#!/usr/bin/env python3
"""Share — local file sharing server (HTTPS)."""

import argparse
import configparser
import email.parser
import http.server
import json
import mimetypes
import socket
import ssl
import stat
import subprocess
import threading
import time
import urllib.parse
from datetime import datetime
from pathlib import Path

# ── Cleanup ──


def cleanup_loop(upload_dir: Path, max_age: int):
    if max_age <= 0:
        return
    while True:
        time.sleep(CLEANUP_INTERVAL)
        now = time.time()
        try:
            entries = list(upload_dir.iterdir())
        except OSError as e:
            print(f"  cleanup error: {e}")
            continue
        for f in entries:
            try:
                if f.is_file() and now - f.stat().st_mtime > max_age:
                    f.unlink()
                    print(f"  - expired: {f.name}")
            except OSError:
                pass


# ── SSL ──


def get_local_ip():
    try:
        with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
            s.connect(("8.8.8.8", 80))
            return s.getsockname()[0]
    except OSError:
        return "127.0.0.1"


def ensure_cert(cert_dir: Path, extra_ips: list[str] | None = None) -> tuple[Path, Path]:
    """Generate self-signed cert if missing. Returns (certfile, keyfile)."""
    cert_dir.mkdir(parents=True, exist_ok=True)
    cert = cert_dir / "cert.pem"
    key = cert_dir / "key.pem"
    if cert.is_file() and key.is_file():
        return cert, key
    cert.unlink(missing_ok=True)
    key.unlink(missing_ok=True)

    ips = {"127.0.0.1", get_local_ip()}
    if extra_ips:
        ips.update(extra_ips)
    san = ",".join([f"IP:{ip}" for ip in sorted(ips)] + ["DNS:localhost"])

    subprocess.run([
        "openssl", "req", "-x509", "-newkey", f"rsa:{CERT_KEY_BITS}",
        "-keyout", str(key), "-out", str(cert),
        "-days", str(CERT_DAYS), "-nodes",
        "-subj", "/CN=Share",
        "-addext", f"subjectAltName={san}",
    ], check=True, capture_output=True)
    print(f"  Generated self-signed cert in {cert_dir}")
    return cert, key


BASE_DIR = Path(__file__).resolve().parent

# ── Config ──

_cp = configparser.ConfigParser()
_cp.read_dict({
    "server": {
        "port": "3001", "dir": str(Path.home() / "Downloads" / "shared"),
        "ttl": "7", "san": "", "lang": "ru", "refresh": "5",
        "per_page": "10,25,50,100",
    },
    "internal": {
        "secs_per_day": "86400", "cleanup_interval": "3600",
        "ssl_handshake_timeout": "5", "sniff_size": "8192",
        "chunk_size": "65536", "cert_days": "3650", "cert_key_bits": "2048",
        "toast_ms": "2500", "progress_hide_ms": "1200",
    },
})
_cp.read(BASE_DIR / "share.config")

SECS_PER_DAY = _cp.getint("internal", "secs_per_day")
CLEANUP_INTERVAL = _cp.getint("internal", "cleanup_interval")
SSL_HANDSHAKE_TIMEOUT = _cp.getint("internal", "ssl_handshake_timeout")
SNIFF_SIZE = _cp.getint("internal", "sniff_size")
CHUNK_SIZE = _cp.getint("internal", "chunk_size")
CERT_DAYS = _cp.getint("internal", "cert_days")
CERT_KEY_BITS = _cp.getint("internal", "cert_key_bits")

def _file_type(path: Path) -> str:
    ct = mimetypes.guess_type(path.name)[0] or ''
    if ct.startswith('image/'):
        return 'image'
    if ct.startswith('text/'):
        return 'text'
    try:
        with path.open('rb') as f:
            return 'text' if b'\x00' not in f.read(SNIFF_SIZE) else 'other'
    except OSError:
        return 'other'


# ── HTTP Handler ──


class ShareServer(http.server.ThreadingHTTPServer):
    def __init__(self, addr, handler, *, upload_dir: Path, html: bytes, ssl_ctx: ssl.SSLContext | None = None):
        super().__init__(addr, handler)
        self.upload_dir = upload_dir
        self.html = html
        self.ssl_ctx = ssl_ctx

    def get_request(self):
        client, addr = self.socket.accept()
        if self.ssl_ctx:
            client.settimeout(SSL_HANDSHAKE_TIMEOUT)
            try:
                client = self.ssl_ctx.wrap_socket(client, server_side=True)
            except (ssl.SSLError, OSError):
                client.close()
                raise
            client.settimeout(None)
        return client, addr


class Handler(http.server.BaseHTTPRequestHandler):
    server: ShareServer

    def finish(self):
        try:
            super().finish()
        except (ssl.SSLError, BrokenPipeError, ConnectionResetError, OSError):
            pass

    def log_message(self, fmt, *args):
        print(f"  [{datetime.now():%H:%M:%S}] {args[0]}")

    def _json(self, data):
        self._respond(json.dumps(data).encode(), "application/json")

    def _respond(self, data: bytes, ct: str):
        self.send_response(200)
        self.send_header("Content-Type", ct)
        self.send_header("Content-Length", str(len(data)))
        self.send_header("Connection", "close")
        self.send_header("Access-Control-Allow-Origin", "*")
        self.end_headers()
        self.wfile.write(data)

