#!/usr/bin/env python3
"""Cycle fan speeds on the dryer for wiring / PWM verification.

Uses the firmware `fan test <pwm>` command (heater stays off). Sends `target 0`
first so the thermal loop is idle.

Example:
  ./fan_test.py
  ./fan_test.py --pct 30 50 100 --interval 3 --loop
"""

from __future__ import annotations

import argparse
import re
import sys
import time

from capture_csv import decode_line, open_serial, resolve_port

OK_RE = re.compile(r"^OK ")
ERR_RE = re.compile(r"^ERR ")
FAN_STATUS_RE = re.compile(r"fan=(\d+)/255\((\d+)%\)")


def pct_to_pwm(pct: int) -> int:
    if pct < 0 or pct > 100:
        raise ValueError(f"fan percent must be 0-100, got {pct}")
    return round(pct * 255 / 100)


def send_command(ser, command: str, timeout: float = 2.0) -> list[str]:
    ser.write((command.strip() + "\n").encode("utf-8"))
    ser.flush()
    lines: list[str] = []
    deadline = time.monotonic() + timeout
    while time.monotonic() < deadline:
        raw = ser.readline()
        if not raw:
            continue
        line = decode_line(raw)
        if not line:
            continue
        lines.append(line)
        if OK_RE.match(line) or ERR_RE.match(line):
            break
    return lines


def drain_status(ser, duration: float) -> str | None:
    """Read serial for `duration` seconds; return last status fan field if seen."""
    fan_field: str | None = None
    deadline = time.monotonic() + duration
    while time.monotonic() < deadline:
        raw = ser.readline()
        if not raw:
            continue
        line = decode_line(raw)
        if not line or line.startswith("csv"):
            continue
        match = FAN_STATUS_RE.search(line)
        if match:
            fan_field = f"{match.group(1)}/255 ({match.group(2)}%)"
        elif line.startswith("target="):
            print(f"  status: {line}", flush=True)
    return fan_field


def main() -> int:
    parser = argparse.ArgumentParser(description="Cycle fan PWM to verify fan control")
    parser.add_argument(
        "-p",
        "--port",
        help="Serial port (default: auto-detect)",
    )
    parser.add_argument("-b", "--baud", type=int, default=115200)
    parser.add_argument(
        "--pct",
        type=int,
        nargs="+",
        default=[0, 30, 100, 200, 255],
        metavar="PCT",
        help="Fan speeds in percent (default: 0 30 100 200 255)",
    )
    parser.add_argument(
        "--interval",
        type=float,
        default=5.0,
        metavar="SEC",
        help="Seconds to hold each step (default: 5)",
    )
    parser.add_argument(
        "--loop",
        action="store_true",
        help="Repeat the sequence until Ctrl+C",
    )
    args = parser.parse_args()

    port = resolve_port(args.port)
    sequence = [(pct, pct_to_pwm(pct)) for pct in args.pct]

    print(f"Port: {port}", file=sys.stderr)
    print(
        f"Sequence: {' -> '.join(str(p) + '%' for p, _ in sequence)} "
        f"every {args.interval:g}s (heater off)",
        file=sys.stderr,
    )
    print("Ctrl+C to stop\n", file=sys.stderr)

    interrupted = False
    with open_serial(port, args.baud) as ser:
        ser.reset_input_buffer()

        lines = send_command(ser, "target 0")
        for line in lines:
            print(line, flush=True)
        if any(ERR_RE.match(line) for line in lines):
            return 1

        try:
            while True:
                for pct, pwm in sequence:
                    print(f">>> fan test {pwm}  ({pct}%)", flush=True)
                    lines = send_command(ser, f"fan test {pwm}")
                    for line in lines:
                        print(f"    {line}", flush=True)
                    if any(ERR_RE.match(line) for line in lines):
                        return 1

                    reported = drain_status(ser, args.interval)
                    if reported:
                        print(f"    reported fan={reported}", flush=True)

                if not args.loop:
                    break
        except KeyboardInterrupt:
            interrupted = True
            print("\nInterrupted", file=sys.stderr)
        finally:
            print(">>> fan test 0 (stop)", flush=True)
            send_command(ser, "fan test 0")

    return 130 if interrupted else 0


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