local lfs = require("lfs")
--检查输入参数 目录不需要加斜杠在末尾
local argCount = #arg
if (argCount ==0) then
  print("input directory,don't add slashes at the end")
  os.exit(0)
end
--检查是有效目录
function dirExists(dirPath)
    local attrs = lfs.attributes(dirPath)
    return attrs and attrs.mode == "directory"
end

if not(dirExists(arg[1])) then
  print("not a valid directory")
  os.exit(0)
end

--获取目录下文件名 不递归
local function getFiles(path)
    local files = {}

    for entry in lfs.dir(path) do
        local fullpath = path  .. entry
        local attr = lfs.attributes(fullpath)

        if attr and attr.mode == "file" then
            table.insert(files, entry)
        end
    end

    return files
end

--转换md文件
function convert_md(filePath,name)

  --读取md内容
  local markdown_text = ""
  local file = io.open(filePath, "r")
  if file then
     -- 读取文件内容
     markdown_text = file:read("*all")
    -- 关闭文件
    file:close()
  else
    print("open file failed!")
    os.exit(0)
  end

  --提取图片地址
  local pattern = "%!%[.-%]%((.-)%)"
  local image_urls = {}

  for url in markdown_text:gmatch(pattern) do
     table.insert(image_urls, url)
  end

  -- 下载提取到的图片地址
  for i, url in ipairs(image_urls) do
      print(i, url)
      local cmd = "wget -c --no-check-certificate -P \""..arg[1].."/converted/resource/"..name.."\" " .. url
      os.execute(cmd)
  end
end

--建立目标目录
local cmd = "mkdir \""..arg[1].."/converted\""
os.execute(cmd)
cmd = "mkdir \""..arg[1].."/converted/resource\""
os.execute(cmd)
cmd = "mkdir \""..arg[1].."/converted/convertedmd\""
os.execute(cmd)
cmd = "mkdir \""..arg[1].."/converted/finalhtml\""
os.execute(cmd)

-- 获取文件名
local files = getFiles(arg[1]..'/')
for _, fileName in ipairs(files) do
  --检查是md结尾的markdown文件
  if(string.match(fileName, "%.md$"))then
    --去除文件扩展名
    local idx = fileName:match(".+()%.%w+$")
    if idx then name = fileName:sub(1, idx - 1) end
    --创建每个md文件保存图片的文件夹
    local cmd = "mkdir \""..arg[1]..'/'.."converted/resource/"..name.."\""
    os.execute(cmd)

    convert_md(arg[1]..'/'..fileName,name)
  end
end