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

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).
  3. Filter to frames where:
       quality      >= MOON_MIN_QUALITY
       altitude_deg >= MOON_MIN_ALTITUDE_DEG
       illumination is within the phase's illumination band
       waxing-state matches the phase target
  4. Pick the qualifying frame closest in time to exact phase UTC.
  5. Composite the cached lunar texture into it (real sky + halo from east,
     borrowed surface detail from the cached reference).
  6. Optionally 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', CONF.get('MOON_FULL_HEIGHT_PCT', 0.70)))
REF_PATH = CONF.get('MOON_REFERENCE_PATH') or str(_here / 'moon-ref' / 'full-moon.jpg')


PHASE_SPEC = {
    'full': {
        'index': 2,
        'label': 'Full Moon',
        'emoji': '🌕',
        'illum_min': float(CONF.get('MOON_FULL_MIN_ILLUMINATION', 0.95)),
        'illum_max': 1.01,
        'waxing': None,
        'window_before': int(CONF.get('MOON_FULL_WINDOW_BEFORE_DAYS', 1)),
        'window_after': int(CONF.get('MOON_FULL_WINDOW_AFTER_DAYS', 2)),
        'post_delay': int(CONF.get('MOON_FULL_POST_DELAY_DAYS', 3)),
        'enabled_key': 'MOON_FULL_ENABLED',
    },
    'first-quarter': {
        'index': 1,
        'label': 'First Quarter (Waxing Half)',
        'emoji': '🌓',
        'illum_min': float(CONF.get('MOON_QUARTER_MIN_ILLUMINATION', 0.40)),
        'illum_max': float(CONF.get('MOON_QUARTER_MAX_ILLUMINATION', 0.65)),
        'waxing': True,
        'window_before': int(CONF.get('MOON_QUARTER_WINDOW_BEFORE_DAYS', 1)),
        'window_after': int(CONF.get('MOON_QUARTER_WINDOW_AFTER_DAYS', 1)),
        'post_delay': int(CONF.get('MOON_QUARTER_POST_DELAY_DAYS', 2)),
        'enabled_key': 'MOON_FIRST_QUARTER_ENABLED',
    },
    'third-quarter': {
        'index': 3,
        'label': 'Third Quarter (Waning Half)',
        'emoji': '🌗',
        'illum_min': float(CONF.get('MOON_QUARTER_MIN_ILLUMINATION', 0.40)),
        'illum_max': float(CONF.get('MOON_QUARTER_MAX_ILLUMINATION', 0.65)),
        'waxing': False,
        'window_before': int(CONF.get('MOON_QUARTER_WINDOW_BEFORE_DAYS', 1)),
        'window_after': int(CONF.get('MOON_QUARTER_WINDOW_AFTER_DAYS', 1)),
        'post_delay': int(CONF.get('MOON_QUARTER_POST_DELAY_DAYS', 2)),
        '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)
    dates = []
    for i in range(-spec['window_before'], spec['window_after'] + 1):
        d = (target_local + timedelta(days=i)).date()
        dates.append(d.strftime('%Y-%m-%d'))
    print(f'scanning dates: {dates}')

    candidates = _candidate_frames(cam, dates)
    print(f'frame count in window: {len(candidates)}')
    if not candidates:
        msg = (
            f'No frames for {cam} in window {dates[0]}..{dates[-1]} '
            f'around {phase} {target_utc.strftime("%Y-%m-%d %H:%MZ")}.'
        )
        _notify(f'{spec["emoji"]} {spec["label"]} — no frames available', msg)
        print(msg)
        return 0

    qualifying = []
    for path, utc_dt in candidates:
        try:
            alt, _ = moon_phase.altaz(utc_dt)
        except Exception as e:
            print(f'ERROR: moon_phase.altaz failed: {e}', file=sys.stderr)
            return 2
        if alt < MIN_ALTITUDE:
            continue
        det = detect_moon(path)
        if det is None or det.quality < MIN_QUALITY:
            continue
        illum = moon_phase.illumination(utc_dt)
        if illum < spec['illum_min'] or illum > spec['illum_max']:
            continue
        if spec['waxing'] is not None:
            if moon_phase.waxing(utc_dt) != spec['waxing']:
                continue
        qualifying.append((path, utc_dt, det, alt, illum))

    print(f'qualifying frames: {len(qualifying)}')
    if not qualifying:
        msg = (
            f'No clear-shot {phase} frame in window {dates[0]}..{dates[-1]} '
            f'(need quality≥{MIN_QUALITY}, altitude≥{MIN_ALTITUDE}°, '
            f'illumination {spec["illum_min"]:.2f}-{spec["illum_max"]:.2f}). '
        )
        if phase == 'first-quarter':
            msg += ('First quarter from east is best-effort because the moon is '
                    'only up during daylight hours — daytime detection often '
                    'fails. Lower MOON_MIN_QUALITY or accept that some months '
                    'will skip.')
        else:
            msg += 'Likely cloudy across the whole window.'
        _notify(f'{spec["emoji"]} {spec["label"]} — no clear shot {target_utc.strftime("%B %Y")}', msg)
        print(msg)
        return 0

    best = min(qualifying, key=lambda t: abs(t[1] - target_utc))
    path, when_utc, det, alt, illum = best
    delta_min = (when_utc - target_utc).total_seconds() / 60.0
    local_dt = when_utc.astimezone(tz)
    print(f'picked: {path}')
    print(f'  when_utc={when_utc.isoformat()}  local={local_dt}  '
          f'altitude={alt:.1f}°  illum={illum:.4f}  quality={det.quality:.3f}  '
          f'Δtarget={delta_min:+.1f} min')

    if dry_run:
        return 0

    if not pathlib.Path(REF_PATH).is_file():
        msg = (f'Lunar reference image missing at {REF_PATH}. Re-run install.sh '
               f'or drop a high-res full moon JPEG there manually.')
        _notify(f'{spec["emoji"]} {spec["label"]} — reference missing', msg)
        print(msg, file=sys.stderr)
        return 3

    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))

    from moon_composite import composite_full_moon
    caption = (
        f"{spec['label']} — {target_utc.strftime('%B %Y')} — "
        f"sky-cam {cam} {local_dt.strftime('%Y-%m-%d %H:%M:%S %Z')}"
    )
    composite_full_moon(
        path, det, when_utc, REF_PATH, out_path,
        output_size=(OUT_W, OUT_H), moon_height_pct=MOON_PCT,
        caption=caption,
    )
    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} — picked {local_dt}, Δtarget {delta_min:+.0f} min',
        )
        return 0

    posted = _post_to_mattermost(
        out_path,
        f"{spec['emoji']} {spec['label']} — {target_utc.strftime('%B %Y')}\n"
        f"Captured by sky-cam {cam} at {local_dt.strftime('%Y-%m-%d %H:%M:%S %Z')} "
        f"({delta_min:+.0f} min from exact {phase}).",
    )
    if posted:
        _notify(
            f'{spec["emoji"]} {spec["label"]} {target_utc.strftime("%B %Y")} posted',
            f'Picked {local_dt} — Δtarget {delta_min:+.0f} min — {out_path}',
        )
    else:
        _notify(
            f'FAILED: {spec["emoji"]} {spec["label"]} {target_utc.strftime("%B %Y")} upload',
            f'Composite 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())