<?php

namespace RoosterLMS\CourseInfo;

use RoosterLMS\Content\Course;
use RoosterLMS\Content\CourseCatalogue;
use RoosterLMS\Data\Db;
use RoosterLMS\Data\SqlPart;
use RoosterLMS\Data\Transaction;
use RoosterLMS\Domain\Actor;
use RoosterLMS\Domain\Authorize;
use RoosterLMS\Domain\DomainError;
use RoosterLMS\Domain\ErrorCode;
use RoosterLMS\Domain\Services;
use RoosterLMS\Domain\Users;
use RoosterLMS\I18n\Names;
use RoosterLMS\I18n\Strings;
use RoosterLMS\I18n\TextObject;

defined( 'ABSPATH' ) || exit;

final class CourseDetails {

	public const MAX_POINTS = 50;

	public const POINT_MAX = 500;

	public const TEXT_MAX = 20000;

	public const TEMPLATE_MAX = 64;

	private array $texts = array();

	private array $points = array();

	public function can_edit( int $course_id, int $user_id ): bool {
		$course = Services::course_repo()->get( $course_id );
		return null !== $course && $user_id > 0 && Users::can( $user_id, 'edit_post', $course->home_post_id );
	}

	private function authorize( int $course_id, Actor $actor ): Course {
		$course = Services::course_repo()->get( $course_id );
		if ( null === $course ) {
			DomainError::raise( ErrorCode::NOT_FOUND );
		}
		Authorize::edit_post( $actor, $course->home_post_id );
		return $course;
	}

	public function update( int $course_id, array $patch, Actor $actor, string $lang = '' ): Course {
		$course = $this->authorize( $course_id, $actor );
		$set    = array();
		if ( array_key_exists( 'level_id', $patch ) ) {
			$id = (int) $patch['level_id'];
			if ( $id > 0 && $id !== $course->level_id && ! ( Services::course_levels()->get( $id )?->is_active() ?? false ) ) {
				DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'level' ) );
			}
			$set['level_id'] = $id > 0 ? $id : null;
		}
		if ( array_key_exists( 'badge_id', $patch ) ) {
			$id = (int) $patch['badge_id'];
			if ( $id > 0 && $id !== $course->badge_id && ! ( Services::course_badges()->get( $id )?->is_active() ?? false ) ) {
				DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'badge' ) );
			}
			$set['badge_id'] = $id > 0 ? $id : null;
		}
		foreach ( array( 'badge_from', 'badge_until', 'available_from' ) as $key ) {
			if ( array_key_exists( $key, $patch ) ) {
				$set[ $key ] = self::utc( $patch[ $key ] );
			}
		}
		$from  = array_key_exists( 'badge_from', $set ) ? $set['badge_from'] : $course->badge_from;
		$until = array_key_exists( 'badge_until', $set ) ? $set['badge_until'] : $course->badge_until;
		if ( null !== $from && null !== $until && $until <= $from ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'badge_window' ) );
		}
		if ( array_key_exists( 'is_featured', $patch ) ) {
			$set['is_featured'] = ! empty( $patch['is_featured'] ) ? 1 : 0;
		}
		foreach ( array(
			'qa_mode'      => \RoosterLMS\CourseBuilder\Settings\CourseModes::QA_MAX,
			'reviews_mode' => 2,
		) as $key => $max ) {
			if ( array_key_exists( $key, $patch ) ) {
				$mode = (int) $patch[ $key ];
				if ( $mode < 0 || $mode > $max ) {
					DomainError::raise( ErrorCode::INVALID, array( 'reason' => $key ) );
				}
				$set[ $key ] = $mode;
			}
		}
		if ( array_key_exists( 'coming_soon_flags', $patch ) ) {
			$set['coming_soon_flags'] = max( 0, min( 63, (int) $patch['coming_soon_flags'] ) );
		}
		if ( array_key_exists( 'page_template', $patch ) ) {
			$set['page_template'] = PageTemplates::clean( (string) $patch['page_template'] );
			if ( '' !== trim( (string) $patch['page_template'] ) && '' === $set['page_template'] ) {
				DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'page_template' ) );
			}
		}
		$labels = array();
		foreach ( array( 'duration_label', 'video_duration_label' ) as $key ) {
			if ( ! array_key_exists( $key, $patch ) ) {
				continue;
			}
			$text = mb_substr( trim( sanitize_text_field( (string) $patch[ $key ] ) ), 0, 100 );
			$old  = 'duration_label' === $key ? $course->duration_label : $course->video_duration_label;
			if ( ! Strings::writes_stored( $lang ) && '' !== $old ) {
				Services::strings()->save_translation( TextObject::COURSE, $course_id, $old, $lang, $text, Actor::system(), $key );
				continue;
			}
			$set[ $key ]    = $text;
			$labels[ $key ] = $old;
		}
		if ( array() !== $set ) {
			Transaction::run(
				static function () use ( $course_id, $set ): void {
				Db::row( 'SELECT id FROM %i WHERE id = %d FOR UPDATE', Db::table( 'courses' ), $course_id );
					foreach ( $set as $column => $value ) {
						if ( null === $value ) {
							Db::query( 'UPDATE %i SET %i = NULL WHERE id = %d', Db::table( 'courses' ), $column, $course_id );
						} elseif ( is_int( $value ) ) {
							Db::query( 'UPDATE %i SET %i = %d WHERE id = %d', Db::table( 'courses' ), $column, $value, $course_id );
						} else {
							Db::query( 'UPDATE %i SET %i = %s WHERE id = %d', Db::table( 'courses' ), $column, $value, $course_id );
						}
					}
					Db::query( 'UPDATE %i SET updated_at = %s WHERE id = %d', Db::table( 'courses' ), Transaction::now(), $course_id );
				}
			);
			Services::course_repo()->forget( array( $course_id ) );
			CourseCatalogue::forget_counts();
			PageTemplates::forget();
			PageTemplates::mark_used( (string) ( $set['page_template'] ?? '' ) );
			if ( array_key_exists( 'available_from', $set ) || array_key_exists( 'coming_soon_flags', $set ) ) {
				Services::gate()->forget();
			}
			if ( array_key_exists( 'qa_mode', $set ) || array_key_exists( 'reviews_mode', $set ) ) {
				\RoosterLMS\Community\CourseFacts::forget();
			}
			foreach ( $labels as $key => $old ) {
				if ( '' === $set[ $key ] ) {
					Services::strings()->unregister_fields( TextObject::COURSE, $course_id, array( $key ) );
				} else {
					Services::strings()->register( TextObject::COURSE, $course_id, (string) $set[ $key ], $key, $old );
				}
			}
			do_action( 'rooster_lms_course_details_changed', $course_id, array_keys( $set ) );
		}
		return Services::course_repo()->get( $course_id ) ?? $course;
	}

