probe_wled(ip: str, timeout_s: float) -> WledHost | None:
    info = probe_wled_info(ip, timeout_s)
    if info is None:
        return None
    return WledHost(ip=info.ip, name=info.name, version=info.version, arch=info.arch)


def discover_hosts(
    nets: list[ipaddress.IPv4Network],
    timeout_s: float,
    workers: int,
) -> list[WledHost]:
    candidates: list[str] = []
    for net in nets:
        for host in net.hosts():
            candidates.append(str(host))

    found: list[WledHost] = []
    with ThreadPoolExecutor(max_workers=workers) as executor:
        futures = [executor.submit(probe_wled, ip, timeout_s) for ip in candidates]
        for fut in as_completed(futures):
            result = fut.result()
            if result is not None:
                found.append(result)

    found.sort(key=lambda h: tuple(int(part) for part in h.ip.split(".")))
    return found


def read_targets_file(path: Path) -> list[str]:
    targets: list[str] = []
    for raw in path.read_text(encoding="utf-8").splitlines():
        line = raw.strip()
        if not line or line.startswith("#"):
            continue
        targets.append(line.split()[0])
    return targets


def write_discovery(path: Path, hosts: list[WledHost]) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    lines = ["# ip name version arch"]
    lines += [f"{h.ip} {h.name} {h.version} {h.arch}" for h in hosts]
    path.write_text("\n".join(lines) + "\n", encoding="utf-8")


def wait_for_online(ip: str, timeout_s: float, interval_s: float) -> bool:
    deadline = time.time() + timeout_s
    while time.time() < deadline:
        if probe_wled(ip, timeout_s=1.2) is not None:
            return True
        time.sleep(interval_s)
    return False


def wait_for_offline(ip: str, timeout_s: float, interval_s: float) -> bool:
    deadline = time.time() + timeout_s
    while time.time() < deadline:
        if probe_wled(ip, timeout_s=1.2) is None:
            return True
        time.sleep(interval_s)
    return False


def wait_for_online_info(ip: str, timeout_s: float, interval_s: float) -> WledInfo | None:
    deadline = time.time() + timeout_s
    while time.time() < deadline:
        info = probe_wled_info(ip, timeout_s=1.2)
        if info is not None:
            return info
        time.sleep(interval_s)
    return None


def reboot_confirmed(before: WledInfo | None, after: WledInfo, offline_seen: bool) -> tuple[bool, str]:
    if offline_seen:
        return True, "offline transition observed"
    if before is None:
        return False, "device was not profiled before upload, and no offline transition was observed"
    if after.uptime_s + 5 < before.uptime_s:
        return True, f"uptime reset from {before.uptime_s}s to {after.uptime_s}s"
    return False, f"device stayed reachable and uptime did not reset ({before.uptime_s}s -> {after.uptime_s}s)"


def ota_flash(ip: str, firmware: Path, connect_timeout_s: float, read_timeout_s: float) -> tuple[str, str]:
    url = f"http://{ip}/update"
    try:
        with firmware.open("rb") as fh:
            resp = requests.post(
                url,
                files={"update": (firmware.name, fh, "application/octet-stream")},
                timeout=(connect_timeout_s, read_timeout_s),
            )
    except requests.ReadTimeout:
        # Common with WLED OTA: upload is accepted but HTTP response never arrives before reboot.
        return "uncertain", "read timeout after upload"
    except requests.ConnectionError:
        # Some devices close the socket abruptly when rebooting after successful OTA.
        return "uncertain", "connection dropped during/after upload"
    except requests.RequestException as exc:
        return "failed", f"request failed: {exc}"

    text = (resp.text or "").lower()
    if resp.status_code >= 400:
        return "failed", f"http {resp.status_code}"
    if "fail" in text or "error" in text:
        return "failed", "device reported update failure"
    return "ok", "ok"


def print_hosts(hosts: list[WledHost]) -> None:
    if not hosts:
        print("No WLED devices found.")
        return
    print(f"Found {len(hosts)} WLED device(s):")
    print(f"{'IP':<16} {'Name':<24} {'Version':<18} {'Arch'}")
    print("-" * 80)
    for h in hosts:
        print(f"{h.ip:<16} {h.name[:24]:<24} {h.version[:18]:<18} {h.arch}")


def cmd_discover(args: argparse.Namespace) -> int:
    nets = parse_networks(args.subnet)
    if not nets:
        print("No private IPv4 networks found. Pass --subnet explicitly.")
        return 2

    print("Scanning networks:", ", ".join(str(n) for n in nets))
    hosts = discover_hosts(nets=nets, timeout_s=args.timeout, workers=args.workers)
    print_hosts(hosts)

    if args.output:
        out = Path(args.output)
        write_discovery(out, hosts)
        print(f"Saved discovery list: {out}")
    return 0


def resolve_targets(args: argparse.Namespace) -> list[str]:
    targets: list[str] = []

    if args.targets:
        targets.extend([t.strip() for t in args.targets.split(",") if t.strip()])

    if args.targets_file:
        targets.extend(read_targets_file(Path(args.targets_file)))

    if args.discover:
        nets = parse_networks(args.subnet)
        hosts = discover_hosts(nets=nets, timeout_s=args.timeout, workers=args.workers)
        targets.extend([h.ip for h in hosts])

    unique: list[str] = []
    seen: set[str] = set()
    for t in targets:
        if t in seen:
            continue
        seen.add(t)
        unique.append(t)
    return unique


