#!/usr/bin/env python3
"""Generate the Tanin-<accent> icon themes.

Each theme is a THIN overlay that `Inherits=Adwaita` and recolours only the
accent-bearing place/folder icons to a Fuji hue — everything else resolves
straight from Adwaita, so app-icon coverage stays exactly Adwaita's.

Recolour = HSL hue/saturation swap that KEEPS each source stop's lightness:
the Adwaita blue ramp (#62a0ea / #438de6 / #a4caee / …) is shifted to the
muted Fuji hue while the gradient depth (light front / dark back) is preserved.
White emblems (music note, download arrow) are untouched — they are
desaturated, so the saturation gate skips them.

Runs at package build time and reads the installed Adwaita theme. Override the
input/output dirs via ADWAITA_DIR / OUT_DIR.
"""
from __future__ import annotations

import colorsys
import os
import re
import shutil
import subprocess
import sys
from pathlib import Path

# Fuji accents — keep in sync with taninux.core.theme / taninux.gui.accents.
ACCENTS = {
    "ume":     "#8f8aac",  # violet
    "shinkai": "#8a98ac",  # blue
    "take":    "#8aac8b",  # green
    "chikyu":  "#aca98a",  # yellow
    "beni":    "#ac8a8c",  # red
}

SRC = Path(os.environ.get("ADWAITA_DIR", "/usr/share/icons/Adwaita"))
OUT = Path(os.environ.get("OUT_DIR", "out"))

# Icons that semantically carry the accent (containers / locations). Anything
# not listed here is left to Adwaita via Inherits.
PLACES = [
    "folder", "folder-documents", "folder-download", "folder-drag-accept",
    "folder-music", "folder-pictures", "folder-publicshare", "folder-remote",
    "folder-templates", "folder-videos",
    "user-home", "user-desktop", "user-bookmarks", "network-workgroup",
]
MIMETYPES = ["inode-directory"]   # the folder mimetype — same look as a folder

HEX = re.compile(r"#([0-9a-fA-F]{3}|[0-9a-fA-F]{6})\b")

INDEX = """[Icon Theme]
Name=Tanin-{key}
Comment=TANINUX Fuji accent ({key}) over Adwaita
Inherits=Adwaita,hicolor
Directories=scalable/places,scalable/mimetypes,16x16/places

[scalable/places]
Context=Places
Size=128
MinSize=8
MaxSize=512
Type=Scalable

[scalable/mimetypes]
Context=MimeTypes
Size=128
MinSize=8
MaxSize=512
Type=Scalable

[16x16/places]
Context=Places
Size=16
Type=Fixed
"""


def _parse(h: str) -> tuple[float, float, float]:
    h = h.lstrip("#")
    if len(h) == 3:
        h = "".join(c * 2 for c in h)
    return tuple(int(h[i:i + 2], 16) / 255 for i in (0, 2, 4))  # type: ignore[return-value]


def _fmt(rgb: tuple[float, float, float]) -> str:
    return "#" + "".join(f"{round(max(0.0, min(1.0, c)) * 255):02x}" for c in rgb)


def _recolour(accent_hex: str):
    ar, ag, ab = _parse(accent_hex)
    ah, _al, a_s = colorsys.rgb_to_hls(ar, ag, ab)

    def repl(m: re.Match) -> str:
        r, g, b = _parse(m.group(0))
        h, l, s = colorsys.rgb_to_hls(r, g, b)
        # Only the Adwaita blue family: saturated + blue hue band (~194-230°).
        if s > 0.12 and 0.54 <= h <= 0.64:
            return _fmt(colorsys.hls_to_rgb(ah, l, a_s))
        return m.group(0)

    return repl


def build_theme(key: str, accent_hex: str, rsvg: str) -> int:
    repl = _recolour(accent_hex)
    root = OUT / f"Tanin-{key}"
    root.mkdir(parents=True, exist_ok=True)
    (root / "index.theme").write_text(INDEX.format(key=key))

    n = 0
    for ctx, names in (("places", PLACES), ("mimetypes", MIMETYPES)):
        sdir = root / "scalable" / ctx
        sdir.mkdir(parents=True, exist_ok=True)
        for name in names:
            src = SRC / "scalable" / ctx / f"{name}.svg"
            if not src.exists():
                print(f"   ! missing in Adwaita: scalable/{ctx}/{name}.svg", file=sys.stderr)
                continue
            (sdir / f"{name}.svg").write_text(HEX.sub(repl, src.read_text()))
            n += 1

    # 16x16 raster: size-exact, else the inherited Adwaita blue PNG wins at 16px.
    pdir = root / "16x16" / "places"
    pdir.mkdir(parents=True, exist_ok=True)
    for name in PLACES:
        svg = root / "scalable" / "places" / f"{name}.svg"
        if not svg.exists():
            continue
        subprocess.run([rsvg, "-w", "16", "-h", "16", "-o",
                        str(pdir / f"{name}.png"), str(svg)], check=True)
    return n


def main() -> int:
    if not SRC.is_dir():
        sys.exit(f"Adwaita theme not found at {SRC} (install adwaita-icon-theme)")
    rsvg = shutil.which("rsvg-convert")
    if not rsvg:
        sys.exit("rsvg-convert not found (install librsvg) — needed for 16px folders")
    # Only ever touch our own Tanin-<key> dirs — OUT may be a shared icon dir
    # (e.g. ~/.local/share/icons), never rmtree the whole thing.
    for key, hexv in ACCENTS.items():
        old = OUT / f"Tanin-{key}"
        if old.exists():
            shutil.rmtree(old)
        n = build_theme(key, hexv, rsvg)
        print(f"==> Tanin-{key:<8} {hexv}  ({n} svg recoloured + 16px raster)")
    print(f"== {len(ACCENTS)} themes written to {OUT} ==")
    return 0


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