<?php

namespace App\Http\Controllers\Frontdesk;

use App\Http\Controllers\Controller;
use App\Http\Controllers\Frontdesk\Concerns\ScopesToAccount;
use App\Models\Branch;
use App\Models\Employee;
use App\Models\EmployeePresence;
use App\Models\EmployeePresenceEvent;
use App\Models\Host;
use App\Models\Member;
use App\Models\User;
use App\Services\Frontdesk\EmployeePresenceService;
use App\Services\Frontdesk\QrCodeService;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Carbon;
use Illuminate\Validation\Rule;
use Illuminate\View\View;
use Symfony\Component\HttpFoundation\StreamedResponse;

class EmployeeController extends Controller
{
    use ScopesToAccount;

    public function index(Request $request): View
    {
        $this->authorizeAbility($request, 'employees.view');
        $organization = $this->organization($request);

        $employees = Employee::owned($this->ownerRef($request))
            ->where('organization_id', $organization->id)
            ->with(['branch', 'presence'])
            ->orderBy('full_name');
        $this->scopeToBranch($request, $employees);
        $employees = $employees->paginate(25);

        $statsQuery = Employee::owned($this->ownerRef($request))
            ->where('organization_id', $organization->id);
        $this->scopeToBranch($request, $statsQuery);

        $heroStats = [
            'total' => (clone $statsQuery)->count(),
            'on_site' => (clone $statsQuery)->whereHas('presence', fn ($q) => $q->where('status', EmployeePresence::STATUS_ON_SITE))->count(),
            'active' => (clone $statsQuery)->where('active', true)->count(),
        ];

        return view('frontdesk.employees.index', compact('employees', 'organization', 'heroStats'));
    }

    public function create(Request $request): View
    {
        $this->authorizeAbility($request, 'employees.manage');
        $organization = $this->organization($request);

        return view('frontdesk.employees.create', [
            'organization' => $organization,
            'branches' => $this->branches($request, $organization->id),
            'hosts' => $this->hosts($request, $organization->id),
            'linkableUsers' => $this->linkableUsers($request, $organization->id),
        ]);
    }

    public function store(Request $request, EmployeePresenceService $presence): RedirectResponse
    {
        $this->authorizeAbility($request, 'employees.manage');
        $organization = $this->organization($request);

        $validated = $this->validatedEmployee($request, $organization->id);
        $pin = $validated['pin'];
        unset($validated['pin']);

        $employee = Employee::create([
            'owner_ref' => $this->ownerRef($request),
            'organization_id' => $organization->id,
            'pin_hash' => $presence->hashPin($pin),
            ...$this->employeePayload($validated),
        ]);

        $presence->presenceFor($employee);

        return redirect()->route('frontdesk.employees.index')->with('success', 'Employee added.');
    }

    public function edit(Request $request, Employee $employee): View
    {
        $this->authorizeAbility($request, 'employees.manage');
        $this->authorizeOwner($request, $employee);

        return view('frontdesk.employees.edit', [
            'employee' => $employee->load('presence'),
            'branches' => $this->branches($request, $employee->organization_id),
            'hosts' => $this->hosts($request, $employee->organization_id),
            'linkableUsers' => $this->linkableUsers($request, $employee->organization_id, $employee),
        ]);
    }

    public function update(Request $request, Employee $employee, EmployeePresenceService $presence): RedirectResponse
    {
        $this->authorizeAbility($request, 'employees.manage');
        $this->authorizeOwner($request, $employee);

        $validated = $this->validatedEmployee($request, $employee->organization_id, updating: true, employee: $employee);

        $payload = $this->employeePayload($validated);
        if (! empty($validated['pin'])) {
            $payload['pin_hash'] = $presence->hashPin($validated['pin']);
        }

        $employee->update([
            ...$payload,
            'active' => $request->boolean('active', true),
        ]);

        return redirect()->route('frontdesk.employees.index')->with('success', 'Employee updated.');
    }

    public function destroy(Request $request, Employee $employee): RedirectResponse
    {
        $this->authorizeAbility($request, 'employees.manage');
        $this->authorizeOwner($request, $employee);
        $employee->delete();

        return redirect()->route('frontdesk.employees.index')->with('success', 'Employee removed.');
    }

    public function importForm(Request $request): View
    {
        $this->authorizeAbility($request, 'employees.manage');
        $organization = $this->organization($request);

        return view('frontdesk.employees.import', compact('organization'));
    }

    public function import(Request $request, EmployeePresenceService $presence): RedirectResponse
    {
        $this->authorizeAbility($request, 'employees.manage');
        $organization = $this->organization($request);

