#!/usr/bin/env python3
"""moon_phase_monthly.py — build the monthly moon-phase close-up.

Handles three phases, controlled by --phase:

  full              ~100% lit, posted MOON_FULL_POST_DELAY_DAYS after exact full
  first-quarter     ~50% lit waxing (right half lit in northern hemisphere)
  third-quarter     ~50% lit waning (left half lit in northern hemisphere)

Algorithm (per phase):
  1. Find the most recent occurrence of the target phase (or honour --target).
  2. Scan east frames across the collection window (D-Δb .. D+Δa) and pick
     the frame closest in time to exact phase UTC where east successfully
     detected the moon and standard quality / altitude / illumination
     thresholds are met.  East is the WITNESS — it confirms you actually had
     a chance to see the moon that night.
  3. Round east's capture timestamp to the nearest hour and fetch the NASA
     SVS Dial-a-Moon render for that hour.  This gives a real-physics moon
     image with correct phase, libration and crater shadows.
  4. Render full-screen on a black background (moon fills ~92% of frame
     height), drop a caption naming the phase / month / capture moment /
     attribution, and upload to Mattermost.

Geometry note — first-quarter from east is HARD: at first quarter the moon is
up from noon to midnight, but east only sees the eastern sky, so it captures
the moon during DAYTIME only (with a bright sky background).  The detector is
brightness-based and may often fail to find a daytime moon.  Set
MOON_FIRST_QUARTER_ENABLED=false in sky-cam.conf if you'd rather not chase it.
Full moon and third-quarter both rise after dark and stay in east's view —
those should land cleanly most months.

Usage:
  moon_phase_monthly.py                  # auto: run any phase whose post-day = today
  moon_phase_monthly.py --phase full     # force a single phase
  moon_phase_monthly.py --phase third-quarter --target 2026-04-09T11:51:00Z --dry-run
"""
from __future__ import annotations

import argparse
import os
import pathlib
import re
import subprocess
import sys
from datetime import datetime, timedelta, timezone

_here = pathlib.Path(__file__).resolve().parent
sys.path.insert(0, str(_here))


def _read_conf(path):
    conf = {}
    try:
        with open(path) as f:
            for line in f:
                line = line.strip()
                if not line or line.startswith('#') or '=' not in line:
                    continue
                k, v = line.split('=', 1)
                k = k.strip()
                v = v.strip()
                v = re.sub(r'\s+#.*$', '', v)
                v = v.strip('"').strip("'")
                m = re.match(r'^\$\{[^}]+:-([^}]*)\}$', v)
                if m:
                    v = m.group(1).strip('"').strip("'")
                conf[k] = v
    except FileNotFoundError:
        pass
    return conf


CONF = _read_conf(_here / 'sky-cam.conf')
CONF.update(_read_conf(_here / '.env'))

BASE_DIR = CONF.get('BASE_DIR') or str(_here / 'data')
MOVIES_DIR = CONF.get('MOVIES_DIR') or f'{BASE_DIR}/movies'
SUNRISE_CAM = CONF.get('SUNRISE_CAM', 'east')
TIMEZONE = CONF.get('TIMEZONE', 'UTC')

MIN_QUALITY = float(CONF.get('MOON_MIN_QUALITY', CONF.get('MOON_FULL_MIN_QUALITY', 0.55)))
MIN_ALTITUDE = float(CONF.get('MOON_MIN_ALTITUDE_DEG', CONF.get('MOON_FULL_MIN_ALTITUDE_DEG', 15.0)))
OUT_W = int(CONF.get('MOON_OUTPUT_W', CONF.get('MOON_FULL_OUTPUT_W', 1920)))
OUT_H = int(CONF.get('MOON_OUTPUT_H', CONF.get('MOON_FULL_OUTPUT_H', 1080)))
MOON_PCT = float(CONF.get('MOON_HEIGHT_PCT', 0.92))
REQUIRE_EAST_VERIFY = CONF.get('MOON_REQUIRE_EAST_VERIFY', 'true').lower() != 'false'

_obs_parts = CONF.get('MOON_OBS_TIME_LOCAL', '22:00').split(':')
OBS_TIME_H = int(_obs_parts[0])
OBS_TIME_M = int(_obs_parts[1]) if len(_obs_parts) > 1 else 0


