"""
web/themes.py — CSS variable themes for oAI-Web.

Each theme is a set of CSS variable overrides injected into base.html as a
<style> block, overriding the :root defaults in style.css.
Non-colour tokens (--radius, --font, --mono) are not overridden so they
inherit from style.css.
"""
from __future__ import annotations

DEFAULT_THEME = "dark"

# Each entry: id → {label, preview (bg, accent), vars}
THEMES: dict[str, dict] = {
    "dark": {
        "label": "Dark",
        "preview": {"bg": "#1a1d27", "accent": "#6c8ef5"},
        "vars": {
            "--bg":         "#0f1117",
            "--bg2":        "#1a1d27",
            "--bg3":        "#22263a",
            "--border":     "#2e3249",
            "--text":       "#e2e4ef",
            "--text-dim":   "#7b82a8",
            "--accent":     "#6c8ef5",
            "--accent-dim": "#3d5099",
            "--green":      "#4caf7d",
            "--red":        "#e05252",
            "--yellow":     "#e0a632",
        },
    },
    "darker": {
        "label": "Darker",
        "preview": {"bg": "#111111", "accent": "#6c8ef5"},
        "vars": {
            "--bg":         "#000000",
            "--bg2":        "#0d0d0d",
            "--bg3":        "#1a1a1a",
            "--border":     "#2a2a2a",
            "--text":       "#e2e4ef",
            "--text-dim":   "#6b7280",
            "--accent":     "#6c8ef5",
            "--accent-dim": "#3d5099",
            "--green":      "#4caf7d",
            "--red":        "#e05252",
            "--yellow":     "#e0a632",
        },
    },
    "light": {
        "label": "Light",
        "preview": {"bg": "#ffffff", "accent": "#4b6ef5"},
        "vars": {
            "--bg":         "#f5f6fa",
            "--bg2":        "#ffffff",
            "--bg3":        "#eef0f7",
            "--border":     "#d1d5e8",
            "--text":       "#1a1d2e",
            "--text-dim":   "#6b7280",
            "--accent":     "#4b6ef5",
            "--accent-dim": "#a3b4fa",
            "--green":      "#2e8a57",
            "--red":        "#c0392b",
            "--yellow":     "#b7791f",
        },
    },
    "nord": {
        "label": "Nord",
        "preview": {"bg": "#3b4252", "accent": "#88c0d0"},
        "vars": {
            "--bg":         "#2e3440",
            "--bg2":        "#3b4252",
            "--bg3":        "#434c5e",
            "--border":     "#4c566a",
            "--text":       "#eceff4",
            "--text-dim":   "#8a97b0",
            "--accent":     "#88c0d0",
            "--accent-dim": "#4a7a8a",
            "--green":      "#a3be8c",
            "--red":        "#bf616a",
            "--yellow":     "#ebcb8b",
        },
    },
    "solarized": {
        "label": "Solarized Dark",
        "preview": {"bg": "#073642", "accent": "#268bd2"},
        "vars": {
            "--bg":         "#002b36",
            "--bg2":        "#073642",
            "--bg3":        "#0d4454",
            "--border":     "#1a5566",
            "--text":       "#839496",
            "--text-dim":   "#586e75",
            "--accent":     "#268bd2",
            "--accent-dim": "#1a5c8c",
            "--green":      "#859900",
            "--red":        "#dc322f",
            "--yellow":     "#b58900",
        },
    },
    "gruvbox": {
        "label": "Gruvbox",
        "preview": {"bg": "#3c3836", "accent": "#d79921"},
        "vars": {
            "--bg":         "#282828",
            "--bg2":        "#3c3836",
            "--bg3":        "#504945",
            "--border":     "#665c54",
            "--text":       "#ebdbb2",
            "--text-dim":   "#928374",
            "--accent":     "#458588",
            "--accent-dim": "#2d5b5e",
            "--green":      "#98971a",
            "--red":        "#cc241d",
            "--yellow":     "#d79921",
        },
    },
    "catppuccin": {
        "label": "Catppuccin",
        "preview": {"bg": "#1e1e2e", "accent": "#cba6f7"},
        "vars": {
            "--bg":         "#1e1e2e",
            "--bg2":        "#181825",
            "--bg3":        "#313244",
            "--border":     "#45475a",
            "--text":       "#cdd6f4",
            "--text-dim":   "#6c7086",
            "--accent":     "#cba6f7",
            "--accent-dim": "#6e4d9e",
            "--green":      "#a6e3a1",
            "--red":        "#f38ba8",
            "--yellow":     "#f9e2af",
        },
    },
}


def get_theme_css(theme_id: str) -> str:
    """Return a CSS :root override block for the given theme, or empty string for the default."""
    if theme_id == DEFAULT_THEME or theme_id not in THEMES:
        return ""
    vars = THEMES[theme_id]["vars"]
    lines = "\n".join(f"  {k}: {v};" for k, v in vars.items())
    return f":root {{\n{lines}\n}}"


def theme_list() -> list[dict]:
    """Return theme metadata for the UI picker (no CSS vars)."""
    return [
        {"id": tid, "label": t["label"], "preview": t["preview"]}
        for tid, t in THEMES.items()
    ]