        $request->validate([
            'csv' => ['required', 'file', 'mimes:csv,txt', 'max:2048'],
        ]);

        $handle = fopen($request->file('csv')->getRealPath(), 'r');
        if ($handle === false) {
            return back()->with('error', 'Could not read the CSV file.');
        }

        $header = fgetcsv($handle);
        if ($header === false) {
            fclose($handle);

            return back()->with('error', 'CSV file is empty.');
        }

        $header = array_map(fn ($col) => strtolower(trim((string) $col)), $header);
        $required = ['employee_code', 'full_name', 'pin'];
        foreach ($required as $column) {
            if (! in_array($column, $header, true)) {
                fclose($handle);

                return back()->with('error', "CSV must include columns: employee_code, full_name, pin.");
            }
        }

        $ownerRef = $this->ownerRef($request);
        $imported = 0;
        $rowNumber = 1;

        while (($row = fgetcsv($handle)) !== false) {
            $rowNumber++;
            if ($row === [null] || $row === []) {
                continue;
            }

            $data = array_combine($header, array_pad($row, count($header), null));
            if ($data === false) {
                continue;
            }

            $code = trim((string) ($data['employee_code'] ?? ''));
            $name = trim((string) ($data['full_name'] ?? ''));
            $pin = trim((string) ($data['pin'] ?? ''));

            if ($code === '' || $name === '' || $pin === '') {
                continue;
            }

            if (! preg_match('/^\d{4,6}$/', $pin)) {
                continue;
            }

            $branchId = null;
            if (! empty($data['branch'])) {
                $branchId = Branch::owned($ownerRef)
                    ->where('organization_id', $organization->id)
                    ->where('name', trim((string) $data['branch']))
                    ->value('id');
            }

            $employee = Employee::query()->updateOrCreate(
                [
                    'organization_id' => $organization->id,
                    'employee_code' => $code,
                ],
                [
                    'owner_ref' => $ownerRef,
                    'full_name' => $name,
                    'department' => trim((string) ($data['department'] ?? '')) ?: null,
                    'email' => trim((string) ($data['email'] ?? '')) ?: null,
                    'phone' => trim((string) ($data['phone'] ?? '')) ?: null,
                    'branch_id' => $branchId,
                    'pin_hash' => $presence->hashPin($pin),
                    'active' => true,
                ],
            );

            $presence->presenceFor($employee);
            $imported++;
        }

        fclose($handle);

        return redirect()->route('frontdesk.employees.index')->with('success', "{$imported} employee(s) imported.");
    }

    public function badge(Request $request, Employee $employee, QrCodeService $qr): View
    {
        $this->authorizeAbility($request, 'employees.view');
        $this->authorizeOwner($request, $employee);

        return view('frontdesk.employees.badge', [
            'employee' => $employee->load('organization'),
            'qrSvg' => $qr->employeeSvg($employee),
        ]);
    }

    public function exportAttendance(Request $request): StreamedResponse
    {
        $this->authorizeAbility($request, 'reports.export');
        $organization = $this->organization($request);
        $owner = $this->ownerRef($request);

        [$from, $to] = $this->dateRange($request);
        $branchId = app(\App\Services\Frontdesk\OrganizationResolver::class)->branchScope($this->member($request));

        $query = EmployeePresenceEvent::owned($owner)
            ->where('organization_id', $organization->id)
            ->whereBetween('created_at', [$from, $to])
            ->with(['employee'])
            ->orderBy('created_at');

        if ($branchId) {
            $query->where('branch_id', $branchId);
        }

        $events = $query->get();
        $filename = 'employee-attendance-'.$from->format('Y-m-d').'-'.$to->format('Y-m-d').'.csv';

        return response()->streamDownload(function () use ($events) {
            $handle = fopen('php://output', 'w');
            fputcsv($handle, ['Date', 'Time', 'Employee', 'Code', 'Department', 'Event', 'Destination', 'Notes']);

            foreach ($events as $event) {
                fputcsv($handle, [
                    $event->created_at->toDateString(),
                    $event->created_at->format('H:i'),
                    $event->employee->full_name,
                    $event->employee->employee_code,
                    $event->employee->department ?? '',
                    config('frontdesk.employee_presence_events.'.$event->event, $event->event),
                    $event->destination ?? '',
                    $event->notes ?? '',
                ]);
            }

