"""从 sing-box Clash API 采集节点连接与流量（官方预编译包不含 v2ray_api）。"""
from __future__ import annotations

import json
import os
import re
import sqlite3
import subprocess
import time
import urllib.error
import urllib.request
from pathlib import Path

from db import connect, list_nodes
from nodes_util import hy2_inbound_tag, ordered_nodes

ROOT = Path(os.environ.get("JIEDIAN_ROOT", Path(__file__).resolve().parents[1]))
ENV_FILE = ROOT / ".env"

CLASH_ADDR = "127.0.0.1:9090"
_VLESS_INBOUND = "vless-reality-in"
_LOG_USER_RE = re.compile(
    r"\[([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12})\]\s+inbound connection"
)
_LOG_INDEX_RE = re.compile(r"\[(\d+)\] inbound connection")

_speed_cache: dict[int, tuple[float, int, int]] = {}
_conn_cache: dict[str, dict[str, int | str]] = {}
_global_bytes_cache: tuple[float, int, int] | None = None


def _load_env() -> dict[str, str]:
    env: dict[str, str] = {}
    if not ENV_FILE.exists():
        return env
    for line in ENV_FILE.read_text(encoding="utf-8").splitlines():
        line = line.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue
        key, _, value = line.partition("=")
        env[key.strip()] = value.strip()
    return env


def format_bytes(num: int | float) -> str:
    n = float(num)
    for unit in ("B", "KB", "MB", "GB", "TB"):
        if n < 1024 or unit == "TB":
            if unit == "B":
                return f"{int(n)} B"
            return f"{n:.1f} {unit}"
        n /= 1024
    return f"{n:.1f} PB"


def format_speed(num: float) -> str:
    return f"{format_bytes(num)}/s"


def fetch_clash_connections() -> tuple[list[dict], bool]:
    env = _load_env()
    secret = env.get("CLASH_API_SECRET", "")
    url = f"http://{CLASH_ADDR}/connections"
    req = urllib.request.Request(url)
    if secret:
        req.add_header("Authorization", f"Bearer {secret}")
    try:
        with urllib.request.urlopen(req, timeout=3) as resp:
            payload = json.loads(resp.read().decode("utf-8"))
    except (urllib.error.URLError, TimeoutError, json.JSONDecodeError, OSError):
        return [], False
    return payload.get("connections") or [], True


def fetch_recent_log_uuids(nodes: list[dict]) -> set[str]:
    """sing-box Clash API 不导出 user 字段，VLESS 多用户需从近期日志补全在线 UUID。"""
    try:
        proc = subprocess.run(
            [
                "journalctl",
                "-u",
                "sing-box",
                "--since",
                "3 min ago",
                "--no-pager",
                "-o",
                "cat",
            ],
            capture_output=True,
            text=True,
            timeout=2,
        )
    except (OSError, subprocess.TimeoutExpired):
        return set()
    if proc.returncode != 0:
        return set()

    known = {node["uuid"] for node in nodes}
    index_to_uuid = {i: node["uuid"] for i, node in enumerate(ordered_nodes(nodes))}
    active: set[str] = set()
    for match in _LOG_USER_RE.finditer(proc.stdout):
        uid = match.group(1)
        if uid in known:
            active.add(uid)
    for match in _LOG_INDEX_RE.finditer(proc.stdout):
        uid = index_to_uuid.get(int(match.group(1)))
        if uid:
            active.add(uid)
    return active


def _global_conn_speed(connections: list[dict]) -> tuple[float, float]:
    """从 /connections 汇总字节增量估算全局速率（/traffic 为 WebSocket 流，不能同步 HTTP 读）。"""
    total_up = sum(int(c.get("upload") or 0) for c in connections)
    total_down = sum(int(c.get("download") or 0) for c in connections)
    now = time.time()
    global _global_bytes_cache
    prev = _global_bytes_cache
    _global_bytes_cache = (now, total_up, total_down)
    if not prev:
        return 0.0, 0.0
    t0, u0, d0 = prev
    dt = now - t0
    if dt <= 0:
        return 0.0, 0.0
    return max(0.0, (total_up - u0) / dt), max(0.0, (total_down - d0) / dt)


def _connection_inbound_tag(conn: dict) -> str:
    meta = conn.get("metadata") or {}
    inbound_type = str(meta.get("type") or "")
    if "/" in inbound_type:
        return inbound_type.split("/", 1)[1]
    return inbound_type