	public function texts( int $course_id ): array {
		if ( ! isset( $this->texts[ $course_id ] ) ) {
			$this->texts[ $course_id ] = array();
			foreach ( Db::rows( 'SELECT kind, html FROM %i WHERE course_id = %d ORDER BY kind', Db::table( 'course_texts' ), $course_id ) as $row ) {
				$this->texts[ $course_id ][ (int) $row['kind'] ] = (string) $row['html'];
			}
		}
		return $this->texts[ $course_id ];
	}

	public function texts_in( int $course_id, string $lang = '' ): array {
		$defaults = array();
		foreach ( $this->texts( $course_id ) as $kind => $html ) {
			$case = CourseTextKind::tryFrom( $kind );
			if ( null !== $case ) {
				$defaults[ $case->field() ] = $html;
			}
		}
		return array() === $defaults ? array() : Services::strings()->translate_fields( TextObject::COURSE, $course_id, $defaults, '' !== $lang ? $lang : Names::display_language() );
	}

	public function set_text( int $course_id, CourseTextKind $kind, string $html, Actor $actor, string $lang = '' ): void {
		$this->authorize( $course_id, $actor );
		$html = CourseTextKind::SUBTITLE === $kind ? self::subtitle( $html ) : mb_substr( trim( wp_kses_post( $html ) ), 0, self::TEXT_MAX );
		$old  = $this->texts( $course_id )[ $kind->value ] ?? '';
		if ( ! Strings::writes_stored( $lang ) && '' !== $old ) {
			Services::strings()->save_translation( TextObject::COURSE, $course_id, $old, $lang, $html, Actor::system(), $kind->field() );
			return;
		}
		if ( $html === $old ) {
			return;
		}
		$this->write_text( $course_id, $kind, $html );
		if ( '' === $html ) {
			Services::strings()->unregister_fields( TextObject::COURSE, $course_id, array( $kind->field() ) );
		} else {
			Services::strings()->register( TextObject::COURSE, $course_id, $html, $kind->field(), $old );
			Services::strings()->created_in( TextObject::COURSE, $course_id, $html, '' === $old ? $lang : '', Actor::system(), $kind->field() );
		}
	}

