"""Augment all_video_info_merged.xlsx with the input video + tracking DB paths.

Each xlsx row represents one fly (date, machine_name, ROI), observed across a
training session and a testing session. We resolve those two sessions to the
on-disk video files (via the inventory CSV) and to their tracking DBs (under
TRACKING_OUTPUT_DIR), then write the result as TSV.

Output columns added:
    training_video_path, training_db_path,
    testing_video_path,  testing_db_path

Empty values mean either no video matched (rare — implies missing inventory
entry) or no DB exists yet (e.g. the one video the completeness gate
rejected).

Usage:
    python export_video_db_index.py
    python export_video_db_index.py --out path/to/output.tsv
"""

from __future__ import annotations

import argparse
import re
from pathlib import Path

import pandas as pd

from config import INVENTORY_CSV, TRACKING_OUTPUT_DIR, VIDEO_INFO_TSV, VIDEO_INFO_XLSX


_TIME_RE = re.compile(r"^(\d{8})_(\d{1,2})(\d{2})?(AM|PM)$", re.IGNORECASE)


def parse_xlsx_time(value: str) -> tuple[str, int] | None:
    """Convert '20241021_11AM' / '20240918_1030AM' to (YYYY-MM-DD, minutes24).

    Resolution is hour-only when no minutes are given (e.g. '11AM' → 11:00).
    Returns minutes-from-midnight so we can do nearest-neighbor matching.
    """
    if not isinstance(value, str):
        return None
    m = _TIME_RE.match(value.strip())
    if not m:
        return None
    ymd, hh, mm, ampm = m.groups()
    date = f"{ymd[:4]}-{ymd[4:6]}-{ymd[6:8]}"
    hour = int(hh)
    minute = int(mm) if mm else 0
    if ampm.upper() == "PM" and hour != 12:
        hour += 12
    if ampm.upper() == "AM" and hour == 12:
        hour = 0
    return date, hour * 60 + minute


def build_session_index(inventory: pd.DataFrame) -> dict[tuple[str, str], list[dict]]:
    """Index inventory rows by (date, machine_name) → list of session dicts."""
    idx: dict[tuple[str, str], list[dict]] = {}
    for row in inventory.itertuples(index=False):
        h, m, _s = (int(p) for p in str(row.session_time).split("-"))
        key = (row.session_date, row.machine_name)
        idx.setdefault(key, []).append({
            "mp4_path": row.mp4_path,
            "session_datetime": row.session_datetime,
            "minutes": h * 60 + m,
        })
    return idx


def db_path_for_video(mp4_path: str) -> Path | None:
    """Tracker writes <video_stem>_tracking.db under TRACKING_OUTPUT_DIR."""
    stem = Path(mp4_path).stem
    db = TRACKING_OUTPUT_DIR / f"{stem}_tracking.db"
    return db if db.exists() else None


_TIME_TOLERANCE_MIN = 90  # xlsx labels are approximate ("11AM" → 10:51 is fine)


def resolve_session(
    machine_name: str,
    when: str,
    fallback_date: str | None,
    index: dict[tuple[str, str], list[dict]],
) -> tuple[str, str]:
    """Look up the video + db whose start time is closest to `when`.

    Match strategy:
    1. Use the date embedded in `when` (training/testing can fall on a
       different calendar day from the row's ``date`` column).
    2. If no candidates exist for that date, fall back to ``fallback_date``
       (the xlsx row's ``date`` column). Reason: the xlsx contains
       date typos like '20240110_11AM' for an Oct 1 experiment.

    Among candidates, pick the video whose start minute is closest to the
    xlsx-claimed time, within ±_TIME_TOLERANCE_MIN.
    """
    parsed = parse_xlsx_time(when)
    if parsed is None:
        return "", ""
    date, target_min = parsed
    candidates = index.get((date, machine_name), [])
    if not candidates and fallback_date:
        candidates = index.get((fallback_date, machine_name), [])
    if not candidates:
        return "", ""

    def _gap(target: int, c: dict) -> int:
        # Reason: xlsx times like '1230AM' are ambiguous (12 AM vs 12 PM).
        # We try both the literal time AND a +12-hour shift, picking the
        # interpretation that brings us closest to a real session.
        return min(abs(c["minutes"] - target), abs(c["minutes"] - (target + 720) % 1440))

    best = min(candidates, key=lambda c: _gap(target_min, c))
    if _gap(target_min, best) > _TIME_TOLERANCE_MIN:
        return "", ""
    db = db_path_for_video(best["mp4_path"])
    return best["mp4_path"], (str(db) if db else "")


# Variants of "naive" the xlsx has accumulated: 'naïve', 'niave', plus
# trailing whitespace. All collapse to a single canonical 'naive'.
_MALE_NAIVE_VARIANTS = {"naïve", "niave", "naive"}


def _normalize_metadata(df: pd.DataFrame) -> None:
    """Strip whitespace and canonicalize the ``male`` column in place."""
    for col in df.select_dtypes(include=("object", "string")).columns:
        df[col] = df[col].astype(str).str.strip()
    df["male"] = df["male"].apply(
        lambda v: "naive" if v.lower() in _MALE_NAIVE_VARIANTS else v
    )


def main() -> None:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--out",
        type=Path,
        default=VIDEO_INFO_TSV,
        help="output TSV path (default: alongside the xlsx)",
    )
    args = parser.parse_args()

    inv = pd.read_csv(INVENTORY_CSV)
    inv = inv[inv["in_xlsx"]].copy()
    index = build_session_index(inv)

    df = pd.read_excel(VIDEO_INFO_XLSX)
    _normalize_metadata(df)
    date_iso = pd.to_datetime(df["date"]).dt.strftime("%Y-%m-%d")

    train_videos, train_dbs, test_videos, test_dbs = [], [], [], []
    for fallback, row in zip(date_iso, df.itertuples(index=False)):
        tv, td = resolve_session(row.machine_name, row.training_date_time, fallback, index)
        sv, sd = resolve_session(row.machine_name, row.testing_date_time, fallback, index)
        train_videos.append(tv)
        train_dbs.append(td)
        test_videos.append(sv)
        test_dbs.append(sd)

    df["training_video_path"] = train_videos
    df["training_db_path"] = train_dbs
    df["testing_video_path"] = test_videos
    df["testing_db_path"] = test_dbs

    # Reason: an analyst flag for excluding individual fly/session rows that
    # turn out to be too noisy or otherwise unusable. Default True; flip to
    # False directly in the TSV to drop a row from analysis without having
    # to delete it. load_roi_data() respects this flag.
    df["include"] = True

    df.to_csv(args.out, sep="\t", index=False)

    n_rows = len(df)
    n_train_video = sum(bool(v) for v in train_videos)
    n_train_db = sum(bool(v) for v in train_dbs)
    n_test_video = sum(bool(v) for v in test_videos)
    n_test_db = sum(bool(v) for v in test_dbs)
    print(f"wrote {args.out}  ({n_rows} rows)")
    print(f"  training:  {n_train_video} with video,  {n_train_db} with DB")
    print(f"  testing:   {n_test_video} with video,  {n_test_db} with DB")


if __name__ == "__main__":
    main()