def _connection_user(conn: dict) -> str:
    meta = conn.get("metadata") or {}
    for key in ("user", "uid", "auth_user", "auth", "username"):
        val = meta.get(key)
        if val:
            return str(val)
    for key in ("user", "uid"):
        val = conn.get(key)
        if val:
            return str(val)
    return ""


def _node_auth_keys(node: dict) -> set[str]:
    keys = {node["uuid"]}
    if node.get("hy2_password"):
        keys.add(node["hy2_password"])
    return keys


def _match_connection(conn: dict, node: dict, *, single_node: bool = False) -> bool:
    user = _connection_user(conn)
    if user and user in _node_auth_keys(node):
        return True

    tag = _connection_inbound_tag(conn)
    node_id = int(node["id"])
    expected_hy2 = hy2_inbound_tag(node_id)
    if tag == expected_hy2:
        return True
    if tag == "hysteria2-in" and single_node:
        return True
    return False


def _match_vless_connection(conn: dict, node: dict, log_active: set[str]) -> bool:
    tag = _connection_inbound_tag(conn)
    if tag != _VLESS_INBOUND:
        return False
    user = _connection_user(conn)
    if user == node["uuid"]:
        return True
    # 共享 VLESS inbound 无法从 Clash API 区分用户；仅唯一活跃用户时归因
    return node["uuid"] in log_active and len(log_active) == 1


def _connection_id(conn: dict) -> str:
    return str(conn.get("id") or "")


def _ensure_traffic_schema(conn: sqlite3.Connection) -> None:
    conn.executescript(
        """
        CREATE TABLE IF NOT EXISTS traffic_counters (
            node_id INTEGER PRIMARY KEY,
            upload_total INTEGER NOT NULL DEFAULT 0,
            download_total INTEGER NOT NULL DEFAULT 0,
            snapshot_upload INTEGER NOT NULL DEFAULT 0,
            snapshot_download INTEGER NOT NULL DEFAULT 0,
            updated_at TEXT,
            FOREIGN KEY (node_id) REFERENCES nodes(id) ON DELETE CASCADE
        );
        """
    )
    for row in conn.execute("SELECT id FROM nodes").fetchall():
        conn.execute(
            "INSERT OR IGNORE INTO traffic_counters (node_id) VALUES (?)",
            (row["id"],),
        )


def _add_closed_traffic(node_id: int, upload: int, download: int) -> None:
    if upload <= 0 and download <= 0:
        return
    conn = connect()
    _ensure_traffic_schema(conn)
    conn.execute(
        """
        UPDATE traffic_counters
        SET upload_total = upload_total + ?,
            download_total = download_total + ?,
            updated_at = datetime('now')
        WHERE node_id = ?
        """,
        (upload, download, node_id),
    )
    conn.commit()
    conn.close()


def _get_stored_totals(node_id: int) -> tuple[int, int]:
    conn = connect()
    _ensure_traffic_schema(conn)
    row = conn.execute(
        "SELECT upload_total, download_total FROM traffic_counters WHERE node_id = ?",
        (node_id,),
    ).fetchone()
    conn.close()
    if row is None:
        return 0, 0
    return int(row["upload_total"]), int(row["download_total"])


def _sync_connections(
    connections: list[dict],
    nodes: list[dict],
    uuid_to_node: dict[str, int],
    log_active: set[str],
) -> dict[str, tuple[int, int]]:
    """同步连接缓存，断开连接时写入累计流量，返回各用户当前活跃会话流量。"""
    seen: set[str] = set()
    active: dict[str, tuple[int, int]] = {}
    single_node = len(nodes) == 1
    only_uuid = nodes[0]["uuid"] if single_node else ""

    for conn in connections:
        matched_uuid = ""
        for node in nodes:
            if _match_connection(conn, node, single_node=single_node) or _match_vless_connection(
                conn, node, log_active
            ):
                matched_uuid = node["uuid"]
                break
        if not matched_uuid and single_node and connections:
            matched_uuid = only_uuid

        if matched_uuid not in uuid_to_node:
            continue

        cid = _connection_id(conn)
        if not cid:
            continue

        upload = int(conn.get("upload") or 0)
        download = int(conn.get("download") or 0)
        seen.add(cid)