	public function write_text( int $course_id, CourseTextKind $kind, string $html ): void {
		Transaction::run(
			static function () use ( $course_id, $kind, $html ): void {
			if ( '' === $html ) {
					Db::query( 'DELETE FROM %i WHERE course_id = %d AND kind = %d', Db::table( 'course_texts' ), $course_id, $kind->value );
					return;
				}
				Db::query( 'INSERT INTO %i (course_id, kind, html, updated_at) VALUES (%d, %d, %s, %s) ON DUPLICATE KEY UPDATE html = VALUES(html), updated_at = VALUES(updated_at)', Db::table( 'course_texts' ), $course_id, $kind->value, $html, Transaction::now() );
			}
		);
		unset( $this->texts[ $course_id ] );
	}

	public static function subtitle( string $text ): string {
		return mb_substr( trim( sanitize_text_field( $text ) ), 0, 255 );
	}

	public function points( int $course_id ): array {
		if ( ! isset( $this->points[ $course_id ] ) ) {
			$this->points[ $course_id ] = array();
			foreach ( Db::rows( 'SELECT id, kind, text FROM %i WHERE course_id = %d ORDER BY kind, position, id', Db::table( 'course_points' ), $course_id ) as $row ) {
				$this->points[ $course_id ][ (int) $row['kind'] ][] = array(
					'id'   => (int) $row['id'],
					'text' => (string) $row['text'],
				);
			}
		}
		return $this->points[ $course_id ];
	}

	public function points_in( int $course_id, string $lang = '' ): array {
		$all      = $this->points( $course_id );
		$defaults = array();
		foreach ( $all as $list ) {
			foreach ( $list as $point ) {
				$defaults[ $point['id'] ] = $point['text'];
			}
		}
		$texts = array() === $defaults ? array() : Services::strings()->translate_many( TextObject::COURSE_POINT, $defaults, '' !== $lang ? $lang : Names::display_language(), 'text' );
		$out   = array();
		foreach ( CoursePointKind::cases() as $kind ) {
			$out[ $kind->slug() ] = array_map( static fn( array $p ): string => $texts[ $p['id'] ] ?? $p['text'], $all[ $kind->value ] ?? array() );
		}
		return $out;
	}

	public function set_points( int $course_id, CoursePointKind $kind, array $texts, Actor $actor, string $lang = '' ): void {
		$this->authorize( $course_id, $actor );
		$texts = self::clean_points( $texts );
		$old   = $this->points( $course_id )[ $kind->value ] ?? array();
		if ( ! Strings::writes_stored( $lang ) && array() !== $old ) {
			if ( count( $texts ) !== count( $old ) ) {
				DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'points_count' ) );
			}
			foreach ( $old as $i => $point ) {
				Services::strings()->save_translation( TextObject::COURSE_POINT, $point['id'], $point['text'], $lang, $texts[ $i ], Actor::system(), 'text' );
			}
			return;
		}
		$ids = $this->write_points( $course_id, $kind, $texts );
		foreach ( $ids as $i => $id ) {
			Services::strings()->register( TextObject::COURSE_POINT, $id, $texts[ $i ], 'text', $old[ $i ]['text'] ?? '' );
			if ( ! isset( $old[ $i ] ) ) {
				Services::strings()->created_in( TextObject::COURSE_POINT, $id, $texts[ $i ], $lang, Actor::system(), 'text' );
			}
		}
	}

	public function write_points( int $course_id, CoursePointKind $kind, array $texts ): array {
		$ids = (array) Transaction::run(
			static function () use ( $course_id, $kind, $texts ): array {
				global $wpdb;
				$table = Db::table( 'course_points' );
				Db::row( 'SELECT id FROM %i WHERE id = %d FOR UPDATE', Db::table( 'courses' ), $course_id );
				$have = array_map( 'intval', Db::col( 'SELECT id FROM %i WHERE course_id = %d AND kind = %d ORDER BY position, id FOR UPDATE', $table, $course_id, $kind->value ) );
				$ids  = array();
				foreach ( array_values( $texts ) as $i => $text ) {
					if ( isset( $have[ $i ] ) ) {
						Db::query( 'UPDATE %i SET text = %s, position = %d WHERE id = %d', $table, $text, $i, $have[ $i ] );
						$ids[] = $have[ $i ];
					} else {
						Db::query( 'INSERT INTO %i (course_id, kind, position, text) VALUES (%d, %d, %d, %s)', $table, $course_id, $kind->value, $i, $text );
						$ids[] = Db::insert_id();
					}
				}
				$gone = array_slice( $have, count( $ids ) );
				if ( array() !== $gone ) {
					Db::query( SqlPart::of( 'DELETE FROM %i WHERE 1 = 1', $table )->add( SqlPart::and_in( 'id', $gone ) ) );
					Services::strings()->delete_objects( TextObject::COURSE_POINT, $gone );
				}
				return $ids;
			}
		);
		unset( $this->points[ $course_id ] );
		return array_map( 'intval', $ids );
	}

