/* eslint-disable max-classes-per-file */

import type { $ZodIssue } from 'zod/v4/core';

/**
 * Formats the Zod validation failures into a single string with one line each: "- <field>: <message>" and top level failures
 * with no field path show as "(root)" for better readability.
 *
 * @param issues The Zod validation failures to format.
 * @returns A human readable error string for better debugging.
 */
export const buildErrorDescription = (issues: $ZodIssue[]): string => {
    // Initialize an empty array to store the formatted lines.
    const lines: string[] = [];

    // Iterate over the issues and format them into a string.
    for (const issue of issues) {
        // Get the issue path.
        const issuePath = issue.path.length > 0 ? issue.path.join('.') : '(root)';

        // The prefix that Zod adds to messages.
        const messagePrefix = 'Invalid input: ';

        // Remove the prefix for better readability.
        const issueMessage = issue.message.startsWith(messagePrefix) ? issue.message.slice(messagePrefix.length) : issue.message;

        // Add the formatted line to the array.
        lines.push(`- ${issuePath}: ${issueMessage}`);
    }

    // Return the formatted string.
    return `\n${lines.join('\n')}`;
};

/**
 * Thrown when the provided template does not satisfy the XOTemplate schema.
 */
export class TemplateInvalidError extends Error {
    constructor(details: string) {
        const message = `Template invalid: ${details}`;
        super(message);
        this.name = 'TemplateInvalidError';
    }
}

/**
 * Thrown when a string passed to `deserializeTemplate` cannot be parsed as JSON.
 */
export class TemplateJsonMalformedError extends Error {
    constructor(reason: string) {
        super(`Template JSON malformed, expected a valid JSON string: ${reason}`);
        this.name = 'TemplateJsonMalformedError';
    }
}

/**
 * Thrown when `serializeTemplate` fails to produce a JSON string from the template.
 */
export class TemplateSerializationFailedError extends Error {
    constructor(reason: string) {
        super(`Template serialization failed: ${reason}`);
        this.name = 'TemplateSerializationFailedError';
    }
}