#
# 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/>.

"""
API routes for nodes.
"""

import aiohttp
import asyncio

from fastapi import APIRouter, Depends, WebSocket, WebSocketDisconnect, Request, Response, status
from fastapi.encoders import jsonable_encoder
from fastapi.routing import APIRoute
from typing import List, Callable
from uuid import UUID

from gns3server.controller import Controller
from gns3server.controller.node import Node
from gns3server.controller.project import Project
from gns3server.utils import force_unix_path
from gns3server.utils.http_client import HTTPClient
from gns3server.controller.controller_error import ControllerForbiddenError, ControllerBadRequestError
from gns3server import schemas

import logging

log = logging.getLogger(__name__)

node_locks = {}


class NodeConcurrency(APIRoute):
    """
    To avoid strange effects, we prevent concurrency
    between the same instance of the node
    (excepting when streaming a PCAP file and for WebSocket consoles).
    """

    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:

            node_id = request.path_params.get("node_id")
            project_id = request.path_params.get("project_id")

            if node_id and "pcap" not in request.url.path and not request.url.path.endswith("console/ws"):
                lock_key = f"{project_id}:{node_id}"
                node_locks.setdefault(lock_key, {"lock": asyncio.Lock(), "concurrency": 0})
                node_locks[lock_key]["concurrency"] += 1

                async with node_locks[lock_key]["lock"]:
                    response = await original_route_handler(request)

                node_locks[lock_key]["concurrency"] -= 1
                if node_locks[lock_key]["concurrency"] <= 0:
                    del node_locks[lock_key]
            else:
                response = await original_route_handler(request)

            return response

        return custom_route_handler


responses = {404: {"model": schemas.ErrorMessage, "description": "Could not find project or node"}}

router = APIRouter(route_class=NodeConcurrency, responses=responses)


async def dep_project(project_id: UUID) -> Project:
    """
    Dependency to retrieve a project.
    """

    project = await Controller.instance().get_loaded_project(str(project_id))
    return project


async def dep_node(node_id: UUID, project: Project = Depends(dep_project)) -> None:
    """
    Dependency to retrieve a node.
    """

    node = project.get_node(str(node_id))
    return node


@router.post(
    "",
    status_code=status.HTTP_201_CREATED,
    response_model=schemas.Node,
    responses={
        404: {"model": schemas.ErrorMessage, "description": "Could not find project"},
        409: {"model": schemas.ErrorMessage, "description": "Could not create node"},
    },
)
async def create_node(node_data: schemas.NodeCreate, project: Project = Depends(dep_project)) -> schemas.Node:
    """
    Create a new node.
    """

    controller = Controller.instance()
    compute = controller.get_compute(str(node_data.compute_id))
    node_data = jsonable_encoder(node_data, exclude_unset=True)
    node = await project.add_node(compute, node_data.pop("name"), node_data.pop("node_id", None), **node_data)
    return node.asdict()


@router.get("", response_model=List[schemas.Node], response_model_exclude_unset=True)
async def get_nodes(project: Project = Depends(dep_project)) -> List[schemas.Node]:
    """
    Return all nodes belonging to a given project.
    """

    return [v.asdict() for v in project.nodes.values()]


@router.post("/start", status_code=status.HTTP_204_NO_CONTENT)
async def start_all_nodes(project: Project = Depends(dep_project)) -> None:
    """
    Start all nodes belonging to a given project.
    """

    await project.start_all()


@router.post("/stop", status_code=status.HTTP_204_NO_CONTENT)
async def stop_all_nodes(project: Project = Depends(dep_project)) -> None:
    """
    Stop all nodes belonging to a given project.
    """

    await project.stop_all()


@router.post("/suspend", status_code=status.HTTP_204_NO_CONTENT)
async def suspend_all_nodes(project: Project = Depends(dep_project)) -> None:
    """
    Suspend all nodes belonging to a given project.
    """

    await project.suspend_all()


@router.post("/reload", status_code=status.HTTP_204_NO_CONTENT)
async def reload_all_nodes(project: Project = Depends(dep_project)) -> None:
    """
    Reload all nodes belonging to a given project.
    """

    await project.stop_all()
    await project.start_all()


@router.get("/{node_id}", response_model=schemas.Node)
def get_node(node: Node = Depends(dep_node)) -> schemas.Node:
    """
    Return a node from a given project.
    """

    return node.asdict()