        prev = _conn_cache.get(cid)
        if prev and prev["uuid"] == matched_uuid:
            prev_up = int(prev["upload"])
            prev_down = int(prev["download"])
            if upload < prev_up or download < prev_down:
                _add_closed_traffic(uuid_to_node[matched_uuid], prev_up, prev_down)
        _conn_cache[cid] = {
            "uuid": matched_uuid,
            "upload": upload,
            "download": download,
        }

        cur_up, cur_down = active.get(matched_uuid, (0, 0))
        active[matched_uuid] = (cur_up + upload, cur_down + download)

    for cid in list(_conn_cache.keys()):
        if cid in seen:
            continue
        info = _conn_cache.pop(cid)
        user = str(info["uuid"])
        node_id = uuid_to_node.get(user)
        if node_id:
            _add_closed_traffic(node_id, int(info["upload"]), int(info["download"]))

    return active


def _calc_speed(node_id: int, up: int, down: int) -> tuple[float, float]:
    now = time.time()
    prev = _speed_cache.get(node_id)
    _speed_cache[node_id] = (now, up, down)
    if not prev:
        return 0.0, 0.0
    t0, u0, d0 = prev
    dt = now - t0
    if dt <= 0:
        return 0.0, 0.0
    return max(0.0, (up - u0) / dt), max(0.0, (down - d0) / dt)


def _connections_for_node(
    connections: list[dict],
    node: dict,
    nodes: list[dict],
    log_active: set[str],
) -> list[dict | None]:
    single_node = len(nodes) == 1
    matched = [
        c
        for c in connections
        if _match_connection(c, node, single_node=single_node)
        or _match_vless_connection(c, node, log_active)
    ]
    if matched:
        return matched

    if single_node and connections:
        return connections

    if node["uuid"] in log_active:
        vless_hits = [c for c in connections if _connection_inbound_tag(c) == _VLESS_INBOUND]
        if vless_hits:
            return vless_hits
        return [None]
    return []


def collect_node_stats() -> dict:
    nodes = list_nodes()
    uuid_to_node = {node["uuid"]: int(node["id"]) for node in nodes}
    connections, clash_ok = fetch_clash_connections()
    log_active = fetch_recent_log_uuids(nodes) if len(nodes) > 1 else set()
    active_by_uuid = _sync_connections(connections, nodes, uuid_to_node, log_active)
    single_node = len(nodes) == 1
    has_connections = len(connections) > 0
    global_up_speed, global_down_speed = _global_conn_speed(connections) if clash_ok else (0.0, 0.0)
    global_active = (global_up_speed + global_down_speed) > 512

    result_nodes: dict[str, dict] = {}
    summary_online = 0
    summary_up_speed = 0.0
    summary_down_speed = 0.0

    for node in nodes:
        uid = node["uuid"]
        node_id = int(node["id"])
        stored_up, stored_down = _get_stored_totals(node_id)
        session_up, session_down = active_by_uuid.get(uid, (0, 0))
        display_up = stored_up + session_up
        display_down = stored_down + session_down
        up_speed, down_speed = _calc_speed(node_id, display_up, display_down)

        matched = _connections_for_node(connections, node, nodes, log_active)
        if not matched and single_node and global_active:
            up_speed = global_up_speed
            down_speed = global_down_speed

        online = (
            len(matched) > 0
            or (session_up + session_down) > 0
            or uid in log_active
            or (up_speed + down_speed) > 512
            or (single_node and (global_active or has_connections))
        )

        if online:
            summary_online += 1
        summary_up_speed += up_speed
        summary_down_speed += down_speed

        result_nodes[str(node_id)] = {
            "online": online,
            "connections": len(matched),
            "upload_speed": round(up_speed),
            "download_speed": round(down_speed),
            "upload_total": display_up,
            "download_total": display_down,
            "upload_speed_human": format_speed(up_speed),
            "download_speed_human": format_speed(down_speed),
            "upload_total_human": format_bytes(display_up),
            "download_total_human": format_bytes(display_down),
        }

    return {
        "ok": True,
        "singbox": clash_ok,
        "nodes": result_nodes,
        "summary": {
            "online": summary_online,
            "total_nodes": len(nodes),
            "upload_speed": round(summary_up_speed),
            "download_speed": round(summary_down_speed),
            "upload_speed_human": format_speed(summary_up_speed),
            "download_speed_human": format_speed(summary_down_speed),
        },
    }