PHASE_SPEC = {
    'full': {
        'index': 2,
        'label': 'Full Moon',
        'emoji': '🌕',
        'post_delay': int(CONF.get('MOON_FULL_POST_DELAY_DAYS', 1)),
        'enabled_key': 'MOON_FULL_ENABLED',
    },
    'first-quarter': {
        'index': 1,
        'label': 'First Quarter (Waxing Half)',
        'emoji': '🌓',
        'post_delay': int(CONF.get('MOON_QUARTER_POST_DELAY_DAYS', 1)),
        'enabled_key': 'MOON_FIRST_QUARTER_ENABLED',
    },
    'third-quarter': {
        'index': 3,
        'label': 'Third Quarter (Waning Half)',
        'emoji': '🌗',
        'post_delay': int(CONF.get('MOON_QUARTER_POST_DELAY_DAYS', 1)),
        'enabled_key': 'MOON_THIRD_QUARTER_ENABLED',
    },
}

_FRAME_RE = re.compile(r'^(\d{2})-(\d{2})-(\d{2})\.jpg$')


def _local_tz():
    try:
        import pytz
        return pytz.timezone(TIMEZONE)
    except Exception:
        return timezone.utc


def _frame_local_dt(date_str: str, fname: str):
    m = _FRAME_RE.match(fname)
    if not m:
        return None
    h, mn, s = (int(x) for x in m.groups())
    y, mo, d = (int(x) for x in date_str.split('-'))
    naive = datetime(y, mo, d, h, mn, s)
    tz = _local_tz()
    if hasattr(tz, 'localize'):
        return tz.localize(naive)
    return naive.replace(tzinfo=tz)


def _candidate_frames(cam: str, dates: list[str]) -> list[tuple[str, datetime]]:
    out = []
    for d in dates:
        fdir = pathlib.Path(BASE_DIR) / cam / d
        if not fdir.is_dir():
            continue
        for fname in sorted(os.listdir(fdir)):
            if not fname.endswith('.jpg'):
                continue
            local_dt = _frame_local_dt(d, fname)
            if local_dt is None:
                continue
            out.append((str(fdir / fname), local_dt.astimezone(timezone.utc)))
    return out


def _format_local(dt_utc: datetime) -> str:
    return dt_utc.astimezone(_local_tz()).strftime('%Y-%m-%d %H:%M:%S %Z')


def _notify(title: str, body: str):
    try:
        subprocess.run([str(_here / 'notify.sh'), title, body], check=False)
    except FileNotFoundError:
        pass


def _post_to_mattermost(image_path: str, message: str) -> bool:
    import requests
    base = CONF.get('mattermost_url', '').rstrip('/')
    token = CONF.get('access_token', '')
    channel_id = CONF.get('channel_id', '')
    if not all([base, token, channel_id]):
        print('mattermost credentials missing — skipping upload', file=sys.stderr)
        return False
    headers = {'Authorization': f'Bearer {token}'}
    with open(image_path, 'rb') as f:
        r = requests.post(
            f'{base}/api/v4/files',
            headers=headers,
            files={'files': f},
            data={'channel_id': channel_id},
        )
    if r.status_code != 201:
        print(f'mattermost upload failed: {r.status_code} {r.text}', file=sys.stderr)
        return False
    file_id = r.json()['file_infos'][0]['id']
    r = requests.post(
        f'{base}/api/v4/posts',
        headers=headers,
        json={'channel_id': channel_id, 'message': message, 'file_ids': [file_id]},
    )
    if r.status_code != 201:
        print(f'mattermost post failed: {r.status_code} {r.text}', file=sys.stderr)
        return False
    return True


def _output_subdir(phase: str) -> str:
    return {
        'full': 'full-moons',
        'first-quarter': 'first-quarter',
        'third-quarter': 'third-quarter',
    }[phase]


def _output_filename(phase: str, target_utc: datetime) -> str:
    slug = {'full': 'full', 'first-quarter': 'first-quarter', 'third-quarter': 'third-quarter'}[phase]
    return f"{target_utc.strftime('%Y-%m')}-{slug}.jpg"


def run_phase(phase: str, target_utc: datetime | None, cam: str,
              dry_run: bool, no_upload: bool, out_path: str | None) -> int:
    spec = PHASE_SPEC[phase]
    if CONF.get(spec['enabled_key'], 'true').lower() == 'false':
        print(f'{spec["enabled_key"]}=false — skipping {phase}')
        return 0

    import moon_phase
    from moon_detect import detect_moon

    if target_utc is None:
        now = datetime.now(timezone.utc)
        events = moon_phase.phase_events_in_range(
            now - timedelta(days=45), now, spec['index'])
        if not events:
            print(f'no recent {phase} found in past 45 days', file=sys.stderr)
            return 1
        target_utc = events[-1]

    print(f'target {phase}: {target_utc.isoformat()}  ({_format_local(target_utc)})')

    tz = _local_tz()
    target_local = target_utc.astimezone(tz)

