import asyncio
import typing

import msgspec
from sanic import Blueprint

from cista import watching
from cista.fileio import FileServer
from cista.protocol import ControlTypes, FileRange, StatusMsg
from cista.util.apphelpers import asend, websocket_wrapper

bp = Blueprint("api", url_prefix="/api")
fileserver = FileServer()


@bp.before_server_start
async def start_fileserver(app, _):
    await fileserver.start()


@bp.after_server_stop
async def stop_fileserver(app, _):
    await fileserver.stop()


@bp.websocket("upload")
@websocket_wrapper
async def upload(req, ws):
    alink = fileserver.alink
    while True:
        req = None
        text = await ws.recv()
        if not isinstance(text, str):
            raise ValueError(
                f"Expected JSON control, got binary len(data) = {len(text)}"
            )
        req = msgspec.json.decode(text, type=FileRange)
        pos = req.start
        data = None
        while pos < req.end and (data := await ws.recv()) and isinstance(data, bytes):
            sentsize = await alink(("upload", req.name, pos, data, req.size))
            pos += typing.cast(int, sentsize)
        if pos != req.end:
            d = f"{len(data)} bytes" if isinstance(data, bytes) else data
            raise ValueError(f"Expected {req.end - pos} more bytes, got {d}")
        # Report success
        res = StatusMsg(status="ack", req=req)
        await asend(ws, res)
        # await ws.drain()


@bp.websocket("download")
@websocket_wrapper
async def download(req, ws):
    alink = fileserver.alink
    while True:
        req = None
        text = await ws.recv()
        if not isinstance(text, str):
            raise ValueError(
                f"Expected JSON control, got binary len(data) = {len(text)}"
            )
        req = msgspec.json.decode(text, type=FileRange)
        pos = req.start
        while pos < req.end:
            end = min(req.end, pos + (1 << 20))
            data = typing.cast(bytes, await alink(("download", req.name, pos, end)))
            await asend(ws, data)
            pos += len(data)
        # Report success
        res = StatusMsg(status="ack", req=req)
        await asend(ws, res)
        # await ws.drain()


@bp.websocket("control")
@websocket_wrapper
async def control(req, ws):
    cmd = msgspec.json.decode(await ws.recv(), type=ControlTypes)
    await asyncio.to_thread(cmd)
    await asend(ws, StatusMsg(status="ack", req=cmd))


@bp.websocket("watch")
@websocket_wrapper
async def watch(req, ws):
    try:
        with watching.tree_lock:
            q = watching.pubsub[ws] = asyncio.Queue()
            # Init with disk usage and full tree
            await ws.send(watching.format_du())
            await ws.send(watching.format_tree())
        # Send updates
        while True:
            await ws.send(await q.get())
    finally:
        del watching.pubsub[ws]