<?php

namespace App\Services;

use App\Models\Budget;
use App\Models\BudgetConsumption;
use App\Models\BudgetEntry;
use App\Models\Requisition;
use App\Models\User;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class BudgetWorkflow
{
    /** Called inside the procurement transaction, after the company lock.
     * @return array<string,int>|null
     */
    public function record(User $user, Requisition $request, string $kind, int $amount = 0, ?int $subtotal = null): ?array
    {
        abort_unless(auth()->id() === $user->id && $user->tenant_id !== null && $request->tenant_id === $user->tenant_id, 403);
        if (DB::connection()->transactionLevel() === 0) {
            throw new \LogicException('Movimentos de orçamento exigem transacção.');
        }
        app(ConflictGuard::class)->lockCompany($user);
        $existing = BudgetEntry::query()->where('requisition_id', $request->id)->orderBy('id')->first();
        $budget = $existing
            ? Budget::query()->lockForUpdate()->findOrFail($existing->budget_id)
            : Budget::query()->where('cost_center_id', $request->cost_center_id)->where('year', now()->year)->lockForUpdate()->first();
        // Unconfigured legacy processes remain development documents, explicitly unchecked.
        if (! $budget) {
            return null;
        }
        if (! $budget->approved_by || ($kind !== 'release' && (int) $budget->year !== now()->year)) {
            throw ValidationException::withMessages(['budget' => 'Dotação pendente de aprovação ou exercício encerrado.']);
        }
        if (! $budget->includes_tax && in_array($kind, ['reserve', 'award', 'commit'])) {
            $amount = $subtotal ?? throw new \LogicException('Subtotal necessário para a base sem IVA.');
        }
        if (BudgetEntry::query()->where('requisition_id', $request->id)->where('kind', $kind)->exists()) {
            return ['budget_id' => $budget->id, 'year' => (int) $budget->year];
        }
        $own = BudgetEntry::query()->where('requisition_id', $request->id);
        $reserved = (int) (clone $own)->sum('reserved_minor');
        $committed = (int) $own->sum('committed_minor');
        if ($committed !== 0 || ($kind !== 'reserve' && ! $existing)) {
            throw ValidationException::withMessages(['budget' => 'Processo sem reserva válida ou já comprometido.']);
        }
        [$reserveDelta, $commitDelta] = match ($kind) {
            'reserve', 'award' => [$amount - $reserved, 0],
            'release' => [-$reserved, 0],
            'commit' => [-$reserved, $amount],
            default => throw new \LogicException('Movimento orçamental inválido.'),
        };
        $ledger = BudgetEntry::query()->where('budget_id', $budget->id);
        $used = (int) (clone $ledger)->sum('reserved_minor') + (int) $ledger->sum('committed_minor');
        $used += (int) BudgetConsumption::query()->where('budget_id', $budget->id)->sum('amount_minor');
        if ($used + $reserveDelta + $commitDelta > $budget->amount_minor) {
            throw ValidationException::withMessages(['budget' => 'Saldo orçamental insuficiente. Não são permitidos excessos.']);
        }
        BudgetEntry::query()->create(['tenant_id' => $user->tenant_id, 'budget_id' => $budget->id, 'requisition_id' => $request->id, 'created_by' => $user->id, 'kind' => $kind, 'reserved_minor' => $reserveDelta, 'committed_minor' => $commitDelta, 'created_at' => now()]);
        app(RequisitionWorkflow::class)->audit($user, 'budget.'.$kind, $request, null, ['budget_id' => $budget->id, 'reserved_minor' => $reserveDelta, 'committed_minor' => $commitDelta]);

        return ['budget_id' => $budget->id, 'year' => (int) $budget->year];
    }
}