<?php

declare(strict_types=1);

namespace ProCalendarWP\Events;

use DateTimeImmutable;
use DateTimeZone;
use InvalidArgumentException;

final class DailySchedule
{
    /** @return array<string,mixed> */
    public static function schema(): array
    {
        $slot = [
            'type' => 'object', 'additionalProperties' => false,
            'required' => ['id', 'start', 'end', 'nextDay'],
            'properties' => [
                'id' => ['type' => 'string', 'pattern' => '^[a-zA-Z0-9_-]{1,64}$'],
                'start' => ['type' => 'string'], 'end' => ['type' => 'string'],
                'nextDay' => ['type' => 'boolean'],
            ],
        ];
        return [
            'type' => 'object', 'additionalProperties' => false,
            'properties' => [
                'type' => ['type' => 'string', 'enum' => ['continuous', 'daily']],
                'startDate' => ['type' => 'string'], 'endDate' => ['type' => 'string'],
                'days' => [
                    'type' => 'array', 'items' => [
                        'type' => 'object', 'additionalProperties' => false,
                        'required' => ['date', 'closed', 'slots'],
                        'properties' => [
                            'date' => ['type' => 'string'], 'closed' => ['type' => 'boolean'],
                            'slots' => ['type' => 'array', 'items' => $slot],
                        ],
                    ],
                ],
            ],
        ];
    }

    /** @return array<string,mixed> */
    public static function validate(mixed $input, string $timezone, bool $series = false): array
    {
        if ($input === '' || $input === null || $input === []) {
            return ['type' => 'continuous'];
        }
        if (! is_array($input) || ! in_array($input['type'] ?? '', ['continuous', 'daily'], true)) {
            throw new InvalidArgumentException(__('Choose a valid schedule type.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
        }
        if ($input['type'] === 'continuous') {
            return ['type' => 'continuous'];
        }
        if ($series) {
            throw new InvalidArgumentException(__('Daily schedules are available only for standalone events.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
        }
        try {
            $zone = new DateTimeZone($timezone);
        } catch (\Exception) {
            throw new InvalidArgumentException(__('Choose a valid event timezone.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
        }
        $start = self::date($input['startDate'] ?? '', $zone);
        $end = self::date($input['endDate'] ?? '', $zone);
        if ($end < $start) {
            throw new InvalidArgumentException(__('The schedule end date must not precede its start.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
        }
        $rows = $input['days'] ?? null;
        if (! is_array($rows) || count($rows) !== (int) $start->diff($end)->days + 1) {
            throw new InvalidArgumentException(__('Provide hours or mark Closed for every date in the range.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
        }
        $days = [];
        $ids = [];
        foreach ($rows as $row) {
            if (! is_array($row)) {
                throw new InvalidArgumentException(__('Invalid schedule date.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
            }
            $date = self::date($row['date'] ?? '', $zone);
            $key = $date->format('Y-m-d');
            if ($date < $start || $date > $end || isset($days[$key]) || ! is_bool($row['closed'] ?? null)) {
                throw new InvalidArgumentException(__('Schedule dates must be unique and inside the selected range.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
            }
            $slots = $row['slots'] ?? null;
            if (! is_array($slots) || ($row['closed'] ? $slots !== [] : $slots === [])) {
                /* translators: %s is a validated ISO calendar date. */
                throw new InvalidArgumentException(sprintf(__('Enter at least one time slot for %s, or mark it Closed.', 'proeventswp'), $key)); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
            }
            $clean = [];
            foreach ($slots as $slot) {
                if (! is_array($slot) || ! is_string($slot['id'] ?? null) || preg_match('/^[a-zA-Z0-9_-]{1,64}$/D', $slot['id']) !== 1 || isset($ids[strtolower($slot['id'])])) {
                    throw new InvalidArgumentException(__('Each time slot needs a unique ID.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
                }
                foreach (['start', 'end'] as $field) {
                    if (! is_string($slot[$field] ?? null) || preg_match('/^(?:[01]\d|2[0-3]):[0-5]\d$/D', $slot[$field]) !== 1) {
                        /* translators: %s is a validated ISO calendar date. */
                        throw new InvalidArgumentException(sprintf(__('Enter valid opening and closing times for %s.', 'proeventswp'), $key)); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
                    }
                }
                if (! is_bool($slot['nextDay'] ?? null)) {
                    throw new InvalidArgumentException(__('Specify whether the slot ends the next day.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
                }
                // Match the projection table's case-insensitive WordPress collation.
                $ids[strtolower($slot['id'])] = true;
                $clean[] = array_intersect_key($slot, array_flip(['id', 'start', 'end', 'nextDay']));
            }
            usort($clean, static fn (array $a, array $b): int => strcmp($a['start'], $b['start']));
            $days[$key] = ['date' => $key, 'closed' => $row['closed'], 'slots' => $clean];
        }
        ksort($days);
        $schedule = ['type' => 'daily', 'startDate' => $start->format('Y-m-d'), 'endDate' => $end->format('Y-m-d'), 'days' => array_values($days)];
        $intervals = self::intervals($schedule, $timezone);
        if ($intervals === []) {
            throw new InvalidArgumentException(__('A daily schedule needs at least one open time slot.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
        }
        $previous = null;
        foreach ($intervals as $interval) {
            $time = $interval['time'];
            if ($time->end <= $time->start) {
                throw new InvalidArgumentException(__('Closing must follow opening; use Ends next day for overnight hours.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
            }
            if ($previous !== null && $time->start < $previous) {
                throw new InvalidArgumentException(__('Time slots overlap, including across midnight. Adjust the hours.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
            }
            $previous = $time->end;
        }
        return $schedule;
    }

    /** @param array<string,mixed> $schedule
     * @return list<array{id:string,time:EventTime}>
     */
    public static function intervals(array $schedule, string $timezone): array
    {
        $result = [];
        foreach ($schedule['days'] ?? [] as $day) {
            foreach ($day['slots'] as $slot) {
                $endDate = new DateTimeImmutable($day['date'], new DateTimeZone($timezone));
                if ($slot['nextDay']) {
                    $endDate = $endDate->modify('+1 day');
                }
                try {
                    $time = EventTime::fromLocal($day['date'] . 'T' . $slot['start'], $endDate->format('Y-m-d') . 'T' . $slot['end'], $timezone);
                } catch (InvalidArgumentException $error) {
                    /* translators: %1$s is the date; %2$s and %3$s are local times; %4$s is the validation error. */
                    throw new InvalidArgumentException(sprintf(__('Check hours for %1$s (%2$s–%3$s): %4$s Use Ends next day for overnight hours.', 'proeventswp'), $day['date'], $slot['start'], $slot['end'], $error->getMessage())); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
                }
                $result[] = ['id' => $slot['id'], 'time' => $time];
            }
        }
        usort($result, static fn (array $a, array $b): int => $a['time']->start <=> $b['time']->start);
        return $result;
    }

    private static function date(mixed $value, DateTimeZone $zone): DateTimeImmutable
    {
        $date = is_string($value) && preg_match('/^\d{4}-\d{2}-\d{2}$/D', $value) === 1 ? DateTimeImmutable::createFromFormat('!Y-m-d', $value, $zone) : false;
        if ($date === false || $date->format('Y-m-d') !== $value) {
            throw new InvalidArgumentException(__('Enter valid schedule start and end dates.', 'proeventswp')); // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Exception messages are data; REST encodes them and admin callers escape output.
        }
        return $date;
    }
}