export class CGError extends Error {
    line?: number;
    column?: number;
    source?: string;
    errorType: 'RuntimeError' | 'ParseError';

    constructor(
        message: string,
        line?: number,
        column?: number,
        source?: string,
        errorType: 'RuntimeError' | 'ParseError' = 'RuntimeError'
    ) {
        super(message);
        this.name = errorType;
        this.line = line;
        this.column = column;
        this.source = source;
        this.errorType = errorType;
    }

    format(): string {
        if (this.line === undefined || this.column === undefined || !this.source) {
            return `${this.name}: ${this.message}`;
        }

        const lines = this.source.split('\n');
        const errorLine = lines[this.line - 1];

        if (!errorLine) {
            return `${this.name}: ${this.message} at line ${this.line}, column ${this.column}`;
        }

        const lineNumStr = `${this.line}`;
        const padding = ' '.repeat(lineNumStr.length);
        const pointer = ' '.repeat(this.column - 1) + '^';

        return `${this.name}: ${this.message}\n\n ${lineNumStr} | ${errorLine}\n${padding} | ${pointer}`;
    }
}

export function RuntimeError(message: string, line?: number, column?: number, source?: string) {
    return new CGError(message, line, column, source, 'RuntimeError');
}

export function ParseError(message: string, line?: number, column?: number, source?: string) {
    return new CGError(message, line, column, source, 'ParseError');
}