<?php

namespace Modules\FinancialManagement\Services;

use Modules\FinancialManagement\Enums\InvoiceStatus;
use Modules\FinancialManagement\Models\FinancialInvoice;
use Modules\FinancialManagement\Models\InvoiceLineItem;
use Modules\FinancialManagement\Models\RetentionEntry;
use Modules\ProjectManagement\Models\Project;

class ProgressBillingService
{
    /**
     * Generate a progress invoice for a project based on completion %.
     */
    public function generateInvoice(
        Project $project,
        float $currentPercentage,
        float $retentionRate = 10.00,
    ): FinancialInvoice {
        $lastBilled = (float) ($project->last_billed_percentage ?? 0);
        $contractValue = (float) ($project->contract_value ?? 0);

        if ($currentPercentage <= $lastBilled) {
            throw new \InvalidArgumentException(
                "Current progress ({$currentPercentage}%) must exceed last billed ({$lastBilled}%)"
            );
        }

        $incrementalPercent = $currentPercentage - $lastBilled;
        $subtotal = $contractValue * ($incrementalPercent / 100);
        $retention = $subtotal * ($retentionRate / 100);
        $totalAmount = $subtotal - $retention;

        $invoice = FinancialInvoice::create([
            'project_id' => $project->id,
            'invoice_number' => 'INV-' . strtoupper(uniqid()),
            'status' => InvoiceStatus::Draft,
            'subtotal' => $subtotal,
            'retention_amount' => $retention,
            'total_amount' => $totalAmount,
            'retention_rate' => $retentionRate,
            'billed_percentage' => $currentPercentage,
            'invoice_date' => now()->toDateString(),
            'due_date' => now()->addDays(30)->toDateString(),
        ]);

        // Create line item for progress billing
        InvoiceLineItem::create([
            'invoice_id' => $invoice->id,
            'description' => "Progress billing: {$lastBilled}% → {$currentPercentage}% ({$incrementalPercent}%)",
            'quantity' => 1,
            'unit_price' => $subtotal,
            'total' => $subtotal,
        ]);

        return $invoice;
    }

    /**
     * On invoice approval, create retention debit entry.
     */
    public function holdRetention(FinancialInvoice $invoice): void
    {
        if ($invoice->retention_amount <= 0) return;

        RetentionEntry::create([
            'project_id' => $invoice->project_id,
            'invoice_id' => $invoice->id,
            'type' => 'debit',
            'amount' => $invoice->retention_amount,
            'description' => "Retention held on Invoice #{$invoice->invoice_number} ({$invoice->retention_rate}%)",
        ]);
    }

    /**
     * On invoice payment, update project's last billed percentage.
     */
    public function recordPayment(FinancialInvoice $invoice, float $amount): void
    {
        $newPaid = (float) $invoice->paid_amount + $amount;
        $totalAmount = (float) $invoice->total_amount;

        $updates = ['paid_amount' => $newPaid];

        if ($newPaid >= $totalAmount) {
            $invoice->transitionTo(InvoiceStatus::Paid);
            // Update project's last billed percentage
            $invoice->project()->update(['last_billed_percentage' => $invoice->billed_percentage]);
        } else {
            $invoice->transitionTo(InvoiceStatus::PartiallyPaid);
        }

        $invoice->update($updates);
    }

    /**
     * Release all retention for a project (on project completion).
     */
    public function releaseRetention(Project $project): void
    {
        $totalRetention = RetentionEntry::where('project_id', $project->id)
            ->where('type', 'debit')
            ->sum('amount');

        $alreadyCredited = RetentionEntry::where('project_id', $project->id)
            ->where('type', 'credit')
            ->sum('amount');

        $remaining = $totalRetention - $alreadyCredited;

        if ($remaining > 0) {
            RetentionEntry::create([
                'project_id' => $project->id,
                'type' => 'credit',
                'amount' => $remaining,
                'description' => 'Retention released on project completion',
            ]);
        }
    }
}