import chalk from "chalk";

import { type Static, Type } from "typebox";

import { Compile } from "typebox/compile";

import { parseStrictNonNegativeInteger } from "../../../../infra/parse-finite-number.js";

import { getCustomThemesDir, getThemesDir } from "../../../config.js";

import type { SourceInfo } from "../../../sessions/source-info.js";

import { closeWatcher, watchWithErrorHandler } from "../../../utils/fs-watch.js";

return createTheme(themeJson, mode);

}

export type TerminalTheme = "dark" | "light";

export interface RgbColor {

r: number;

g: number;

b: number;

}

export interface TerminalThemeDetection {

theme: TerminalTheme;

source: "terminal background" | "COLORFGBG" | "fallback";

detail: string;

confidence: "high" | "low";

}

export interface TerminalThemeDetectionOptions {

env?: NodeJS.ProcessEnv;

}

function getColorFgBgBackgroundIndex(colorfgbg: string): number | undefined {

const parts = colorfgbg.split(";");

for (let i = parts.length - 1; i >= 0; i--) {

const bg = parseStrictNonNegativeInteger(parts[i].trim());

if (bg !== undefined && bg <= 255) {

return bg;

}

}

return undefined;

}

function getRgbColorLuminance({ r, g, b }: RgbColor): number {

const toLinear = (channel: number) => {

const value = channel / 255;

return value <= 0.03928 ? value / 12.92 : ((value + 0.055) / 1.055) ** 2.4;

};

return 0.2126 * toLinear(r) + 0.7152 * toLinear(g) + 0.0722 * toLinear(b);

}

function getAnsiColorLuminance(index: number): number {

return getRgbColorLuminance(hexToRgb(ansi256ToHex(index)));

}

export function detectTerminalBackground(

options: TerminalThemeDetectionOptions = {},

): TerminalThemeDetection {

const env = options.env ?? process.env;

const colorfgbg = env.COLORFGBG || "";

const bg = getColorFgBgBackgroundIndex(colorfgbg);

if (bg !== undefined) {

return {

theme: getAnsiColorLuminance(bg) >= 0.5 ? "light" : "dark",

source: "COLORFGBG",

detail: `background color index ${bg}`,

confidence: "high",

};

}

return {

theme: "dark",

source: "fallback",

detail: "no terminal background hint found",

confidence: "low",

};

}

export function getDefaultTheme(): string {

return detectTerminalBackground().theme;

}

// ============================================================================

// Global Theme Instance

// ============================================================================

get(_target, prop) {

const t = (globalThis as Record<symbol, Theme>)[THEME_KEY];

if (!t) {

throw new Error("Theme not initialized. Call initTheme() first.");

throw new Error("Theme not initialized. Call setTheme() first.");

}

return (t as unknown as Record<string | symbol, unknown>)[prop];

},

let themeReloadTimer: NodeJS.Timeout | undefined;

const registeredThemes = new Map<string, Theme>();

export function initTheme(themeName?: string, enableWatcher = false): void {

const name = themeName ?? getDefaultTheme();

currentThemeName = name;

try {

setGlobalTheme(loadTheme(name));

if (enableWatcher) {

startThemeWatcher();

}

} catch {

// Theme is invalid - fall back to dark theme silently

currentThemeName = "dark";

setGlobalTheme(loadTheme("dark"));

// Don't start watcher for fallback theme

}

}

export function setTheme(

name: string,

enableWatcher = false,

// HTML Export Helpers

// ============================================================================

/**

* Convert a 256-color index to hex string.

* Indices 0-15: basic colors (approximate)

* Indices 16-231: 6x6x6 color cube

* Indices 232-255: grayscale ramp

*/

function ansi256ToHex(index: number): string {

// Basic colors (0-15) - approximate common terminal values

const basicColors = [

"#000000",

"#800000",

"#008000",

"#808000",

"#000080",

"#800080",

"#008080",

"#c0c0c0",

"#808080",

"#ff0000",

"#00ff00",

"#ffff00",

"#0000ff",

"#ff00ff",

"#00ffff",

"#ffffff",

];

if (index < 16) {

return basicColors[index];

}

// Color cube (16-231): 6x6x6 = 216 colors

if (index < 232) {

const cubeIndex = index - 16;

const r = Math.floor(cubeIndex / 36);

const g = Math.floor((cubeIndex % 36) / 6);

const b = cubeIndex % 6;

const toHex = (n: number) => (n === 0 ? 0 : 55 + n * 40).toString(16).padStart(2, "0");

return `#${toHex(r)}${toHex(g)}${toHex(b)}`;

}

// Grayscale (232-255): 24 shades

const gray = 8 + (index - 232) * 10;

const grayHex = gray.toString(16).padStart(2, "0");

return `#${grayHex}${grayHex}${grayHex}`;

}

// ============================================================================

// TUI Helpers

// ============================================================================