#!/usr/bin/env python3
"""First controller tick of every B01 MPC episode (input of d3_range.py).

For each episode b01_<scenario_id>_mpc of the B01 logs, writes the first row of ticks.csv.gz with status 'ok'
(the first tick at which the controller received a state): the controller's lookahead error e0 and the tracking
error et0, et1, et2. Values are copied as logged (strings), so the downstream floats are exact.

Usage: python first_tick.py <B01_main_tr run dir (contains episodes/)> <out.csv>
"""
import csv
import glob
import gzip
import os
import sys

RUN, OUT = sys.argv[1:3]
rows = []
for d in sorted(glob.glob(os.path.join(RUN, 'episodes', 'b01_*_mpc'))):
    sid = os.path.basename(d)[len('b01_'):-len('_mpc')]
    with gzip.open(os.path.join(d, 'ticks.csv.gz'), 'rt') as fh:
        t = next(x for x in csv.DictReader(fh) if x['status'] == 'ok')
    rows.append({'scenario_id': sid, 'tick': t['tick'], 'e0': t['e0'], 'et0': t['et0'], 'et1': t['et1'], 'et2': t['et2']})
with open(OUT, 'w', newline='') as f:
    w = csv.DictWriter(f, fieldnames=list(rows[0].keys()))
    w.writeheader()
    w.writerows(rows)
print(f'{len(rows)} episodes -> {OUT}')