"""Fail-fast native-token encoding API for the released Music 3 checkpoint.

The public checkpoint does not contain the RVQ quantizer/codebooks required by
this operation.  This module exists so callers get a precise, reusable failure
instead of accidentally treating continuous DAV latents as discrete tokens.
"""

from __future__ import annotations

import argparse
import json
import os
from pathlib import Path
from typing import Any

import torch

from inspect_dav import inspect_checkpoint


DAV_PATH_ENV = "MINIMAX_DAV_PATH"


class NativeTokenizerUnavailableError(RuntimeError):
    """The supplied release checkpoint cannot produce native Music 3 tokens."""

    def __init__(self, message: str, *, report: dict[str, Any] | None = None) -> None:
        super().__init__(message)
        self.report = report


def resolve_dav_path(dav_path: str | os.PathLike[str] | None = None) -> Path:
    value = dav_path if dav_path is not None else os.environ.get(DAV_PATH_ENV)
    if value is None or not str(value).strip():
        raise NativeTokenizerUnavailableError(
            f"no DAV checkpoint supplied; pass dav_path or set {DAV_PATH_ENV}"
        )
    return Path(value).expanduser()


def require_native_tokenizer(
    dav_path: str | os.PathLike[str] | None = None,
) -> dict[str, Any]:
    """Inspect ``dav.pth`` and return its report only if a native tokenizer exists."""

    resolved = resolve_dav_path(dav_path)
    report = inspect_checkpoint(resolved)
    capabilities = report["capabilities"]
    if not capabilities["can_encode_native_music3_tokens"]:
        missing = [
            label
            for label, available in (
                ("waveform/tokenizer encoder weights", capabilities["waveform_analysis_encoder_weights"]),
                ("RVQ/VQ quantizer weights", capabilities["rvq_or_vq_quantizer_weights"]),
                ("codebook embedding weights", capabilities["codebook_embedding_weights"]),
                ("serialized tokenizer architecture/config", capabilities["serialized_architecture_config"]),
            )
            if not available
        ]
        if missing:
            reason = "released dav.pth cannot encode native Music 3 tokens: missing " + ", ".join(missing) + "."
        else:
            reason = (
                "released dav.pth has tokenizer-like candidate weights/config, but no exact compatible "
                "executable Music 3 tokenizer architecture/API has been implemented and verified."
            )
        continuous_evidence = (
            capabilities["waveform_analysis_encoder_weights"]
            and capabilities["continuous_gaussian_posterior_heads"]
            and capabilities["continuous_flow_weights"]
        )
        if continuous_evidence:
            reason += (
                " encoder.* plus mean_proj.* and logs_proj.* form a continuous "
                "Flow-VAE analysis path; they do not emit integer RVQ codes."
            )
        raise NativeTokenizerUnavailableError(reason, report=report)
    return report


def encode_audio(
    audio_path: str | os.PathLike[str],
    *,
    dav_path: str | os.PathLike[str] | None = None,
) -> torch.Tensor:
    """Return native tokens as ``[frames, 8]`` or fail before reading the WAV.

    The release inspected for this project always takes the failure path.  The
    return annotation records the intended contract without manufacturing token
    IDs or using a third-party codec.
    """

    # Capability inspection intentionally precedes even checking the input path.
    require_native_tokenizer(dav_path)
    raise NativeTokenizerUnavailableError(
        "checkpoint advertises tokenizer-like weights, but no released Music 3 "
        "tokenizer architecture/API is available to execute them safely"
    )


def _blocked_payload(error: NativeTokenizerUnavailableError, audio_path: str) -> dict[str, Any]:
    payload: dict[str, Any] = {
        "status": "BLOCKED",
        "operation": "encode_audio",
        "audio_path": audio_path,
        "audio_was_read": False,
        "reason": str(error),
    }
    if error.report is not None:
        payload["capabilities"] = error.report["capabilities"]
        payload["state_dict"] = error.report["state_dict"]
    return payload


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("audio", help="Input WAV path (not opened when capability is blocked)")
    parser.add_argument("--dav", help=f"Path to dav.pth; defaults to {DAV_PATH_ENV}")
    parser.add_argument("--json", action="store_true", help="Emit machine-readable JSON")
    return parser


def main(argv: list[str] | None = None) -> int:
    args = build_parser().parse_args(argv)
    try:
        tokens = encode_audio(args.audio, dav_path=args.dav)
    except (NativeTokenizerUnavailableError, FileNotFoundError, RuntimeError, ValueError) as error:
        if isinstance(error, NativeTokenizerUnavailableError):
            native_error = error
        else:
            native_error = NativeTokenizerUnavailableError(str(error))
        payload = _blocked_payload(native_error, args.audio)
        print(json.dumps(payload, indent=2) if args.json else f"BLOCKED: {payload['reason']}")
        return 2

    # Kept for API completeness if an official tokenizer is released later.
    payload = {"status": "OK", "shape": list(tokens.shape), "dtype": str(tokens.dtype)}
    print(json.dumps(payload, indent=2) if args.json else f"tokens: {tuple(tokens.shape)}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())