#!/usr/bin/env python3
"""Log the coupon test rig's serial output to CSV files.

Usage:
    pip install pyserial
    python3 coupon_logger.py /dev/ttyACM0            # Linux (COM3 etc. on Windows)
    python3 coupon_logger.py /dev/ttyACM0 --new      # start a fresh test

Files in --out (default ./coupon_logs), appended across restarts:
    data.csv      one row per channel per minute (D records)
    summary.csv   one row per channel per cycle (S records)
    events.csv    step changes, faults, resumes (E records)
    raw.txt       every line from the rig, with the PC time

Type rig commands (STATUS, STOP, CAL, RUN, NEW, HELP) and press Enter
to send them. Ctrl+C quits; the rig keeps running without the PC.

Opening the port resets the Arduino. The sketch saves its state to
EEPROM and resumes, so restarting this logger does not restart the test.
"""
import argparse
import csv
import datetime
import pathlib
import sys
import threading
import time

try:
    import serial
except ImportError:
    sys.exit("pyserial is missing: pip install pyserial")

HEADERS = {
    "D": ["pc_time", "time_s", "ch", "state", "cycle", "V", "mA", "mAh", "mWh"],
    "S": ["pc_time", "time_s", "ch", "cycle", "dis_mAh", "dis_mWh", "avg_dis_V",
          "chg_mAh", "chg_mWh", "CE_pct", "EE_pct"],
    "E": ["pc_time", "time_s", "ch", "message"],
}
NAMES = {"D": "data.csv", "S": "summary.csv", "E": "events.csv"}


def open_csv(path, header):
    new = not path.exists() or path.stat().st_size == 0
    f = open(path, "a", newline="")
    w = csv.writer(f)
    if new:
        w.writerow(header)
    return f, w


def send_keyboard(port):
    for line in sys.stdin:
        port.write((line.strip() + "\n").encode())


def main():
    ap = argparse.ArgumentParser(description=__doc__.splitlines()[0])
    ap.add_argument("port", help="serial port, e.g. /dev/ttyACM0 or COM3")
    ap.add_argument("--out", default="coupon_logs", help="output folder")
    ap.add_argument("--new", action="store_true",
                    help="send NEW: clear the saved state and start a new test")
    a = ap.parse_args()

    out = pathlib.Path(a.out)
    out.mkdir(parents=True, exist_ok=True)
    files = {k: open_csv(out / NAMES[k], HEADERS[k]) for k in NAMES}
    raw = open(out / "raw.txt", "a")

    with serial.Serial(a.port, 115200, timeout=2) as port:
        time.sleep(2.5)                     # the Uno resets when the port opens
        if a.new:
            port.write(b"NEW\n")
        threading.Thread(target=send_keyboard, args=(port,), daemon=True).start()
        print(f"logging to {out.resolve()}  (Ctrl+C to quit)")
        try:
            while True:
                line = port.readline().decode(errors="replace").strip()
                if not line:
                    continue
                pc = datetime.datetime.now().isoformat(timespec="seconds")
                raw.write(f"{pc} {line}\n")
                raw.flush()
                kind, _, rest = line.partition(",")
                if kind in files and rest:
                    if kind == "E":         # the message may contain commas
                        t, ch, msg = (rest.split(",", 2) + ["", ""])[:3]
                        fields = [t, ch, msg]
                    else:
                        fields = rest.split(",")
                    f, w = files[kind]
                    w.writerow([pc] + fields)
                    f.flush()
                    if kind == "S":
                        h = HEADERS["S"][1:]
                        r = dict(zip(h, fields))
                        print(f"{pc}  CH{r['ch']} cycle {r['cycle']}: "
                              f"dis {r['dis_mAh']} mAh, chg {r['chg_mAh']} mAh, "
                              f"CE {r['CE_pct'] or '-'} %")
                    elif kind == "E":
                        print(f"{pc}  CH{fields[1]}  {fields[2]}")
                else:
                    print(line)             # comments, STATUS output
        except KeyboardInterrupt:
            print("\nstopped logging (the rig keeps running)")
        finally:
            for f, _ in files.values():
                f.close()
            raw.close()


if __name__ == "__main__":
    main()