/**
 * This code is inspired by and adapted from:
 * https://github.com/bitauth/libauth
 */

import type { XOTemplate } from '@xo-cash/types';
import type { AjvValidator } from './ajv/ajv-types.ts';
import { parseJson, validateSchema } from './ajv/ajv-utils.ts';
import { InvalidTemplateError } from '../errors.ts';
import xoTemplateValidator from './ajv/validate-xo-template.js';

/**
 * Safely parse and validate a XO template, returning either an
 * error message as a string or a valid {@link XOTemplate}. The
 * template may be provided either as an untrusted JSON string or as a
 * pre-parsed object.
 *
 * This method validates both the structure and the contents of a template:
 * - All properties and sub-properties are verified to be of the expected type.
 * - The template contains no unknown properties.
 * - The ID of each entity, script, and scenario is confirmed to be unique.
 * - Script IDs referenced by entities and other scripts (via `unlocks`) are
 *   confirmed to exist.
 * - The derivation paths of each HdKey are validated against each other.
 *
 * This method does not perform the following:
 * - TODO: Validate the CashAssembly contents of scripts (by
 * attempting compilation, evaluating {@link XOTemplateScriptTest}s,
 * or testing scenario generation).
 * - TODO: Perform search to verify references.
 *
 * @param {unknown} untrustedJsonOrObject - the JSON string or object to validate as a
 * XO template
 * @returns {XOTemplate} The parsed and validated template
 * @throws {InvalidTemplateError} If the template is invalid
 */
export const parseTemplate = (untrustedJsonOrObject: unknown): XOTemplate => {
    // Parse the JSON string or object into an unknown object.
    const parsed = parseJson<unknown>(untrustedJsonOrObject);

    // Validate the unknown object against the XO template schema.
    const templateOrError = validateSchema(parsed, xoTemplateValidator as AjvValidator<XOTemplate>);

    // If the template is invalid, throw an error.
    if (typeof templateOrError === 'string') {
        throw new InvalidTemplateError(templateOrError);
    }

    // Return the validated template.
    return templateOrError;
};