<?php

declare(strict_types=1);

namespace App\Services;

use App\Data\Ticket\{CreateTicketRequest, PostReplyRequest};
use App\Data\Ui\Ticket\{ReplyData, TicketData, TicketListData};
use App\Enums\TicketStatusEnum;
use App\Models\{Ticket, TicketReply, TicketStatus, User};
use App\Notifications\{TicketAssignedNotification, TicketCommentedNotification, TicketRaisedNotification, TicketStatusChangedNotification};
use Illuminate\Auth\Access\AuthorizationException;
use Illuminate\Http\UploadedFile;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use InvalidArgumentException;
use Spatie\LaravelData\PaginatedDataCollection;
use Throwable;

final class TicketService
{
    public function __construct(
        private readonly TicketAttachmentService $attachmentService
    ) {}

    /**
     * Get all tickets raised by a specific user.
     *
     * @return Collection<int, TicketData>
     */
    public function getAllForUser(int $userId): Collection
    {
        if ($userId <= 0) {
            throw new InvalidArgumentException('Invalid user ID');
        }

        $tickets = Ticket::with(['user', 'connectedApp', 'status', 'notifiedRoles', 'notifiedUsers', 'attachments', 'assignedUser', 'replies.user.roles'])
            ->where('user_id', $userId)
            ->latest()
            ->get();

        return TicketData::collect($tickets);
    }

    /**
     * Get all tickets in the system (for admins/support).
     *
     * @return Collection<int, TicketData>
     */
    public function getAll(): Collection
    {
        $tickets = Ticket::with(['user', 'connectedApp', 'status', 'notifiedRoles', 'notifiedUsers', 'attachments', 'assignedUser', 'replies.user.roles'])
            ->latest()
            ->get();

        return TicketData::collect($tickets);
    }

    /**
     * Get lightweight ticket list for a specific user with search and status filtering.
     *
     * @return PaginatedDataCollection<int, TicketListData>
     */
    public function getListForUser(int $userId, ?string $search = null, ?string $statusName = null, int $perPage = 10): PaginatedDataCollection
    {
        if ($userId <= 0) {
            throw new InvalidArgumentException('Invalid user ID');
        }

        $user = User::findOrFail($userId);
        $roleIds = $user->roles->pluck('id')->toArray();

        $tickets = Ticket::with(['user', 'connectedApp', 'status'])
            ->where(function ($query) use ($userId, $roleIds): void {
                $query->where('user_id', $userId)
                    ->orWhere('assigned_user_id', $userId)
                    ->orWhereHas('notifiedUsers', function ($q) use ($userId): void {
                        $q->where('users.id', $userId);
                    })
                    ->orWhereHas('notifiedRoles', function ($q) use ($roleIds): void {
                        $q->whereIn('roles.id', $roleIds);
                    });
            })
            ->when($search, function ($query) use ($search): void {
                $query->where('ticket_id', 'like', "%{$search}%");
            })
            ->when($statusName && 'all' !== $statusName, function ($query) use ($statusName): void {
                $query->whereHas('status', function ($q) use ($statusName): void {
                    $q->where('name', $statusName);
                });
            })
            ->latest()
            ->paginate($perPage);

        return TicketListData::collect($tickets, PaginatedDataCollection::class);
    }

    /**
     * Get lightweight ticket list of all tickets with search and status filtering.
     *
     * @return PaginatedDataCollection<int, TicketListData>
     */
    public function getList(?string $search = null, ?string $statusName = null, int $perPage = 10): PaginatedDataCollection
    {
        $tickets = Ticket::with(['user', 'connectedApp', 'status'])
            ->when($search, function ($query) use ($search): void {
                $query->where('ticket_id', 'like', "%{$search}%");
            })
            ->when($statusName && 'all' !== $statusName, function ($query) use ($statusName): void {
                $query->whereHas('status', function ($q) use ($statusName): void {
                    $q->where('name', $statusName);
                });
            })
            ->latest()
            ->paginate($perPage);

        return TicketListData::collect($tickets, PaginatedDataCollection::class);
    }

    /**
     * Get a specific ticket.
     */
    public function getTicket(int $id): TicketData
    {
        if ($id <= 0) {
            throw new InvalidArgumentException('Invalid ticket ID');
        }

        $ticket = Ticket::with(['user', 'connectedApp', 'status', 'notifiedRoles', 'notifiedUsers', 'attachments', 'assignedUser', 'replies.user.roles'])
            ->findOrFail($id);

