""" Python Server implementation """

import errno
import http.server
import importlib
import importlib.metadata
import json
import logging
import os
import random
import re
import socket
import socketserver
import threading
import time
import urllib.parse
import webbrowser

__version__ = "0.0.0"

logger = logging.getLogger(__name__)

class _ContentProvider:
    data = bytearray()
    base_dir = ""
    base = ""
    identifier = ""
    def __init__(self, data, path, file, name):
        self.data = data if data else bytearray()
        self.identifier = os.path.basename(file) if file else ""
        self.name = name
        if path:
            self.dir = os.path.dirname(path) if os.path.dirname(path) else "."
            self.base = os.path.basename(path)
    def read(self, path):
        if path == self.base and self.data:
            return self.data
        base_dir = os.path.realpath(self.dir)
        filename = os.path.normpath(os.path.realpath(base_dir + "/" + path))
        if os.path.commonpath([ base_dir, filename ]) == base_dir:
            if os.path.exists(filename) and not os.path.isdir(filename):
                with open(filename, "rb") as file:
                    return file.read()
        return None

class _HTTPRequestHandler(http.server.BaseHTTPRequestHandler):
    content = None
    mime_types = {
        ".html": "text/html",
        ".js":   "text/javascript",
        ".css":  "text/css",
        ".png":  "image/png",
        ".gif":  "image/gif",
        ".jpg":  "image/jpeg",
        ".ico":  "image/x-icon",
        ".json": "application/json",
        ".pb": "application/octet-stream",
        ".ttf": "font/truetype",
        ".otf": "font/opentype",
        ".eot": "application/vnd.ms-fontobject",
        ".woff": "font/woff",
        ".woff2": "font/woff2",
        ".svg": "image/svg+xml"
    }
    def do_HEAD(self):
        self.do_GET()
    def do_GET(self):
        path = urllib.parse.urlparse(self.path).path
        path = "/index.html" if path == "/" else path
        status_code = 404
        content = None
        content_type = None
        if path.startswith("/data/"):
            path = urllib.parse.unquote(path[len("/data/"):])
            content = self.content.read(path)
            if content:
                content_type = "application/octet-stream"
                status_code = 200
        else:
            base_dir = os.path.dirname(os.path.realpath(__file__))
            filename = os.path.normpath(os.path.realpath(base_dir + path))
            extension = os.path.splitext(filename)[1]
            if os.path.commonpath([base_dir, filename]) == base_dir and \
                os.path.exists(filename) and not os.path.isdir(filename) and \
                extension in self.mime_types:
                content_type = self.mime_types[extension]
                with open(filename, "rb") as file:
                    content = file.read()
                if path == "/index.html":
                    content = content.decode("utf-8")
                    meta = [
                        '<meta name="type" content="Python">',
                        '<meta name="version" content="' + __version__ + '">'
                    ]
                    base = self.content.base
                    if base:
                        meta.append('<meta name="file" content="/data/' + base + '">')
                    name = self.content.name
                    if name:
                        meta.append('<meta name="name" content="' + name + '">')
                    identifier = self.content.identifier
                    if identifier:
                        meta.append(f'<meta name="identifier" content="{identifier}">')
                    meta = "\n".join(meta)
                    regex = r'<meta name="version" content=".*">'
                    content = re.sub(regex, lambda _: meta, content)
                    content = content.encode("utf-8")
                status_code = 200
        self._write(status_code, content_type, content)
    def log_message(self, format, *args):
        logger.debug(" ".join(args))
    def _write(self, status_code, content_type, content):
        self.send_response(status_code)
        if content:
            self.send_header("Content-Type", content_type)
            self.send_header("Content-Length", len(content))
        self.end_headers()
        if self.command != "HEAD":
            if status_code == 404 and content is None:
                self.wfile.write(str(status_code).encode("utf-8"))
            elif (status_code in (200, 404)) and content is not None:
                self.wfile.write(content)

class _ThreadedHTTPServer(socketserver.ThreadingMixIn, http.server.HTTPServer):
    pass

class _HTTPServerThread(threading.Thread):
    def __init__(self, content, address):
        threading.Thread.__init__(self)
        self.daemon = True
        self.address = address
        self.url = "http://" + address[0] + ":" + str(address[1])
        self.server = _ThreadedHTTPServer(address, _HTTPRequestHandler)
        self.server.timeout = 0.25
        self.server.block_on_close = False
        self.server.RequestHandlerClass.content = content
        self.terminate_event = threading.Event()
        self.terminate_event.set()
        self.stop_event = threading.Event()

    def run(self):
        self.stop_event.clear()
        self.terminate_event.clear()
        try:
            while not self.stop_event.is_set():
                self.server.handle_request()
        except: # noqa: E722
            pass
        self.terminate_event.set()
        self.stop_event.clear()

    def stop(self):
        if self.alive():
            logger.info("Stopping " + self.url)
            self.stop_event.set()
            self.server.server_close()

    def alive(self):
        value = not self.terminate_event.is_set()
        return value

