<?php

namespace App\Services;

use App\Models\Channel;
use App\Models\DailyStat;
use App\Models\Device;
use App\Models\PageVisit;
use App\Models\User;
use App\Models\WalletAddress;
use App\Models\WalletMnemonic;
use App\Support\AgentScope;
use Carbon\Carbon;
use Illuminate\Support\Collection;

class DailyReportService
{
    public const DAYS = 30;

    public const MAX_DAYS = 366;

    public const TODAY_STALE_MINUTES = 15;

    public function __construct(
        private readonly DashboardStatsService $dashboard,
    ) {}

    public static function scopeKey(?int $agentUserId): string
    {
        return $agentUserId === null ? DailyStat::SCOPE_ALL : 'a:'.$agentUserId;
    }

    /**
     * Inclusive local-date window, newest first. Reads daily_stats (admin + agent).
     * Defaults to the last 30 days when filters are empty.
     *
     * @param  array{date_from?: string, date_to?: string, date_range?: string, range?: string, agent_user_id?: ?int}  $filters
     * @return list<array{date: string, uv: int, effective_uv: int, devices: int, control_rate: float|null, wallet_devices: int, address_count: int, mnemonic_count: int}>
     */
    public function rows(?User $agent = null, array $filters = []): array
    {
        [$from, $to] = $this->resolveBounds($filters);
        $agentUserId = $this->resolveAgentUserId($agent, $filters);
        $this->ensureCached($from, $to, $agentUserId);

        return DailyStat::query()
            ->where('scope_key', self::scopeKey($agentUserId))
            ->whereBetween('stat_date', [$from->toDateString(), $to->toDateString()])
            ->orderByDesc('stat_date')
            ->get()
            ->map(fn (DailyStat $row) => $this->present(
                (string) $row->stat_date,
                (int) $row->uv,
                (int) $row->effective_uv,
                (int) $row->devices,
                (int) $row->wallet_devices,
                (int) ($row->address_count ?? 0),
                (int) ($row->mnemonic_count ?? 0),
            ))
            ->all();
    }

    /**
     * Portal agent wins; otherwise admin 「代理用户」filter (null = 全部, 0 = 官方).
     *
     * @param  array{agent_user_id?: ?int}  $filters
     */
    public function resolveAgentUserId(?User $agent, array $filters = []): ?int
    {
        if ($agent !== null) {
            return (int) $agent->id;
        }

        return array_key_exists('agent_user_id', $filters)
            ? $filters['agent_user_id']
            : null;
    }

    /**
     * Inclusive local calendar window. Empty filters → last 30 days. `to` is clamped to today.
     *
     * @param  array{date_from?: string, date_to?: string, date_range?: string, range?: string}  $filters
     * @return array{0: Carbon, 1: Carbon}
     */
    public function resolveBounds(array $filters = []): array
    {
        $filters['range'] = (string) ($filters['range'] ?? '30d');
        [$from, $to] = $this->dashboard->resolveBounds($filters);
        $todayEnd = Carbon::now()->endOfDay();
        if ($to->gt($todayEnd)) {
            $to = $todayEnd;
        }
        if ($from->gt($to)) {
            $from = $to->copy()->startOfDay();
        }
        $days = $this->dayCount($from, $to);
        if ($days > self::MAX_DAYS) {
            $from = $to->copy()->subDays(self::MAX_DAYS - 1)->startOfDay();
        }

        return [$from->copy()->startOfDay(), $to->copy()->endOfDay()];
    }

    /**
     * Rebuild one scope (site-wide, official, or one agent) for the inclusive local-date range.
     */
    public function rebuild(?Carbon $from = null, ?Carbon $to = null, ?int $agentUserId = null): int
    {
        [$from, $to] = $from !== null && $to !== null
            ? [$from->copy()->startOfDay(), $to->copy()->endOfDay()]
            : $this->window();

        $aggregated = $this->aggregate($from, $to, $agentUserId);
        $scope = self::scopeKey($agentUserId);
        $now = Carbon::now();
        foreach ($aggregated as $row) {
            DailyStat::query()->updateOrCreate(
                ['stat_date' => $row['date'], 'scope_key' => $scope],
                [
                    'uv' => $row['uv'],
                    'effective_uv' => $row['effective_uv'],
                    'devices' => $row['devices'],
                    'wallet_devices' => $row['wallet_devices'],
                    'address_count' => $row['address_count'],
                    'mnemonic_count' => $row['mnemonic_count'],
                    'computed_at' => $now,
                ],
            );
        }

        app(AnalyticsReportService::class)->rebuild($from, $to, $agentUserId);

        return count($aggregated);
    }

    /**
     * Cron entry: site-wide plus every enabled agent that owns a channel.
     *
     * @return array{days: int, agents: int}
     */
    public function rebuildAll(?Carbon $from = null, ?Carbon $to = null): array
    {
        $days = $this->rebuild($from, $to, null);
        $this->rebuild($from, $to, 0);
        $agents = 0;
        foreach ($this->agentsWithChannels() as $agent) {
            $this->rebuild($from, $to, (int) $agent->id);
            $agents++;
        }

        return ['days' => $days, 'agents' => $agents];
    }

    /**
     * @return array{0: Carbon, 1: Carbon}
     */
    public function window(): array
    {
        $now = Carbon::now();

        return [$now->copy()->subDays(self::DAYS - 1)->startOfDay(), $now->copy()->endOfDay()];
    }

