local conf = require("config")
local tpl = require("template")
local util = require("util")


local writer = {}

writer.app = {
  exec_name = "gw",
  last_updated = "2022-07-24",
  name = "gemwriter",
  version = "0.1",
}

writer.conf = {}
writer.defaults = {
  atom_file = "atom.xml",
  author = "Gem",
  -- Atom feed date format
  entry_date_format = "%Y-%m-%dT%X+00:00",
  entry_ext = ".gmi",
  entry_slug = os.date("%Y-%m-%d-%H%M%S"),
  entry_file_pattern = "[%/](%d%d%d%d%-%d%d%-%d%d)(.*)[%.](%a*)",
  gen_atom_feed = true,
  gen_index_page = true,
  index_file = "index.gmi",
  page_slug = "untitled-" .. os.date("%Y%m%d%H%M%S"),
  title = "gemlog",
  subtitle = "a Gemini log",
  url = "",
  output_dir = "log",
  rsync_exec = "/usr/bin/rsync",
  rsync_options = "-avz",
  rsync_remote = "",
}

writer.entries = {}

writer.msg = {
  add_entry = "Created ",
  help = writer.app.exec_name .. [[ [options] [slug]

Options:

page [slug]     Add a new page with the given name
post [slug]     Add a new entry with the given name
index           Generate an index page and feed of entries
publish         Index and copy posts to a remote server (requires rsync)
help            Show this help message
version         Print version info
  ]],
  index = "Created index page and feed.",
  publish = "Published log.",
}


function writer.load_config(config)
  for k, v in pairs(writer.defaults) do
    if config[k] == nil then
      writer.conf[k] = writer.defaults[k]
    else
      writer.conf[k] = config[k]
    end
  end
end


function writer.replace_vars(str, vars, vals)
  local text = str
  for k, v in pairs(vars) do
    text = string.gsub(text, v, vals[k])
  end
  return text
end


function writer.add_entry(slug)
  local text = tpl.log_gmi
  text = string.gsub(text, tpl.vars.entry.date,
    os.date(writer.conf.entry_date_format))
  text = string.gsub(text, tpl.vars.entry.author, writer.conf.author)

  local entry_name = slug .. writer.conf.entry_ext
  os.execute("test -d " .. writer.conf.output_dir .. " || mkdir -p " ..
    writer.conf.output_dir)
  util.write_file(writer.conf.output_dir .. "/" .. entry_name, text)
end


function writer.get_entries()
  local ls_cmd = io.popen("ls " .. writer.conf.output_dir .. " | grep " ..
    writer.conf.entry_ext)
  local ls = ls_cmd:read("*a")
  local entries = {}
  local n = 0
  local files_list = util.split_str(ls)
  for f = 1, #files_list do
    if files_list[f] ~= writer.conf.index_file then
      n = n + 1
      entries[n] = { files_list[f], util.read_file(writer.conf.output_dir ..
        "/" .. files_list[f]) }
    end
  end
  return entries
end


function writer.get_entries_meta()
  local meta = {}
  local entries = writer.get_entries()
  for e = 1, #entries do
    meta[e] = {}
    if string.find(entries[e][2], "# ") == nil then
      meta[e]["title"] = entries[e][1]
      meta[e]["content"] = entries[e][2]
    else
      meta[e]["title"] = util.extract_str(entries[e][2], "# ", "\n")
      hi1, hi2 = string.find(entries[e][2], "# ")
      meta[e]["content"] = string.sub(entries[e][2], hi1,
        string.len(entries[e][2]))
    end
    if string.find(entries[e][2], "author: ") == nil then
      meta[e]["author"] = writer.conf.author
    else
      meta[e]["author"] = util.extract_str(entries[e][2], "author: ", "\n")
    end
    if string.find(entries[e][2], "date: ") == nil then
      meta[e]["date"] = util.extract_file_date(writer.conf.output_dir,
        entries[e][1])
      if (meta[e]["date"] == "") or (meta[e]["date"] == nil) then
        meta[e]["date"] = os.date(writer.conf.entry_date_format)
      end
    else
      meta[e]["date"] = util.extract_str(entries[e][2], "date: ", "\n")
    end
    if string.find(entries[e][2], "summary: ") == nil then
      meta[e]["summary"] = meta[e]["title"]
    else
      meta[e]["summary"] = util.extract_str(entries[e][2], "summary: ", "\n")
    end
    if string.find(entries[e][2], "tags: ") == nil then
      meta[e]["tags"] = ""
    else
      meta[e]["tags"] = util.extract_str(entries[e][2], "tags: ", "\n")
    end
    meta[e]["url"] =  writer.conf.url .. "/" .. entries[e][1]
  end
  return meta
end


