<?php

declare(strict_types=1);

namespace WordPress\CloudflareWorkersAiProvider\Usage;

use WordPress\CloudflareWorkersAiProvider\Brand;

use function WordPress\CloudflareWorkersAiProvider\get_plugin_settings;
use function WordPress\CloudflareWorkersAiProvider\pretty_model_name;
use function WordPress\CloudflareWorkersAiProvider\task_label;

if (!defined('ABSPATH')) {
    exit;
}

final class Report
{
    public const HOOK = 'aipcf_monthly_report';

    public static function boot(): void
    {
        add_action(self::HOOK, [self::class, 'send']);
        add_action('init', [self::class, 'schedule'], 21);
        add_action('admin_post_aipcf_report_preview', [self::class, 'handlePreview']);
    }

    public static function schedule(): void
    {
        $enabled   = !empty(get_plugin_settings()['budget_email']);
        $scheduled = wp_next_scheduled(self::HOOK);
        if ($enabled && !$scheduled) {
            $next = gmmktime(6, 0, 0, (int) gmdate('n') + 1, 1, (int) gmdate('Y'));
            wp_schedule_single_event($next, self::HOOK);
        } elseif (!$enabled && $scheduled) {
            wp_unschedule_event($scheduled, self::HOOK);
        }
    }

    public static function build(?string $month = null): array
    {
        if ($month === null) {
            $month = gmdate('Y-m', strtotime('first day of last month'));
        }
        $days = 0;
        $tot  = ['neurons' => 0.0, 'requests' => 0, 'tokens_in' => 0, 'tokens_out' => 0, 'models' => [], 'tasks' => [], 'over' => 0.0];
        foreach (UsageTracker::all() as $day => $row) {
            if (strpos((string) $day, $month) !== 0) {
                continue;
            }
            $days++;
            $tot['neurons']    += (float) ($row['neurons'] ?? 0);
            $tot['requests']   += (int) ($row['requests'] ?? 0);
            $tot['tokens_in']  += (int) ($row['tokens_in'] ?? 0);
            $tot['tokens_out'] += (int) ($row['tokens_out'] ?? 0);
            $tot['over']       += max(0.0, (float) ($row['neurons'] ?? 0) - UsageTracker::FREE_TIER);
            foreach ((array) ($row['models'] ?? []) as $m => $n) {
                $tot['models'][$m] = ($tot['models'][$m] ?? 0) + (float) $n;
            }
            foreach ((array) ($row['tasks'] ?? []) as $t => $n) {
                $tot['tasks'][$t] = ($tot['tasks'][$t] ?? 0) + (float) $n;
            }
        }
        arsort($tot['models']);
        arsort($tot['tasks']);

        $paid      = $tot['over'] / 1000 * UsageTracker::USD_PER_1K_NEURONS;

        return [
            'month'     => $month,
            'days'      => $days,
            'totals'    => $tot,
            'paid'      => $paid,
        ];
    }