            fclose($handle);
        }, $filename, ['Content-Type' => 'text/csv']);
    }

    /** @return array{0: Carbon, 1: Carbon} */
    protected function dateRange(Request $request): array
    {
        $from = $request->filled('from')
            ? Carbon::parse($request->string('from'))->startOfDay()
            : now()->subDays(30)->startOfDay();
        $to = $request->filled('to')
            ? Carbon::parse($request->string('to'))->endOfDay()
            : now()->endOfDay();

        return [$from, $to];
    }

    /** @return array<string, mixed> */
    protected function validatedEmployee(Request $request, int $organizationId, bool $updating = false, ?Employee $employee = null): array
    {
        $pinRules = $updating
            ? ['nullable', 'string', 'regex:/^\d{4,6}$/']
            : ['required', 'string', 'regex:/^\d{4,6}$/'];

        $linkableRefs = collect($this->linkableUsers($request, $organizationId, $employee))
            ->reject(fn (array $user) => $user['taken'])
            ->pluck('user_ref')
            ->all();

        return $request->validate([
            'employee_code' => ['required', 'string', 'max:32'],
            'full_name' => ['required', 'string', 'max:255'],
            'department' => ['nullable', 'string', 'max:255'],
            'email' => ['nullable', 'email', 'max:255'],
            'phone' => ['nullable', 'string', 'max:50'],
            'pin' => $pinRules,
            'branch_id' => ['nullable', 'integer'],
            'host_id' => ['nullable', 'integer'],
            'user_ref' => [
                'nullable',
                'string',
                'max:64',
                Rule::when(
                    filled($request->input('user_ref')),
                    [Rule::in($linkableRefs)]
                ),
            ],
        ]);
    }

    /**
     * Ladill users that can be linked to an employee (team members and linked hosts).
     *
     * @return list<array{user_ref: string, label: string, taken: bool}>
     */
    protected function linkableUsers(Request $request, int $organizationId, ?Employee $employee = null): array
    {
        $ownerRef = $this->ownerRef($request);

        $refs = collect()
            ->merge(
                Member::owned($ownerRef)
                    ->where('organization_id', $organizationId)
                    ->pluck('user_ref')
            )
            ->merge(
                Host::owned($ownerRef)
                    ->where('organization_id', $organizationId)
                    ->whereNotNull('user_ref')
                    ->pluck('user_ref')
            )
            ->merge(
                Employee::owned($ownerRef)
                    ->where('organization_id', $organizationId)
                    ->whereNotNull('user_ref')
                    ->pluck('user_ref')
            );

        if ($employee?->user_ref) {
            $refs->push($employee->user_ref);
        }

        $refs = $refs->filter()->unique()->values();

        $users = User::query()
            ->whereIn('public_id', $refs)
            ->get(['public_id', 'name', 'email'])
            ->keyBy('public_id');

        $takenRefs = Employee::owned($ownerRef)
            ->where('organization_id', $organizationId)
            ->whereNotNull('user_ref')
            ->when($employee, fn ($query) => $query->where('id', '!=', $employee->id))
            ->pluck('user_ref')
            ->flip();

        return $refs
            ->map(function (string $ref) use ($users, $takenRefs, $employee) {
                $user = $users->get($ref);
                $label = $user
                    ? trim($user->name.' · '.$user->email)
                    : $ref;

                return [
                    'user_ref' => $ref,
                    'label' => $label,
                    'taken' => $takenRefs->has($ref) && $employee?->user_ref !== $ref,
                ];
            })
            ->sortBy('label', SORT_NATURAL | SORT_FLAG_CASE)
            ->values()
            ->all();
    }

    protected function employeePayload(array $validated): array
    {
        $payload = $validated;
        unset($payload['pin']);

        return array_filter($payload, fn ($value) => $value !== null && $value !== '');
    }

    protected function branches(Request $request, int $organizationId)
    {
        return Branch::owned($this->ownerRef($request))
            ->where('organization_id', $organizationId)
            ->where('is_active', true)
            ->orderBy('name')
            ->get();
    }

    protected function hosts(Request $request, int $organizationId)
    {
        return Host::owned($this->ownerRef($request))
            ->where('organization_id', $organizationId)
            ->orderBy('name')
            ->get();
    }
}