<?php

namespace App\Services;

use App\Models\Tenants\Department;
use App\Models\Tenants\TenantUserProfile;
use Illuminate\Support\Facades\DB;

class OrgChartService extends Service
{
    /**
     * 조직도 전체 조회 (부서 트리 + 직원 + 통계)
     */
    public function getOrgChart(array $params): array
    {
        $tenantId = $this->tenantId();

        $includeHidden = filter_var($params['include_hidden'] ?? true, FILTER_VALIDATE_BOOLEAN);

        // 부서 전체 조회 (트리 구성을 위해 flat으로 가져옴)
        $deptQuery = Department::where('tenant_id', $tenantId)
            ->where('is_active', true);

        if (! $includeHidden) {
            $deptQuery->where(function ($q) {
                $q->whereNull('options->orgchart_hidden')
                    ->orWhere('options->orgchart_hidden', false);
            });
        }

        $departments = $deptQuery
            ->orderBy('sort_order')
            ->orderBy('name')
            ->get();

        // 전체 활성 직원
        $employees = TenantUserProfile::where('tenant_id', $tenantId)
            ->active()
            ->with(['user:id,name,email'])
            ->orderBy('display_name')
            ->get()
            ->map(fn ($e) => [
                'id' => $e->id,
                'user_id' => $e->user_id,
                'department_id' => $e->department_id,
                'display_name' => $e->display_name ?? $e->user?->name ?? '(이름없음)',
                'position_label' => $e->position_label,
            ])
            ->values();

        // 회사 정보
        $tenant = \App\Models\Tenants\Tenant::find($tenantId);

        // 통계
        $total = $employees->count();
        $assigned = $employees->whereNotNull('department_id')->count();

        // 부서 트리 구성
        $deptTree = $this->buildTree($departments, $employees);

        // 숨겨진 부서 목록 (include_hidden=true일 때만 의미)
        $hiddenDepts = $departments->filter(fn ($d) => ($d->options['orgchart_hidden'] ?? false) === true)
            ->map(fn ($d) => ['id' => $d->id, 'name' => $d->name, 'code' => $d->code])
            ->values();

        return [
            'company' => [
                'name' => $tenant->company_name ?? 'SAM',
                'ceo_name' => $tenant->ceo_name ?? '',
            ],
            'departments' => $deptTree,
            'hidden_departments' => $hiddenDepts,
            'unassigned' => $employees->whereNull('department_id')->values(),
            'stats' => [
                'total' => $total,
                'assigned' => $assigned,
                'unassigned' => $total - $assigned,
            ],
        ];
    }

    /**
     * 조직도 통계
     */
    public function getStats(): array
    {
        $tenantId = $this->tenantId();

        $total = TenantUserProfile::where('tenant_id', $tenantId)->active()->count();
        $assigned = TenantUserProfile::where('tenant_id', $tenantId)->active()->whereNotNull('department_id')->count();

        return [
            'total' => $total,
            'assigned' => $assigned,
            'unassigned' => $total - $assigned,
        ];
    }

    /**
     * 미배치 직원 목록
     */
    public function getUnassigned(array $params): array
    {
        $tenantId = $this->tenantId();

        $query = TenantUserProfile::where('tenant_id', $tenantId)
            ->active()
            ->whereNull('department_id')
            ->with(['user:id,name,email'])
            ->orderBy('display_name');

        if (! empty($params['q'])) {
            $q = $params['q'];
            $query->where(function ($w) use ($q) {
                $w->where('display_name', 'like', "%{$q}%")
                    ->orWhereHas('user', function ($u) use ($q) {
                        $u->where('name', 'like', "%{$q}%");
                    });
            });
        }

        return $query->get()
            ->map(fn ($e) => [
                'id' => $e->id,
                'user_id' => $e->user_id,
                'display_name' => $e->display_name ?? $e->user?->name ?? '(이름없음)',
                'position_label' => $e->position_label,
            ])
            ->values()
            ->toArray();
    }

    /**
     * 직원 부서 배치
     */
    public function assign(array $params): array
    {
        $tenantId = $this->tenantId();

        $employee = TenantUserProfile::where('tenant_id', $tenantId)
            ->where('id', $params['employee_id'])
            ->first();

        if (! $employee) {
            return ['error' => __('error.not_found'), 'code' => 404];
        }

