<?php

namespace App\Services;

use App\Models\Price;
use App\Models\PriceCandle;
use Carbon\Carbon;

class PriceSnapshotService
{
    /** هر تیک کران — ذخیره در prices برای نمودار (هرگز صفر ثبت نمی‌شود) */
    public function recordTick(array $payload): void
    {
        $priceValue = (int) ($payload['price'] ?? 0);
        if ($priceValue <= 30_000_000) {
            $last = Price::orderByDesc('id')->first();
            if (! $last || (int) $last->price <= 30_000_000) {
                return;
            }
            $priceValue = (int) $last->price;
        }

        Price::create([
            'price' => $priceValue,
            'date_at' => Carbon::now()->toDateString(),
            'time_at' => Carbon::now()->toTimeString(),
            'user_id' => null,
        ]);

        $this->touchCandle($priceValue);
    }

    private function touchCandle(int $priceValue): void
    {
        $candle = PriceCandle::whereDate('date_at', date('Y-m-d'))->first();

        if ($candle) {
            $candle->end = $priceValue;
            if ($priceValue < $candle->low) {
                $candle->low = $priceValue;
            } elseif ($priceValue > $candle->high) {
                $candle->high = $priceValue;
            }
            $candle->save();

            return;
        }

        PriceCandle::create([
            'start' => $priceValue,
            'end' => $priceValue,
            'high' => $priceValue,
            'low' => $priceValue,
            'date_at' => date('Y-m-d'),
        ]);
    }

    /**
     * پاک‌سازی شبانه:
     * - قبل از ۳۱ روز: حذف
     * - ۷ تا ۳۱ روز: هر ۱۲ ساعت یک رکورد
     * - ۲۴ ساعت تا ۷ روز: هر ۳۰ دقیقه یک رکورد
     * - ۲۴ ساعت اخیر: نگه‌داری همه (هر ۱۰ ثانیه)
     */
    public function pruneHistory(): array
    {
        $deletedOld = Price::query()
            ->where('created_at', '<', now()->subDays(31))
            ->delete();

        $deleted7to31 = $this->downsampleRange(now()->subDays(31), now()->subDays(7), 12 * 3600);
        $deleted1to7 = $this->downsampleRange(now()->subDays(7), now()->subDay(), 30 * 60);

        return [
            'deleted_older_than_31d' => $deletedOld,
            'downsampled_7_to_31d' => $deleted7to31,
            'downsampled_1_to_7d' => $deleted1to7,
        ];
    }

    private function downsampleRange(Carbon $from, Carbon $to, int $bucketSeconds): int
    {
        $rows = Price::query()
            ->where('created_at', '>=', $from)
            ->where('created_at', '<', $to)
            ->orderBy('created_at')
            ->get(['id', 'created_at']);

        if ($rows->isEmpty()) {
            return 0;
        }

        $keepIds = [];
        $lastBucket = null;

        foreach ($rows as $row) {
            $ts = $row->created_at?->timestamp ?? 0;
            $bucket = (int) floor($ts / $bucketSeconds);
            if ($bucket !== $lastBucket) {
                $keepIds[] = $row->id;
                $lastBucket = $bucket;
            } else {
                $keepIds[count($keepIds) - 1] = $row->id;
            }
        }

        return Price::query()
            ->where('created_at', '>=', $from)
            ->where('created_at', '<', $to)
            ->whereNotIn('id', $keepIds)
            ->delete();
    }

    /** @return array{DAILY: array<int, array{timestamp: int, value: int}>, WEEKLY: array, MONTHLY: array} */
    public function chartFromDatabase(): array
    {
        $daily = Price::query()
            ->where('created_at', '>=', now()->subDay())
            ->orderBy('created_at')
            ->get(['price', 'created_at']);

        $dailyPoints = $daily->map(function (Price $row) {
            $ts = ($row->created_at ?? now())->timestamp * 1000;

            return ['timestamp' => $ts, 'value' => (int) $row->price];
        })->values()->all();

        $weekRows = Price::query()
            ->where('created_at', '>=', now()->subDays(7))
            ->orderBy('created_at')
            ->get(['id', 'price', 'created_at']);

        $weeklyPoints = $this->bucketRows($weekRows, 30 * 60);

        $monthRows = Price::query()
            ->where('created_at', '>=', now()->subDays(31))
            ->orderBy('created_at')
            ->get(['id', 'price', 'created_at']);

        $monthlyPoints = $this->bucketRows($monthRows, 12 * 3600);

        return [
            'DAILY' => $dailyPoints,
            'WEEKLY' => $weeklyPoints,
            'MONTHLY' => $monthlyPoints,
        ];
    }

    /** @param \Illuminate\Support\Collection<int, Price> $rows */
    private function bucketRows($rows, int $bucketSeconds): array
    {
        $points = [];
        $lastBucket = null;

        foreach ($rows as $row) {
            $ts = $row->created_at?->timestamp ?? 0;
            $bucket = (int) floor($ts / $bucketSeconds);
            $point = [
                'timestamp' => $ts * 1000,
                'value' => (int) $row->price,
            ];

            if ($bucket !== $lastBucket) {
                $points[] = $point;
                $lastBucket = $bucket;
            } else {
                $points[count($points) - 1] = $point;
            }
        }

        return $points;
    }
}