<?php

namespace App\Services\Holding;

use App\Category;
use App\EmploymentAssignment;
use App\HoldingEntity;
use App\OrgUnit;
use App\User;
use Illuminate\Support\Facades\DB;

class HoldingHrmSyncService
{
    public function __construct(protected HoldingEntityLocationSyncService $entityLocationSyncService)
    {
    }

    public function syncForBusiness(int $businessId): array
    {
        $stats = ['departments' => 0, 'assignments' => 0, 'designations' => 0];

        DB::transaction(function () use ($businessId, &$stats) {
            $entity = $this->resolveDefaultEntity($businessId);
            $departments = Category::where('business_id', $businessId)
                ->where('category_type', 'hrm_department')
                ->get();

            foreach ($departments as $department) {
                $orgUnit = $this->syncDepartmentCategory($department, $entity);
                if ($orgUnit && $orgUnit->wasRecentlyCreated) {
                    $stats['departments']++;
                }
            }

            $users = User::where('business_id', $businessId)
                ->user()
                ->where(function ($query) {
                    $query->whereNotNull('essentials_department_id')
                        ->orWhereNotNull('essentials_designation_id');
                })
                ->get();

            foreach ($users as $user) {
                $result = $this->syncUserAssignment($user);
                if ($result === 'created') {
                    $stats['assignments']++;
                } elseif ($result === 'updated') {
                    $stats['designations']++;
                }
            }
        });

        return $stats;
    }

    /**
     * @return 'created'|'updated'|null
     */
    public function syncUserAssignment(User $user): ?string
    {
        if (! config('constants.enable_holding_context_rbac') || $user->user_type !== 'user') {
            return null;
        }

        $businessId = (int) $user->business_id;
        $departmentId = $user->essentials_department_id;
        $designationId = $user->essentials_designation_id;

        if (empty($departmentId) && empty($designationId)) {
            return null;
        }

        return DB::transaction(function () use ($user, $businessId, $departmentId, $designationId) {
            $entity = $this->resolveDefaultEntity($businessId);

            if (! empty($departmentId)) {
                $department = Category::where('business_id', $businessId)
                    ->where('category_type', 'hrm_department')
                    ->find($departmentId);
                if ($department) {
                    $this->syncDepartmentCategory($department, $entity);
                }
            }

            $orgUnitId = $this->resolveOrgUnitId($businessId, $entity->id, $departmentId);
            $designation = $this->resolveDesignation($designationId);
            $meta = [
                'hrm_department_id' => $departmentId,
                'hrm_designation_id' => $designationId,
            ];
            $roleId = $user->roles->first()?->id;

            $assignment = EmploymentAssignment::where('business_id', $businessId)
                ->where('user_id', $user->id)
                ->where('entity_id', $entity->id)
                ->where('is_primary', true)
                ->first();

            $payload = [
                'org_unit_id' => $orgUnitId,
                'title' => $designation?->name,
                'role_id' => $roleId,
                'employment_type' => 'employee',
                'is_primary' => true,
                'is_active' => true,
                'meta' => $meta,
            ];

            if ($assignment) {
                $payload['meta'] = array_merge($assignment->meta ?? [], $meta);
                if ($assignment->fill($payload)->isDirty()) {
                    $assignment->save();

                    return 'updated';
                }

                return null;
            }

            EmploymentAssignment::create(array_merge([
                'business_id' => $businessId,
                'user_id' => $user->id,
                'entity_id' => $entity->id,
            ], $payload));

            return 'created';
        });
    }

    public function syncDepartmentCategory(Category $department, ?HoldingEntity $entity = null): ?OrgUnit
    {
        if ($department->category_type !== 'hrm_department') {
            return null;
        }

        $entity = $entity ?: $this->resolveDefaultEntity((int) $department->business_id);