	public static function clean_points( array $texts ): array {
		$out = array();
		foreach ( $texts as $text ) {
			$text = is_scalar( $text ) ? mb_substr( trim( sanitize_text_field( (string) $text ) ), 0, self::POINT_MAX ) : '';
			if ( '' !== $text ) {
				$out[] = $text;
			}
		}
		return array_slice( $out, 0, self::MAX_POINTS );
	}

	public function delete_course( int $course_id ): void {
		$points = array_map( 'intval', Db::col( 'SELECT id FROM %i WHERE course_id = %d', Db::table( 'course_points' ), $course_id ) );
		$files  = array_map( 'intval', Db::col( 'SELECT id FROM %i WHERE course_id = %d', Db::table( 'course_files' ), $course_id ) );
		Db::query( 'DELETE FROM %i WHERE course_id = %d', Db::table( 'course_points' ), $course_id );
		Db::query( 'DELETE FROM %i WHERE course_id = %d', Db::table( 'course_texts' ), $course_id );
		Db::query( 'DELETE FROM %i WHERE course_id = %d', Db::table( 'course_files' ), $course_id );
		Services::strings()->delete_objects( TextObject::COURSE_POINT, $points );
		Services::strings()->delete_objects( TextObject::COURSE_FILE, $files );
		Services::strings()->delete_objects( TextObject::COURSE, array( $course_id ) );
		$this->forget();
		Services::course_files()->forget();
	}

	public function shape( Course $course, string $lang ): array {
		$labels = array();
		foreach ( array( 'duration_label', 'video_duration_label' ) as $key ) {
			if ( '' !== $course->$key ) {
				$labels[ $key ] = $course->$key;
			}
		}
		$labels = array() === $labels ? array() : Services::strings()->translate_fields( TextObject::COURSE, $course->id, $labels, $lang );
		$level  = $course->level_id > 0 ? Services::course_levels()->get( $course->level_id ) : null;
		$badge  = $course->badge_id > 0 ? Services::course_badges()->get( $course->badge_id ) : null;
		$now    = Transaction::now();
		return array(
			'id'                   => $course->id,
			'level'                => null === $level ? null : array(
				'id'    => $level->id,
				'slug'  => $level->slug,
				'label' => Services::course_levels()->label( $level, $lang ),
			),
			'badge'                => null === $badge ? null : array(
				'id'     => $badge->id,
				'slug'   => $badge->slug,
				'label'  => Services::course_badges()->label( $badge, $lang ),
				'color'  => $badge->color,
				'icon'   => $badge->icon,
				'active' => $course->badge_active( $now ),
			),
			'badge_from'           => $course->badge_from,
			'badge_until'          => $course->badge_until,
			'is_featured'          => $course->is_featured,
			'duration_label'       => $labels['duration_label'] ?? '',
			'video_duration_label' => $labels['video_duration_label'] ?? '',
			'coming_soon'          => array(
				'flags'   => ComingSoonFlag::slugs( $course->coming_soon_flags ),
				'launch'  => $course->available_from,
				'active'  => $course->is_coming_soon( $now ),
				'enrol'   => ComingSoon::enrolment_open( $course, $now ),
				'message' => $this->texts_in( $course->id, $lang )['coming_soon'] ?? '',
			),
			'page_template'        => $course->page_template,
			'texts'                => $this->texts_in( $course->id, $lang ),
			'points'               => $this->points_in( $course->id, $lang ),
		);
	}

	public function forget(): void {
		$this->texts  = array();
		$this->points = array();
	}

	public static function utc( $value ): ?string {
		if ( null === $value || '' === $value || false === $value ) {
			return null;
		}
		if ( is_int( $value ) || ( is_string( $value ) && ctype_digit( $value ) ) ) {
			return (int) $value > 0 ? gmdate( 'Y-m-d H:i:s', (int) $value ) : null;
		}
		if ( ! is_string( $value ) ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'date' ) );
		}
		$value = trim( $value );
		if ( 1 === preg_match( '/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}$/', $value ) ) {
			$date = \DateTimeImmutable::createFromFormat( 'Y-m-d H:i:s', $value, new \DateTimeZone( 'UTC' ) );
		} else {
			try {
				$date = new \DateTimeImmutable( $value, new \DateTimeZone( 'UTC' ) );
			} catch ( \Exception $e ) {
				unset( $e );
				$date = false;
			}
		}
		if ( false === $date ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'date' ) );
		}
		return $date->setTimezone( new \DateTimeZone( 'UTC' ) )->format( 'Y-m-d H:i:s' );
	}
}