<?php

namespace App\Services;

use App\Enums\PurchasingRole;
use App\Models\AdmissionAdoption;
use App\Models\AdmissionDecision;
use App\Models\AdmissionPolicy;
use App\Models\AdmissionReview;
use App\Models\PurchaseAward;
use App\Models\PurchaseOrder;
use App\Models\QualificationAssessment;
use App\Models\QualificationSet;
use App\Models\Quotation;
use App\Models\QuotationItem;
use App\Models\Requisition;
use App\Models\Supplier;
use App\Models\User;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class FormalAdmission
{
    private function invalid(string $message): never
    {
        throw ValidationException::withMessages(['admission' => $message]);
    }

    public function adoption(Requisition $request): ?AdmissionAdoption
    {
        return AdmissionAdoption::query()->where('requisition_id', $request->id)->latest('revision')->first();
    }

    private function process(User $actor, int $id): Requisition
    {
        $request = Requisition::query()->visibleTo($actor)->lockForUpdate()->findOrFail($id);
        if ($request->status !== 'approved' || PurchaseAward::query()->where('requisition_id', $id)->exists() || PurchaseOrder::query()->where('requisition_id', $id)->exists()) {
            $this->invalid('O regime e as decisões só podem ser registados num pedido aprovado, antes da adjudicação.');
        }
        app(ConflictGuard::class)->assertParticipation($actor, $request);
        $quotes = Quotation::query()->where('requisition_id', $id)->orderBy('id')->lockForUpdate()->get(['id', 'supplier_id']);
        Supplier::query()->whereIn('id', $quotes->pluck('supplier_id'))->orderBy('id')->lockForUpdate()->get();
        QuotationItem::query()->whereIn('quotation_id', $quotes->pluck('id'))->orderBy('id')->lockForUpdate()->get();

        return $request;
    }

    /** @param array<string,mixed> $data */
    public function policy(User $actor, array $data): AdmissionPolicy
    {
        if (! is_bool($data['enabled']) || ! is_array($data['roles']) || $data['roles'] === [] || count(array_unique($data['roles'])) !== count($data['roles']) || array_diff($data['roles'], ['finance', 'department_head']) !== [] || filter_var($data['required_count'], FILTER_VALIDATE_INT) === false || $data['required_count'] < 1 || $data['required_count'] > 50 || mb_strlen(trim($data['reason'])) < 10) {
            $this->invalid('Defina expressamente perfis, quantidade de conferentes e fundamento da política.');
        }

        return DB::transaction(function () use ($actor, $data) {
            app(ConflictGuard::class)->lockCompany($actor);
            $actor = app(CurrentActor::class)->lock($actor, [PurchasingRole::Admin]);
            $latest = AdmissionPolicy::query()->latest('revision')->first();
            if ((int) $data['previous_id'] !== ($latest->id ?? 0)) {
                $this->invalid('A política mudou. Actualize antes de criar outra versão.');
            }
            $policy = AdmissionPolicy::query()->create(['tenant_id' => $actor->tenant_id, 'created_by' => $actor->id, 'revision' => ($latest->revision ?? 0) + 1, 'enabled' => $data['enabled'], 'roles' => array_values($data['roles']), 'required_count' => $data['required_count'], 'reason' => $data['reason'], 'created_at' => now()]);
            app(RequisitionWorkflow::class)->audit($actor, 'admission.policy', null, null, $policy->toArray());

            return $policy;
        });
    }

    public function adopt(User $actor, Requisition $request, int $policyId, int $previousId, string $reason): AdmissionAdoption
    {
        return DB::transaction(function () use ($actor, $request, $policyId, $previousId, $reason) {
            app(ConflictGuard::class)->lockCompany($actor);
            $actor = app(CurrentActor::class)->lock($actor, [PurchasingRole::Procurement]);
            $request = $this->process($actor, $request->id);
            $previous = $this->adoption($request);
            $policy = AdmissionPolicy::query()->latest('revision')->first();
            if (! $policy || ! $policy->enabled || $policy->id !== $policyId || ($previous->id ?? 0) !== $previousId) {
                $this->invalid('Seleccione a política activa e a adopção actual. Não se altera um regime implicitamente.');
            }
            if ($previous?->admission_policy_id === $policy->id || mb_strlen(trim($reason)) < 10) {
                $this->invalid('A adopção exige outra versão de política e fundamento próprio.');
            }
            $adoption = AdmissionAdoption::query()->create(['tenant_id' => $actor->tenant_id, 'requisition_id' => $request->id, 'admission_policy_id' => $policy->id, 'created_by' => $actor->id, 'revision' => ($previous->revision ?? 0) + 1, 'snapshot' => ['roles' => $policy->roles, 'required_count' => $policy->required_count, 'policy_revision' => $policy->revision], 'reason' => $reason, 'created_at' => now()]);
            app(RequisitionWorkflow::class)->audit($actor, 'admission.adopted', $request, null, ['adoption' => $adoption->toArray(), 'previous_id' => $previous?->id]);