    # If east-verification is disabled the user wants a post regardless of
    # whether east could see the moon that night.  Fetch dial-a-moon for the
    # exact phase moment, render full-screen, post.  Skips all east scanning.
    if not REQUIRE_EAST_VERIFY:
        print('MOON_REQUIRE_EAST_VERIFY=false — skipping east scan, using exact phase UTC')
        return _render_and_post(phase, spec, target_utc, target_utc, target_local,
                                cam, dry_run, no_upload, out_path,
                                witness_text='not requiring east verification (set MOON_REQUIRE_EAST_VERIFY=true to require)')

    # ── Fixed observation time on the night of the phase event ──────────────
    # Instead of scanning a multi-day window for the best detection, we look
    # at a short window around a configured local time (default 22:30) on the
    # night of the exact phase.  That single timestamp drives both the NASA
    # Dial-a-Moon fetch (rounded to the nearest hour) and the atmosphere check.
    obs_naive = datetime(
        target_local.year, target_local.month, target_local.day,
        OBS_TIME_H, OBS_TIME_M, 0,
    )
    if hasattr(tz, 'localize'):
        obs_utc = tz.localize(obs_naive).astimezone(timezone.utc)
    else:
        obs_utc = obs_naive.replace(tzinfo=tz).astimezone(timezone.utc)
    print(f'obs time: {obs_utc.isoformat()}  ({_format_local(obs_utc)})')

    # Check moon altitude at the observation time
    try:
        alt_at_obs, _ = moon_phase.altaz(obs_utc)
    except Exception as e:
        print(f'ERROR: moon_phase.altaz: {e}', file=sys.stderr)
        return 2
    print(f'moon altitude at obs time: {alt_at_obs:.1f}°')

    # Scan east frames in the 22:00–23:00 window for any clear moon detection
    obs_end = obs_utc + timedelta(hours=1)
    obs_dates: list[str] = []
    d = obs_utc.astimezone(tz).date()
    while d <= obs_end.astimezone(tz).date():
        obs_dates.append(d.strftime('%Y-%m-%d'))
        d += timedelta(days=1)
    all_frames = _candidate_frames(cam, obs_dates)
    window_frames = [(p, dt) for p, dt in all_frames if obs_utc <= dt <= obs_end]
    print(f'east frames in 22:00-23:00 window: {len(window_frames)}')

    if alt_at_obs < MIN_ALTITUDE:
        print(f'moon below horizon at obs time ({alt_at_obs:.1f}deg) — skipping')
        _notify(
            f'{spec["emoji"]} {spec["label"]} {target_utc.strftime("%B %Y")} '
            f'— moon below horizon at {OBS_TIME_H:02d}:{OBS_TIME_M:02d} local',
            f'Adjust MOON_OBS_TIME_LOCAL in sky-cam.conf.',
        )
        return 0

    # Binary go/no-go: any frame in the window with quality >= MIN_QUALITY?
    clear_frame: str | None = None
    for fpath, fdt in window_frames:
        det = detect_moon(fpath)
        if det is not None and det.quality >= MIN_QUALITY:
            clear_frame = fpath
            offset_min = (fdt - obs_utc).total_seconds() / 60.0
            print(f'clear moon detected: {fpath}')
            print(f'  quality={det.quality:.3f}  offset=+{offset_min:.1f} min')
            break
        else:
            q = det.quality if det is not None else None
            print(f'  {fpath}: quality={q} — not clear enough')

    if clear_frame is None:
        print('no clear moon detection in window — skipping (overcast or moon absent)')
        _notify(
            f'{spec["emoji"]} {spec["label"]} {target_utc.strftime("%B %Y")} — skipped',
            f'No clear moon detection in the 22:00-23:00 window.',
        )
        return 0

    obs_local_str = _format_local(obs_utc)
    witness_text = f'sky-cam {cam} — clear at {obs_local_str} — NASA SVS Dial-a-Moon'

    if dry_run:
        print(f'dry-run: would post using NASA image for {obs_utc.isoformat()}')
        return 0

    return _render_and_post(
        phase, spec, target_utc, obs_utc, obs_utc.astimezone(tz),
        cam, dry_run, no_upload, out_path,
        witness_text=witness_text,
    )


def _render_and_post(phase, spec, target_utc, when_utc, local_dt, cam,
                     dry_run, no_upload, out_path, witness_text):
    if out_path is None:
        out_dir = pathlib.Path(MOVIES_DIR) / cam / _output_subdir(phase)
        out_dir.mkdir(parents=True, exist_ok=True)
        out_path = str(out_dir / _output_filename(phase, target_utc))

