"""ASGI bridge for existing Microdot route handlers."""

from __future__ import annotations

from typing import Any

from microdot.microdot import Microdot, NoCaseDict, Request, Response


class MicrodotASGI:
    """Dispatch HTTP requests to a :class:`Microdot` application."""

    def __init__(self, microdot_app: Microdot):
        self.app = microdot_app

    async def __call__(self, scope: dict, receive: Any, send: Any) -> None:
        if scope.get("type") != "http":
            return

        body = b""
        while True:
            message = await receive()
            if message["type"] != "http.request":
                continue
            body += message.get("body", b"")
            if not message.get("more_body"):
                break

        headers = NoCaseDict()
        for key, value in scope.get("headers", ()):
            headers[key.decode("latin-1")] = value.decode("latin-1")

        path = scope.get("path", "/") or "/"
        query = scope.get("query_string", b"").decode("latin-1")
        url = path + (f"?{query}" if query else "")

        client = scope.get("client") or ("127.0.0.1", 0)
        req = Request(
            self.app,
            client,
            scope.get("method", "GET"),
            url,
            "1.1",
            headers,
            body=body,
        )

        res = await self.app.dispatch_request(req)
        if res is Response.already_handled:
            return
        await _send_microdot_response(res, send)


async def _send_microdot_response(res: Response, send: Any) -> None:
    res.complete()
    headers: list[tuple[bytes, bytes]] = []
    for header, value in res.headers.items():
        values = value if isinstance(value, list) else [value]
        for item in values:
            headers.append(
                (header.lower().encode("latin-1"), str(item).encode("latin-1"))
            )

    body = res.body
    if isinstance(body, str):
        payload = body.encode()
    elif isinstance(body, bytes):
        payload = body
    else:
        parts: list[bytes] = []
        async for chunk in res.body_iter():
            if isinstance(chunk, str):
                chunk = chunk.encode()
            parts.append(chunk)
        payload = b"".join(parts)

    await send(
        {
            "type": "http.response.start",
            "status": res.status_code,
            "headers": headers,
        }
    )
    await send({"type": "http.response.body", "body": payload})