<?php

namespace App\Services;

use App\Enums\PurchasingRole;
use App\Models\PurchaseControlPolicy;
use App\Models\PurchaseControlReview;
use App\Models\User;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class PurchaseControlPolicyWorkflow
{
    /** @return Builder<PurchaseControlPolicy> */
    protected function policies(): Builder
    {
        return PurchaseControlPolicy::query();
    }

    /** @return Builder<PurchaseControlReview> */
    protected function reviews(): Builder
    {
        return PurchaseControlReview::query();
    }

    protected function mode(): string
    {
        return 'unissued_award';
    }

    protected function auditPrefix(): string
    {
        return 'purchase_control';
    }

    private function admin(User $user): void
    {
        abort_unless(auth()->id() === $user->id && $user->tenant_id !== null && $user->hasFunctions([PurchasingRole::Admin]), 403);
    }

    /** @param array<string,mixed> $data */
    public function propose(User $user, array $data): PurchaseControlPolicy
    {
        $this->admin($user);

        return DB::transaction(function () use ($user, $data) {
            app(ConflictGuard::class)->lockCompany($user);
            $user = User::query()->where('tenant_id', $user->tenant_id)->lockForUpdate()->findOrFail($user->id);
            $this->admin($user);
            $latest = $this->policies()->latest('revision')->first();
            if ((int) $data['previous_id'] !== ($latest->id ?? 0) || $data['mode'] !== $this->mode()) {
                throw ValidationException::withMessages(['cancellation' => 'Versão desactualizada ou regra não suportada. Não se presume um circuito de excepção.']);
            }
            $policy = $this->policies()->create(['tenant_id' => $user->tenant_id, 'created_by' => $user->id, 'revision' => ($latest->revision ?? 0) + 1, 'mode' => $data['mode'], 'enabled' => $data['enabled'], 'valid_from' => $data['valid_from'], 'valid_until' => $data['valid_until'], 'reason' => $data['reason']]);
            app(RequisitionWorkflow::class)->audit($user, $this->auditPrefix().'.proposed', null, null, $policy->toArray());

            return $policy;
        });
    }

    public function review(User $user, PurchaseControlPolicy $policy, string $decision, string $reason): void
    {
        $this->admin($user);
        abort_unless($policy->getTable() === $this->policies()->getModel()->getTable(), 403);
        abort_unless($policy->tenant_id === $user->tenant_id && $policy->created_by !== $user->id, 403);
        if (! in_array($decision, ['approved', 'rejected']) || trim($reason) === '') {
            throw ValidationException::withMessages(['cancellation' => 'Decisão e fundamento obrigatórios.']);
        }
        DB::transaction(function () use ($user, $policy, $decision, $reason) {
            app(ConflictGuard::class)->lockCompany($user);
            $user = User::query()->where('tenant_id', $user->tenant_id)->lockForUpdate()->findOrFail($user->id);
            $this->admin($user);
            $policy = $this->policies()->lockForUpdate()->findOrFail($policy->id);
            $existing = $this->reviews()->where('purchase_control_policy_id', $policy->id)->where('reviewed_by', $user->id)->first();
            if ($existing) {
                if ($existing->decision !== $decision || $existing->reason !== $reason) {
                    throw ValidationException::withMessages(['cancellation' => 'Decisão anterior imutável.']);
                }

                return;
            }
            if ($policy->status !== 'pending' || $this->policies()->max('revision') !== $policy->revision) {
                throw ValidationException::withMessages(['cancellation' => 'Versão decidida ou substituída por proposta mais recente.']);
            }
            if ($decision === 'approved') {
                $ids = $this->reviews()->where('purchase_control_policy_id', $policy->id)->where('decision', 'approved')->pluck('reviewed_by')->push($policy->created_by)->push($user->id)->unique();
                $actors = User::query()->where('tenant_id', $user->tenant_id)->whereIn('id', $ids)->orderBy('id')->lockForUpdate()->get();
                if ($actors->count() !== $ids->count() || $actors->contains(fn (User $actor) => ! $actor->hasFunctions([PurchasingRole::Admin]))) {
                    throw ValidationException::withMessages(['cancellation' => 'Proponente e validadores devem continuar elegíveis até à publicação.']);
                }
            }
            $this->reviews()->create(['tenant_id' => $user->tenant_id, 'purchase_control_policy_id' => $policy->id, 'reviewed_by' => $user->id, 'decision' => $decision, 'reason' => $reason, 'created_at' => now()]);
            if ($decision === 'rejected') {
                $policy->update(['status' => 'rejected', 'decided_at' => now()]);
            } elseif ($this->reviews()->where('purchase_control_policy_id', $policy->id)->where('decision', 'approved')->count() === 2) {
                $policy->update(['status' => 'approved', 'decided_at' => now()]);
            }
            app(RequisitionWorkflow::class)->audit($user, $this->auditPrefix().'.'.$decision, null, null, ['policy_id' => $policy->id, 'status' => $policy->status]);
        });
    }

    public function current(): ?PurchaseControlPolicy
    {
        return $this->policies()->where('status', 'approved')->where('valid_from', '<=', today()->format('Y-m-d'))->latest('revision')->first();
    }

    public function requireCurrent(): PurchaseControlPolicy
    {
        $policy = $this->current();
        if (! $policy || $policy->valid_until < today()->format('Y-m-d') || $policy->mode !== $this->mode() || ! $policy->enabled) {
            throw ValidationException::withMessages(['cancellation' => 'A empresa deve activar o cancelamento de adjudicações sem ordem emitida numa política vigente, com duas aprovações administrativas independentes.']);
        }

        return $policy;
    }
}