<?php

namespace App\DTOs;

class GutendexBook
{
    public function __construct(
        public int $id,
        public string $title,
        public array $authors,
        public array $subjects,
        public array $bookshelves,
        public array $languages,
        public ?string $copyright,
        public string $mediaType,
        public array $formats,
        public int $downloadCount,
    ) {}

    /**
     * Create a GutendexBook DTO from the Gutendex API response.
     *
     * @param array $data API response data
     * @return self
     */
    public static function fromApiResponse(array $data): self
    {
        return new self(
            id: $data['id'] ?? 0,
            title: $data['title'] ?? '',
            authors: self::parseAuthors($data['authors'] ?? []),
            subjects: $data['subjects'] ?? [],
            bookshelves: $data['bookshelves'] ?? [],
            languages: $data['languages'] ?? [],
            copyright: $data['copyright'] ?? null,
            mediaType: $data['media_type'] ?? 'Text',
            formats: $data['formats'] ?? [],
            downloadCount: $data['download_count'] ?? 0,
        );
    }

    /**
     * Parse authors from API response into a simplified array.
     *
     * @param array $authors Raw authors data from API
     * @return array Formatted authors with name, birth_year, death_year
     */
    protected static function parseAuthors(array $authors): array
    {
        return array_map(function ($author) {
            return [
                'name' => $author['name'] ?? 'Unknown',
                'birth_year' => $author['birth_year'] ?? null,
                'death_year' => $author['death_year'] ?? null,
            ];
        }, $authors);
    }

    /**
     * Get the primary author name.
     *
     * @return string
     */
    public function getPrimaryAuthorName(): string
    {
        if (empty($this->authors)) {
            return 'Unknown Author';
        }

        return $this->authors[0]['name'] ?? 'Unknown Author';
    }

    /**
     * Get all author names as a string.
     *
     * @param string $separator Separator between author names
     * @return string
     */
    public function getAuthorNamesString(string $separator = ', '): string
    {
        $names = array_map(fn($author) => $author['name'], $this->authors);
        return implode($separator, $names) ?: 'Unknown Author';
    }

    /**
     * Get the plain text URL if available.
     *
     * @return string|null
     */
    public function getPlainTextUrl(): ?string
    {
        // Priority order for text formats
        $preferredFormats = [
            'text/plain; charset=utf-8',
            'text/plain; charset=us-ascii',
            'text/plain',
        ];

        foreach ($preferredFormats as $format) {
            if (isset($this->formats[$format])) {
                return $this->formats[$format];
            }
        }

        // Fallback: look for any text/plain format
        foreach ($this->formats as $format => $url) {
            if (str_contains($format, 'text/plain')) {
                return $url;
            }
        }

        return null;
    }

    /**
     * Get the HTML URL if available.
     *
     * @return string|null
     */
    public function getHtmlUrl(): ?string
    {
        return $this->formats['text/html'] ?? null;
    }

    /**
     * Get the cover image URL.
     *
     * @return string|null
     */
    public function getCoverImageUrl(): ?string
    {
        return $this->formats['image/jpeg'] ?? null;
    }

    /**
     * Get the primary language.
     *
     * @return string
     */
    public function getPrimaryLanguage(): string
    {
        return $this->languages[0] ?? 'en';
    }

    /**
     * Determine the most appropriate category from subjects and bookshelves.
     *
     * @return string|null
     */
    public function suggestCategory(): ?string
    {
        $categoryMapping = config('gutendex.category_mapping', []);

        // Check bookshelves first (usually more specific)
        foreach ($this->bookshelves as $bookshelf) {
            foreach ($categoryMapping as $key => $slug) {
                if (stripos($bookshelf, $key) !== false) {
                    return $slug;
                }
            }
        }

        // Then check subjects
        foreach ($this->subjects as $subject) {
            foreach ($categoryMapping as $key => $slug) {
                if (stripos($subject, $key) !== false) {
                    return $slug;
                }
            }
        }

        // Default category based on common patterns
        $allText = implode(' ', array_merge($this->subjects, $this->bookshelves));
        $allTextLower = strtolower($allText);

        if (str_contains($allTextLower, 'fiction')) {
            return 'fiction';
        }

        if (str_contains($allTextLower, 'history')) {
            return 'history';
        }

        if (str_contains($allTextLower, 'science')) {
            return 'science';
        }

        if (str_contains($allTextLower, 'philosophy')) {
            return 'philosophy';
        }

        return null;
    }

    /**
     * Get a description from subjects and bookshelves.
     *
     * @param int $maxLength Maximum length of description
     * @return string
     */
    public function generateDescription(int $maxLength = 200): string
    {
        $parts = [];

        if (!empty($this->subjects)) {
            $parts[] = 'Subjects: ' . implode(', ', array_slice($this->subjects, 0, 3));
        }

        if (!empty($this->bookshelves)) {
            $parts[] = 'Categories: ' . implode(', ', array_slice($this->bookshelves, 0, 2));
        }

        $description = implode('. ', $parts);

        if (strlen($description) > $maxLength) {
            $description = substr($description, 0, $maxLength - 3) . '...';
        }

        return $description ?: 'A book from Project Gutenberg.';
    }

    /**
     * Check if this book is in the public domain.
     *
     * @return bool
     */
    public function isPublicDomain(): bool
    {
        return $this->copyright === null || $this->copyright === false;
    }

    /**
     * Convert the DTO to an array suitable for database insertion.
     *
     * @return array
     */
    public function toBookArray(): array
    {
        return [
            'gutenberg_id' => $this->id,
            'title' => $this->title,
            'author' => $this->getPrimaryAuthorName(),
            'cover_image' => $this->getCoverImageUrl(),
            'description' => $this->generateDescription(),
            'language' => $this->getPrimaryLanguage(),
            'full_text_url' => $this->getPlainTextUrl(),
            'source' => 'gutendex',
        ];
    }

    /**
     * Get all author names for the many-to-many relationship.
     *
     * @return array Array of author names
     */
    public function getAuthorNames(): array
    {
        return array_map(fn($author) => $author['name'], $this->authors);
    }
}