<?php

namespace App\Http\Controllers;

use App\Models\Project;
use App\Models\ProjectCostLine;
use App\Models\ProjectCostSnapshot;
use App\Models\ProjectEvent;
use App\Services\ProjectCosting;
use App\Support\FixedPoint;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\Rule;
use Illuminate\Validation\ValidationException;
use Throwable;

class ProjectCostSnapshotController extends Controller
{
    public function store(Request $request, Project $project): RedirectResponse
    {
        abort_unless($request->user()->can('manageCosts', $project), 403);
        $data = $request->validate([
            'revision_id' => ['required', 'integer'],
            'basis' => ['required', Rule::in([ProjectCostSnapshot::BASIS_ESTIMATE, ProjectCostSnapshot::BASIS_ACTUAL])],
            'currency' => ['required', 'string', 'size:3', Rule::in(ProjectCosting::ALLOWED_CURRENCIES)],
            'batch_units' => ['required', 'integer', 'min:1', 'max:100000'],
            'lines.*.confirmed_reference' => ['nullable', 'string', 'max:255'],
            'source_reference' => ['nullable', 'string', 'max:255'],
            'notes' => ['nullable', 'string'],
            'lines' => ['required', 'array', 'min:1'],
            'lines.*.category' => ['required', Rule::in(ProjectCostLine::CATEGORIES)],
            'lines.*.description' => ['required', 'string', 'max:255'],
            'lines.*.quantity' => ['required', 'string'],
            'lines.*.quantity_unit' => ['required', 'string', 'max:16'],
            'lines.*.unit_rate' => ['required', 'string'],
            'lines.*.waste_quantity' => ['sometimes', 'string'],
            'lines.*.units_per_parcel' => ['required_if:lines.*.category,shipping', 'nullable', 'integer', 'min:1'],
            'lines.*.source_price_date' => ['nullable', 'date'],
            'lines.*.source_reference' => ['nullable', 'string', 'max:255'],
        ]);

        if ($data['currency'] !== $project->currency) {
            throw ValidationException::withMessages(['currency' => 'Use the project currency; no currency conversion is implied.']);
        }
        $revision = $project->revisions()->find($data['revision_id']);
        abort_unless($revision, 404);

        try {
            $linesWithTotals = array_map(function (array $line) use ($data): array {
                $line['line_total'] = ProjectCosting::lineTotal(
                    $line['category'], (string) $line['quantity'], $line['quantity_unit'],
                    (string) $line['unit_rate'], (string) ($line['waste_quantity'] ?? '0'),
                );
                if ($line['category'] === ProjectCostLine::CATEGORY_SHIPPING) {
                    if ($data['basis'] === 'actual' && empty($line['source_reference'])) {
                        throw new \InvalidArgumentException('Actual shipping needs a confirmed shipment or invoice reference.');
                    }
                    $scaled = FixedPoint::toScaled($line['line_total'], 4);
                    $allocated = FixedPoint::divideByInt(
                        FixedPoint::multiply($scaled, (int) $data['batch_units']),
                        (int) $line['units_per_parcel'],
                    );
                    $line['line_total'] = FixedPoint::format($allocated, 4);
                }

                return $line;
            }, $data['lines']);
            $totals = ProjectCosting::aggregate($linesWithTotals);
        } catch (Throwable $exception) {
            throw ValidationException::withMessages(['lines' => $exception->getMessage()]);
        }

        $snapshot = DB::transaction(function () use ($request, $project, $revision, $data, $linesWithTotals, $totals): ProjectCostSnapshot {
            $snapshot = ProjectCostSnapshot::create([
                'project_id' => $project->id,
                'revision_id' => $revision->id,
                'currency' => $data['currency'],
                'basis' => $data['basis'],
                'batch_units' => $data['batch_units'],
                'filament_total' => $totals['filament_total'],
                'packaging_total' => $totals['packaging_total'],
                'shipping_total' => $totals['shipping_total'],
                'grand_total' => $totals['grand_total'],
                'source_reference' => $data['source_reference'] ?? null,
                'notes' => $data['notes'] ?? null,
                'recorded_by' => $request->user()->id,
                'recorded_at' => now(),
            ]);

            foreach ($linesWithTotals as $line) {
                ProjectCostLine::create([
                    'cost_snapshot_id' => $snapshot->id,
                    'category' => $line['category'],
                    'description' => $line['description'],
                    'quantity' => $line['quantity'],
                    'quantity_unit' => $line['quantity_unit'],
                    'unit_rate' => $line['unit_rate'],
                    'waste_quantity' => $line['waste_quantity'] ?? '0',
                    'units_per_parcel' => $line['units_per_parcel'] ?? null,
                    'line_total' => $line['line_total'],
                    'source_price_date' => $line['source_price_date'] ?? null,
                    'source_reference' => $line['source_reference'] ?? null,
                ]);
            }

            ProjectEvent::record($project->id, 'cost_snapshot_recorded', $request->user()->id, ProjectCostSnapshot::class, $snapshot->id, [
                'basis' => $data['basis'], 'grand_total' => $totals['grand_total'],
            ]);

            return $snapshot;
        });

        return redirect()->route('projects.show', $project)->with('status', 'Cost snapshot recorded.');
    }
}