<?php
declare(strict_types=1);

namespace Esun\BlogImport\Model;

use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\Serialize\Serializer\Json;

class SourceReader
{
    private const SOURCE_FILES = [
        'industry' => 'esun_industry_details.json',
        'activities' => 'esun_activities_details.json',
        'exhibition' => 'esun_exhibition_details.json',
        'news' => 'esun_news_details.json',
    ];

    private const LIST_FILES = [
        'industry' => 'esun_industry_all.json',
        'activities' => 'esun_activities_all.json',
        'exhibition' => 'esun_exhibition_all.json',
        'news' => 'esun_news_all.json',
    ];

    public function __construct(private readonly Json $json)
    {
    }

    /**
     * @return array{records: array<string, array<string, mixed>>, json_records: int, duplicate_records: int}
     * @throws LocalizedException
     */
    public function read(string $sourceDirectory): array
    {
        $sourceRoot = realpath($sourceDirectory);
        if ($sourceRoot === false || !is_dir($sourceRoot) || !is_readable($sourceRoot)) {
            throw new LocalizedException(__('Import source is not a readable directory: %1', $sourceDirectory));
        }

        $records = [];
        $jsonRecords = 0;
        foreach (self::SOURCE_FILES as $category => $filename) {
            $listItems = $this->readListItems($sourceRoot, $category);
            $jsonPath = $sourceRoot . DIRECTORY_SEPARATOR . $filename;
            if (!is_file($jsonPath) || !is_readable($jsonPath)) {
                throw new LocalizedException(__('Required JSON file is missing or unreadable: %1', $jsonPath));
            }

            try {
                $data = $this->json->unserialize((string)file_get_contents($jsonPath));
            } catch (\InvalidArgumentException $exception) {
                throw new LocalizedException(__('Invalid JSON in %1: %2', $filename, $exception->getMessage()));
            }
            if (!is_array($data) || !isset($data['details']) || !is_array($data['details'])) {
                throw new LocalizedException(__('The details array is missing from %1.', $filename));
            }
            if (isset($data['total_count']) && (int)$data['total_count'] !== count($data['details'])) {
                throw new LocalizedException(
                    __('The total_count in %1 does not match its details count.', $filename)
                );
            }

            foreach ($data['details'] as $index => $item) {
                $jsonRecords++;
                if (!is_array($item)) {
                    throw new LocalizedException(__('Invalid item %1 in %2.', $index + 1, $filename));
                }
                $this->validateItem($item, $index, $filename);

                $sourceUrl = trim((string)$item['sourceUrl']);
                if (!isset($listItems[$sourceUrl])) {
                    throw new LocalizedException(
                        __('No matching list item was found for %1 in %2.', $sourceUrl, self::LIST_FILES[$category])
                    );
                }
                $listItem = $listItems[$sourceUrl];
                $path = (string)parse_url($sourceUrl, PHP_URL_PATH);
                $pathSegments = array_values(array_filter(explode('/', trim($path, '/')), 'strlen'));
                $sourceUrlKey = $pathSegments ? (string)end($pathSegments) : '';
                if ($sourceUrlKey === '') {
                    throw new LocalizedException(
                        __('Cannot derive a URL key from item %1 in %2.', $index + 1, $filename)
                    );
                }

                $htmlPath = $this->resolveHtmlPath($sourceRoot, (string)$item['localHtmlFile']);
                if (isset($records[$sourceUrl])) {
                    $existing = $records[$sourceUrl];
                    if ($existing['title'] !== trim((string)$item['title'])
                        || $existing['publish_date'] !== (string)$item['publishDate']
                    ) {
                        throw new LocalizedException(
                            __('Conflicting duplicate post data for source URL %1.', $sourceUrl)
                        );
                    }
                    if ($records[$sourceUrl]['short_description'] !== ''
                        && $listItem['summary'] !== ''
                        && $records[$sourceUrl]['short_description'] !== $listItem['summary']
                    ) {
                        throw new LocalizedException(__('Conflicting summaries for source URL %1.', $sourceUrl));
                    }
                    if ($records[$sourceUrl]['image_filename'] !== ''
                        && $listItem['image_filename'] !== ''
                        && $records[$sourceUrl]['image_filename'] !== $listItem['image_filename']
                    ) {
                        throw new LocalizedException(__('Conflicting list images for source URL %1.', $sourceUrl));
                    }
                    if ($records[$sourceUrl]['short_description'] === '') {
                        $records[$sourceUrl]['short_description'] = $listItem['summary'];
                    }
                    if ($records[$sourceUrl]['image_filename'] === '') {
                        $records[$sourceUrl]['image_filename'] = $listItem['image_filename'];
                    }
                    $records[$sourceUrl]['categories'][$category] = $category;
                    continue;
                }