def _open(data):
    registry = dict([
        ("onnx.onnx_ml_pb2.ModelProto", ".onnx"),
        ("torch.jit._script.ScriptModule", ".pytorch"),
        ("torch.Graph", ".pytorch"),
        ("torch._C.Graph", ".pytorch"),
        ("torch.nn.modules.module.Module", ".pytorch")
    ])
    queue = [ data.__class__ ]
    while len(queue) > 0:
        current = queue.pop(0)
        if current.__module__ and current.__name__:
            name = current.__module__ + "." + current.__name__
            if name in registry:
                module_name = registry[name]
                module = importlib.import_module(module_name, package=__package__)
                model_factory = module.ModelFactory()
                return model_factory.open(data)
        queue.extend(_ for _ in current.__bases__ if isinstance(_, type))
    return None

def _threads(address=None):
    threads = []
    for thread in threading.enumerate():
        if isinstance(thread, _HTTPServerThread) and thread.alive():
            threads.append(thread)
    if address is not None:
        address = _make_address(address)
        threads = [ _ for _ in threads if address[0] == _.address[0] ]
        if address[1]:
            threads = [ _ for _ in threads if address[1] == _.address[1] ]
    return threads

def _make_address(address):
    if address is None or isinstance(address, int):
        port = address
        address = ("localhost", port)
    if isinstance(address, tuple) and len(address) == 2:
        host = address[0]
        port = address[1]
        if isinstance(host, str) and (port is None or isinstance(port, int)):
            return address
    raise ValueError("Invalid address.")

def _make_port(address):
    if address[1] is None or address[1] == 0:
        ports = []
        if address[1] != 0:
            ports.append(8080)
            ports.append(8081)
            rnd = random.Random()
            for _ in range(4):
                port = rnd.randrange(15000, 25000)
                if port not in ports:
                    ports.append(port)
        ports.append(0)
        for port in ports:
            temp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            temp_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
            temp_socket.settimeout(1)
            try:
                temp_socket.bind((address[0], port))
                sockname = temp_socket.getsockname()
                address = (address[0], sockname[1])
                return address
            except: # noqa: E722
                pass
            finally:
                temp_socket.close()
    if isinstance(address[1], int):
        return address
    raise ValueError("Failed to allocate port.")

def stop(address=None):
    """Stop serving model at address.

    Args:
        address (tuple, optional): A (host, port) tuple, or a port number.
    """
    threads = _threads(address)
    for thread in threads:
        thread.stop()

def status(address=None):
    """Is model served at address.

    Args:
        address (tuple, optional): A (host, port) tuple, or a port number.
    """
    threads = _threads(address)
    return len(threads) > 0

def wait():
    """Wait for console exit and stop all model servers."""
    try:
        while len(_threads()) > 0:
            time.sleep(0.1)
    except (KeyboardInterrupt, SystemExit):
        stop()

def serve(file, data=None, address=None, browse=False):
    """Start serving model from file or data buffer at address and open in web browser.

    Args:
        file (string): Model file to serve. Required to detect format.
        data (bytes): Model data to serve. None will load data from file.
        address (tuple, optional): A (host, port) tuple, or a port number.
        browse (bool, optional): Launch web browser. Default: True

    Returns:
        A (host, port) address tuple.
    """
    if not logging.getLogger().hasHandlers():
        logging.basicConfig(level=logging.INFO, format="%(message)s")

    if not data and file and not os.path.exists(file):
        raise FileNotFoundError(errno.ENOENT, os.strerror(errno.ENOENT), file)

    content = _ContentProvider(data, file, file, file)

    if data and not isinstance(data, bytearray) and isinstance(data.__class__, type):
        logger.info("Experimental")
        model = _open(data)
        if model:
            text = json.dumps(model.to_json(), indent=2, ensure_ascii=False)
            content = _ContentProvider(text.encode("utf-8"), "model.netron", None, file)

    address = _make_address(address)
    if isinstance(address[1], int) and address[1] != 0:
        stop(address)
    else:
        address = _make_port(address)

    thread = _HTTPServerThread(content, address)
    thread.start()
    while not thread.alive():
        time.sleep(0.01)
    state = ("Serving '" + file + "'") if file else "Serving"
    logger.info(f"{state} at {thread.url}")
    if browse:
        webbrowser.open(thread.url)

    return address

def start(file=None, address=None, browse=True):
    """Start serving model file at address and open in web browser.

    Args:
        file (string): Model file to serve.
        browse (bool, optional): Launch web browser, Default: True
        address (tuple, optional): A (host, port) tuple, or a port number.

    Returns:
        A (host, port) address tuple.
    """
    return serve(file, None, browse=browse, address=address)

def widget(address, height=800):
    """ Open address as Jupyter Notebook IFrame.

    Args:
        address (tuple, optional): A (host, port) tuple, or a port number.
        height (int, optional): Height of the IFrame, Default: 800

    Returns:
        A Jupyter Notebook IFrame.
    """
    address = _make_address(address)
    url = f"http://{address[0]}:{address[1]}"
    IPython = __import__("IPython")
    return IPython.display.IFrame(url, width="100%", height=height)