    # Fetch the NASA SVS Dial-a-Moon render for the hour east captured the
    # moon (or the exact phase moment if east-verification is off).  The
    # render carries the correct phase, libration and crater shadows for
    # that UTC moment — the strongest possible match for what east "saw,"
    # and free of the white-blob limitation.
    import moon_dialamoon
    try:
        nasa_path = moon_dialamoon.fetch_for_time(when_utc)
    except Exception as e:
        msg = (
            f'NASA SVS Dial-a-Moon fetch failed for '
            f'{when_utc.strftime("%Y-%m-%dT%HZ")}: {e}'
        )
        _notify(f'{spec["emoji"]} {spec["label"]} — dial-a-moon fetch failed', msg)
        print(msg, file=sys.stderr)
        return 4
    print(f'dial-a-moon: {nasa_path}')

    from moon_composite import render_phase_closeup
    caption = (
        f"{spec['label']} — {target_utc.strftime('%B %Y')} — "
        f"sky-cam {cam} {witness_text} — render: NASA SVS Dial-a-Moon"
    )
    render_phase_closeup(
        str(nasa_path), out_path,
        output_size=(OUT_W, OUT_H), moon_height_pct=MOON_PCT,
        caption=caption,
        when_utc=when_utc,
    )
    print(f'wrote {out_path}')

    if no_upload:
        _notify(
            f'{spec["emoji"]} {spec["label"]} {target_utc.strftime("%B %Y")} (built, not posted)',
            f'{out_path} — {witness_text}',
        )
        return 0

    posted = _post_to_mattermost(
        out_path,
        f"{spec['emoji']} {spec['label']} — {target_utc.strftime('%B %Y')}\n"
        f"sky-cam {cam} {witness_text}.\n"
        f"Surface render from NASA SVS Dial-a-Moon for that hour.",
    )
    if posted:
        _notify(
            f'{spec["emoji"]} {spec["label"]} {target_utc.strftime("%B %Y")} posted',
            f'{witness_text} — {out_path}',
        )
    else:
        _notify(
            f'FAILED: {spec["emoji"]} {spec["label"]} {target_utc.strftime("%B %Y")} upload',
            f'Image built at {out_path} but Mattermost upload failed.',
        )
    return 0


def auto_run(cam: str, dry_run: bool, no_upload: bool) -> int:
    """Daily check: run any phase whose post-day equals today (UTC)."""
    import moon_phase
    today_utc = datetime.now(timezone.utc).date()
    ran_any = False
    rc = 0
    for phase, spec in PHASE_SPEC.items():
        if CONF.get(spec['enabled_key'], 'true').lower() == 'false':
            print(f'-- {phase}: {spec["enabled_key"]}=false → skip')
            continue
        events = moon_phase.phase_events_in_range(
            datetime.combine(today_utc - timedelta(days=45), datetime.min.time(), tzinfo=timezone.utc),
            datetime.now(timezone.utc),
            spec['index'])
        if not events:
            continue
        last_event = events[-1]
        days_since = (today_utc - last_event.date()).days
        if days_since == spec['post_delay']:
            print(f'== running {phase} (last event {last_event.date()}, +{spec["post_delay"]} days = today) ==')
            sub = run_phase(phase, last_event, cam, dry_run, no_upload, None)
            rc = rc or sub
            ran_any = True
        else:
            print(f'-- {phase}: last {last_event.date()}, days_since={days_since}, post_delay={spec["post_delay"]} → skip')
    if not ran_any:
        print('no phase scheduled for today')
    return rc


def main():
    p = argparse.ArgumentParser()
    p.add_argument('--phase', choices=list(PHASE_SPEC.keys()),
                   help='Run a single phase regardless of schedule')
    p.add_argument('--target', help='Override phase event UTC, ISO 8601 (requires --phase)')
    p.add_argument('--cam', default=SUNRISE_CAM)
    p.add_argument('--dry-run', action='store_true')
    p.add_argument('--no-upload', action='store_true')
    p.add_argument('--out', help='Override output path (requires --phase)')
    args = p.parse_args()

    if args.phase:
        target = None
        if args.target:
            target = datetime.fromisoformat(args.target.replace('Z', '+00:00'))
        return run_phase(args.phase, target, args.cam, args.dry_run, args.no_upload, args.out)
    return auto_run(args.cam, args.dry_run, args.no_upload)


if __name__ == '__main__':
    sys.exit(main())