<?php

namespace App\Services\Care\Workflow;

use App\Models\FinancialObligation;
use App\Models\Visit;
use App\Models\WorkflowStage;

/**
 * Owns FinancialObligation lifecycle and answers whether a stage's financial
 * gate is satisfied for a given visit.
 *
 * A "before" gate blocks entry to the stage's service queue until the stage's
 * obligation is cleared (paid / authorized / waived / deferred). An "after"
 * gate never blocks entry but is created so the balance is collected at exit.
 */
class FinancialGateService
{
    /**
     * Create (or return existing) obligation for a visit + stage. Only stages
     * that require payment produce an obligation.
     *
     * @param  array<string, mixed>  $overrides
     */
    public function obligationFor(Visit $visit, WorkflowStage $stage, array $overrides = []): ?FinancialObligation
    {
        if (! $stage->requires_payment) {
            return null;
        }

        $existing = FinancialObligation::query()
            ->where('visit_id', $visit->id)
            ->where('workflow_stage_id', $stage->id)
            ->whereNull('deleted_at')
            ->first();

        if ($existing !== null) {
            return $existing;
        }

        return FinancialObligation::create(array_merge([
            'owner_ref' => $visit->owner_ref,
            'organization_id' => $visit->organization_id,
            'branch_id' => $visit->branch_id,
            'visit_id' => $visit->id,
            'patient_id' => $visit->patient_id,
            'workflow_stage_id' => $stage->id,
            'stage_code' => $stage->code,
            'charge_code' => $stage->charge_code,
            'label' => $stage->charge_label ?? $stage->name,
            'amount_minor' => $stage->default_amount_minor ?? $this->defaultAmountFor($stage),
            'status' => FinancialObligation::STATUS_PENDING,
        ], $overrides));
    }

    /**
     * Whether the visit may enter the stage. Stages with a "before" payment
     * gate require a cleared obligation; everything else is allowed.
     */
    public function isSatisfied(Visit $visit, WorkflowStage $stage): bool
    {
        if (! $stage->gatesBeforeService()) {
            return true;
        }

        $obligation = FinancialObligation::query()
            ->where('visit_id', $visit->id)
            ->where('workflow_stage_id', $stage->id)
            ->whereNull('deleted_at')
            ->first();

        return $obligation !== null && $obligation->isCleared();
    }

    public function blockedReason(Visit $visit, WorkflowStage $stage): ?string
    {
        if ($this->isSatisfied($visit, $stage)) {
            return null;
        }

        return 'awaiting_payment';
    }

    /**
     * Clear an obligation (paid / insurance authorized / waived / credit).
     */
    public function clear(
        FinancialObligation $obligation,
        string $method,
        ?string $actorRef = null,
        ?string $paymentMode = null,
        ?string $externalReference = null,
    ): FinancialObligation {
        $status = match ($method) {
            'insurance' => FinancialObligation::STATUS_AUTHORIZED,
            'waiver' => FinancialObligation::STATUS_WAIVED,
            'credit' => FinancialObligation::STATUS_DEFERRED,
            default => FinancialObligation::STATUS_PAID,
        };

        $obligation->forceFill([
            'status' => $status,
            'clearance_method' => $method,
            'payment_mode' => $paymentMode,
            'external_reference' => $externalReference,
            'cleared_by' => $actorRef,
            'cleared_at' => now(),
        ])->save();

        return $obligation;
    }

    public function void(FinancialObligation $obligation): FinancialObligation
    {
        $obligation->forceFill(['status' => FinancialObligation::STATUS_VOID])->save();

        return $obligation;
    }

    protected function defaultAmountFor(WorkflowStage $stage): int
    {
        if ($stage->charge_code === 'consultation') {
            return (int) config('care.billing.consultation_fee_minor', 0);
        }

        return 0;
    }
}