#!/usr/bin/env python3
# udt-palette: generate every themed config from one palette and one role map.
# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
# Licensed under the GNU General Public License v2 only.
"""Render the palette into each consumer's own syntax.

Usage: udt-palette [--roles <file>] [--out <dir>]
       udt-palette --selftest

The point of this script is that a colour is written down once. palette/<scheme>
.conf holds the colours under the scheme's own names, palette/roles.conf says
what each is for, and everything else here is generated. Editing a generated
file is pointless: the next install.sh overwrites it.
"""

import re
import sys
from pathlib import Path

REPO = Path(__file__).resolve().parent.parent
PALETTE_DIR = REPO / "palette"


def parse_conf(path):
    """Parse `key = value` lines into a dict, preserving order.

    [section] headers are read but not nested: roles are a flat namespace, and
    the sections exist to group the file for a human reader. A duplicate key is
    an error rather than a silent last-wins, because two roles quietly fighting
    is exactly the drift this file exists to prevent.
    """
    out = {}
    for lineno, raw in enumerate(path.read_text().splitlines(), 1):
        # A comment is a whole line starting with #, or a trailing "# " after
        # a value. Splitting on a bare "#" would eat every colour, since the
        # values are hex literals that start with one.
        line = raw.strip()
        if line.startswith("#"):
            continue
        line = re.split(r"\s#\s", line, maxsplit=1)[0].strip()
        if not line or line.startswith("["):
            continue
        if "=" not in line:
            raise ValueError(f"{path}:{lineno}: expected 'key = value', got {raw!r}")
        key, value = (p.strip() for p in line.split("=", 1))
        if key in out:
            raise ValueError(f"{path}:{lineno}: duplicate key {key!r}")
        out[key] = value
    return out


def resolve(roles, palette, roles_path):
    """Turn every role into (r, g, b, alpha). Unknown colour names are fatal.

    A role names a palette colour, optionally with an alpha percentage:
    `text/75`. Failing here is the whole safety story: a typo or a name the new
    scheme does not carry stops the build, rather than emitting a config with a
    black hole where a colour should be.
    """
    resolved = {}
    for role, spec in roles.items():
        if role in ("scheme", "snap"):
            continue
        # `name/75` is 75% alpha; `name*50` is the colour at 50% brightness.
        # shade exists because GTK's shade() has no palette name to point at:
        # half-brightness crust is darker than the darkest colour a scheme
        # ships, so it can only be computed.
        rest, _, alpha_s = spec.partition("/")
        name, _, shade_s = rest.partition("*")
        name = name.strip()
        if name not in palette:
            available = ", ".join(sorted(palette))
            raise ValueError(
                f"{roles_path}: role {role!r} wants colour {name!r}, which the "
                f"{roles['scheme']} palette does not define.\nAvailable: {available}")
        alpha = 100
        if alpha_s:
            alpha = int(alpha_s.strip())
            if not 0 <= alpha <= 100:
                raise ValueError(f"{roles_path}: role {role!r} alpha {alpha} out of 0-100")
        hexval = palette[name]
        r, g, b = (int(hexval[i:i + 2], 16) for i in (1, 3, 5))
        if shade_s:
            factor = int(shade_s.strip()) / 100
            if not 0 <= factor <= 2:
                raise ValueError(f"{roles_path}: role {role!r} shade out of 0-200")
            r, g, b = (min(255, round(c * factor)) for c in (r, g, b))
        resolved[role] = (r, g, b, alpha)
    return resolved


def hex6(c):
    r, g, b, _ = c
    return f"#{r:02x}{g:02x}{b:02x}"


def hex8(c):
    r, g, b, a = c
    return f"#{r:02x}{g:02x}{b:02x}{round(a * 255 / 100):02x}"


def rgba(c):
    r, g, b, a = c
    return f"rgb({r},{g},{b})" if a == 100 else f"rgba({r},{g},{b},{a / 100:.2f})"


BANNER = "Generated by udt-palette from palette/{scheme}.conf. Do not edit."


def gen_rofi(res, scheme, palette):
    """rofi: the structural palette, under the scheme's own colour names.

