#!/usr/bin/env python3
"""Read the COSMIC theme out of cosmic-config and write it as ClojureDart.

libcosmic asks cosmic-config for the user's theme at run time, so `just run`
already paints frq in whatever accent and surfaces are set in COSMIC Settings.
A phone has no cosmic-config, so the APK cannot ask — the values are read here
instead, on the machine that has them, and compiled in.

That is a real difference and worth naming: the desktop follows the theme as
it changes, and the APK carries the theme as it was when the APK was built.
`just theme` moves it.

The config is RON. Not parsed as RON: every value this needs is either a
`key: "#RRGGBBAA"` line or a `key: N` line inside a named block, and a general
RON parser to read colours out of a flat file is a dependency nobody needs.
"""

import pathlib
import re
import sys

CONFIG = pathlib.Path.home() / ".config" / "cosmic"

# What frq asks of a theme, as (token, file, field). `component` fields are one
# block deep — see the `component: (` in background/primary/secondary.
COLOURS = [
    ("accent",            "accent",     "base"),
    ("on-accent",         "accent",     "on"),
    ("bg",                "background", "base"),
    ("on-bg",             "background", "component.on"),
    ("component",         "background", "component.base"),
    ("component-hover",   "background", "component.hover"),
    ("divider",           "background", "component.divider"),
    ("card",              "primary",    "base"),
    ("card-component",    "primary",    "component.base"),
    ("on-card",           "primary",    "component.on"),
    ("destructive",       "destructive", "base"),
    ("on-destructive",    "destructive", "on"),
    ("success",           "success",    "base"),
]


def read(mode: str, name: str) -> str:
    for version in ("v2", "v1"):
        p = CONFIG / f"com.system76.CosmicTheme.{mode}" / version / name
        if p.exists():
            return p.read_text()
    raise SystemExit(f"cosmic2cljd: no {name} under {CONFIG} — is COSMIC installed?")


def field(text: str, path: str) -> str:
    """`base`, or `component.base` for the one inside the component block."""
    if "." in path:
        outer, inner = path.split(".", 1)
        m = re.search(rf"\b{outer}:\s*\(", text)
        if not m:
            raise SystemExit(f"cosmic2cljd: no {outer} block")
        text = text[m.end():]
        path = inner
    m = re.search(rf'^\s*{path}:\s*"(#[0-9A-Fa-f]{{6,8}})"', text, re.M)
    if not m:
        raise SystemExit(f"cosmic2cljd: no {path}")
    return m.group(1)


def argb(hex_rgba: str) -> str:
    """#RRGGBBAA (COSMIC) to 0xAARRGGBB (Flutter's Color)."""
    h = hex_rgba.lstrip("#")
    if len(h) == 6:
        h += "FF"
    r, g, b, a = h[0:2], h[2:4], h[4:6], h[6:8]
    return f"0x{a}{r}{g}{b}".upper().replace("0X", "0x")


def number(text: str, key: str, default: float) -> float:
    m = re.search(rf"^\s*{key}:\s*\(?\s*([0-9.]+)", text, re.M)
    return float(m.group(1)) if m else default


def main() -> None:
    out = pathlib.Path(sys.argv[1] if len(sys.argv) > 1
                       else "flutter/src/frq/theme/cosmic.cljd")
    dark = (CONFIG / "com.system76.CosmicTheme.Mode" / "v1" / "is_dark")
    is_dark = dark.exists() and dark.read_text().strip() == "true"
    mode = "Dark" if is_dark else "Light"

    radii = read(mode, "corner_radii")
    spacing = read(mode, "spacing")
    files = {n: read(mode, n) for n in {f for _, f, _ in COLOURS}}

    lines = [
        "(ns frq.theme.cosmic",
        '  "The COSMIC theme, as it was on the machine that built this.',
        "",
        "  GENERATED by tools/cosmic2cljd.py — `just theme`. Do not edit.",
        "",
        "  libcosmic asks cosmic-config for these at run time, so `just run`",
        "  follows COSMIC Settings as it changes. A phone has no cosmic-config,",
        "  so the APK carries them instead. That is the one real difference",
        f'  between the two, and it is why this file is in git."',
        '  (:require ["package:flutter/material.dart" :as m]))',
        "",
        f";; {mode} theme, from ~/.config/cosmic.",
        f"(def dark? {str(is_dark).lower()})",
        "",
    ]
    for token, fname, path in COLOURS:
        val = field(files[fname], path)
        lines.append(f";; {fname}.{path} = {val}")
        lines.append(f"(def {token} (m/Color. {argb(val)}))")
    lines.append("")
    lines.append(";; corner_radii")
    for token, key, default in [("radius-xs", "radius_xs", 2.0),
                                ("radius-s", "radius_s", 8.0),
                                ("radius-m", "radius_m", 8.0)]:
        lines.append(f"(def {token} {number(radii, key, default)})")
    lines.append("")
    lines.append(";; spacing")
    for token, key, default in [("space-xxxs", "space_xxxs", 4.0),
                                ("space-xxs", "space_xxs", 8.0),
                                ("space-xs", "space_xs", 12.0),
                                ("space-s", "space_s", 16.0),
                                ("space-m", "space_m", 24.0)]:
        lines.append(f"(def {token} {number(spacing, key, default)})")

    out.parent.mkdir(parents=True, exist_ok=True)
    out.write_text("\n".join(lines) + "\n")
    print(f"wrote {out} ({mode}, accent {field(files['accent'], 'base')})")


if __name__ == "__main__":
    main()