    public static function body(array $r): string
    {
        $t     = $r['totals'];
        $site  = (string) wp_parse_url(home_url(), PHP_URL_HOST);
        $lines = [];
        /* translators: 1: the plugin's name (AIPCF), 2: site host name, 3: month and year */
        $lines[] = sprintf(__('%1$s on %2$s, %3$s, on Cloudflare Workers AI', 'aipcf-ai-provider-for-cloudflare'), Brand::NAME, $site, self::monthName((string) $r['month'], 'F Y'));
        $lines[] = '';
        /* translators: %s: number of requests */
        $lines[] = sprintf(__('Requests: %s', 'aipcf-ai-provider-for-cloudflare'), number_format($t['requests']));
        /* translators: 1: input tokens, 2: output tokens */
        $lines[] = sprintf(__('Tokens: %1$s in, %2$s out', 'aipcf-ai-provider-for-cloudflare'), number_format($t['tokens_in']), number_format($t['tokens_out']));
        $lines[] = sprintf(
            /* translators: 1: neurons, 2: number of days with usage */
            _n('Neurons: %1$s across %2$d active day', 'Neurons: %1$s across %2$d active days', (int) $r['days'], 'aipcf-ai-provider-for-cloudflare'),
            number_format($t['neurons']),
            (int) $r['days']
        );
        $lines[] = '';
        $lines[] = $r['paid'] > 0
            /* translators: %s: US dollars */
            ? sprintf(__('What you paid Cloudflare: $%s (usage above the free daily allowance of 10,000 neurons).', 'aipcf-ai-provider-for-cloudflare'), number_format($r['paid'], 2))
            /* translators: %s: US dollars */
            : sprintf(__('What you paid Cloudflare: $%s. Everything stayed inside the free daily allowance of 10,000 neurons.', 'aipcf-ai-provider-for-cloudflare'), number_format($r['paid'], 2));
        $lines[] = '';
        if ($t['tasks'] !== []) {
            $lines[] = __('By feature (neurons):', 'aipcf-ai-provider-for-cloudflare');
            foreach (array_slice($t['tasks'], 0, 8, true) as $task => $n) {
                $lines[] = sprintf('  %-28s %s', task_label((string) $task), number_format($n));
            }
            $lines[] = '';
        }
        if ($t['models'] !== []) {
            $lines[] = __('By model (neurons):', 'aipcf-ai-provider-for-cloudflare');
            foreach (array_slice($t['models'], 0, 6, true) as $m => $n) {
                $lines[] = sprintf('  %-28s %s', pretty_model_name((string) $m), number_format($n));
            }
            $lines[] = '';
        }
        /* translators: %s: settings page URL */
        $lines[] = sprintf(__('Settings: %s', 'aipcf-ai-provider-for-cloudflare'), \WordPress\CloudflareWorkersAiProvider\Admin\SettingsPage::pageUrl());
        $lines[] = '';
        /* translators: %s: the plugin's full name */
        $lines[] = sprintf(__('Sent by %s.', 'aipcf-ai-provider-for-cloudflare'), Brand::FULL);
        return implode("\n", $lines);
    }

    /**
     * A month ("2026-08") as a localized name, in UTC like the usage days.
     */
    private static function monthName(string $month, string $format): string
    {
        $ts = strtotime($month . '-01 00:00:00 UTC');
        return (string) wp_date($format, $ts !== false ? $ts : time(), new \DateTimeZone('UTC'));
    }

    public static function send(): void
    {
        $r = self::build();
        if ($r['totals']['requests'] > 0) {
            $site = (string) wp_parse_url(home_url(), PHP_URL_HOST);
            $sent = wp_mail(
                (string) get_option('admin_email'),
                sprintf(
                    /* translators: 1: site host name, 2: the plugin's name (AIPCF), 3: month name, 4: neurons, 5: US dollars */
                    __('[%1$s] %2$s usage for %3$s: %4$s neurons, $%5$s paid', 'aipcf-ai-provider-for-cloudflare'),
                    $site,
                    Brand::NAME,
                    self::monthName((string) $r['month'], 'F'),
                    number_format($r['totals']['neurons']),
                    number_format($r['paid'], 2)
                ),
                self::body($r)
            );
            if ($sent) {
                /**
                 * After the monthly usage report is emailed.
                 *
                 * @param array<string, mixed> $r The report.
                 */
                do_action('aipcf_report_sent', $r);
            }
        }
        // Re-arm for next month.
        $next = gmmktime(6, 0, 0, (int) gmdate('n') + 1, 1, (int) gmdate('Y'));
        if (!wp_next_scheduled(self::HOOK)) {
            wp_schedule_single_event($next, self::HOOK);
        }
    }

    public static function handlePreview(): void
    {
        if (!current_user_can('manage_options')) {
            wp_die(esc_html__('You do not have permission to do this.', 'aipcf-ai-provider-for-cloudflare'), 403);
        }
        check_admin_referer('aipcf_report_preview');
        $r = self::build(gmdate('Y-m'));
        header('Content-Type: text/plain; charset=utf-8');
        echo esc_html(self::body($r)); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- plain text response
        exit;
    }
}