// Copyright (c) 2024 Mattermost Community Enterprise
// Notification Interface Implementation (ID-loaded push notifications)

package notification

import (
	"net/http"

	"github.com/mattermost/mattermost/server/public/model"
	"github.com/mattermost/mattermost/server/public/shared/mlog"
	"github.com/mattermost/mattermost/server/public/shared/request"
	"github.com/mattermost/mattermost/server/v8/channels/store"
)

// NotificationConfig holds configuration for the notification interface
type NotificationConfig struct {
	Store  store.Store
	Config func() *model.Config
	Logger mlog.LoggerIFace
}

// NotificationImpl implements the NotificationInterface
type NotificationImpl struct {
	store  store.Store
	config func() *model.Config
	logger mlog.LoggerIFace
}

// NewNotificationInterface creates a new notification interface
func NewNotificationInterface(cfg *NotificationConfig) *NotificationImpl {
	return &NotificationImpl{
		store:  cfg.Store,
		config: cfg.Config,
		logger: cfg.Logger,
	}
}

// GetNotificationMessage retrieves the full notification message for an ID-loaded push notification
// This is used when a push notification was sent with minimal data (ID-only) and the client
// needs to fetch the full message content
func (n *NotificationImpl) GetNotificationMessage(rctx request.CTX, ack *model.PushNotificationAck, userID string) (*model.PushNotification, *model.AppError) {
	if ack == nil {
		return nil, model.NewAppError("GetNotificationMessage", "notification.ack_nil", nil, "Push notification ack is nil", http.StatusBadRequest)
	}

	if ack.PostId == "" {
		return nil, model.NewAppError("GetNotificationMessage", "notification.post_id_missing", nil, "Post ID is missing from ack", http.StatusBadRequest)
	}

	if n.store == nil {
		return nil, model.NewAppError("GetNotificationMessage", "notification.store_not_available", nil, "Store is not available", http.StatusInternalServerError)
	}

	// Get the post
	post, err := n.store.Post().GetSingle(rctx, ack.PostId, false)
	if err != nil {
		return nil, model.NewAppError("GetNotificationMessage", "notification.post_not_found", map[string]any{"PostId": ack.PostId}, err.Error(), http.StatusNotFound)
	}

	// Verify the user has access to this post
	channel, err := n.store.Channel().Get(post.ChannelId, true)
	if err != nil {
		return nil, model.NewAppError("GetNotificationMessage", "notification.channel_not_found", map[string]any{"ChannelId": post.ChannelId}, err.Error(), http.StatusNotFound)
	}

	// Check if user is a member of the channel
	member, err := n.store.Channel().GetMember(rctx, post.ChannelId, userID)
	if err != nil || member == nil {
		return nil, model.NewAppError("GetNotificationMessage", "notification.user_not_member", map[string]any{"UserId": userID, "ChannelId": post.ChannelId}, "User is not a member of the channel", http.StatusForbidden)
	}

	// Get the sender information
	sender, err := n.store.User().Get(rctx.Context(), post.UserId)
	if err != nil {
		n.logger.Warn("Could not get sender for notification",
			mlog.String("sender_id", post.UserId),
			mlog.Err(err),
		)
	}

	// Get team information
	var teamID string
	if channel.TeamId != "" {
		teamID = channel.TeamId
	}

	// Build the push notification
	notification := &model.PushNotification{
		PostId:      post.Id,
		ChannelId:   post.ChannelId,
		ChannelName: channel.DisplayName,
		TeamId:      teamID,
		Message:     post.Message,
		Type:        ack.NotificationType,
		IsIdLoaded:  true,
	}

	// Add sender info if available
	if sender != nil {
		notification.SenderId = sender.Id
		notification.SenderName = sender.GetDisplayName(model.ShowNicknameFullName)
	}

	// Handle root post for threads
	if post.RootId != "" {
		notification.RootId = post.RootId
	}

	// Set the category based on notification type
	switch ack.NotificationType {
	case model.PushTypeMessage:
		notification.Category = "CAN_REPLY"
	case model.PushTypeClear:
		notification.Category = ""
	case model.PushTypeUpdateBadge:
		notification.Category = ""
	default:
		notification.Category = "CAN_REPLY"
	}

	n.logger.Debug("Retrieved notification message",
		mlog.String("post_id", post.Id),
		mlog.String("user_id", userID),
		mlog.String("channel_id", post.ChannelId),
	)

	return notification, nil
}

// CheckLicense validates that the license allows ID-loaded push notifications
// For community enterprise, we always allow this feature
func (n *NotificationImpl) CheckLicense() *model.AppError {
	// In the community enterprise implementation, we don't require a license
	// The official Mattermost enterprise requires a valid license for this feature

	n.logger.Debug("CheckLicense called - community enterprise allows ID-loaded notifications without license")

	return nil
}