        $dept = Department::where('tenant_id', $tenantId)
            ->where('id', $params['department_id'])
            ->first();

        if (! $dept) {
            return ['error' => __('error.not_found'), 'code' => 404];
        }

        $employee->department_id = $params['department_id'];
        $employee->save();

        return [
            'employee_id' => $employee->id,
            'department_id' => $params['department_id'],
        ];
    }

    /**
     * 직원 미배치 처리
     */
    public function unassign(array $params): array
    {
        $tenantId = $this->tenantId();

        $employee = TenantUserProfile::where('tenant_id', $tenantId)
            ->where('id', $params['employee_id'])
            ->first();

        if (! $employee) {
            return ['error' => __('error.not_found'), 'code' => 404];
        }

        $employee->department_id = null;
        $employee->save();

        return ['employee_id' => $employee->id, 'department_id' => null];
    }

    /**
     * 직원 일괄 배치/이동
     */
    public function reorderEmployees(array $params): array
    {
        $tenantId = $this->tenantId();

        DB::transaction(function () use ($params, $tenantId) {
            foreach ($params['moves'] as $move) {
                TenantUserProfile::where('tenant_id', $tenantId)
                    ->where('id', $move['employee_id'])
                    ->update(['department_id' => $move['department_id']]);
            }
        });

        return ['processed' => count($params['moves'])];
    }

    /**
     * 부서 순서/계층 일괄 변경
     */
    public function reorderDepartments(array $params): array
    {
        $tenantId = $this->tenantId();

        // 순환 참조 검증
        $orders = collect($params['orders']);
        foreach ($orders as $order) {
            if ($order['parent_id'] !== null && $order['parent_id'] === $order['id']) {
                return ['error' => '자기 자신을 상위 부서로 설정할 수 없습니다.', 'code' => 422];
            }
        }

        // 순환 참조 심층 검증 (A→B→C→A 같은 케이스)
        $parentMap = $orders->pluck('parent_id', 'id')->toArray();
        foreach ($parentMap as $id => $parentId) {
            if ($parentId === null) {
                continue;
            }
            $visited = [$id];
            $current = $parentId;
            while ($current !== null && isset($parentMap[$current])) {
                if (in_array($current, $visited)) {
                    return ['error' => '순환 참조가 감지되었습니다.', 'code' => 422];
                }
                $visited[] = $current;
                $current = $parentMap[$current];
            }
        }

        DB::transaction(function () use ($params, $tenantId) {
            foreach ($params['orders'] as $order) {
                Department::where('tenant_id', $tenantId)
                    ->where('id', $order['id'])
                    ->update([
                        'parent_id' => $order['parent_id'],
                        'sort_order' => $order['sort_order'],
                    ]);
            }
        });

        return ['processed' => count($params['orders'])];
    }

    /**
     * 부서 숨기기/표시 토글
     */
    public function toggleHide(int $departmentId, array $params): array
    {
        $tenantId = $this->tenantId();

        $dept = Department::where('tenant_id', $tenantId)
            ->where('id', $departmentId)
            ->first();

        if (! $dept) {
            return ['error' => __('error.not_found'), 'code' => 404];
        }

        $options = $dept->options ?? [];
        $options['orgchart_hidden'] = $params['hidden'];
        $dept->options = $options;
        $dept->save();

        return [
            'id' => $dept->id,
            'orgchart_hidden' => $params['hidden'],
        ];
    }

    /**
     * flat 부서 목록 → 트리 구조 변환
     */
    private function buildTree($departments, $employees): array
    {
        $deptMap = [];
        foreach ($departments as $dept) {
            $deptMap[$dept->id] = [
                'id' => $dept->id,
                'name' => $dept->name,
                'code' => $dept->code,
                'parent_id' => $dept->parent_id,
                'sort_order' => $dept->sort_order,
                'is_active' => $dept->is_active,
                'orgchart_hidden' => $dept->options['orgchart_hidden'] ?? false,
                'children' => [],
                'employees' => $employees->where('department_id', $dept->id)->values()->toArray(),
            ];
        }

        $tree = [];
        foreach ($deptMap as $id => &$node) {
            if ($node['parent_id'] === null || ! isset($deptMap[$node['parent_id']])) {
                $tree[] = &$node;
            } else {
                $deptMap[$node['parent_id']]['children'][] = &$node;
            }
        }
        unset($node);

        return $tree;
    }
}