    Emits palette names rather than roles because the rofi themes were written
    against Catppuccin names and still use them. The role layer reaches rofi
    through accent.rasi, which udt-accent generates per wallpaper.
    """
    rows = "\n".join(f"    {k + ':':11}{v}ff;" for k, v in sorted(palette.items()))
    return (
        f"/*\n * {BANNER.format(scheme=scheme)}\n *\n"
        " * Structural colors only. The accent lives in accent.rasi.\n */\n\n"
        f"* {{\n{rows}\n}}\n"
    )


def gen_waybar(res, scheme, palette):
    """waybar: one file holding the palette and the role layer.

    Both halves together because style.css imports a single themes/<scheme>.css,
    and the stylesheets reference names from each: @lavender and @surface1 from
    the palette, @cpu and @hover-bg from the roles.

    Role names keep their existing hyphenated spelling (main-bg, not main_bg):
    the stylesheets reference them and are not generated.
    """
    palette_rows = "\n".join(f"@define-color {k:<12}{v};"
                              for k, v in sorted(palette.items()))

    def emit(role, css_name=None):
        c = res[role]
        return f"@define-color {(css_name or role.replace('_', '-')):<12}{rgba(c)};"

    ui = ["main_br", "main_bg", "main_fg", "hover_bg", "hover_fg", "outline"]
    modules = ["workspaces", "temperature", "memory", "cpu", "time", "date",
               "tray", "volume", "backlight", "battery"]
    states = ["warning", "critical", "charging"]

    return "\n".join([
        f"/* {BANNER.format(scheme=scheme)} */",
        "",
        palette_rows,
        "",
        "/* br - border, bg - background, fg - foreground */",
        "",
        "/* main colors */",
        f"@define-color accent      {rgba(res['accent'])};",
        *(emit(r) for r in ui),
        "",
        "/* module colors */",
        *(emit(r) for r in modules),
        "",
        "/* state colors */",
        *(emit(r) for r in states),
        "",
    ])


def gen_kitty(res, scheme, palette):
    """kitty: the 16 ANSI slots plus chrome.

    kitty has no include-with-override, so this is the whole colour section of
    the theme file rather than a fragment.
    """
    ansi = ["black", "red", "green", "yellow", "blue", "magenta", "cyan", "white"]
    lines = [f"# {BANNER.format(scheme=scheme)}", ""]
    for key, role in [("foreground", "fg"), ("background", "bg"),
                      ("selection_foreground", "selection_fg"),
                      ("selection_background", "selection_bg"),
                      ("cursor", "cursor"), ("cursor_text_color", "bg"),
                      ("url_color", "url"),
                      ("active_border_color", "border_active"),
                      ("inactive_border_color", "border_inactive"),
                      ("active_tab_foreground", "tab_active_fg"),
                      ("active_tab_background", "tab_active_bg"),
                      ("inactive_tab_foreground", "tab_inactive_fg"),
                      ("inactive_tab_background", "tab_inactive_bg"),
                      ("tab_bar_background", "tab_bar_bg"),
                      ("scrollbar_handle_color", "scrollbar_handle"),
                      ("scrollbar_track_color", "scrollbar_track"),
                      ("bell_border_color", "bell_border"),
                      ("mark1_foreground", "bg"), ("mark1_background", "mark1"),
                      ("mark2_foreground", "bg"), ("mark2_background", "mark2"),
                      ("mark3_foreground", "bg"), ("mark3_background", "mark3")]:
        lines.append(f"{key:<24}{hex6(res[role])}")
    lines.append("")
    for i, name in enumerate(ansi):
        lines.append(f"color{i:<3}{' ' * 16}{hex6(res[name])}")
    for i, name in enumerate(ansi):
        lines.append(f"color{i + 8:<3}{' ' * 16}{hex6(res['bright_' + name])}")
    return "\n".join(lines) + "\n"


def gen_dunst(res, scheme, palette, template):
    """dunst: substitute colours into the shipped template.