def cmd_flash(args: argparse.Namespace) -> int:
    firmware = Path(args.firmware)
    if not firmware.exists():
        print(f"Firmware file not found: {firmware}")
        return 2

    targets = resolve_targets(args)
    if not targets:
        print("No targets selected. Use --targets, --targets-file, or --discover.")
        return 2
    if args.start_from:
        if args.start_from not in targets:
            print(f"--start-from target not found in target set: {args.start_from}")
            return 2
        start_idx = targets.index(args.start_from)
        targets = targets[start_idx:]

    print(f"Flashing {len(targets)} device(s) sequentially with: {firmware}")
    failures: list[str] = []

    for idx, ip in enumerate(targets, start=1):
        before = probe_wled_info(ip, timeout_s=args.timeout)
        if before is not None:
            print(
                f"[{idx}/{len(targets)}] {ip}: current firmware {before.version}, "
                f"uptime {before.uptime_s}s, name '{before.name}'"
            )
        print(f"[{idx}/{len(targets)}] {ip}: uploading...")
        status, msg = ota_flash(
            ip=ip,
            firmware=firmware,
            connect_timeout_s=args.connect_timeout,
            read_timeout_s=args.upload_timeout,
        )
        if status == "failed":
            print(f"[{idx}/{len(targets)}] {ip}: FAILED ({msg})")
            failures.append(ip)
            continue

        if status == "uncertain":
            print(f"[{idx}/{len(targets)}] {ip}: upload response uncertain ({msg}), verifying via reboot check...")
        else:
            print(f"[{idx}/{len(targets)}] {ip}: uploaded, waiting {args.reboot_wait:.1f}s for reboot...")
        time.sleep(args.reboot_wait)

        offline_seen = wait_for_offline(ip=ip, timeout_s=args.offline_timeout, interval_s=0.5)
        if offline_seen:
            print(f"[{idx}/{len(targets)}] {ip}: reboot detected, device went offline.")
        else:
            print(f"[{idx}/{len(targets)}] {ip}: warning, no offline transition observed. Checking uptime reset...")

        after = wait_for_online_info(ip=ip, timeout_s=args.online_timeout, interval_s=1.0)
        if after is None:
            print(f"[{idx}/{len(targets)}] {ip}: no online response after upload window.")
            failures.append(ip)
            continue

        reboot_ok, reason = reboot_confirmed(before=before, after=after, offline_seen=offline_seen)
        if not reboot_ok:
            print(f"[{idx}/{len(targets)}] {ip}: FAILED (could not prove reboot: {reason})")
            failures.append(ip)
            continue

        print(
            f"[{idx}/{len(targets)}] {ip}: OK "
            f"(now {after.version}, uptime {after.uptime_s}s, {reason})"
        )

    if failures:
        print("\nFailed targets:")
        for ip in failures:
            print(f"- {ip}")
        return 1

    print("\nAll targets flashed successfully.")
    return 0


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(description="Discover and OTA-flash WLED devices.")
    sub = parser.add_subparsers(dest="cmd", required=True)

    p_discover = sub.add_parser("discover", help="Scan network(s) for WLED devices.")
    p_discover.add_argument("--subnet", action="append", help="Subnet CIDR, repeatable (example: 192.168.1.0/24).")
    p_discover.add_argument("--timeout", type=float, default=0.8, help="HTTP probe timeout in seconds.")
    p_discover.add_argument("--workers", type=int, default=128, help="Parallel probe workers.")
    p_discover.add_argument("--output", default=DEFAULT_OUTPUT_FILE, help="Output file for discovered hosts.")
    p_discover.set_defaults(func=cmd_discover)

    p_flash = sub.add_parser("flash", help="Flash firmware.bin to selected hosts sequentially.")
    p_flash.add_argument("--firmware", required=True, help="Path to firmware.bin")
    p_flash.add_argument("--targets", help="Comma-separated IP list")
    p_flash.add_argument("--targets-file", help="Text file with one IP per line")
    p_flash.add_argument("--discover", action="store_true", help="Discover targets before flashing")
    p_flash.add_argument("--subnet", action="append", help="Subnet CIDR for discovery mode")
    p_flash.add_argument("--start-from", help="Start flashing from this IP within the resolved target list")
    p_flash.add_argument("--timeout", type=float, default=0.8, help="HTTP probe timeout in seconds")
    p_flash.add_argument("--workers", type=int, default=128, help="Parallel probe workers for discovery")
    p_flash.add_argument("--connect-timeout", type=float, default=5.0, help="HTTP connect timeout in seconds")
    p_flash.add_argument("--upload-timeout", type=float, default=90.0, help="HTTP upload timeout in seconds")
    p_flash.add_argument("--reboot-wait", type=float, default=10.0, help="Sleep after upload before online check")
    p_flash.add_argument("--offline-timeout", type=float, default=20.0, help="How long to wait for the device to disappear during reboot")
    p_flash.add_argument("--online-timeout", type=float, default=60.0, help="How long to wait for device to come back")
    p_flash.set_defaults(func=cmd_flash)

    return parser


def main() -> int:
    parser = build_parser()
    args = parser.parse_args()
    try:
        return int(args.func(args))
    except KeyboardInterrupt:
        print("\nAborted by user (Ctrl+C).")
        print("Tip: rerun with --start-from <ip> to continue at a specific device.")
        return 130


if __name__ == "__main__":
    os.environ.setdefault("PYTHONUNBUFFERED", "1")
    raise SystemExit(main())