#!/usr/bin/env python
#
# Copyright (C) 2020 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
FastAPI app
"""

import sys
import asyncio
import time

from fastapi import FastAPI, Request
from starlette.exceptions import HTTPException as StarletteHTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse

from gns3server.controller import Controller
from gns3server.compute import MODULES
from gns3server.compute.port_manager import PortManager
from gns3server.controller.controller_error import (
    ControllerError,
    ControllerNotFoundError,
    ControllerTimeoutError,
    ControllerForbiddenError,
    ControllerUnauthorizedError
)

from gns3server.endpoints import controller
from gns3server.endpoints import index
from gns3server.endpoints.compute import compute_api
from gns3server.utils.http_client import HTTPClient
from gns3server.version import __version__

import logging
log = logging.getLogger(__name__)

app = FastAPI(title="GNS3 controller API",
              description="This page describes the public controller API for GNS3",
              version="v3")

origins = [
    "http://127.0.0.1",
    "http://localhost",
    "http://127.0.0.1:8080",
    "http://localhost:8080",
    "http://127.0.0.1:3080",
    "http://localhost:3080",
    "http://gns3.github.io",
    "https://gns3.github.io"
]

app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

app.include_router(index.router, tags=["Index"])
app.include_router(controller.router, prefix="/v3")
app.mount("/v3/compute", compute_api)


@app.exception_handler(ControllerError)
async def controller_error_handler(request: Request, exc: ControllerError):
    log.error(f"Controller error: {exc}")
    return JSONResponse(
        status_code=409,
        content={"message": str(exc)},
    )


@app.exception_handler(ControllerTimeoutError)
async def controller_timeout_error_handler(request: Request, exc: ControllerTimeoutError):
    log.error(f"Controller timeout error: {exc}")
    return JSONResponse(
        status_code=408,
        content={"message": str(exc)},
    )


@app.exception_handler(ControllerUnauthorizedError)
async def controller_unauthorized_error_handler(request: Request, exc: ControllerUnauthorizedError):
    log.error(f"Controller unauthorized error: {exc}")
    return JSONResponse(
        status_code=401,
        content={"message": str(exc)},
    )


@app.exception_handler(ControllerForbiddenError)
async def controller_forbidden_error_handler(request: Request, exc: ControllerForbiddenError):
    log.error(f"Controller forbidden error: {exc}")
    return JSONResponse(
        status_code=403,
        content={"message": str(exc)},
    )


@app.exception_handler(ControllerNotFoundError)
async def controller_not_found_error_handler(request: Request, exc: ControllerNotFoundError):
    log.error(f"Controller not found error: {exc}")
    return JSONResponse(
        status_code=404,
        content={"message": str(exc)},
    )


# make sure the content key is "message", not "detail" per default
@app.exception_handler(StarletteHTTPException)
async def http_exception_handler(request: Request, exc: StarletteHTTPException):
    return JSONResponse(
        status_code=exc.status_code,
        content={"message": exc.detail},
    )


@app.middleware("http")
async def add_extra_headers(request: Request, call_next):
    start_time = time.time()
    response = await call_next(request)
    process_time = time.time() - start_time
    response.headers["X-Process-Time"] = str(process_time)
    response.headers["X-GNS3-Server-Version"] = "{}".format(__version__)
    return response


@app.on_event("startup")
async def startup_event():

    loop = asyncio.get_event_loop()
    logger = logging.getLogger("asyncio")
    logger.setLevel(logging.ERROR)

    if sys.platform.startswith("win"):

        # Add a periodic callback to give a chance to process signals on Windows
        # because asyncio.add_signal_handler() is not supported yet on that platform
        # otherwise the loop runs outside of signal module's ability to trap signals.

        def wakeup():
            loop.call_later(0.5, wakeup)

        loop.call_later(0.5, wakeup)

    if log.getEffectiveLevel() == logging.DEBUG:
        # On debug version we enable info that
        # coroutine is not called in a way await/await
        loop.set_debug(True)

    await Controller.instance().start()
    # Because with a large image collection
    # without md5sum already computed we start the
    # computing with server start

    from gns3server.compute.qemu import Qemu
    asyncio.ensure_future(Qemu.instance().list_images())

    for module in MODULES:
        log.debug("Loading module {}".format(module.__name__))
        m = module.instance()
        m.port_manager = PortManager.instance()


@app.on_event("shutdown")
async def shutdown_event():

    await HTTPClient.close_session()
    await Controller.instance().stop()

    for module in MODULES:
        log.debug("Unloading module {}".format(module.__name__))
        m = module.instance()
        await m.unload()

    if PortManager.instance().tcp_ports:
        log.warning("TCP ports are still used {}".format(PortManager.instance().tcp_ports))

    if PortManager.instance().udp_ports:
        log.warning("UDP ports are still used {}".format(PortManager.instance().udp_ports))