    Kept as a template rather than fully generated: dunstrc is mostly geometry
    and behaviour that has nothing to do with colour. @ACCENT@ is left alone,
    because udt-accent substitutes it per wallpaper after pywal renders it.
    """
    out = template.replace("@SCHEME@", scheme)
    for role in ("bg", "bg_alt", "fg", "fg_dim", "border", "critical"):
        out = out.replace(f"@{role.upper()}@", hex6(res[role]))
    return out


def gen_conky(res, scheme, palette, template):
    """conky: substitute into the shipped template.

    conky.text is laid out with absolute ${goto} offsets tuned to label widths,
    so it is never regenerated, only its colour block is substituted.
    """
    out = template.replace("@SCHEME@", scheme)
    for role in ("heading", "label", "rule", "value", "highlight", "ok",
                 "body", "body_outline", "body_shade"):
        out = out.replace(f"@{role.upper()}@", hex6(res[role]))
    return out


def gen_accent_py(res, scheme, palette, snap_names):
    """The accent table and Macchiato dict udt-accent carries for Firefox.

    Written as a Python fragment that udt-accent imports, so the accent snapping
    and the pywalfox palette both follow the scheme instead of hardcoding one.
    """
    # The snap candidates are declared per scheme, not derived: which hues make
    # good accents is a judgement about the palette (drop near-neutrals, drop
    # near-duplicate hues) that the colour values alone do not carry.
    candidates = {n: palette[n] for n in snap_names}
    rows = "\n".join(f'    {n!r}: {v!r},' for n, v in candidates.items())

    ansi = ["black", "red", "green", "yellow", "blue", "magenta", "cyan", "white"]
    normal = ", ".join(f'"{hex6(res[n])}"' for n in ansi)
    bright = ", ".join(f'"{hex6(res["bright_" + n])}"' for n in ansi)

    return (
        f"# {BANNER.format(scheme=scheme)}\n"
        '"""Generated colour tables. See palette/roles.conf."""\n\n'
        f"SCHEME = {scheme!r}\n\n"
        "# The candidate accents udt-accent snaps a wallpaper to.\n"
        f"ACCENTS = {{\n{rows}\n}}\n\n"
        f"FALLBACK = {accent_name(res, palette, candidates)!r}\n\n"
        "# Firefox, via pywalfox, which reads colors.json and nothing else.\n"
        "PALETTE = {\n"
        f'    "background": "{hex6(res["bg"])}",\n'
        f'    "foreground": "{hex6(res["fg"])}",\n'
        f'    "cursor": "{hex6(res["cursor"])}",\n'
        f"    \"colors\": [{normal},\n"
        f"               {bright}],\n"
        "}\n"
    )


def accent_name(res, palette, candidates):
    """Which candidate udt-accent falls back to when a wallpaper is too grey.

    The accent role's own colour, so the fallback matches what every consumer
    that does not track the wallpaper is already sitting on.
    """
    target = hex6(res["accent"])
    for name, hexval in candidates.items():
        if hexval == target:
            return name
    return next(iter(candidates))


def schemes():
    """Every scheme that ships both a palette and a role map."""
    return sorted(p.stem for p in PALETTE_DIR.glob("*.conf")
                  if p.stem != "roles" and not p.stem.startswith("roles-"))


def load(selector_path, scheme=None):
    """Read the selected scheme's palette and role map.

    The selector names a scheme; the scheme names two files. Keeping the role
    map per-scheme is what lets a palette use its own colour names: Nord has no
    `base` and Dracula no `surface0`, so one shared map could not satisfy both.
    """
    if scheme is None:
        scheme = parse_conf(selector_path).get("scheme")
    if not scheme:
        raise ValueError(f"{selector_path}: no 'scheme' line")

    palette_path = PALETTE_DIR / f"{scheme}.conf"
    roles_path = PALETTE_DIR / f"roles-{scheme}.conf"
    for needed in (palette_path, roles_path):
        if not needed.exists():
            raise ValueError(
                f"scheme {scheme!r} is missing {needed.name}. "
                f"Available: {', '.join(schemes())}")

    roles = parse_conf(roles_path)
    palette = parse_conf(palette_path)
    for name, value in palette.items():
        if not re.fullmatch(r"#[0-9a-fA-F]{6}", value):
            raise ValueError(f"{palette_path}: {name} = {value!r} is not #rrggbb")
    snap_names = roles.get("snap", "").split()
    if not snap_names:
        raise ValueError(f"{roles_path}: no [accents] snap list")
    for name in snap_names:
        if name not in palette:
            raise ValueError(
                f"{roles_path}: snap candidate {name!r} is not in the {scheme} palette")

    roles["scheme"] = scheme
    return scheme, palette, resolve(roles, palette, roles_path), snap_names


