term-color-render/index.ts

interface ColorToken {
    type: "color" | "text";
    content?: string;
    colorStart?: boolean;
    color?: string;
}

function parseColorTokens(message: string): ColorToken[] {
    const tokens: ColorToken[] = [];
    if (message) {
        let inColorStart = false;
        let inColorEnd = false;
        let chars: string[] = [];
        const messageLength = message.length;
        for (let i = 0; i < messageLength; i++) {
            const c = message.charAt(i);
            const nextC = (i + 1) < messageLength
                ? message.charAt(i + 1)
                : null;
            switch (c) {
                case "\\":
                    if (nextC === null) {
                        chars.push(c);
                    } else {
                        chars.push(nextC);
                        i++;
                    }
                    break;
                case "[":
                    if (inColorStart || inColorEnd) {
                        // SHOULD NOT HAPPEN
                        break;
                    } else if (nextC == "/") {
                        inColorEnd = true;
                        i++;
                    } else {
                        inColorStart = true;
                    }
                    if (chars.length > 0) {
                        tokens.push({
                            type: "text",
                            content: chars.join(""),
                        });
                        chars = [];
                    }
                    break;
                case "]":
                    if (inColorStart || inColorEnd) {
                        if (chars.length > 0) {
                            tokens.push({
                                type: "color",
                                colorStart: inColorStart,
                                color: chars.join(""),
                            });
                            chars = [];
                        }
                        inColorStart = false;
                        inColorEnd = false;
                    } else {
                        chars.push(c);
                    }
                    break;
                default:
                    chars.push(c);
                    break;
            }
        }
        const inColor = inColorStart || inColorEnd;
        if (chars.length > 0 && !inColor) {
            tokens.push({
                type: "text",
                content: chars.join(""),
            });
        }
    }
    return tokens;
}

const COLOR_MAP: Record<string, string> = {
    blink: "5",
    bold: "1",
    under: "4",
    red: "31",
    green: "32",
    yellow: "33",
    blue: "34",
    pink: "35",
    cyan: "36",
};

function renderColorTokens(tokens: ColorToken[]): string {
    const text: string[] = [];
    const colorMapStack = new Map<string, number[]>();
    for (const token of tokens) {
        if (token.type === "color") {
            const color = token.color;
            if (color) {
                const colorCode = COLOR_MAP[color];
                if (!colorCode) {
                    text.push(`[${token.colorStart ? "" : "/"}${color}]`);
                    continue;
                }
                const colorStack = colorMapStack.get(color) ?? [];
                if (colorStack.length == 0) {
                    colorMapStack.set(color, colorStack);
                }
                if (token.colorStart) {
                    colorStack.push(1);
                } else {
                    colorStack.pop();
                    text.push("\x1b[0m");
                }
                const colors: string[] = [];
                for (const [color, colorStack] of colorMapStack) {
                    if (colorStack.length > 0) {
                        colors.push(colorCode);
                    }
                }
                if (colors.length > 0) {
                    text.push(`\x1b[${colors.join(";")}m`);
                }
            }
        } else {
            if (token.content) {
                text.push(token.content);
            }
        }
    }
    text.push("\x1b[0m"); // FINALLY END ALL COLOR
    return text.join("");
}

export function renderColor(message: string): string {
    return renderColorTokens(parseColorTokens(message));
}