@router.put("/{node_id}", response_model=schemas.Node, response_model_exclude_unset=True)
async def update_node(node_data: schemas.NodeUpdate, node: Node = Depends(dep_node)) -> schemas.Node:
    """
    Update a node.
    """

    node_data = jsonable_encoder(node_data, exclude_unset=True)

    # Ignore these because we only use them when creating a node
    node_data.pop("node_id", None)
    node_data.pop("node_type", None)
    node_data.pop("compute_id", None)

    await node.update(**node_data)
    return node.asdict()


@router.delete(
    "/{node_id}",
    status_code=status.HTTP_204_NO_CONTENT,
    responses={**responses, 409: {"model": schemas.ErrorMessage, "description": "Cannot delete node"}},
)
async def delete_node(node_id: UUID, project: Project = Depends(dep_project)) -> None:
    """
    Delete a node from a project.
    """

    await project.delete_node(str(node_id))


@router.post("/{node_id}/duplicate", response_model=schemas.Node, status_code=status.HTTP_201_CREATED)
async def duplicate_node(duplicate_data: schemas.NodeDuplicate, node: Node = Depends(dep_node)) -> schemas.Node:
    """
    Duplicate a node.
    """

    new_node = await node.project.duplicate_node(node, duplicate_data.x, duplicate_data.y, duplicate_data.z)
    return new_node.asdict()


@router.post("/{node_id}/start", status_code=status.HTTP_204_NO_CONTENT)
async def start_node(start_data: dict, node: Node = Depends(dep_node)) -> None:
    """
    Start a node.
    """

    await node.start(data=start_data)


@router.post("/{node_id}/stop", status_code=status.HTTP_204_NO_CONTENT)
async def stop_node(node: Node = Depends(dep_node)) -> None:
    """
    Stop a node.
    """

    await node.stop()


@router.post("/{node_id}/suspend", status_code=status.HTTP_204_NO_CONTENT)
async def suspend_node(node: Node = Depends(dep_node)) -> None:
    """
    Suspend a node.
    """

    await node.suspend()


@router.post("/{node_id}/reload", status_code=status.HTTP_204_NO_CONTENT)
async def reload_node(node: Node = Depends(dep_node)) -> None:
    """
    Reload a node.
    """

    await node.reload()


@router.post("/{node_id}/isolate", status_code=status.HTTP_204_NO_CONTENT)
async def isolate_node(node: Node = Depends(dep_node)) -> None:
    """
    Isolate a node (suspend all attached links).
    """

    for link in node.links:
        await link.update_suspend(True)


@router.post("/{node_id}/unisolate", status_code=status.HTTP_204_NO_CONTENT)
async def unisolate_node(node: Node = Depends(dep_node)) -> None:
    """
    Un-isolate a node (resume all attached suspended links).
    """

    for link in node.links:
        await link.update_suspend(False)


@router.get("/{node_id}/links", response_model=List[schemas.Link], response_model_exclude_unset=True)
async def get_node_links(node: Node = Depends(dep_node)) -> List[schemas.Link]:
    """
    Return all the links connected to a node.
    """

    links = []
    for link in node.links:
        links.append(link.asdict())
    return links


@router.get("/{node_id}/dynamips/auto_idlepc")
async def auto_idlepc(node: Node = Depends(dep_node)) -> dict:
    """
    Compute an Idle-PC value for a Dynamips node
    """

    if node.node_type != "dynamips":
        raise ControllerBadRequestError("Auto Idle-PC is only supported on a Dynamips node")
    return await node.dynamips_auto_idlepc()


@router.get("/{node_id}/dynamips/idlepc_proposals")
async def idlepc_proposals(node: Node = Depends(dep_node)) -> List[str]:
    """
    Compute a list of potential idle-pc values for a Dynamips node
    """

    if node.node_type != "dynamips":
        raise ControllerBadRequestError("Idle-PC proposals is only supported on a Dynamips node")
    return await node.dynamips_idlepc_proposals()


@router.post("/{node_id}/qemu/disk_image/{disk_name}", status_code=status.HTTP_204_NO_CONTENT)
async def create_disk_image(
        disk_name: str,
        disk_data: schemas.QemuDiskImageCreate,
        node: Node = Depends(dep_node)
) -> None:
    """
    Create a Qemu disk image.
    """

    if node.node_type != "qemu":
        raise ControllerBadRequestError("Creating a disk image is only supported on a Qemu node")
    await node.post(f"/disk_image/{disk_name}", data=disk_data.dict(exclude_unset=True))


