import os
import sys
import time
import threading
import argparse
import RNS
from http.server import HTTPServer

from db import init_db, get_setting, set_setting
from handlers import dispatch_request
from gateway import GatewayState, GatewayHandler, GATEWAY_PORT

APP_NAME = "tinyweb"
ASPECTS = ["server"]
IDENTITY_FILE = "tinyweb_identity"
DEFAULT_TRANSPORT_HOST = "reticulum.derickphan.com"
DEFAULT_TRANSPORT_PORT = 4242
DATA_DIR = os.path.expanduser("~/.tinyweb")


def get_transport_config():
    host = get_setting("transport_host", DEFAULT_TRANSPORT_HOST)
    port = get_setting("transport_port", str(DEFAULT_TRANSPORT_PORT))
    return host, int(port)


def find_available_port(start=8080, max_attempts=20):
    """Find an available port starting from start."""
    import socket
    for port in range(start, start + max_attempts):
        try:
            with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
                s.bind(("0.0.0.0", port))
            return port
        except OSError:
            continue
    return start


def get_version():
    """Get version from git tag or VERSION file."""
    try:
        import subprocess
        tag = subprocess.check_output(
            ["git", "describe", "--tags", "--abbrev=0"],
            stderr=subprocess.DEVNULL,
            text=True
        ).strip()
        if tag.startswith("v"):
            return tag[1:]
        return tag
    except Exception:
        version_file = os.path.join(os.path.dirname(__file__), "VERSION")
        if os.path.exists(version_file):
            with open(version_file) as f:
                return f.read().strip()
        return "0.0.0"


def load_or_create_identity():
    os.makedirs(DATA_DIR, exist_ok=True)
    identity_path = os.path.join(DATA_DIR, IDENTITY_FILE)
    if os.path.isfile(identity_path):
        current = os.stat(identity_path).st_mode & 0o777
        if current != 0o600:
            os.chmod(identity_path, 0o600)
        return RNS.Identity.from_file(identity_path)
    identity = RNS.Identity()
    identity.to_file(identity_path)
    os.chmod(identity_path, 0o600)
    return identity


def rns_request_handler(path, data, request_id, link_id, remote_identity, requested_at):
    if data is None:
        data = {"method": "GET", "path": "/", "query": {}, "body": {}, "gateway_host": ""}
    return dispatch_request(data)


def start_gateway(reticulum):
    GatewayState.reticulum = reticulum
    GatewayState.local_dispatch = dispatch_request
    server = HTTPServer(("0.0.0.0", GATEWAY_PORT), GatewayHandler)
    thread = threading.Thread(target=server.serve_forever, daemon=True)
    thread.start()


def _transport_settings_match(config_file, desired_host, desired_port):
    """Check if existing config transport settings match desired values."""
    import configparser
    try:
        config = configparser.ConfigParser()
        config.read(config_file)
        if config.has_section("TCP Transport"):
            existing_host = config.get("TCP Transport", "target_host")
            existing_port = config.get("TCP Transport", "target_port")
            return existing_host == desired_host and existing_port == str(desired_port)
    except Exception:
        pass
    return False


def ensure_rns_config(config_dir, transport_host=None, transport_port=None):
    """Generate a default Reticulum config with internet transport if none exists."""
    if config_dir is None:
        config_dir = os.path.expanduser("~/.reticulum")
    config_file = os.path.join(config_dir, "config")
    if transport_host is None:
        transport_host = get_setting("transport_host", DEFAULT_TRANSPORT_HOST)
    if transport_port is None:
        transport_port = int(get_setting("transport_port", str(DEFAULT_TRANSPORT_PORT)))

    if os.path.exists(config_file):
        if _transport_settings_match(config_file, transport_host, transport_port):
            return

    os.makedirs(config_dir, exist_ok=True)
    with open(config_file, "w") as f:
        f.write(f"""[reticulum]
  enable_transport = False
  share_instance = No

[logging]
  loglevel = 4

[interfaces]
  [[Default Interface]]
    type = AutoInterface
    enabled = Yes

  [[TCP Transport]]
    type = TCPClientInterface
    enabled = yes
    target_host = {transport_host}
    target_port = {transport_port}
""")
    print(f"Created Reticulum config at {config_file}")


def _preload_embeddings():
    """Pre-load the embedding model and build the HNSW index in background."""
    if get_setting("semantic_search", "1") != "1":
        print("Semantic search disabled.")
        return
    try:
        from embeddings import _get_session, _get_reranker, build_index
        _get_session()
        build_index()
        if get_setting("use_reranker", "1") == "1":
            _get_reranker()
            print("Semantic search ready (with reranker).")
        else:
            print("Semantic search ready.")
    except Exception as e:
        print(f"Semantic search unavailable: {e}")


def main():
    parser = argparse.ArgumentParser(prog="tinyweb", description="Personal decentralized search engine")
    parser.add_argument("--version", "-v", action="store_true", help="Show version")
    parser.add_argument("--port", "-p", type=int, default=None, help="HTTP gateway port (default: 8080)")
    args = parser.parse_args()

    if args.version:
        print(f"TinyWeb {get_version()}")
        return

    port = args.port or 8080
    import gateway
    gateway.GATEWAY_PORT = find_available_port(port)

    init_db()
    transport_host = get_setting("transport_host", DEFAULT_TRANSPORT_HOST)
    transport_port = int(get_setting("transport_port", str(DEFAULT_TRANSPORT_PORT)))
    threading.Thread(target=_preload_embeddings, daemon=True).start()
    config_dir = os.environ.get("RNS_CONFIG_DIR")
    ensure_rns_config(config_dir, transport_host, transport_port)
    reticulum = RNS.Reticulum(configdir=config_dir)
    identity = load_or_create_identity()

    destination = RNS.Destination(
        identity,
        RNS.Destination.IN,
        RNS.Destination.SINGLE,
        APP_NAME,
        *ASPECTS,
    )

    destination.register_request_handler(
        "/tinyweb",
        response_generator=rns_request_handler,
        allow=RNS.Destination.ALLOW_ALL,
    )

    # Brief delay to ensure all interfaces (especially TCP) are fully ready
    time.sleep(2)
    destination.announce()
    set_setting("dest_hash", destination.hash.hex())
    start_gateway(reticulum)

    print(f"TinyWeb running!")
    print(f"Open http://localhost:{GATEWAY_PORT} in your browser")
    print(f"Destination hash: {RNS.prettyhexrep(destination.hash)} (share this so friends can subscribe)")

    while True:
        time.sleep(1)


if __name__ == "__main__":
    main()