"""Explicit local-file input adapter with safe error reporting."""

from __future__ import annotations

from collections.abc import Iterator
from pathlib import Path

from yovision_brain.config import BrainInputConfig

from .models import CancellationToken, InputError, InputPacket


class LocalFileInput:
    def __init__(self, config: BrainInputConfig) -> None:
        if config.source.kind != "local_file" or config.source.path is None:
            raise ValueError("LocalFileInput requires a local_file source config")
        self._config = config
        self._path = config.source.path

    @property
    def source_label(self) -> str:
        """Return a safe label rather than exposing the internal absolute path."""
        return self._path.name

    def packets(self, cancellation: CancellationToken | None = None) -> Iterator[InputPacket]:
        profile = self._config.profile
        source = self._config.source
        try:
            stream = self._path.open("rb")
        except FileNotFoundError as exc:
            raise InputError(f"local video source not found: {self.source_label}") from exc
        except OSError as exc:
            raise InputError(f"local video source cannot be opened: {self.source_label}: {exc.strerror}") from exc

        with stream:
            sequence = 0
            while cancellation is None or not cancellation.cancelled:
                try:
                    payload = stream.read(source.chunk_size)
                except OSError as exc:
                    raise InputError(f"local video source read failed: {self.source_label}: {exc.strerror}") from exc
                if not payload:
                    return
                yield InputPacket(
                    sequence=sequence,
                    timestamp_ns=None,
                    logical_device_id=self._config.logical_device_id,
                    profile_id=profile.profile_id,
                    width=profile.width,
                    height=profile.height,
                    media_format="container-bytes",
                    payload=payload,
                )
                sequence += 1