#!/usr/bin/env lua
--
-- Convert koreader metadata to markdown.
--

-- Sort by page number
function compare(a, b)
  return a.page < b.page
end

-- Check if a file exists
-- Thanks https://stackoverflow.com/questions/4990990/check-if-a-file-exists-with-lua#4991602
function file_exists(name)
  local f=io.open(name,"r")
  if f~=nil then io.close(f) return true else return false end
end

-- Get filename
file = arg[1]

-- Usage
if file == nil then
  print('usage: ' .. arg[0] .. ' <filename>')
  os.exit(1)
else
  if not file_exists(file) then
    print('file not found: ' .. file)
    os.exit(1)
  end
end

-- Load metadata
content     = assert(loadfile(file))
data        = content()
bookmarks   = data.bookmarks
annotations = data.annotations

-- Sort
table.sort(bookmarks,   compare)
table.sort(annotations, compare)

-- Iterate over bookmarks
for key, item in ipairs(bookmarks) do
  print('Page ' .. item.page .. ':')
  print('')
  print('> ' .. item.notes)
  print('')
end

-- Iterate over annotations
for key, item in ipairs(annotations) do
  print('Page ' .. item.page .. ':')
  print('')
  print('> ' .. item.text)
  print('')
end