<?php
/**
 * Bible books: complete canonical list (66 books), installation of missing
 * terms, biblical sort order and the admin book selector.
 *
 * @package Kanzelbuch
 */

defined( 'ABSPATH' ) || exit;

/**
 * Version of the bundled book list. Raise it when the list changes.
 */
define( 'FEGP_BOOKS_VERSION', '1' );

/**
 * All 66 books in canonical order (German names as used on the site).
 * Index 0-38: Old Testament, 39-65: New Testament.
 *
 * @return string[]
 */
function fegp_bible_books() {
	return array(
		// Altes Testament.
		'1. Mose', '2. Mose', '3. Mose', '4. Mose', '5. Mose',
		'Josua', 'Richter', 'Rut', '1. Samuel', '2. Samuel',
		'1. Könige', '2. Könige', '1. Chronik', '2. Chronik',
		'Esra', 'Nehemia', 'Ester', 'Hiob', 'Psalmen', 'Sprüche',
		'Prediger', 'Hohelied', 'Jesaja', 'Jeremia', 'Klagelieder',
		'Hesekiel', 'Daniel', 'Hosea', 'Joel', 'Amos', 'Obadja',
		'Jona', 'Micha', 'Nahum', 'Habakuk', 'Zefanja', 'Haggai',
		'Sacharja', 'Maleachi',
		// Neues Testament.
		'Matthäus', 'Markus', 'Lukas', 'Johannes', 'Apostelgeschichte',
		'Römer', '1. Korinther', '2. Korinther', 'Galater', 'Epheser',
		'Philipper', 'Kolosser', '1. Thessalonicher', '2. Thessalonicher',
		'1. Timotheus', '2. Timotheus', 'Titus', 'Philemon', 'Hebräer',
		'Jakobus', '1. Petrus', '2. Petrus', '1. Johannes', '2. Johannes',
		'3. Johannes', 'Judas', 'Offenbarung',
	);
}

/**
 * Number of Old Testament books in fegp_bible_books().
 */
define( 'FEGP_OT_BOOKS', 39 );

/**
 * Normalise a book name or slug for matching: lowercase, umlauts → ae/oe/ue,
 * ß → ss, everything except a-z and 0-9 removed. "1. Mose", "1.Mose",
 * "1-mose" all become "1mose"; "Matthäus" and "matthaeus" become "matthaeus".
 *
 * @param string $s Name or slug.
 * @return string
 */
function fegp_book_key( $s ) {
	$s = function_exists( 'mb_strtolower' ) ? mb_strtolower( (string) $s, 'UTF-8' ) : strtolower( (string) $s );
	$s = strtr(
		$s,
		array(
			'ä' => 'ae',
			'ö' => 'oe',
			'ü' => 'ue',
			'ß' => 'ss',
		)
	);
	return preg_replace( '/[^a-z0-9]/', '', $s );
}

/**
 * Map of normalised key → canonical position (1-66), including common
 * alternative spellings so existing terms are recognised instead of duplicated.
 *
 * @return int[]
 */
function fegp_book_key_map() {
	static $map = null;
	if ( null !== $map ) {
		return $map;
	}
	$map = array();
	foreach ( fegp_bible_books() as $i => $name ) {
		$map[ fegp_book_key( $name ) ] = $i + 1;
	}
	// Slugs generated without the German locale drop the umlaut ("matthaus").
	foreach ( fegp_bible_books() as $i => $name ) {
		$plain = fegp_book_key( strtr( $name, array( 'ä' => 'a', 'ö' => 'o', 'ü' => 'u' ) ) );
		if ( ! isset( $map[ $plain ] ) ) {
			$map[ $plain ] = $i + 1;
		}
	}
	$aliases = array(
		'Psalm'                    => 'Psalmen',
		'Hoheslied'                => 'Hohelied',
		'Hohelied Salomos'         => 'Hohelied',
		'Prediger Salomo'          => 'Prediger',
		'Kohelet'                  => 'Prediger',
		'Klagelieder Jeremias'     => 'Klagelieder',
		'Ruth'                     => 'Rut',
		'Esther'                   => 'Ester',
		'Ezechiel'                 => 'Hesekiel',
		'Zephanja'                 => 'Zefanja',
		'Apg'                      => 'Apostelgeschichte',
		'Offenbarung des Johannes' => 'Offenbarung',
		'Johannes-Offenbarung'     => 'Offenbarung',
	);
	$pos = array_flip( fegp_bible_books() );
	foreach ( $aliases as $alias => $name ) {
		$k = fegp_book_key( $alias );
		if ( ! isset( $map[ $k ] ) ) {
			$map[ $k ] = $pos[ $name ] + 1;
		}
	}
	return $map;
}

