<?php

namespace Modules\FluxoCaixaPro\Services;

use Modules\FluxoCaixaPro\Models\Transaction;
use Modules\FluxoCaixaPro\Models\Category;
use Illuminate\Database\Capsule\Manager as DB;
use Carbon\Carbon;

/**
 * Class CashFlowService
 *
 * Handles business logic for cash flow management.
 *
 * @package Modules\FluxoCaixaPro\Services
 */
class CashFlowService
{
    /**
     * Get summary of cash flow for a specific period.
     *
     * @param string|null $startDate
     * @param string|null $endDate
     * @return array
     */
    public function getSummary(?string $startDate = null, ?string $endDate = null): array
    {
        $query = Transaction::query();

        if ($startDate) {
            $query->where('transaction_date', '>=', $startDate);
        }
        if ($endDate) {
            $query->where('transaction_date', '<=', $endDate);
        }

        $transactions = $query->get();

        // Total amounts (including personal)
        $totalIncome = $transactions->where('type', 'income')->sum('amount');
        $totalExpense = $transactions->where('type', 'expense')->sum('amount');
        $netBalance = $totalIncome - $totalExpense;

        // Operational amounts (Business only)
        $businessTransactions = $transactions->where('is_personal', false);
        $opIncome = $businessTransactions->where('type', 'income')->sum('amount');
        $opExpense = $businessTransactions->where('type', 'expense')->sum('amount');
        $opBalance = $opIncome - $opExpense;

        // Personal amounts
        $personalTransactions = $transactions->where('is_personal', true);
        $personalIncome = $personalTransactions->where('type', 'income')->sum('amount');
        $personalExpense = $personalTransactions->where('type', 'expense')->sum('amount');

        // Accounts Payable/Receivable
        $pendingIncome = Transaction::where('type', 'income')->where('status', 'pending')->sum('amount');
        $pendingExpense = Transaction::where('type', 'expense')->where('status', 'pending')->sum('amount');

        return [
            'total_income' => $totalIncome,
            'total_expense' => $totalExpense,
            'net_balance' => $netBalance,
            'operational_income' => $opIncome,
            'operational_expense' => $opExpense,
            'operational_balance' => $opBalance,
            'personal_income' => $personalIncome,
            'personal_expense' => $personalExpense,
            'pending_income' => $pendingIncome,
            'pending_expense' => $pendingExpense,
            'transaction_count' => $transactions->count()
        ];
    }

    /**
     * Get monthly breakdown of cash flow.
     *
     * @param int $months
     * @return array
     */
    public function getMonthlyBreakdown(int $months = 6): array
    {
        $startDate = Carbon::now()->subMonths($months)->startOfMonth();

        $data = Transaction::where('transaction_date', '>=', $startDate)
            ->select(
                \Illuminate\Database\Capsule\Manager::raw('DATE_FORMAT(transaction_date, "%Y-%m") as month'),
                \Illuminate\Database\Capsule\Manager::raw('SUM(CASE WHEN type = "income" THEN amount ELSE 0 END) as income'),
                \Illuminate\Database\Capsule\Manager::raw('SUM(CASE WHEN type = "expense" THEN amount ELSE 0 END) as expense')
            )
            ->groupBy('month')
            ->orderBy('month', 'asc')
            ->get();

        return $data->toArray();
    }

    /**
     * Get distribution by category.
     *
     * @param string $type 'income' or 'expense'
     * @return array
     */
    public function getCategoryDistribution(string $type = 'expense'): array
    {
        return Transaction::where('type', $type)
            ->with('category')
            ->select('category_id', \Illuminate\Database\Capsule\Manager::raw('SUM(amount) as total'))
            ->groupBy('category_id')
            ->get()
            ->map(function ($item) {
                return [
                    'category' => $item->category->name ?? 'Sem Categoria',
                    'total' => $item->total,
                    'color' => $item->category->color ?? '#6c757d'
                ];
            })
            ->toArray();
    }

    /**
     * Get long term projections with scenarios.
     *
     * @param int $months
     * @return array
     */
    public function getProjections(int $months = 12): array
    {
        $startDate = Carbon::now()->subMonths(12);
        $history = Transaction::where('transaction_date', '>=', $startDate)
            ->where('is_personal', false)
            ->get();

        if ($history->isEmpty()) {
            return [];
        }

        $avgMonthlyIncome = $history->where('type', 'income')->sum('amount') / 12;
        $avgMonthlyExpense = $history->where('type', 'expense')->sum('amount') / 12;

        $projections = [];
        for ($i = 1; $i <= $months; $i++) {
            $month = Carbon::now()->addMonths($i)->format('Y-m');

            // Realistic Scenario (Current average + slight growth)
            $realisticIncome = $avgMonthlyIncome * (1 + ($i * 0.01));
            $realisticExpense = $avgMonthlyExpense * (1 + ($i * 0.005));

            // Optimistic Scenario (+5% income, -2% expense vs realistic)
            $optimisticIncome = $realisticIncome * 1.05;
            $optimisticExpense = $realisticExpense * 0.98;

            // Pessimistic Scenario (-10% income, +5% expense vs realistic)
            $pessimisticIncome = $realisticIncome * 0.90;
            $pessimisticExpense = $realisticExpense * 1.05;

            $projections[] = [
                'month' => $month,
                'realistic' => [
                    'income' => $realisticIncome,
                    'expense' => $realisticExpense,
                    'balance' => $realisticIncome - $realisticExpense
                ],
                'optimistic' => [
                    'income' => $optimisticIncome,
                    'expense' => $optimisticExpense,
                    'balance' => $optimisticIncome - $optimisticExpense
                ],
                'pessimistic' => [
                    'income' => $pessimisticIncome,
                    'expense' => $pessimisticExpense,
                    'balance' => $pessimisticIncome - $pessimisticExpense
                ]
            ];
        }

        return $projections;
    }
}