Create plotting dataset for plotly

wide_to_long.R

#### Select the countries for plotting, and convert wide format to long
current_dat = country_data %>%
  filter(Country.Region %in% selected_countries) %>%
  reshape2::melt(.) %>%
  set_colnames(c('Country', 'Status', 'Date', 'Total'))

## starts with the date when 1st case confirmed
find_case1_onwards <- function(country_name) {
  case1_idx = which(current_dat[current_dat$Country == country_name, 'Total'] > 0)[1]
  
  this_country = current_dat %>%
    filter(Country == country_name) %>%
    .[case1_idx:nrow(.), ]
}

current_dat_list = lapply(unique(current_dat$Country), find_case1_onwards)
current_dat = do.call(rbind, current_dat_list)