"""Figure: the transient search and why its six finalists are not transients.

Top block, one column per finalist: the 60 min luminance master beside a
Digitized Sky Survey red plate of the same patch of sky from the 1990s. If a
source is on both, it is not a transient, and that is a judgement a reader can
make from the picture without trusting any of the catalogue machinery.

Bottom left: where the catalogues run out. Almost every source brighter than
G = 19 has a Gaia DR3 counterpart; below that the unmatched fraction climbs
steeply, not because transients appear but because Gaia's G < 20.5 point-source
catalogue stops being complete against a bright galaxy. This is what sets the
honest limit of the search.

Bottom middle: the point-source selection. Half-light radius against magnitude,
with the image's own PSF measured from Gaia stars. Note that Centaurus A's
globular clusters sit inside the stellar locus - at 3.8 Mpc they are unresolved
in 2.7 arcsec seeing - so morphology cannot separate a cluster from a
supernova here, and five of the six finalists are clusters.

Bottom right: where the finalists are, on the master.
"""
import os

import numpy as np
import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
from astropy import units as u
from astropy.coordinates import SkyCoord
from astropy.io import fits
from astropy.stats import sigma_clipped_stats
from astropy.wcs import WCS

import mo_common as C

OUTPNG = os.path.join(C.OUT, "NGC5128-mo-transient-search.png")
HALF = 26          # px in the master = 28 arcsec across

# Identifications established by cross-matching the six catalogue non-matches
# against published Centaurus A cluster catalogues, SIMBAD and the VizieR
# archive as a whole (see notes-transient-search.md).
IDENT = {
    "201.672625": ("WHH-31", "Cen A globular cluster", "V=19.50 (Woodley+07)"),
    "201.500583": ("pff_gc-081", "Cen A globular cluster",
                   "V=19.34 (Woodley+07)"),
    "201.441625": ("WHH-24", "Cen A globular cluster", "V=19.63 (Woodley+07)"),
    "201.407000": ("at CAVS 210",
                   "RESOLVED (1.34x PSF), archival 1996-2020",
                   "DENIS I=18.23; Gaia pt src G=21.03 at 1.32\" - see 4.3"),
    "201.303542": ("WHH-10", "Cen A globular cluster", "V=19.57 (Woodley+07)"),
    "201.256708": ("pff_gc-029", "Cen A globular cluster",
                   "V=19.37 (Woodley+07)"),
}


def ident_for(ra):
    for k, v in IDENT.items():
        if abs(float(k) - ra) < 1e-4:
            return v
    return ("unidentified", "", "")


def stretch(a, lo=25.0, hi=99.6):
    a = np.asarray(a, dtype=float)
    good = np.isfinite(a)
    if not good.any():
        return 0.0, 1.0
    return np.percentile(a[good], lo), np.percentile(a[good], hi)


def main():
    rows = list(np.load(os.path.join(C.OUT, "_mo_vetted.npy"),
                        allow_pickle=True))
    rows.sort(key=lambda r: r["dist_cenA_arcmin"])
    z = np.load(os.path.join(C.OUT, "_mo_transient.npz"))

    with fits.open(os.path.join(C.OUT, "master-Luminance.fit")) as hd:
        master = hd[0].data.astype(np.float32)
        hdr = hd[0].header
    wcs = WCS(hdr)

    import sep
    bkg = sep.Background(master, bw=64, bh=64, fw=3, fh=3)
    msub = master - bkg.back()

    n = len(rows)
    fig = plt.figure(figsize=(15.0, 11.6))
    gs = fig.add_gridspec(3, n, height_ratios=[1.0, 1.0, 1.55],
                          hspace=0.30, wspace=0.09,
                          left=0.055, right=0.985, top=0.845, bottom=0.075)

