<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;
use App\Models\PayrollEntry;
use App\Services\PayrollService;
use Carbon\Carbon;

class AuditPayroll extends Command
{
    protected $signature = 'payroll:audit {start_date?} {end_date?}';
    protected $description = 'Audit existing payroll entries against dynamic calculation results to detect inconsistencies';

    public function handle(PayrollService $payrollService)
    {
        $startDate = $this->argument('start_date');
        $endDate = $this->argument('end_date');

        $query = PayrollEntry::with(['employee.employee', 'payrollRun']);

        if ($startDate && $endDate) {
            $query->whereHas('payrollRun', function ($q) use ($startDate, $endDate) {
                $q->where('pay_period_start', '>=', $startDate)
                  ->where('pay_period_end', '<=', $endDate);
            });
            $this->info("Auditing payroll entries for period: $startDate to $endDate");
        } else {
            $this->info("Auditing all existing payroll entries");
        }

        $entries = $query->get();

        if ($entries->isEmpty()) {
            $this->warn("No payroll entries found to audit.");
            return 0;
        }

        $totalChecked = 0;
        $inconsistenciesFound = 0;
        $headers = ['Employee', 'Period', 'Metric', 'Stored', 'Computed', 'Diff'];
        $rows = [];

        foreach ($entries as $entry) {
            $user = $entry->employee;
            if (!$user) {
                $this->warn("Payroll Entry ID {$entry->id} has no associated user.");
                continue;
            }

            $employee = $user->employee;
            if (!$employee) {
                $this->warn("User {$user->name} (ID: {$user->id}) has no employee profile.");
                continue;
            }

            $run = $entry->payrollRun;
            if (!$run) {
                $this->warn("Payroll Entry ID {$entry->id} has no associated payroll run.");
                continue;
            }

            $totalChecked++;

            $computed = $payrollService->calculateForPeriod(
                $employee,
                $run->pay_period_start->toDateString(),
                $run->pay_period_end->toDateString()
            );

            // Metrics to compare
            $metrics = [
                'Basic Salary' => [(float)$entry->basic_salary, (float)$computed['basic_salary']],
                'Total Earnings' => [(float)$entry->total_earnings, (float)$computed['total_earnings']],
                'Total Deductions' => [(float)$entry->total_deductions, (float)$computed['total_deductions']],
                'Net Pay' => [(float)$entry->net_pay, (float)$computed['net_pay']],
            ];

            $entryHasInconsistency = false;
            foreach ($metrics as $metricName => $values) {
                $storedVal = $values[0];
                $computedVal = $values[1];
                $diff = abs($storedVal - $computedVal);

                // Flag if difference is greater than 0.05 PHP
                if ($diff > 0.05) {
                    $entryHasInconsistency = true;
                    $rows[] = [
                        $user->name,
                        $run->pay_period_start->format('Y-m-d') . ' / ' . $run->pay_period_end->format('Y-m-d'),
                        $metricName,
                        number_format($storedVal, 2),
                        number_format($computedVal, 2),
                        number_format($storedVal - $computedVal, 2),
                    ];
                }
            }

            if ($entryHasInconsistency) {
                $inconsistenciesFound++;
            }
        }

        if ($inconsistenciesFound > 0) {
            $this->error("\nFound $inconsistenciesFound inconsistent payroll entries out of $totalChecked checked:");
            $this->table($headers, $rows);
            
            $this->info("\nDetailed Breakdown of Inconsistencies:");
            foreach ($rows as $row) {
                $this->line(" - <fg=red>{$row[0]}</> ({$row[1]}): {$row[2]} differs by <fg=yellow>{$row[5]} PHP</> (Stored: {$row[3]} vs Computed: {$row[4]})");
            }
        } else {
            $this->info("\nAll $totalChecked audited payroll entries match computed values perfectly! ✅");
        }

        return $inconsistenciesFound > 0 ? 1 : 0;
    }
}