@router.put("/{node_id}/qemu/disk_image/{disk_name}", status_code=status.HTTP_204_NO_CONTENT)
async def update_disk_image(
        disk_name: str,
        disk_data: schemas.QemuDiskImageUpdate,
        node: Node = Depends(dep_node)
) -> None:
    """
    Update a Qemu disk image.
    """

    if node.node_type != "qemu":
        raise ControllerBadRequestError("Updating a disk image is only supported on a Qemu node")
    await node.put(f"/disk_image/{disk_name}", data=disk_data.dict(exclude_unset=True))


@router.delete("/{node_id}/qemu/disk_image/{disk_name}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_disk_image(
        disk_name: str,
        node: Node = Depends(dep_node)
) -> None:
    """
    Delete a Qemu disk image.
    """

    if node.node_type != "qemu":
        raise ControllerBadRequestError("Deleting a disk image is only supported on a Qemu node")
    await node.delete(f"/disk_image/{disk_name}")


@router.get("/{node_id}/files/{file_path:path}")
async def get_file(file_path: str, node: Node = Depends(dep_node)) -> Response:
    """
    Return a file in the node directory
    """

    path = force_unix_path(file_path)

    # Raise error if user try to escape
    if path[0] == ".":
        raise ControllerForbiddenError("It is forbidden to get a file outside the project directory")

    node_type = node.node_type
    path = f"/project-files/{node_type}/{node.id}/{path}"

    res = await node.compute.http_query("GET", f"/projects/{node.project.id}/files{path}", timeout=None, raw=True)
    return Response(res.body, media_type="application/octet-stream", status_code=res.status)


@router.post("/{node_id}/files/{file_path:path}", status_code=status.HTTP_201_CREATED)
async def post_file(file_path: str, request: Request, node: Node = Depends(dep_node)):
    """
    Write a file in the node directory.
    """

    path = force_unix_path(file_path)

    # Raise error if user try to escape
    if path[0] == ".":
        raise ControllerForbiddenError("Cannot write outside the node directory")

    node_type = node.node_type
    path = f"/project-files/{node_type}/{node.id}/{path}"

    data = await request.body()  # FIXME: are we handling timeout or large files correctly?
    await node.compute.http_query("POST", f"/projects/{node.project.id}/files{path}", data=data, timeout=None, raw=True)
    # FIXME: response with correct status code (from compute)


@router.websocket("/{node_id}/console/ws")
async def ws_console(websocket: WebSocket, node: Node = Depends(dep_node)) -> None:
    """
    WebSocket console.
    """

    compute = node.compute
    await websocket.accept()
    log.info(
        f"New client {websocket.client.host}:{websocket.client.port} has connected to controller console WebSocket"
    )
    ws_console_compute_url = (
        f"ws://{compute.host}:{compute.port}/v3/compute/projects/"
        f"{node.project.id}/{node.node_type}/nodes/{node.id}/console/ws"
    )

    async def ws_receive(ws_console_compute):
        """
        Receive WebSocket data from client and forward to compute console WebSocket.
        """

        try:
            while True:
                data = await websocket.receive_text()
                if data:
                    await ws_console_compute.send_str(data)
        except WebSocketDisconnect:
            await ws_console_compute.close()
            log.info(
                f"Client {websocket.client.host}:{websocket.client.port} has disconnected from controller"
                f" console WebSocket"
            )

    try:
        # receive WebSocket data from compute console WebSocket and forward to client.
        async with HTTPClient.get_client().ws_connect(ws_console_compute_url) as ws_console_compute:
            asyncio.ensure_future(ws_receive(ws_console_compute))
            async for msg in ws_console_compute:
                if msg.type == aiohttp.WSMsgType.TEXT:
                    await websocket.send_text(msg.data)
                elif msg.type == aiohttp.WSMsgType.BINARY:
                    await websocket.send_bytes(msg.data)
                elif msg.type == aiohttp.WSMsgType.ERROR:
                    break
    except aiohttp.ClientError as e:
        log.error(f"Client error received when forwarding to compute console WebSocket: {e}")


@router.post("/console/reset", status_code=status.HTTP_204_NO_CONTENT)
async def reset_console_all_nodes(project: Project = Depends(dep_project)) -> None:
    """
    Reset console for all nodes belonging to the project.
    """

    await project.reset_console_all()


@router.post("/{node_id}/console/reset", status_code=status.HTTP_204_NO_CONTENT)
async def console_reset(node: Node = Depends(dep_node)) -> None:

    await node.post("/console/reset")