    # ── Routes ──

    ROUTES = {
        "GET": [
            ("/",          "_route_index"),
            ("/index.html","_route_index"),
            ("/files",     "_route_files"),
            ("/dl/",       "_route_download"),
        ],
        "POST":   [("/upload", "_route_upload")],
        "DELETE": [("/del/",   "_route_delete")],
    }

    def _dispatch(self):
        for prefix, method in self.ROUTES.get(self.command, []):
            if self.path == prefix or (len(prefix) > 1 and prefix.endswith("/") and self.path.startswith(prefix)):
                return getattr(self, method)(prefix)
        self.send_error(404)

    do_GET = do_POST = do_DELETE = _dispatch

    def _route_index(self, _prefix):
        self._respond(self.server.html, "text/html; charset=utf-8")

    def _route_files(self, _prefix):
        entries = []
        for p in self.server.upload_dir.iterdir():
            if p.is_file():
                entries.append((p, p.stat()))
        entries.sort(key=lambda e: e[1].st_mtime, reverse=True)
        self._json([{"name": p.name, "size": st.st_size, "type": _file_type(p)} for p, st in entries])

    def _safe_path(self, prefix: str) -> Path:
        name = urllib.parse.unquote(self.path[len(prefix):])
        return self.server.upload_dir / Path(name).name

    def _route_download(self, prefix):
        safe = self._safe_path(prefix)
        try:
            st = safe.stat()
        except FileNotFoundError:
            self.send_error(404)
            return
        if not stat.S_ISREG(st.st_mode):
            self.send_error(404)
            return
        ct = mimetypes.guess_type(safe.name)[0] or "application/octet-stream"
        fname = safe.name.replace("\\", "\\\\").replace('"', '\\"')
        self.send_response(200)
        self.send_header("Content-Type", ct)
        self.send_header("Content-Disposition", f'attachment; filename="{fname}"')
        self.send_header("Content-Length", str(st.st_size))
        self.send_header("Connection", "close")
        self.end_headers()
        with safe.open("rb") as f:
            while chunk := f.read(CHUNK_SIZE):
                self.wfile.write(chunk)

    def _route_upload(self, _prefix):
        ct = self.headers.get("Content-Type", "")
        if "multipart/form-data" not in ct:
            self.send_error(400)
            return
        length = int(self.headers.get("Content-Length", 0))
        if not length:
            self.send_error(400)
            return
        body = self.rfile.read(length)
        count = self._save_parts(ct, body)
        self._json({"ok": True, "count": count})

    def _route_delete(self, prefix):
        safe = self._safe_path(prefix)
        if safe.is_file():
            safe.unlink()
        self._json({"ok": True})

    # ── Helpers ──

    def _save_parts(self, content_type: str, body: bytes) -> int:
        header = f"Content-Type: {content_type}\r\n\r\n".encode()
        msg = email.parser.BytesParser().parsebytes(header + body)
        count = 0
        for part in msg.walk():
            fname = part.get_filename()
            if not fname:
                continue
            fname = Path(fname).name or f"paste_{datetime.now():%H%M%S}"
            data = part.get_payload(decode=True)
            if not data:
                continue
            dest = self._unique_path(fname)
            dest.write_bytes(data)
            count += 1
            print(f"  + {dest.name} ({len(data)} bytes)")
        return count

    def _unique_path(self, filename: str) -> Path:
        dest = self.server.upload_dir / filename
        if not dest.exists():
            return dest
        stem, suffix = dest.stem, dest.suffix
        i = 1
        while dest.exists():
            dest = self.server.upload_dir / f"{stem}_{i}{suffix}"
            i += 1
        return dest


# ── Main ──


def load_config() -> dict:
    """Load config: share.config defaults ← CLI args."""
    conf = dict(_cp["server"])

    p = argparse.ArgumentParser(description="Share — local file sharing server")
    p.add_argument("-p", "--port", type=int)
    p.add_argument("-d", "--dir")
    p.add_argument("--ttl", type=int)
    p.add_argument("--san", nargs="*")
    p.add_argument("--lang")
    p.add_argument("--refresh", type=int)
    args = p.parse_args()

    for key, val in vars(args).items():
        if val is not None:
            conf[key] = " ".join(val) if isinstance(val, list) else str(val)

    return conf


def main():
    conf = load_config()

    port = int(conf["port"])
    upload_dir = Path(conf["dir"]).expanduser().resolve()
    max_age = int(conf["ttl"]) * SECS_PER_DAY
    san_list = conf["san"].split() if conf["san"] else None

    upload_dir.mkdir(parents=True, exist_ok=True)

    threading.Thread(target=cleanup_loop, args=(upload_dir, max_age), daemon=True).start()

    ip = get_local_ip()
    cfg_json = json.dumps({
        "lang": conf["lang"],
        "refresh": int(conf["refresh"]),
        "perPage": [int(x) for x in conf["per_page"].split(",")],
        "toastMs": _cp.getint("internal", "toast_ms"),
        "progressHideMs": _cp.getint("internal", "progress_hide_ms"),
    })
    cfg_tag = f"<script>const CFG={cfg_json}</script>".encode()
    html = (BASE_DIR / "static" / "index.html").read_bytes()
    html = html.replace(b"<!--CFG-->", cfg_tag)

    cert_dir = BASE_DIR / ".certs"
    cert, key = ensure_cert(cert_dir, extra_ips=san_list)
    ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
    ctx.load_cert_chain(cert, key)

    server = ShareServer(("0.0.0.0", port), Handler, upload_dir=upload_dir, html=html, ssl_ctx=ctx)

    print("\n  Share running")
    print(f"  Local:   https://localhost:{port}")
    print(f"  Network: https://{ip}:{port}")
    print(f"  Files:   {upload_dir}\n")
    try:
        server.serve_forever()
    except KeyboardInterrupt:
        print("\n  Stopped.")
        server.server_close()


if __name__ == "__main__":
    main()