        $orgUnit = OrgUnit::firstOrCreate(
            [
                'business_id' => $department->business_id,
                'entity_id' => $entity->id,
                'name' => $department->name,
            ],
            [
                'code' => $department->short_code,
                'depth' => 0,
                'path' => $department->name,
                'is_active' => true,
                'meta' => ['hrm_department_id' => $department->id],
            ]
        );

        if (! $orgUnit->wasRecentlyCreated && empty($orgUnit->meta['hrm_department_id'])) {
            $orgUnit->update([
                'meta' => array_merge($orgUnit->meta ?? [], ['hrm_department_id' => $department->id]),
                'code' => $orgUnit->code ?: $department->short_code,
            ]);
        } elseif (! $orgUnit->wasRecentlyCreated) {
            $updates = [];
            if ($orgUnit->name !== $department->name) {
                $updates['name'] = $department->name;
                $updates['path'] = $department->name;
            }
            if ($department->short_code && $orgUnit->code !== $department->short_code) {
                $updates['code'] = $department->short_code;
            }
            if (! empty($updates)) {
                $orgUnit->update($updates);
            }
        }

        return $orgUnit;
    }

    public function syncUserHrmFromAssignment(EmploymentAssignment $assignment): void
    {
        if (! config('constants.enable_holding_context_rbac')) {
            return;
        }

        $user = $assignment->user;
        if (empty($user) || $user->user_type !== 'user') {
            return;
        }

        $updates = [];

        if (! empty($assignment->org_unit_id)) {
            $orgUnit = OrgUnit::find($assignment->org_unit_id);
            if (! empty($orgUnit->meta['hrm_department_id'])) {
                $updates['essentials_department_id'] = $orgUnit->meta['hrm_department_id'];
            }
        }

        if (! empty($assignment->meta['hrm_designation_id'])) {
            $updates['essentials_designation_id'] = $assignment->meta['hrm_designation_id'];
        }

        if (! empty($updates)) {
            $user->update($updates);
        }
    }

    public function resolveOrgUnitMeta(?int $orgUnitId): array
    {
        if (empty($orgUnitId)) {
            return [];
        }

        $orgUnit = OrgUnit::find($orgUnitId);
        if (empty($orgUnit) || empty($orgUnit->meta['hrm_department_id'])) {
            return [];
        }

        return ['hrm_department_id' => (int) $orgUnit->meta['hrm_department_id']];
    }

    public function getUserFormContext(int $businessId, ?User $user = null): array
    {
        $departmentToOrgUnit = OrgUnit::where('business_id', $businessId)
            ->get(['id', 'name', 'meta'])
            ->filter(fn ($unit) => ! empty($unit->meta['hrm_department_id']))
            ->mapWithKeys(fn ($unit) => [
                (int) $unit->meta['hrm_department_id'] => [
                    'id' => $unit->id,
                    'name' => $unit->name,
                ],
            ]);

        $primaryAssignment = null;
        if ($user) {
            $primaryAssignment = EmploymentAssignment::where('business_id', $businessId)
                ->where('user_id', $user->id)
                ->where('is_primary', true)
                ->with(['entity', 'orgUnit'])
                ->first();
        }

        return [
            'departmentToOrgUnit' => $departmentToOrgUnit,
            'primaryAssignment' => $primaryAssignment,
            'holdingUrl' => route('holding.index'),
        ];
    }

    public function resolveOrgUnitId(int $businessId, int $entityId, ?int $departmentId): ?int
    {
        if (empty($departmentId)) {
            return null;
        }

        $orgUnitId = OrgUnit::where('business_id', $businessId)
            ->where('entity_id', $entityId)
            ->where('meta->hrm_department_id', $departmentId)
            ->value('id');

        if (! empty($orgUnitId)) {
            return (int) $orgUnitId;
        }

        $category = Category::find($departmentId);
        if (empty($category)) {
            return null;
        }

        return OrgUnit::where('business_id', $businessId)
            ->where('entity_id', $entityId)
            ->where('name', $category->name)
            ->value('id');
    }

    public function resolveDesignation(?int $designationId): ?Category
    {
        if (empty($designationId)) {
            return null;
        }

        return Category::where('id', $designationId)
            ->where('category_type', 'hrm_designation')
            ->first();
    }

    public function resolveTitleFromDesignation(?int $designationId, ?string $fallback = null): ?string
    {
        $designation = $this->resolveDesignation($designationId);

        return $designation?->name ?: $fallback;
    }

    public function resolveDefaultEntity(int $businessId): HoldingEntity
    {
        $entity = HoldingEntity::where('business_id', $businessId)
            ->where('entity_type', 'company')
            ->where('is_internal', true)
            ->first();

        if ($entity) {
            return $entity;
        }

        return $this->entityLocationSyncService->createEntityWithLocation($businessId, [
            'business_id' => $businessId,
            'name' => __('lang_v1.holding_default_entity_name', ['id' => $businessId]),
            'entity_type' => 'company',
            'is_internal' => true,
            'is_active' => true,
        ]);
    }
}