function writer.gen_index_page()
  local index_text = writer.replace_vars(tpl.index_gmi, tpl.vars.log,
    writer.conf)
  local entries_text = ""
  -- Reverse insert links to log entries, newest first
  for e = #writer.entries, 1, -1 do
    local entry_date = util.split_str(writer.entries[e]["date"], "(.*)[T]")[1]
    -- Get entry filename from the url
    local fi1, fi2 = string.find(writer.entries[e]["url"],
      writer.conf.entry_file_pattern)
    entries_text = entries_text .. "\n=> " ..
      string.sub(writer.entries[e]["url"], fi1 + 1, fi2) .. " " ..
      entry_date .. "    " .. writer.entries[e]["title"]
  end
  index_text = string.gsub(index_text, tpl.vars.index.entries, entries_text)
  util.write_file(writer.conf.output_dir .. "/" .. writer.conf.index_file,
    index_text)
end


function writer.gen_atom_feed()
  local feed_meta = {
    date = os.date(writer.conf.entry_date_format),
    url = writer.conf.url .. "/" .. writer.conf.atom_file,
  }
  local feed_text = writer.replace_vars(tpl.atom_header, tpl.vars.log,
    writer.conf)
  feed_text = writer.replace_vars(feed_text, tpl.vars.feed, feed_meta)
  local feed_entry = ""
  -- Reverse insert log entries, newest first
  for e = #writer.entries, 1, -1 do
    feed_entry = tpl.atom_entry
    feed_entry = writer.replace_vars(feed_entry, tpl.vars.entry,
      writer.entries[e])
    feed_text = feed_text .. feed_entry
  end
  feed_text = feed_text .. tpl.atom_footer
  util.write_file(writer.conf.output_dir .. "/" .. writer.conf.atom_file,
    feed_text)
end


function writer.publish()
  os.execute(writer.conf.rsync_exec .. " " .. writer.conf.rsync_options ..
    " " .. writer.conf.output_dir .. " " .. writer.conf.rsync_remote)
end



local cli = {}

function cli.handle_args(args)
  if (args[1] ~= "help") and (args[1] ~= "version") then
    writer.load_config(conf)
  end

  if (args[1] == "index") or (args[1] == "publish") then
    writer.entries = writer.get_entries_meta()
    if writer.conf.gen_index_page then writer.gen_index_page() end
    if writer.conf.gen_atom_feed then writer.gen_atom_feed() end
  end

  if args[1] == "post" then
    local slug = args[2]
    if slug == "" then
      slug = writer.conf.entry_slug
    else
      slug = os.date("%Y-%m-%d") .. "-" .. slug
    end
    writer.add_entry(slug)
    print(writer.msg.add_entry .. slug .. writer.conf.entry_ext)

  elseif args[1] == "page" then
    local slug = args[2]
    if slug == "" then slug = writer.conf.page_slug end
    writer.add_entry(slug)
    print(writer.msg.add_entry .. slug .. writer.conf.entry_ext)

  elseif args[1] == "index" then
    print(writer.msg.index)

  elseif args[1] == "publish" then
    writer.publish()
    print(writer.msg.publish)

  elseif args[1] == "help" then
    print(writer.msg.help)

  elseif args[1] == "version" then
    print(writer.app.name .. " " .. writer.app.version ..
      " (" .. writer.app.last_updated .. ")")
  end
end


cli.handle_args(arg)