    for i, r in enumerate(rows):
        name, kind, phot = ident_for(r["ra_deg"])
        x, y = int(round(r["x"])), int(round(r["y"]))
        cut = msub[y - HALF:y + HALF + 1, x - HALF:x + HALF + 1]
        ax = fig.add_subplot(gs[0, i])
        vlo, vhi = stretch(cut, 20, 99.5)
        ax.imshow(cut, origin="lower", cmap="gray", vmin=vlo, vmax=vhi)
        ax.plot([HALF, HALF], [HALF + 6, HALF + 11], color="#f0c05a", lw=1.1)
        ax.plot([HALF + 6, HALF + 11], [HALF, HALF], color="#f0c05a", lw=1.1)
        ax.set_xticks([]); ax.set_yticks([])
        for sp in ax.spines.values():
            sp.set_color("#2f7d54" if kind.startswith("Cen") else "#b5484f")
            sp.set_linewidth(1.4)
        ax.set_title(f"{name}\n{r['ra_hms']} {r['dec_dms']}", fontsize=8.6,
                     color="#1b1e23", pad=5)
        if i == 0:
            ax.set_ylabel("this image\n60 min luminance", fontsize=9,
                          color="#3b3f45")

        # archival plate
        tag = f"{r['ra_deg']:.5f}{r['dec_deg']:+.5f}_mred.fits"
        path = os.path.join(C.OUT, "_dss", tag)
        ax2 = fig.add_subplot(gs[1, i])
        if os.path.exists(path):
            with fits.open(path) as h2:
                d = np.asarray(h2[0].data, dtype=float)
            v1, v2 = stretch(d, 20, 99.5)
            ax2.imshow(d, origin="lower", cmap="gray", vmin=v1, vmax=v2)
            m = d.shape[0] / 2.0
            f = d.shape[0] / (2.0 * HALF + 1)
            ax2.plot([m, m], [m + 6 * f, m + 11 * f], color="#f0c05a", lw=1.1)
            ax2.plot([m + 6 * f, m + 11 * f], [m, m], color="#f0c05a", lw=1.1)
        else:
            ax2.text(0.5, 0.5, "no DSS cutout", ha="center", va="center",
                     fontsize=8, color="#8a9099", transform=ax2.transAxes)
        ax2.set_xticks([]); ax2.set_yticks([])
        for sp in ax2.spines.values():
            sp.set_color("#9aa0a8")
            sp.set_linewidth(0.9)
        ax2.set_xlabel(f"{kind}\n{phot}\nG(this image) = {r['g_mag']:.2f}, "
                       f"{r['dist_cenA_arcmin']:.1f}' from nucleus",
                       fontsize=7.8, color="#4a4f57", labelpad=5)
        if i == 0:
            ax2.set_ylabel("archival\nDSS2 red, 1990s", fontsize=9,
                           color="#3b3f45")

    # ---------------- magnitude completeness ----------------
    axm = fig.add_subplot(gs[2, 0:2])
    good = z["good"] & z["pointlike"]
    mag = z["mag"][good]
    matched = z["gaia_ok"][good]
    bins = np.arange(14.0, 21.01, 0.25)
    axm.hist([mag[matched], mag[~matched]], bins=bins, stacked=True,
             color=["#3d7ba6", "#b5484f"],
             label=["matched to Gaia DR3", "no Gaia counterpart"])
    axm.axvline(20.5, color="#4a4f57", ls="--", lw=1.2)
    axm.text(20.42, axm.get_ylim()[1] * 0.92, "Gaia cat.\nlimit G=20.5",
             fontsize=7.6, color="#4a4f57", ha="right", va="top")
    axm.set_xlabel("G magnitude (5 px aperture, master)", fontsize=9.5)
    axm.set_ylabel("point-like sources per 0.25 mag", fontsize=9.5)
    axm.set_title("where the reference catalogue runs out", fontsize=10.5,
                  color="#1b1e23", pad=7)
    axm.legend(fontsize=8.2, frameon=False, loc="upper left")
    axm.grid(alpha=0.22, lw=0.6)
    for sp in ("top", "right"):
        axm.spines[sp].set_visible(False)

