# See https://datamaps.uk/webapps/uk_covid_vaccine_adverse_reactions/ for a webapp using Shiny
library('data.table')

brands <- c(
  'Pfizer' = 'https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/968413/COVID-19_mRNA_Pfizer-_BioNTech_Vaccine_Analysis_Print__2_.pdf',
  'AstraZ' = 'https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/968414/COVID-19_AstraZeneca_Vaccine_Analysis_Print.pdf'
)

get_data <- function(x){
  
    message('\nProcessing brand: ', names(x), '...')
  
    message(' - Downloading file and extracting tables...')
    y <- tabulizer::extract_tables(x, method = 'stream')
    
    message(' - Processing output... ')
    ydt <- data.table()
    for(idx in 1:length(y)){
        yt <- y[[idx]]
        if(length(yt) > 1){
            if(ncol(yt) > 3){
                if(ncol(yt) == 4){
                    if(yt[1,2] == ''){
                        yt <- yt[, c(1, 3, 4)]
                    } else if(yt[1,4] == ''){
                        yt <- yt[, c(1, 2, 4)]
                    } else {
                        message('Format not recognized!')
                    }
                } else if(ncol(yt) == 5){
                    yt <- yt[, c(1, 3, 5)]
                } else {
                    message('Too many columns!')
                }
            }
            ydt <- rbindlist(list( ydt, data.table(yt[-(1:2), ]) ), use.names = FALSE)
        }
    }
    
    message(' - Data Engineering... ')
    ydt <- ydt[!grepl('^TOTAL', V1)]
    ydt[, V4 := ifelse(V3 == '', V1, NA)][, V4 := zoo::na.locf(V4)]
    ydt[, V5 := ifelse(grepl('TOTAL$', V1), V1, NA)][, V5 := zoo::na.locf(V5, fromLast = TRUE)]
    ydt <- ydt[!(V3 == '' | grepl('TOTAL$', V1))]
    ydt[, `:=`( V2 = as.integer(V2), V3 = as.integer(V3), 'Brand' = names(x) )]
    setcolorder(ydt, c('Brand', 'V5', 'V4'))
    setnames(ydt, c('Brand', 'SOC', 'NEC', 'Reaction', 'Total', 'Fatal'))
    ydt[, SOC := gsub(' SOC TOTAL', '', SOC)]

    message(' - Add Rank over Total by SOC... ')
    ydt[, rnk := frank(-Total, ties.method = 'random'), SOC]

}

ydt <- rbindlist(list( get_data(brands[1]), get_data(brands[2]) ))

message('Data Checks... ')
ydt[, .(Total = sum(Total), Fatal = sum(Fatal)), Brand]
ydt[, .(Total = sum(Total), Fatal = sum(Fatal)), .(Brand, SOC)]

message('Select 5 major reactions by SOC (for SOCs with at least 50 cases)... ')
yr <- ydt[!SOC %chin% ydt[, .(Total = sum(Total)), SOC][Total < 50, SOC]][rnk <= 5]

message('Build table...')
y <- dcast(dts, SOC+NEC+Reaction~Brand, value.var = c('Total', 'Fatal', 'rnk'), fill = 0)
setcolorder(y, c('SOC', 'NEC', 'Reaction', 'Total_AstraZ', 'Fatal_AstraZ', 'rnk_AstraZ', 'Total_Pfizer', 'Fatal_Pfizer', 'rnk_Pfizer'))
sketch <- withTags(table(
				class = 'display',
                thead(
                	tr(
                		th(rowspan = 2, 'SOC'),
                    	th(rowspan = 2, 'NEC'),
                    	th(rowspan = 2, 'Reaction'),
                    	th(colspan = 3, span('AstraZeneca', style = "color:gold; font-family:'times'; font-size:20pt; display:table; margin:0 auto;") ),
                    	th(colspan = 3, span('Pfizer', style = "color:cyan; font-family:'times'; font-size:20pt; display:table; margin:0 auto;") )
					),
                	tr( th('Total'), th('Fatal'), th('Rank'), th('Total'), th('Fatal'), th('Rank') )
				)
))

dt <- datatable(
			y, 
            rownames = FALSE, 
            container = sketch, 
            selection = 'none',
            class = 'cell-border nowrap',
            extensions = c('Buttons', 'Scroller'),
            caption = tags$caption(
                style = 'caption-side:bottom;text-align:right;font-size:10px',
                em('Last Updated: 11 March 2021')
            ),        
            options = list(
                scrollX = TRUE,
                scrollY = 400,
                scroller = TRUE,
                ordering = TRUE,
                searchHighlight = TRUE,
                deferRender = TRUE,
                buttons = c('copy', 'csv', 'print'),
                initComplete = JS(
                    "function(settings, json) {",
                    "$(this.api().table().header()).css({'background-color': '#000', 'color': '#fff'});",
                    "}"
                ),
                dom = 'Biftp'
            )
)
dt <- dt %>%  formatCurrency(c('Total_AstraZ', 'Fatal_AstraZ', 'Total_Pfizer', 'Fatal_Pfizer'), '', digits = 0)