# What gets written where. Templates are read from the repo, everything else is
# generated whole.
TARGETS = [
    ("rofi/udt/palette.rasi", gen_rofi, None),
    ("templates/waybar/theme.css", gen_waybar, None),
    ("templates/terminal/kitty-theme.conf", gen_kitty, None),
    ("templates/dunstrc", gen_dunst, "templates/dunstrc.in"),
    ("templates/conky.conf", gen_conky, "templates/conky.conf.in"),
    ("bin/udt_colors.py", gen_accent_py, None),
]


def generate(roles_path, out_dir):
    scheme, palette, res, snap_names = load(roles_path)
    written = []
    for target, fn, template in TARGETS:
        dest = out_dir / target
        if template:
            src = REPO / template
            if not src.exists():
                raise ValueError(f"missing template {src}")
            content = fn(res, scheme, palette, src.read_text())
        elif fn is gen_accent_py:
            content = fn(res, scheme, palette, snap_names)
        else:
            content = fn(res, scheme, palette)
        dest.parent.mkdir(parents=True, exist_ok=True)
        dest.write_text(content)
        written.append(target)
    return scheme, written


def selftest():
    # Every shipped scheme must satisfy every role, or switching to it breaks
    # at install time. load() raises on any role the palette cannot supply.
    names = schemes()
    assert names, "no palettes found"

    seen = {}
    for scheme in names:
        _, _, res, snap = load(None, scheme=scheme)
        assert res["bg"] != res["fg"], f"{scheme}: bg and fg are the same colour"
        assert len(snap) >= 5, f"{scheme}: only {len(snap)} snap candidates"
        seen[scheme] = set(res)
        print(f"  {scheme}: {len(res)} roles, {len(snap)} accents")

    # Every scheme must define the SAME roles: a generator asks for a role by
    # name, so one scheme missing it would fail only once that scheme was
    # selected, which is exactly the late failure this check exists to prevent.
    reference = seen[names[0]]
    for scheme, roles in seen.items():
        missing = reference - roles
        extra = roles - reference
        assert not missing, f"{scheme} is missing roles: {sorted(missing)}"
        assert not extra, f"{scheme} has roles no other scheme has: {sorted(extra)}"

    # Alpha survives the round trip into each syntax.
    assert hex8((202, 211, 245, 75)) == "#cad3f5bf", hex8((202, 211, 245, 75))
    assert hex8((202, 211, 245, 100)) == "#cad3f5ff"
    assert rgba((202, 211, 245, 100)) == "rgb(202,211,245)"
    assert rgba((202, 211, 245, 75)) == "rgba(202,211,245,0.75)"

    # A role naming a colour the palette lacks must fail, not emit a hole.
    try:
        resolve({"scheme": "x", "bad": "nosuchcolour"}, {"base": "#000000"}, "probe")
    except ValueError as exc:
        assert "nosuchcolour" in str(exc)
    else:
        raise AssertionError("unknown colour did not raise")

    print("selftest OK")


def main(argv):
    if "--selftest" in argv:
        selftest()
        return 0

    roles_path = PALETTE_DIR / "roles.conf"
    out_dir = REPO
    if "--roles" in argv:
        roles_path = Path(argv[argv.index("--roles") + 1]).expanduser()
    if "--out" in argv:
        out_dir = Path(argv[argv.index("--out") + 1]).expanduser()

    try:
        scheme, written = generate(roles_path, out_dir)
    except ValueError as exc:
        print(f"udt-palette: {exc}", file=sys.stderr)
        return 1

    print(f"{scheme}: {len(written)} files")
    for w in written:
        print(f"  {w}")
    return 0


if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))