/**
 * Canonical position (1-66) of a term, or 0 if unknown.
 *
 * @param WP_Term $term Term.
 * @return int
 */
function fegp_book_position( $term ) {
	$order = (int) get_term_meta( $term->term_id, 'fegp_book_order', true );
	if ( $order > 0 ) {
		return $order;
	}
	$map = fegp_book_key_map();
	foreach ( array( $term->name, rawurldecode( $term->slug ) ) as $v ) {
		$k = fegp_book_key( $v );
		if ( isset( $map[ $k ] ) ) {
			return $map[ $k ];
		}
	}
	return 0;
}

/**
 * Sort book terms in biblical order; unknown books follow alphabetically.
 *
 * @param WP_Term[] $terms Terms.
 * @return WP_Term[]
 */
function fegp_sort_books( $terms ) {
	if ( ! is_array( $terms ) ) {
		return $terms;
	}
	usort(
		$terms,
		function ( $a, $b ) {
			$pa = fegp_book_position( $a );
			$pb = fegp_book_position( $b );
			$pa = $pa ? $pa : 1000;
			$pb = $pb ? $pb : 1000;
			if ( $pa !== $pb ) {
				return $pa - $pb;
			}
			return strcasecmp( $a->name, $b->name );
		}
	);
	return $terms;
}

/**
 * Create the missing books and store the canonical order. Existing terms are
 * matched by normalised name or slug (incl. alternative spellings) and never
 * renamed or duplicated. Idempotent.
 *
 * @return array{created:string[],matched:string[]}
 */
function fegp_install_books() {
	$result = array(
		'created' => array(),
		'matched' => array(),
	);
	if ( ! taxonomy_exists( 'sermon_book' ) ) {
		return $result;
	}
	$existing = get_terms(
		array(
			'taxonomy'   => 'sermon_book',
			'hide_empty' => false,
		)
	);
	if ( is_wp_error( $existing ) ) {
		return $result;
	}
	$map   = fegp_book_key_map();
	$found = array(); // position => term.
	foreach ( $existing as $t ) {
		foreach ( array( $t->name, rawurldecode( $t->slug ) ) as $v ) {
			$k = fegp_book_key( $v );
			if ( isset( $map[ $k ] ) && ! isset( $found[ $map[ $k ] ] ) ) {
				$found[ $map[ $k ] ] = $t;
				break;
			}
		}
	}
	foreach ( fegp_bible_books() as $i => $name ) {
		$pos = $i + 1;
		if ( isset( $found[ $pos ] ) ) {
			$term_id             = $found[ $pos ]->term_id;
			$result['matched'][] = $found[ $pos ]->name;
		} else {
			$ins = wp_insert_term( $name, 'sermon_book' );
			if ( is_wp_error( $ins ) ) {
				// A term with this name exists after all: reuse it.
				$term_id = (int) $ins->get_error_data( 'term_exists' );
				if ( ! $term_id ) {
					continue;
				}
			} else {
				$term_id             = (int) $ins['term_id'];
				$result['created'][] = $name;
			}
		}
		if ( (int) get_term_meta( $term_id, 'fegp_book_order', true ) !== $pos ) {
			update_term_meta( $term_id, 'fegp_book_order', $pos );
		}
	}
	return $result;
}

/**
 * Run the installation once per book-list version (activation and upgrade).
 */
function fegp_maybe_install_books() {
	if ( get_option( 'fegp_books_version' ) === FEGP_BOOKS_VERSION || ! taxonomy_exists( 'sermon_book' ) ) {
		return;
	}
	$res = fegp_install_books();
	update_option( 'fegp_books_version', FEGP_BOOKS_VERSION );
	update_option( 'fegp_books_install_log', array_merge( $res, array( 'time' => time() ) ), false );
}
add_action( 'init', 'fegp_maybe_install_books', 30 );

