import { isConstantNode, isFunctionNode, isSymbolNode, type MathNode } from 'mathjs';
import type { State } from './state.js';
import { migrateNode } from './node.js';
import { isResult, type Result } from './interface.js';

/** 生成转义序列 */
function escapeString(str: string | number): string {
    return String(str)
        .replaceAll('\\', String.raw`\\`)
        .replaceAll('`', '\\`')
        .replaceAll('$', String.raw`\$`)
        .replaceAll('\n', String.raw`\n`)
        .replaceAll('\r', String.raw`\r`)
        .replaceAll('\t', String.raw`\t`);
}

/** 连接字符串 */
export function concat(state: State, args: ReadonlyArray<MathNode | string | number | Result>): Result {
    const parts: string[] = [];
    for (const arg of args) {
        if (typeof arg != 'object') {
            parts.push(escapeString(arg));
        } else if (isConstantNode(arg)) {
            const value = escapeString(String(arg.value));
            parts.push(value);
        } else if (isResult(arg)) {
            if (arg.literal && typeof arg.literal != 'object') {
                parts.push(String(arg.literal).replaceAll('`', '\\`'));
            } else if (arg.type === 'string' && arg.code.startsWith('to_string(') && arg.code.endsWith(')')) {
                parts.push(`$(${arg.code.slice(10, -1)})`);
            } else {
                parts.push(`$(${arg.code})`);
            }
        } else if (isFunctionNode(arg) && isSymbolNode(arg.fn) && arg.fn.name === 'string') {
            parts.push(`$(${migrateNode(state, arg.args[0]!, { format: 'no-paren' }).code})`);
        } else {
            parts.push(`$(${migrateNode(state, arg, { format: 'no-paren' }).code})`);
        }
    }
    return { code: '`' + parts.join('') + '`', type: 'string' };
}