                $records[$sourceUrl] = [
                    'title' => trim((string)$item['title']),
                    'source_url' => $sourceUrl,
                    'source_url_key' => $sourceUrlKey,
                    'publish_date' => (string)$item['publishDate'],
                    'html_path' => $htmlPath,
                    'short_description' => $listItem['summary'],
                    'image_filename' => $listItem['image_filename'],
                    'categories' => [$category => $category],
                ];
            }
        }

        return [
            'records' => $records,
            'json_records' => $jsonRecords,
            'duplicate_records' => $jsonRecords - count($records),
        ];
    }

    /**
     * @return array<string, array{summary: string, image_filename: string}>
     * @throws LocalizedException
     */
    private function readListItems(string $sourceRoot, string $category): array
    {
        $filename = self::LIST_FILES[$category];
        $jsonPath = $sourceRoot . DIRECTORY_SEPARATOR . $filename;
        if (!is_file($jsonPath) || !is_readable($jsonPath)) {
            throw new LocalizedException(__('Required list JSON file is missing or unreadable: %1', $jsonPath));
        }

        try {
            $data = $this->json->unserialize((string)file_get_contents($jsonPath));
        } catch (\InvalidArgumentException $exception) {
            throw new LocalizedException(__('Invalid JSON in %1: %2', $filename, $exception->getMessage()));
        }
        if (!is_array($data) || !isset($data['news']) || !is_array($data['news'])) {
            throw new LocalizedException(__('The news array is missing from %1.', $filename));
        }
        if (isset($data['total_count']) && (int)$data['total_count'] !== count($data['news'])) {
            throw new LocalizedException(__('The total_count in %1 does not match its news count.', $filename));
        }

        $result = [];
        foreach ($data['news'] as $index => $item) {
            if (!is_array($item) || !isset($item['link']) || !is_string($item['link']) || trim($item['link']) === '') {
                throw new LocalizedException(__('Missing or invalid link in item %1 of %2.', $index + 1, $filename));
            }
            $link = trim($item['link']);
            if (isset($result[$link])) {
                throw new LocalizedException(__('Duplicate link %1 in %2.', $link, $filename));
            }
            $summary = isset($item['summary']) && is_string($item['summary']) ? trim($item['summary']) : '';
            $imageUrl = isset($item['imageUrl']) && is_string($item['imageUrl']) ? trim($item['imageUrl']) : '';
            $result[$link] = [
                'summary' => $summary,
                'image_filename' => $this->extractImageFilename($imageUrl, $index, $filename),
            ];
        }

        return $result;
    }

    /** @throws LocalizedException */
    private function extractImageFilename(string $imageUrl, int $index, string $filename): string
    {
        if ($imageUrl === '') {
            return '';
        }
        $path = (string)preg_split('/[?#]/', $imageUrl, 2)[0];
        $imageFilename = rawurldecode(basename($path));
        if ($imageFilename === '' || $imageFilename === '.' || $imageFilename === '..') {
            throw new LocalizedException(__('Invalid imageUrl in item %1 of %2.', $index + 1, $filename));
        }

        return $imageFilename;
    }

    /** @throws LocalizedException */
    private function validateItem(array $item, int $index, string $filename): void
    {
        foreach (['title', 'sourceUrl', 'publishDate', 'localHtmlFile'] as $field) {
            if (!isset($item[$field]) || !is_string($item[$field]) || trim($item[$field]) === '') {
                throw new LocalizedException(
                    __('Missing or invalid %1 in item %2 of %3.', $field, $index + 1, $filename)
                );
            }
        }

        $sourceUrl = (string)$item['sourceUrl'];
        $parts = parse_url($sourceUrl);
        if (!is_array($parts)
            || ($parts['scheme'] ?? '') !== 'https'
            || strtolower((string)($parts['host'] ?? '')) !== 'www.esun3d.com'
            || !str_starts_with((string)($parts['path'] ?? ''), '/news/')
        ) {
            throw new LocalizedException(__('Invalid sourceUrl in item %1 of %2.', $index + 1, $filename));
        }

        $date = \DateTimeImmutable::createFromFormat('!Y-m-d', (string)$item['publishDate']);
        if ($date === false || $date->format('Y-m-d') !== $item['publishDate']) {
            throw new LocalizedException(__('Invalid publishDate in item %1 of %2.', $index + 1, $filename));
        }
    }

    /** @throws LocalizedException */
    private function resolveHtmlPath(string $sourceRoot, string $relativePath): string
    {
        if ($relativePath === '' || str_contains($relativePath, "\0") || str_starts_with($relativePath, '/')) {
            throw new LocalizedException(__('Invalid localHtmlFile path: %1', $relativePath));
        }
        $htmlPath = realpath($sourceRoot . DIRECTORY_SEPARATOR . $relativePath);
        $rootPrefix = rtrim($sourceRoot, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;
        if ($htmlPath === false
            || !is_file($htmlPath)
            || !is_readable($htmlPath)
            || !str_starts_with($htmlPath, $rootPrefix)
        ) {
            throw new LocalizedException(__('HTML file is missing, unreadable, or outside the source: %1', $relativePath));
        }

        return $htmlPath;
    }
}