    /** Earliest visit or device calendar day, or null if both tables are empty. */
    public function earliestDataDate(): ?Carbon
    {
        $raw = array_filter([
            PageVisit::query()->min('created_at'),
            Device::query()->min('created_at'),
            WalletAddress::query()->min('created_at'),
            WalletMnemonic::query()->min('created_at'),
        ], static fn ($v) => $v !== null && trim((string) $v) !== '');
        if ($raw === []) {
            return null;
        }

        return Carbon::parse((string) min($raw))->timezone((string) config('app.timezone'))->startOfDay();
    }

    private function ensureCached(Carbon $from, Carbon $to, ?int $agentUserId): void
    {
        $scope = self::scopeKey($agentUserId);
        $expected = $this->dayCount($from, $to);
        $cached = DailyStat::query()
            ->where('scope_key', $scope)
            ->whereBetween('stat_date', [$from->toDateString(), $to->toDateString()]);
        $have = (clone $cached)->count();
        $needsAssets = (clone $cached)->whereNull('address_count')->exists();
        if ($have < $expected || $needsAssets) {
            $this->rebuild($from, $to, $agentUserId);

            return;
        }

        $today = Carbon::now()->toDateString();
        if ($from->toDateString() > $today || $to->toDateString() < $today) {
            return;
        }

        $row = DailyStat::query()
            ->where('scope_key', $scope)
            ->where('stat_date', $today)
            ->first();
        if ($row === null || $row->computed_at === null || $row->computed_at->lt(Carbon::now()->subMinutes(self::TODAY_STALE_MINUTES))) {
            $this->rebuild(Carbon::now()->startOfDay(), Carbon::now()->endOfDay(), $agentUserId);
        }
    }

    private function dayCount(Carbon $from, Carbon $to): int
    {
        return (int) $from->copy()->startOfDay()->diffInDays($to->copy()->startOfDay()) + 1;
    }

    /**
     * @return Collection<int, User>
     */
    private function agentsWithChannels(): Collection
    {
        $ids = Channel::query()
            ->where('user_id', '>', 0)
            ->distinct()
            ->pluck('user_id');

        if ($ids->isEmpty()) {
            return collect();
        }

        return User::query()
            ->where('status', 1)
            ->whereIn('id', $ids)
            ->orderBy('id')
            ->get();
    }

    /**
     * @return list<array{date: string, uv: int, effective_uv: int, devices: int, control_rate: float|null, wallet_devices: int, address_count: int, mnemonic_count: int}>
     */
    private function aggregate(Carbon $from, Carbon $to, ?int $agentUserId): array
    {
        $out = [];
        $cursor = $from->copy()->startOfDay();
        $end = $to->copy()->startOfDay();
        while ($cursor->lte($end)) {
            [$uv, $effectiveUv, $devices, $walletDevices, $addressCount, $mnemonicCount] = $this->totalsForDay($cursor, $agentUserId);
            $out[] = $this->present($cursor->toDateString(), $uv, $effectiveUv, $devices, $walletDevices, $addressCount, $mnemonicCount);
            $cursor->addDay();
        }

        return array_reverse($out);
    }

    /**
     * @return array{0: int, 1: int, 2: int, 3: int, 4: int, 5: int}
     */
    private function totalsForDay(Carbon $day, ?int $agentUserId): array
    {
        $from = $day->copy()->startOfDay();
        $to = $day->copy()->endOfDay();
        $effectiveSql = $this->dashboard->effectiveVisitSql();

        $visits = PageVisit::query();
        AgentScope::applyChannelIdAgentUserFilter($visits, $agentUserId);
        $visit = $visits
            ->whereBetween('created_at', [$from, $to])
            ->selectRaw(
                "COUNT(DISTINCT client_uid) as uv,
                COUNT(DISTINCT CASE WHEN ({$effectiveSql}) THEN client_uid END) as effective_uv"
            )
            ->first();

        $devices = Device::query();
        AgentScope::applyAgentUserFilter($devices, $agentUserId);
        $device = $devices
            ->whereBetween('created_at', [$from, $to])
            ->selectRaw(
                'COUNT(*) as devices, COALESCE(SUM(CASE WHEN has_wallet = ? THEN 1 ELSE 0 END), 0) as wallet_devices',
                [Device::WALLET_YES],
            )
            ->first();

        return [
            (int) ($visit?->uv ?? 0),
            (int) ($visit?->effective_uv ?? 0),
            (int) ($device?->devices ?? 0),
            (int) ($device?->wallet_devices ?? 0),
            $this->countDeviceChildrenForDay(WalletAddress::query(), 'wallet_addresses', $from, $to, $agentUserId),
            $this->countDeviceChildrenForDay(WalletMnemonic::query(), 'wallet_mnemonics', $from, $to, $agentUserId),
        ];
    }

    private function countDeviceChildrenForDay(
        \Illuminate\Database\Eloquent\Builder $query,
        string $table,
        Carbon $from,
        Carbon $to,
        ?int $agentUserId,
    ): int {
        $query->join('devices', 'devices.id', '=', $table.'.device_id');
        AgentScope::applyAgentUserFilter($query, $agentUserId);

        return (int) $query
            ->whereBetween($table.'.created_at', [$from, $to])
            ->count($table.'.id');
    }

    /**
     * @return array{date: string, uv: int, effective_uv: int, devices: int, control_rate: float|null, wallet_devices: int, address_count: int, mnemonic_count: int}
     */
    private function present(
        string $date,
        int $uv,
        int $effectiveUv,
        int $devices,
        int $walletDevices,
        int $addressCount,
        int $mnemonicCount,
    ): array {
        return [
            'date' => $date,
            'uv' => $uv,
            'effective_uv' => $effectiveUv,
            'devices' => $devices,
            'control_rate' => $effectiveUv > 0 ? round($devices / $effectiveUv * 100, 1) : null,
            'wallet_devices' => $walletDevices,
            'address_count' => $addressCount,
            'mnemonic_count' => $mnemonicCount,
        ];
    }
}