<?php
/**
 * Date and time selection step.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Domain\Steps\Core;

use Bookline\Domain\Steps\BookingSession;
use Bookline\Domain\Steps\StepDescriptor;
use Bookline\Domain\Steps\ValidationResult;
use DateTimeImmutable;
use DateTimeZone;

/**
 * Choose date and time — never skipped.
 *
 * @since 0.1.0
 */
final class DatetimeStep extends AbstractStep {

	/**
	 * Step name.
	 */
	public function name(): string {
		return 'datetime';
	}

	/**
	 * Progress label.
	 */
	public function label(): string {
		return 'Date & time';
	}

	/**
	 * Front-end component key.
	 */
	protected function component(): string {
		return 'calendar';
	}

	/**
	 * Whether the step should be skipped.
	 *
	 * @param BookingSession $session Session.
	 */
	public function should_skip( BookingSession $session ): bool {
		unset( $session );
		return false;
	}

	/**
	 * Build the step descriptor.
	 *
	 * @param BookingSession $session Session.
	 */
	public function descriptor( BookingSession $session ): StepDescriptor {
		return $this->build_descriptor(
			$session,
			[
				'timezone' => $session->customer_timezone() ?? $session->draft()->timezone(),
			],
			[
				[
					'key'      => 'start_utc',
					'type'     => 'datetime',
					'required' => true,
				],
				[
					'key'      => 'end_utc',
					'type'     => 'datetime',
					'required' => true,
				],
				[
					'key'      => 'timezone',
					'type'     => 'string',
					'required' => true,
				],
				[
					'key'      => 'agent_id',
					'type'     => 'integer',
					'required' => false,
				],
			]
		);
	}

	/**
	 * Validate submitted input.
	 *
	 * @param BookingSession       $session Session.
	 * @param array<string, mixed> $input   Payload.
	 */
	public function validate( BookingSession $session, array $input ): ValidationResult {
		unset( $session );
		$errors = [];
		$start  = $this->string_value( $input, 'start_utc' );
		$end    = $this->string_value( $input, 'end_utc' );
		$tz     = $this->string_value( $input, 'timezone' );
		if ( null === $start ) {
			$errors['start_utc'] = 'Please choose a start time.';
		}
		if ( null === $end ) {
			$errors['end_utc'] = 'Please choose an end time.';
		}
		if ( null === $tz ) {
			$errors['timezone'] = 'Timezone is required.';
		} else {
			try {
				new DateTimeZone( $tz );
			} catch ( \Exception ) {
				$errors['timezone'] = 'Timezone is not valid.';
			}
		}
		if ( null !== $start && null !== $end && [] === $errors ) {
			try {
				$start_dt = new DateTimeImmutable( $start );
				$end_dt   = new DateTimeImmutable( $end );
				if ( $end_dt <= $start_dt ) {
					$errors['end_utc'] = 'End time must be after start time.';
				}
			} catch ( \Exception ) {
				$errors['start_utc'] = 'Start or end time is not valid.';
			}
		}
		return [] === $errors ? ValidationResult::ok() : ValidationResult::invalid( $errors );
	}

	/**
	 * Apply validated input.
	 *
	 * @param BookingSession       $session Session.
	 * @param array<string, mixed> $input   Payload.
	 */
	public function apply( BookingSession $session, array $input ): BookingSession {
		$start = new DateTimeImmutable( (string) $input['start_utc'] );
		$end   = new DateTimeImmutable( (string) $input['end_utc'] );
		$tz    = (string) $input['timezone'];
		$buf_s = isset( $input['buffer_start_utc'] ) && is_string( $input['buffer_start_utc'] )
			? new DateTimeImmutable( $input['buffer_start_utc'] )
			: $start;
		$buf_e = isset( $input['buffer_end_utc'] ) && is_string( $input['buffer_end_utc'] )
			? new DateTimeImmutable( $input['buffer_end_utc'] )
			: $end;
		$hold  = $this->positive_int( $input, 'hold_id' );
		$draft = $session->draft()->with_datetime( $start, $end, $buf_s, $buf_e, $tz, $hold );
		$agent = $this->positive_int( $input, 'agent_id' );
		if ( null !== $agent ) {
			$draft = $draft->with_agent( $agent, false );
		}
		return $session->with_draft( $draft );
	}
}