"""KITTI Odometry sequence <-> raw drive lookup, backed by configs/sequence_mapping.yaml.

See that file's header comment for provenance. Sequence 03's raw drive is not
publicly available anywhere (confirmed 404 on KITTI's official mirror, a
long-standing unresolved community-wide gap) -- its `SequenceInfo.available`
is False, and `AVAILABLE_SEQUENCES` / `kitti-c2l generate` exclude it.
"""

from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path

import yaml

DEFAULT_CONFIG_PATH = Path(__file__).with_name("sequence_mapping.yaml")
if not DEFAULT_CONFIG_PATH.exists():  # source checkout; wheel contains the packaged copy
    DEFAULT_CONFIG_PATH = Path(__file__).resolve().parents[2] / "configs" / "sequence_mapping.yaml"


@dataclass(frozen=True)
class SequenceInfo:
    sequence: str  # "00".."10"
    date: str  # e.g. "2011_09_30"
    drive: str  # e.g. "0016"
    start: int  # 0-based raw-frame index where the sequence begins
    end: int  # 0-based raw-frame index (inclusive) where the sequence ends
    frame_count: int
    split: str  # "train" | "test"
    available: bool = (
        True  # False for sequence 03 -- raw drive not publicly available, see module docstring
    )

    def raw_frame_index(self, sequence_frame_index: int) -> int:
        """Maps a 0-based frame index within this odometry sequence to the raw drive's frame index."""
        if not 0 <= sequence_frame_index < self.frame_count:
            raise IndexError(
                f"frame {sequence_frame_index} out of range for sequence {self.sequence} "
                f"(frame_count={self.frame_count})"
            )
        return self.start + sequence_frame_index

    @property
    def drive_name(self) -> str:
        return f"{self.date}_drive_{self.drive}_sync"


def load_sequence_mapping(config_path: str | Path | None = None) -> dict[str, SequenceInfo]:
    path = Path(config_path) if config_path is not None else DEFAULT_CONFIG_PATH
    raw = yaml.safe_load(path.read_text())
    mapping: dict[str, SequenceInfo] = {}
    for seq_id, fields in raw["sequences"].items():
        mapping[seq_id] = SequenceInfo(
            sequence=seq_id,
            date=fields["date"],
            drive=fields["drive"],
            start=fields["start"],
            end=fields["end"],
            frame_count=fields["frame_count"],
            split=fields["split"],
            available=fields["available"],
        )
    return mapping


TRAIN_SEQUENCES: tuple[str, ...] = ("00", "01", "02", "03", "04", "05", "06", "07", "08")
TEST_SEQUENCES: tuple[str, ...] = ("09", "10")
ALL_SEQUENCES: tuple[str, ...] = TRAIN_SEQUENCES + TEST_SEQUENCES

# All sequences except 03 (see module docstring) -- what `kitti-c2l generate` uses by default.
AVAILABLE_SEQUENCES: tuple[str, ...] = tuple(seq for seq in ALL_SEQUENCES if seq != "03")