“Divide each difficulty into as many parts
as is feasible and necessary to resolve it.”

This is my contribution to the fields of data science, business analytics, information technology, and related topics.

# here I manually define which blog posts to include
blog_df <- data.frame(
  filename = c("create_interesting_datasets"
               ,"ifelse_NA_trap"
               ,"building_this_site"
               # ,"ed_api"
               ,"monty_hall"
               ,"Report")
)
# eventually, I will read all .rmd files in main dir
  # and exclude non-blog posts because blog posts will 
    # quickly outnumber non-blog posts

# pull some text from each post for a content sample
blog_df <- blog_df %>% 
  mutate(intro = sapply(
  paste0(blog_df$filename,".Rmd"),function(x){
    paste0(substr(gsub(".*##",
     "",
     paste(readLines(x)[1:100],collapse = " "),
     perl = TRUE
    ),
    1,140)," ...")
    }
  )
  , lines = sapply(
  paste0(blog_df$filename,".Rmd"),function(x) blog_df$filename = length(readLines(x)))
  , title = sapply(
  paste0(blog_df$filename,".Rmd"),function(x){
    gsub('"',
         "",
         gsub("title: ",
           "",
           readLines(x)[2]
          )
    )
    }
  )) %>%
  bind_rows(data.frame(filename = 'ed_api'
                       ,intro = 'Function for Easy Calling To help alleviate some of the headache, I wrote a function below that builds the call and traverses all pages ...'
                       ,lines = 188
                       , title = 'Department of Ed API'))

# identify metadata
blog_df$created_at <- as.Date(file.info(paste0(blog_df$filename,".html"))$ctime)
blog_df$updated_at <- as.Date(file.info(paste0(blog_df$filename,".html"))$mtime)
blog_df$created_updated_at <- paste0(
  blog_df$created_at
  , " /<br>"
  , blog_df$updated_at
  )

#wrap filename in raw html
#use post title as visible text
blog_df$filename <- paste0(
  "<h7> <a class='minimal' href='"
  , blog_df$filename
  , ".html' target='_blank'>"
  , blog_df$title," "
  , "<i class='fa fa-sign-in fa-lg'></i>","</a></h7>")

# no longer need plain text titles
blog_df$title <- NULL

blog_df <- blog_df %>%
  arrange(desc(created_at)) %>%
  select(filename,intro,created_updated_at,lines)

# define formate for header
col_format <- JS(
  "function(settings, json) {",
  "$(this.api().table().header()).css({'background-color': '#252525', 'color': '#FFFFFF'});",
  "}")

datatable(blog_df
          ,escape = FALSE
          ,rownames=FALSE
          ,colnames = c('Title',
                        'Content Snippet',
                        'Created / Updated',
                       # 'Created At',
                       # 'Updated At',
                       'Post Length (lines)')
          ,options=list(
            autoWidth = TRUE,
            initComplete = col_format,
            pageLength=25,
            columnDefs = list( # center all but first column
              list(className = 'dt-center',targets=2)
              , list(className = 'dt-right',targets=3)
              , list(width = '100px', targets = c(2,3))
              , list(width = '250px', targets = 0)
              , list(verticalAlign = 'top', targets = "_all")), 
            dom = 'frtpB'
          )) %>%
        formatStyle(
        'lines',
        background = styleColorBar(range(0,max(blog_df$lines)), 'orange'),
        align = 'bottom',
        backgroundSize = '98% 45%',
        backgroundRepeat = 'no-repeat',
        backgroundPosition = 'left') %>%
      formatStyle(columns = "filename", 
              color = 'black',
              fontWeight = 'bold') %>%
      formatStyle(names(blog_df), 'vertical-align'='top')