        $user = auth()->user();
        if ($user) {
            activity()
                ->performedOn($ticket)
                ->causedBy($user)
                ->event('ticket_opened')
                ->log("Ticket {$ticket->ticket_id} opened by {$user->name}");
        }

        return TicketData::fromModel($ticket);
    }

    /**
     * Update the status of a ticket.
     *
     * @throws Throwable
     */
    public function updateStatus(int $ticketId, string $statusSlug): void
    {
        if ($ticketId <= 0) {
            throw new InvalidArgumentException('Invalid ticket ID');
        }

        DB::transaction(function () use ($ticketId, $statusSlug): void {
            $ticket = Ticket::findOrFail($ticketId);

            $user = auth()->user();
            if (! $user) {
                throw new AuthorizationException('Unauthenticated');
            }

            if (! $user->hasRole('Admin') && ! $user->hasRole('admin') && ! $user->can('ticket:update') && $ticket->assigned_user_id !== $user->id) {
                throw new AuthorizationException('You are not authorized to update this ticket\'s status.');
            }

            $status = TicketStatus::where('name', $statusSlug)->firstOrFail();
            $oldStatus = $ticket->status->name;

            if ($oldStatus !== $status->name) {
                $ticket->update(['status_id' => $status->id]);

                activity()
                    ->performedOn($ticket)
                    ->causedBy($user)
                    ->event('status_changed')
                    ->withProperties([
                        'old_status' => $oldStatus,
                        'new_status' => $status->name,
                    ])
                    ->log("Status updated from {$oldStatus} to {$status->name}");

                if ($ticket->user_id !== $user->id) {
                    $ticket->user->notify(new TicketStatusChangedNotification($ticket));
                    $this->logNotificationActivity($ticket, $ticket->user, TicketStatusChangedNotification::class);
                }
            }
        });
    }

    /**
     * Assign/remove assigned user to ticket.
     *
     * @throws Throwable
     */
    public function assignUser(int $ticketId, ?int $assignedUserId): void
    {
        if ($ticketId <= 0) {
            throw new InvalidArgumentException('Invalid ticket ID');
        }

        DB::transaction(function () use ($ticketId, $assignedUserId): void {
            $ticket = Ticket::findOrFail($ticketId);
            $oldAssignedUserId = $ticket->assigned_user_id;

            $ticket->update(['assigned_user_id' => $assignedUserId]);

            if ($assignedUserId && $assignedUserId !== $oldAssignedUserId) {
                $assignedUser = User::findOrFail($assignedUserId);
                $assignedUser->notify(new TicketAssignedNotification($ticket));
                $this->logNotificationActivity($ticket, $assignedUser, TicketAssignedNotification::class);
            }
        });
    }

    /**
     * Post a comment/reply to a ticket.
     *
     * @throws Throwable
     */
    public function postReply(PostReplyRequest $request): ReplyData
    {
        return DB::transaction(function () use ($request): ReplyData {
            $user = User::findOrFail($request->userId);
            $ticket = Ticket::findOrFail($request->ticketId);

            // Authorization check: Admin, Creator, Assigned, or Notified directly/via role
            $isAuthorized = $user->hasRole('Admin')
                || $user->hasRole('admin')
                || $ticket->user_id === $user->id
                || $ticket->assigned_user_id === $user->id
                || $ticket->notifiedUsers()->where('users.id', $user->id)->exists()
                || $ticket->notifiedRoles()->whereIn('roles.id', $user->roles->pluck('id')->toArray())->exists();

            if (! $isAuthorized) {
                throw new AuthorizationException('You are not authorized to comment on this ticket.');
            }

            /** @var TicketReply $reply */
            $reply = TicketReply::query()->create([
                'ticket_id' => $request->ticketId,
                'user_id' => $request->userId,
                'message' => mb_trim($request->message),
            ]);

            activity()
                ->performedOn($ticket)
                ->causedBy($user)
                ->event('comment_posted')
                ->withProperties([
                    'comment_id' => $reply->id,
                    'message' => $reply->message,
                ])
                ->log("Comment posted on ticket {$ticket->ticket_id}");