/**
 * Replace the tag-style box with an ordered checkbox list.
 */
function fegp_book_metabox_setup() {
	if ( ! taxonomy_exists( 'sermon_book' ) ) {
		return;
	}
	remove_meta_box( 'tagsdiv-sermon_book', 'sermons', 'side' );
	add_meta_box( 'fegp_books', __( 'Bible books', 'kanzelbuch' ), 'fegp_render_book_metabox', 'sermons', 'side', 'default' );
}
add_action( 'add_meta_boxes_sermons', 'fegp_book_metabox_setup' );

/**
 * Hide the block editor's own panel for books (the ordered metabox replaces it).
 *
 * @param WP_REST_Response $response Response.
 * @param WP_Taxonomy      $taxonomy Taxonomy.
 * @return WP_REST_Response
 */
function fegp_hide_book_panel( $response, $taxonomy ) {
	if ( 'sermon_book' === $taxonomy->name ) {
		$data = $response->get_data();
		if ( isset( $data['visibility'] ) ) {
			$data['visibility']['show_ui'] = false;
			$response->set_data( $data );
		}
	}
	return $response;
}
add_filter( 'rest_prepare_taxonomy', 'fegp_hide_book_panel', 10, 2 );

/**
 * Markup of the book selector (also used for the preview).
 *
 * @param WP_Term[] $terms    All book terms, sorted.
 * @param int[]     $selected Selected term IDs.
 * @return string
 */
function fegp_book_selector_html( $terms, $selected ) {
	$groups = array(
		'ot'    => array( __( 'Old Testament', 'kanzelbuch' ), '' ),
		'nt'    => array( __( 'New Testament', 'kanzelbuch' ), '' ),
		'other' => array( __( 'Other', 'kanzelbuch' ), '' ),
	);
	foreach ( $terms as $t ) {
		$pos = fegp_book_position( $t );
		$g   = ! $pos || $pos > 66 ? 'other' : ( $pos <= FEGP_OT_BOOKS ? 'ot' : 'nt' );

		$groups[ $g ][1] .= '<li><label><input type="checkbox" name="fegp_books[]" value="' . esc_attr( $t->term_id ) . '"' . checked( in_array( (int) $t->term_id, $selected, true ), true, false ) . '> ' . esc_html( $t->name ) . '</label></li>';
	}
	$html = '<div class="fegp-books" style="max-height:340px;overflow:auto;border:1px solid #dcdcde;padding:4px 8px;background:#fff">';
	foreach ( $groups as $g ) {
		if ( '' === $g[1] ) {
			continue;
		}
		$html .= '<p style="margin:8px 0 4px;font-weight:600">' . esc_html( $g[0] ) . '</p><ul style="margin:0 0 6px">' . $g[1] . '</ul>';
	}
	return $html . '</div>';
}

/**
 * Render the book metabox.
 *
 * @param WP_Post $post Post.
 */
function fegp_render_book_metabox( $post ) {
	wp_nonce_field( 'fegp_save_books', 'fegp_books_nonce' );
	$terms = get_terms(
		array(
			'taxonomy'   => 'sermon_book',
			'hide_empty' => false,
		)
	);
	$terms    = is_wp_error( $terms ) ? array() : fegp_sort_books( $terms );
	$selected = wp_get_object_terms( $post->ID, 'sermon_book', array( 'fields' => 'ids' ) );
	$selected = is_wp_error( $selected ) ? array() : array_map( 'intval', $selected );
	echo wp_kses( fegp_book_selector_html( $terms, $selected ), fegp_kses_allowed() );
}

/**
 * Save the selected books.
 *
 * @param int $post_id Post ID.
 */
function fegp_save_books( $post_id ) {
	if ( ! isset( $_POST['fegp_books_nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['fegp_books_nonce'] ) ), 'fegp_save_books' ) ) {
		return;
	}
	if ( ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) || ! current_user_can( 'edit_post', $post_id ) ) {
		return;
	}
	$ids = isset( $_POST['fegp_books'] ) ? array_map( 'absint', (array) wp_unslash( $_POST['fegp_books'] ) ) : array();
	$ids = array_values( array_filter( $ids ) );
	wp_set_object_terms( $post_id, $ids, 'sermon_book', false );
}
add_action( 'save_post_sermons', 'fegp_save_books' );