<?php

namespace App\Services;

use App\Models\Process;
use App\Models\ProcessStep;
use Illuminate\Support\Facades\DB;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

class ProcessStepService extends Service
{
    /**
     * 공정 단계 목록 조회
     */
    public function index(int $processId)
    {
        $process = $this->findProcess($processId);

        return $process->steps()
            ->with('documentTemplate:id,name,category')
            ->orderBy('sort_order')
            ->get();
    }

    /**
     * 공정 단계 상세 조회
     */
    public function show(int $processId, int $stepId)
    {
        $this->findProcess($processId);

        $step = ProcessStep::where('process_id', $processId)
            ->with('documentTemplate:id,name,category')
            ->find($stepId);
        if (! $step) {
            throw new NotFoundHttpException(__('error.not_found'));
        }

        return $step;
    }

    /**
     * 공정 단계 생성
     */
    public function store(int $processId, array $data)
    {
        $process = $this->findProcess($processId);

        $data['process_id'] = $process->id;
        $data['step_code'] = $this->generateStepCode($process->id);
        $data['sort_order'] = ($process->steps()->max('sort_order') ?? 0) + 1;
        $data['is_active'] = $data['is_active'] ?? true;

        return ProcessStep::create($data);
    }

    /**
     * 공정 단계 수정
     */
    public function update(int $processId, int $stepId, array $data)
    {
        $this->findProcess($processId);

        $step = ProcessStep::where('process_id', $processId)->find($stepId);
        if (! $step) {
            throw new NotFoundHttpException(__('error.not_found'));
        }

        $step->update($data);

        return $step->fresh();
    }

    /**
     * 공정 단계 삭제
     */
    public function destroy(int $processId, int $stepId)
    {
        $this->findProcess($processId);

        $step = ProcessStep::where('process_id', $processId)->find($stepId);
        if (! $step) {
            throw new NotFoundHttpException(__('error.not_found'));
        }

        $step->delete();

        return true;
    }

    /**
     * 공정 단계 순서 변경
     */
    public function reorder(int $processId, array $items)
    {
        $this->findProcess($processId);

        return DB::transaction(function () use ($processId, $items) {
            foreach ($items as $item) {
                ProcessStep::where('process_id', $processId)
                    ->where('id', $item['id'])
                    ->update(['sort_order' => $item['sort_order']]);
            }

            return ProcessStep::where('process_id', $processId)
                ->orderBy('sort_order')
                ->get();
        });
    }

    /**
     * 부모 공정 조회 (tenant scope)
     */
    private function findProcess(int $processId): Process
    {
        $tenantId = $this->tenantId();

        $process = Process::where('tenant_id', $tenantId)->find($processId);
        if (! $process) {
            throw new NotFoundHttpException(__('error.not_found'));
        }

        return $process;
    }

    /**
     * 단계코드 자동 생성 (STP-001, STP-002, ...)
     */
    private function generateStepCode(int $processId): string
    {
        $lastStep = ProcessStep::where('process_id', $processId)
            ->orderByRaw('CAST(SUBSTRING(step_code, 5) AS UNSIGNED) DESC')
            ->first();

        if ($lastStep && preg_match('/^STP-(\d+)$/', $lastStep->step_code, $matches)) {
            $nextNum = (int) $matches[1] + 1;
        } else {
            $nextNum = 1;
        }

        return sprintf('STP-%03d', $nextNum);
    }
}