            // Transition ticket status from open to in-progress if it's currently open
            $ticket->load(['status', 'user', 'assignedUser']);
            if ($ticket->status->name === TicketStatusEnum::Open->value) {
                $inProgressStatus = TicketStatus::where('name', TicketStatusEnum::InProgress->value)->first();
                if ($inProgressStatus) {
                    $oldStatus = $ticket->status->name;
                    $ticket->update(['status_id' => $inProgressStatus->id]);

                    activity()
                        ->performedOn($ticket)
                        ->causedBy($user)
                        ->event('status_changed')
                        ->withProperties([
                            'old_status' => $oldStatus,
                            'new_status' => TicketStatusEnum::InProgress->value,
                        ])
                        ->log("Status updated from {$oldStatus} to ".TicketStatusEnum::InProgress->value);

                    if ($ticket->user_id !== $user->id) {
                        $ticket->user->notify(new TicketStatusChangedNotification($ticket));
                        $this->logNotificationActivity($ticket, $ticket->user, TicketStatusChangedNotification::class);
                    }
                }
            }

            // Notify ticket raiser if they did not make this comment
            if ($ticket->user_id !== $request->userId) {
                $ticket->user->notify(new TicketCommentedNotification($ticket, $reply));
                $this->logNotificationActivity($ticket, $ticket->user, TicketCommentedNotification::class);
            }

            // Notify assigned support user if they are set and did not make this comment
            if ($ticket->assigned_user_id && $ticket->assigned_user_id !== $request->userId) {
                $ticket->assignedUser->notify(new TicketCommentedNotification($ticket, $reply));
                $this->logNotificationActivity($ticket, $ticket->assignedUser, TicketCommentedNotification::class);
            }

            return ReplyData::fromModel($reply->load('user.roles'));
        });
    }

    /**
     * Create a new support ticket.
     *
     * @throws Throwable
     */
    public function create(CreateTicketRequest $request): TicketData
    {
        return DB::transaction(function () use ($request): TicketData {
            $defaultStatus = TicketStatus::query()
                ->where('name', TicketStatusEnum::Open->value)
                ->firstOrFail();

            /** @var Ticket $ticket */
            $ticket = Ticket::query()->create([
                'user_id' => $request->userId,
                'connected_app_id' => $request->connectedAppId,
                'issue_category' => $request->issueCategory,
                'description' => $request->description,
                'status_id' => $defaultStatus->id,
            ]);

            if (! empty($request->notifiedRoleIds)) {
                $ticket->notifiedRoles()->sync($request->notifiedRoleIds);
            }

            if (! empty($request->notifiedUserIds)) {
                $ticket->notifiedUsers()->sync($request->notifiedUserIds);
            }

            if ($request->attachment instanceof UploadedFile) {
                $this->attachmentService->store($ticket->id, $request->attachment);
            }

            // Load relations to build complete DTO and trigger notifications
            $ticket->load(['user', 'connectedApp', 'status', 'notifiedRoles', 'notifiedUsers', 'attachments', 'assignedUser', 'replies.user.roles']);

            $this->sendNotifications($ticket);

            return TicketData::fromModel($ticket);
        });
    }

    /**
     * Send notifications to all routed recipients.
     */
    private function sendNotifications(Ticket $ticket): void
    {
        $notification = new TicketRaisedNotification($ticket);
        $notifiedUserIds = [];

        // Notify specific users
        foreach ($ticket->notifiedUsers as $user) {
            $user->notify($notification);
            $this->logNotificationActivity($ticket, $user, TicketRaisedNotification::class);
            $notifiedUserIds[] = $user->id;
        }

        // Notify role users
        foreach ($ticket->notifiedRoles as $role) {
            $users = User::role($role->name)->get();
            foreach ($users as $user) {
                // Avoid double notifications
                if (! in_array($user->id, $notifiedUserIds, true)) {
                    $user->notify($notification);
                    $this->logNotificationActivity($ticket, $user, TicketRaisedNotification::class);
                    $notifiedUserIds[] = $user->id;
                }
            }
        }

        // Always notify all administrators when a ticket is raised
        $admins = User::whereHas('roles', function ($q): void {
            $q->whereIn('name', ['Admin', 'admin']);
        })->get();
        foreach ($admins as $admin) {
            if (! in_array($admin->id, $notifiedUserIds, true)) {
                $admin->notify($notification);
                $this->logNotificationActivity($ticket, $admin, TicketRaisedNotification::class);
                $notifiedUserIds[] = $admin->id;
            }
        }
    }

    /**
     * Log notification dispatch activity.
     */
    private function logNotificationActivity(Ticket $ticket, User $recipient, string $notificationClass): void
    {
        $user = auth()->user();
        activity()
            ->performedOn($ticket)
            ->causedBy($user)
            ->event('user_notified')
            ->withProperties([
                'recipient_id' => $recipient->id,
                'recipient_name' => $recipient->name,
                'notification_type' => $notificationClass,
            ])
            ->log("Notified user {$recipient->name} about ticket {$ticket->ticket_id}");
    }
}