            return $adoption;
        });
    }

    /** @return array{set_id:int,payload:array<string,mixed>,hash:string,clear:bool}|null */
    public function basis(Requisition $request, int $quoteId): ?array
    {
        $set = QualificationSet::query()->where('requisition_id', $request->id)->latest('revision')->first();
        if (! $set) {
            return null;
        }
        $opening = app(ProposalOpeningWorkflow::class);
        $quotes = $opening->proposals($request);
        if ($set->basis_hash !== $opening->basis($quotes)) {
            return null;
        }
        $quote = collect($quotes)->firstWhere('id', $quoteId);
        if (! $quote) {
            return null;
        }
        $ids = QualificationAssessment::query()->where('qualification_set_id', $set->id)->where('quotation_id', $quoteId)->selectRaw('MAX(id)')->groupBy('analyst_id');
        $records = QualificationAssessment::query()->whereIn('id', $ids)->orderBy('analyst_id')->get();
        $clear = $records->isNotEmpty();
        foreach ($set->criteria as $criterion) {
            $results = [];
            foreach ($records as $record) {
                $answer = collect($record->answers)->firstWhere('criterion_id', $criterion['id']);
                if (! $answer || ! in_array($answer['result'], ['met', 'not_met', 'not_applicable'], true) || ($criterion['required'] && $answer['result'] !== 'met')) {
                    $clear = false;
                }
                if ($answer) {
                    $results[] = $answer['result'];
                }
            }
            if (count(array_unique($results)) !== 1) {
                $clear = false;
            }
        }
        $payload = ['set_id' => $set->id, 'criteria' => $set->criteria, 'quotes_hash' => $set->basis_hash, 'quote' => $quote, 'analyses' => $records->map(fn ($record) => $record->only(['id', 'analyst_id', 'revision', 'answers', 'snapshot']))->all()];

        return ['set_id' => $set->id, 'payload' => $payload, 'hash' => hash('sha256', json_encode($payload, JSON_THROW_ON_ERROR)), 'clear' => $clear];
    }

    public function status(AdmissionDecision $decision, AdmissionAdoption $adoption): string
    {
        $reviews = AdmissionReview::query()->where('admission_decision_id', $decision->id)->get();
        if ($reviews->contains('verdict', 'returned')) {
            return 'returned';
        }

        return $reviews->where('verdict', 'approved')->count() >= $adoption->snapshot['required_count'] ? 'confirmed' : 'pending';
    }

    /** @param array<string,mixed> $data */
    public function propose(User $actor, Requisition $request, array $data): AdmissionDecision
    {
        if (! in_array($data['outcome'], ['admit', 'exclude', 'clarify'], true) || mb_strlen(trim($data['reason'])) < 10) {
            $this->invalid('Seleccione uma decisão e fundamente a tentativa.');
        }

        return DB::transaction(function () use ($actor, $request, $data) {
            app(ConflictGuard::class)->lockCompany($actor);
            $actor = app(CurrentActor::class)->lock($actor, [PurchasingRole::Procurement]);
            $request = $this->process($actor, $request->id);
            abort_if($actor->id === $request->requester_id, 403);
            $adoption = $this->adoption($request);
            if (! $adoption) {
                $this->invalid('O processo ainda não adoptou expressamente o regime.');
            }
            $quote = Quotation::query()->where('requisition_id', $request->id)->whereKey($data['quotation_id'])->firstOrFail();
            app(ConflictGuard::class)->assertProcess($request, $quote->supplier_id, $actor);
            $basis = $this->basis($request, $quote->id);
            if (! $basis || $basis['hash'] !== $data['basis_hash']) {
                $this->invalid('Confira requisitos e análises actuais antes de propor uma decisão.');
            }
            if ($data['outcome'] === 'admit' && ! $basis['clear']) {
                $this->invalid('A admissão exige análise sem pendências, divergências ou requisitos obrigatórios não resolvidos.');
            }
            $previous = AdmissionDecision::query()->where('admission_adoption_id', $adoption->id)->where('quotation_id', $quote->id)->latest('revision')->first();
            if ((int) $data['previous_id'] !== ($previous->id ?? 0)) {
                $this->invalid('A tentativa mudou. Actualize a página para preservar o antecedente correcto.');
            }
            $decision = AdmissionDecision::query()->create(['tenant_id' => $actor->tenant_id, 'admission_adoption_id' => $adoption->id, 'qualification_set_id' => $basis['set_id'], 'quotation_id' => $quote->id, 'created_by' => $actor->id, 'revision' => ($previous->revision ?? 0) + 1, 'outcome' => $data['outcome'], 'basis_hash' => $basis['hash'], 'snapshot' => ['basis' => $basis['payload'], 'proponent' => $actor->only(['id', 'name'])], 'reason' => $data['reason'], 'created_at' => now()]);
            app(RequisitionWorkflow::class)->audit($actor, 'admission.proposed', $request, null, ['decision' => $decision->toArray(), 'previous_id' => $previous?->id]);

