CSV format

[admin]

Then you probably need something like this. For it to work correctly all trends included in the export must have the same resolution.

Code:

require('trends')

dates = {}
dates['start'] = os.date('*t')
dates['start'].day = dates['start'].day - 1
dates['end'] = os.date('*t')

now = os.time()

function fetch(tname)
  local res = {}
  local values = trends.fetch(tname, dates)
  local count = #values
  local step = 86400 / count

  for i, value in ipairs(values) do
    table.insert(res, {
      now - (count - i) * step,
      value
    })
  end

  return res
end

buf = {
  fetch('Trend name 1'),
  fetch('Trend name 2')
}

csv = {}

for i, row1 in ipairs(buf[ 1 ]) do
  date = os.date('%Y-%m-%d %H:%M', row1[ 1 ])
  value1 = row1[ 2 ]

  row2 = buf[ 2 ][ i ] or {}
  value2 = row2[ 2 ] or 0

  csv[ #csv + 1 ] = string.format(',,,%s,%.2f,,,,%.0f,,',
    date, value1, value2)
end

csv = table.concat(csv, '\n')
log(csv)