library(R2HTML) 
library(desc)
suppressMessages(library(tidyverse))

# parse DESCRIPTION to get list of Imports
packages <- desc_get_deps()$package

# load packages
sapply(packages, require, character.only=TRUE, warn.conflicts=FALSE,
       quietly=TRUE)

# Functions
get_doc = function(package = 'mi', dataset = 'nlsyV') {
    help.ref = try(help(eval(dataset), package=eval(package)), silent = TRUE)
    out = try(utils:::.getHelpFile(help.ref), silent = TRUE)
    return(out)
}

get_data = function(package = 'mi', dataset = 'nlsyV') {
    e = new.env(hash = TRUE, parent = parent.frame(), size = 29L)
    data(list = dataset, package = package, envir = e)
    out = e[[dataset]]
    return(out)
}

tidy_data = function(dat) {
    if(class(dat)[1]=='ts'){
        dat = try(data.frame('time' = time(dat), 'value' = dat), silent = TRUE)
    } else {
        dat = try(as.data.frame(dat), silent = TRUE)
    }
    if (class(dat)[1] == 'data.frame') {
        out = dat
    } else {
        out = NA
        class(out) = 'try-error'
    }
    return(out)
}

write_data = function(i) {
    package = index$Package[i]
    dataset = index$Item[i]
    dat = data[[i]]
    doc = docs[[i]]
    cat(package, ' -- ', dataset, '\n')
    try(dir.create('csv'), silent = TRUE)
    try(dir.create('doc'), silent = TRUE)
    try(dir.create(paste0('csv/', package)), silent = TRUE)
    try(dir.create(paste0('doc/', package)), silent = TRUE)
    fn_csv = paste0('csv/', package, '/', dataset, '.csv')
    fn_doc = paste0('doc/', package, '/', dataset, '.html')
    write.csv(data[[i]], file = fn_csv)
    tools::Rd2HTML(docs[[i]], out = fn_doc)
}

# Index
index = data(package=packages)$results[,c(1,3,4)]
index = data.frame(index, stringsAsFactors=FALSE)

# Extract Data and Docs and exclude non-data.frames and errors
data = lapply(1:nrow(index), function(i) get_data(index$Package[i], index$Item[i]))
docs = lapply(1:nrow(index), function(i) get_doc(index$Package[i], index$Item[i]))
data = lapply(data, tidy_data)
idx1 = sapply(docs, class) != 'try-error'
idx2 = sapply(data, class) != 'try-error'
idx = as.logical(pmin(idx1, idx2))
data = data[idx]
docs = docs[idx]
index = index[idx,]

# Write to file
for (i in 1:nrow(index)) {
    try(write_data(i), silent = TRUE)
}

# Index
is.binary <- function(x) {
    tryCatch(length(unique(na.omit(x))) == 2, 
             error = function(e) FALSE, silent = TRUE)
}
index$Rows = sapply(data, nrow)
index$Cols = sapply(data, ncol)
index$n_binary <- sapply(data, function(x) sum(sapply(x, is.binary)))
index$n_character <- sapply(data, function(x) sum(sapply(x, is.character)))
index$n_factor <- sapply(data, function(x) sum(sapply(x, is.factor)))
index$n_logical <- sapply(data, function(x) sum(sapply(x, is.logical)))
index$n_numeric <- sapply(data, function(x) sum(sapply(x, is.numeric)))

index$CSV = paste('https://vincentarelbundock.github.io/Rdatasets/csv/',
                  index$Package, '/', index$Item, '.csv', sep='')
index$Doc = paste('https://vincentarelbundock.github.io/Rdatasets/doc/',
                  index$Package, '/', index$Item, '.html', sep='')

# case insensitive sorting
index = index[order(tolower(index$Package), 
                    tolower(index$Item)),]

# Index CSV
write.csv(index, file = 'datasets.csv', row.names = FALSE)

# Index HTML
index$CSV = paste("<a href='", index$CSV, "'> CSV </a>", sep='')
index$Doc = paste("<a href='", index$Doc, "'> DOC </a>", sep='')
unlink('datasets.html')
rss = '
<style type="text/css">
  tr:nth-child(even){
          background-color: #E5E7E5;
  }
</style>
'
cat(rss, file='datasets.html')
HTML(index, file='datasets.html', row.names=FALSE, append=TRUE)