            return $decision;
        });
    }

    public function eligible(User $actor, Requisition $request, AdmissionAdoption $adoption, AdmissionDecision $decision): bool
    {
        return $actor->tenant_id === $request->tenant_id && in_array($actor->purchasing_role->value, $adoption->snapshot['roles'], true) && ! in_array($actor->id, [$request->requester_id, $decision->created_by], true) && ($actor->purchasing_role !== PurchasingRole::DepartmentHead || $actor->department_id === $request->department_id);
    }

    public function review(User $actor, AdmissionDecision $decision, string $verdict, string $reason): void
    {
        if (! in_array($verdict, ['approved', 'returned'], true) || mb_strlen(trim($reason)) < 10) {
            $this->invalid('Seleccione uma conferência válida e fundamente-a.');
        }
        DB::transaction(function () use ($actor, $decision, $verdict, $reason) {
            app(ConflictGuard::class)->lockCompany($actor);
            $actor = app(CurrentActor::class)->lock($actor, [PurchasingRole::Finance, PurchasingRole::DepartmentHead]);
            $original = AdmissionAdoption::query()->findOrFail($decision->admission_adoption_id);
            $request = $this->process($actor, $original->requisition_id);
            $adoption = $this->adoption($request);
            abort_unless($adoption && $this->eligible($actor, $request, $adoption, $decision), 403);
            $latest = AdmissionDecision::query()->where('admission_adoption_id', $adoption->id)->where('quotation_id', $decision->quotation_id)->latest('revision')->first();
            $basis = $this->basis($request, $decision->quotation_id);
            if ($decision->admission_adoption_id !== $adoption->id || $latest?->id !== $decision->id || ! $basis || $basis['hash'] !== $decision->basis_hash) {
                $this->invalid('A política do processo, tentativa ou base mudou. Registe outra tentativa e novas conferências.');
            }
            $existing = AdmissionReview::query()->where('admission_decision_id', $decision->id)->where('reviewed_by', $actor->id)->first();
            if ($existing) {
                if ($existing->verdict !== $verdict || $existing->reason !== $reason) {
                    $this->invalid('A conferência anterior é imutável.');
                }

                return;
            }
            if ($this->status($decision, $adoption) !== 'pending') {
                $this->invalid('Esta tentativa já foi concluída ou devolvida.');
            }
            if ($verdict === 'approved') {
                foreach (AdmissionReview::query()->where('admission_decision_id', $decision->id)->where('verdict', 'approved')->get() as $review) {
                    $reviewer = User::query()->where('tenant_id', $actor->tenant_id)->lockForUpdate()->find($review->reviewed_by);
                    if (! $reviewer || ! $this->eligible($reviewer, $request, $adoption, $decision)) {
                        $this->invalid('Um conferente anterior deixou de ser elegível antes da conclusão. Devolva e prepare outra tentativa.');
                    }
                }
            }
            $review = AdmissionReview::query()->create(['tenant_id' => $actor->tenant_id, 'admission_decision_id' => $decision->id, 'reviewed_by' => $actor->id, 'verdict' => $verdict, 'reason' => $reason, 'snapshot' => $actor->only(['id', 'name', 'purchasing_role', 'department_id']), 'created_at' => now()]);
            app(RequisitionWorkflow::class)->audit($actor, 'admission.reviewed', $request, null, $review->toArray());
        });
    }

    /** @return array<string,mixed>|null */
    public function selection(Requisition $request, int $quoteId): ?array
    {
        $adoption = $this->adoption($request);
        if (! $adoption) {
            return null;
        }
        $decision = AdmissionDecision::query()->where('admission_adoption_id', $adoption->id)->where('quotation_id', $quoteId)->latest('revision')->first();
        $basis = $this->basis($request, $quoteId);
        if (! $decision || $decision->outcome !== 'admit' || ! $basis || ! $basis['clear'] || $basis['hash'] !== $decision->basis_hash || $this->status($decision, $adoption) !== 'confirmed') {
            $this->invalid('A proposta exige admissão confirmada na base actual do regime adoptado.');
        }

        return ['adoption_id' => $adoption->id, 'policy_id' => $adoption->admission_policy_id, 'decision_id' => $decision->id, 'qualification_set_id' => $decision->qualification_set_id, 'basis_hash' => $decision->basis_hash, 'review_ids' => AdmissionReview::query()->where('admission_decision_id', $decision->id)->orderBy('id')->pluck('id')->all()];
    }

    public function admitted(Requisition $request, int $quoteId): bool
    {
        try {
            $this->selection($request, $quoteId);

            return true;
        } catch (ValidationException) {
            return false;
        }
    }
}