"""Resolve the 7-way content dial into an audio source + video on/off (§6).

The single source of truth for design §6's table: which audio source plays and
whether the projector shows video, for each dial position.
"""

from __future__ import annotations

from dataclasses import dataclass

# The four distinct audio sources. "white_noise" is generated at runtime;
# "music" is the public-domain classical pool; "audio_track" is the clip's own
# field audio; "none" is silence.
AUDIO_SOURCES = frozenset({"none", "white_noise", "music", "audio_track"})


@dataclass(frozen=True)
class ContentResolution:
    audio_source: str
    video: bool


# Design §6, one row per dial position.
_TABLE = {
    "off": ContentResolution("none", False),
    "white_noise": ContentResolution("white_noise", False),
    "music": ContentResolution("music", False),
    "audio_track": ContentResolution("audio_track", False),
    "video": ContentResolution("none", True),
    "music_video": ContentResolution("music", True),
    "audio_video": ContentResolution("audio_track", True),
}


def resolve_content(position: str) -> ContentResolution:
    """Map a content-dial position to its audio source and video flag (§6)."""
    try:
        return _TABLE[position]
    except KeyError:
        raise ValueError(
            f"unknown content position {position!r}; expected one of {sorted(_TABLE)}"
        ) from None