    # ---------------- morphology ----------------
    axr = fig.add_subplot(gs[2, 2:4])
    sel = z["good"]
    axr.scatter(z["mag"][sel], z["r50"][sel] / z["r50_star"], s=2.5,
                c="#9fb6c6", alpha=0.35, lw=0, label="all detections")
    ci = z["cand_idx"]
    axr.scatter(z["mag"][ci], z["r50"][ci] / z["r50_star"], s=9,
                c="#e0a13c", alpha=0.8, lw=0,
                label="no Gaia / SkyMapper match")
    for r in rows:
        axr.scatter([r["g_mag"]], [r["r50_over_psf"]], s=64,
                    facecolor="none",
                    edgecolor="#2f7d54" if ident_for(r["ra_deg"])[1]
                    .startswith("Cen") else "#b5484f", lw=1.5, zorder=5)
    axr.axhline(1.0, color="#4a4f57", ls=":", lw=1.1)
    axr.text(14.3, 1.03, "PSF (Gaia stars)", fontsize=7.6, color="#4a4f57")
    axr.set_ylim(0.4, 3.2)
    axr.set_xlim(14.0, 21.0)
    axr.set_xlabel("G magnitude", fontsize=9.5)
    axr.set_ylabel("half-light radius / PSF", fontsize=9.5)
    axr.set_title("morphology cannot separate clusters from transients",
                  fontsize=10.5, color="#1b1e23", pad=7)
    axr.legend(fontsize=8.0, frameon=False, loc="upper left",
               markerscale=2.2)
    axr.grid(alpha=0.22, lw=0.6)
    for sp in ("top", "right"):
        axr.spines[sp].set_visible(False)

    # ---------------- field map ----------------
    axf = fig.add_subplot(gs[2, 4:6])
    sm = master[::6, ::6]
    v1, v2 = np.percentile(sm[np.isfinite(sm)], [12, 99.75])
    axf.imshow(np.arcsinh((sm - v1) / max(v2 - v1, 1e-6)), origin="lower",
               cmap="gray", vmin=0, vmax=np.arcsinh(1.0))
    for r in rows:
        c = "#2f7d54" if ident_for(r["ra_deg"])[1].startswith("Cen") \
            else "#b5484f"
        axf.scatter([r["x"] / 6], [r["y"] / 6], s=90, facecolor="none",
                    edgecolor=c, lw=1.5)
        axf.annotate(ident_for(r["ra_deg"])[0], (r["x"] / 6, r["y"] / 6),
                     textcoords="offset points", xytext=(9, 5), fontsize=7.4,
                     color=c)
    axf.set_xticks([]); axf.set_yticks([])
    axf.set_title("positions on the field (43' x 29')", fontsize=10.5,
                  color="#1b1e23", pad=7)
    for sp in axf.spines.values():
        sp.set_color("#9aa0a8")

    fig.text(0.02, 0.962,
             "Transient search in the 60 min luminance master of NGC 5128 "
             "(Centaurus A), 2026-07-21", fontsize=14, weight="bold",
             color="#1b1e23", ha="left")
    fig.text(0.02, 0.936,
             "7,519 point-like sources detected above SNR 10.  603 had no "
             "Gaia DR3 counterpart; 567 also had none in SkyMapper DR2; 6 of "
             "those survived the requirement of an independent detection in "
             "at least 6 of the 12 subs.",
             fontsize=9.4, color="#4a4f57", ha="left")
    fig.text(0.02, 0.917,
             "All 6 are identified below. Five are catalogued Centaurus A "
             "globular clusters; the sixth is a resolved object with archival "
             "detections from 1996 to 2020. No transient candidate remains.",
             fontsize=9.4, color="#4a4f57", ha="left")

    fig.savefig(OUTPNG, dpi=130, facecolor="white")
    print(f"wrote {OUTPNG}")


if __name__ == "__main__":
    main()