<?php

/* Copyright (C) 2026 Moko Consulting <hello@mokoconsulting.tech>
 *
 * This file is part of a Moko Consulting project.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 * FILE INFORMATION
 * DEFGROUP: MokoStandards.Enterprise
 * INGROUP: MokoStandards.Enterprise
 * REPO: https://git.mokoconsulting.tech/MokoConsulting/moko-platform
 * PATH: /lib/Enterprise/ConfigValidator.php
 * BRIEF: Validate project config against plugin JSON schema
 */

declare(strict_types=1);

namespace MokoEnterprise;

/**
 * Configuration Validator
 *
 * Validates moko-platform configuration files (YAML, JSON, HCL)
 * against expected schemas and reports errors.
 *
 * @since 04.00.00
 */
class ConfigValidator
{
    /** @var array<int, string> */
    private array $errors = [];

    /** @var array<int, string> */
    private array $warnings = [];

    /**
     * Validate config data against a JSON schema.
     *
     * @param array<string, mixed> $config Config to validate
     * @param array<string, mixed> $schema JSON Schema definition
     * @return bool True if valid
     */
    public function validate(array $config, array $schema): bool
    {
        $this->errors = [];
        $this->warnings = [];

        $this->validateNode($config, $schema, '');

        return empty($this->errors);
    }

    /** @return array<int, string> */
    public function getErrors(): array
    {
        return $this->errors;
    }

    /** @return array<int, string> */
    public function getWarnings(): array
    {
        return $this->warnings;
    }

    /**
     * @param mixed $data
     * @param array<string, mixed> $schema
     */
    private function validateNode(
        mixed $data,
        array $schema,
        string $path
    ): void {
        $type = $schema['type'] ?? null;

        if ($type !== null && !$this->checkType($data, $type)) {
            $actual = gettype($data);
            $this->errors[] = $path === ''
                ? "Root must be {$type}, got {$actual}"
                : "{$path}: expected {$type}, got {$actual}";
            return;
        }

        if ($type === 'object') {
            $this->validateObject($data, $schema, $path);
        }

        if ($type === 'array' && isset($schema['items'])) {
            $this->validateArray($data, $schema, $path);
        }

        if (isset($schema['enum'])) {
            $this->validateEnum($data, $schema['enum'], $path);
        }

        if ($type === 'string') {
            $this->validateString($data, $schema, $path);
        }

        if ($type === 'integer' || $type === 'number') {
            $this->validateNumber($data, $schema, $path);
        }
    }

    /**
     * @param array<string, mixed> $data
     * @param array<string, mixed> $schema
     */
    private function validateObject(
        array $data,
        array $schema,
        string $path
    ): void {
        $properties = $schema['properties'] ?? [];
        $required = $schema['required'] ?? [];

        foreach ($required as $field) {
            if (!array_key_exists($field, $data)) {
                $fieldPath = $path === '' ? $field : "{$path}.{$field}";
                $this->errors[] = "{$fieldPath}: required field missing";
            }
        }

        foreach ($properties as $field => $fieldSchema) {
            if (!array_key_exists($field, $data)) {
                continue;
            }

            $fieldPath = $path === '' ? $field : "{$path}.{$field}";
            $this->validateNode($data[$field], $fieldSchema, $fieldPath);
        }

        $known = array_keys($properties);

        foreach (array_keys($data) as $field) {
            if (!in_array($field, $known, true)) {
                $fieldPath = $path === '' ? $field : "{$path}.{$field}";
                $this->warnings[] = "{$fieldPath}: unknown property";
            }
        }
    }

    /**
     * @param array<int, mixed> $data
     * @param array<string, mixed> $schema
     */
    private function validateArray(
        array $data,
        array $schema,
        string $path
    ): void {
        $itemSchema = $schema['items'];

        foreach ($data as $i => $item) {
            $this->validateNode(
                $item,
                $itemSchema,
                "{$path}[{$i}]"
            );
        }

        if (
            isset($schema['minItems'])
            && count($data) < $schema['minItems']
        ) {
            $this->errors[] = "{$path}: "
                . "needs at least {$schema['minItems']} items";
        }
    }

    /**
     * @param mixed $data
     * @param array<int, mixed> $allowed
     */
    private function validateEnum(
        mixed $data,
        array $allowed,
        string $path
    ): void {
        if (!in_array($data, $allowed, true)) {
            $values = implode(', ', $allowed);
            $label = $path ?: 'value';
            $this->errors[] = "{$label}: "
                . "'{$data}' not in [{$values}]";
        }
    }

    /**
     * @param array<string, mixed> $schema
     */
    private function validateString(
        mixed $data,
        array $schema,
        string $path
    ): void {
        if (!is_string($data)) {
            return;
        }

        if (
            isset($schema['minLength'])
            && strlen($data) < $schema['minLength']
        ) {
            $this->errors[] = "{$path}: "
                . "too short (min {$schema['minLength']})";
        }

        if (
            isset($schema['pattern'])
            && !preg_match('/' . $schema['pattern'] . '/', $data)
        ) {
            $this->errors[] = "{$path}: "
                . "does not match pattern {$schema['pattern']}";
        }
    }

    /**
     * @param array<string, mixed> $schema
     */
    private function validateNumber(
        mixed $data,
        array $schema,
        string $path
    ): void {
        if (!is_numeric($data)) {
            return;
        }

        if (isset($schema['minimum']) && $data < $schema['minimum']) {
            $this->errors[] = "{$path}: "
                . "below minimum {$schema['minimum']}";
        }

        if (isset($schema['maximum']) && $data > $schema['maximum']) {
            $this->errors[] = "{$path}: "
                . "above maximum {$schema['maximum']}";
        }
    }

    private function checkType(mixed $data, string $type): bool
    {
        return match ($type) {
            'object' => is_array($data),
            'array' => is_array($data)
                && array_is_list($data),
            'string' => is_string($data),
            'integer' => is_int($data),
            'number' => is_int($data) || is_float($data),
            'boolean' => is_bool($data),
            'null' => is_null($data),
            default => true,
        };
    }
}