local env = require("env")
local lang = require("lang.en")
local util = require("util")


local writer = {}
writer.docs = {}
writer.conf = {}
writer.posts = {}

writer.docs.gen_config = [[
  Generate a default config directory.
  ]]
function writer.gen_config()
  writer.conf.config_dir = util.replace_shell_vars(env.defaults.config_dir)
  util.make_dir(writer.conf.config_dir)
  for name, file in pairs(env.defaults.config_files) do
    -- Check each file individually anyway to avoid overwriting existing
    -- files
    if util.read_file(writer.conf.config_dir .. "/" .. file) == "" then
      if file == env.defaults.config_files.config then
        util.write_file(writer.conf.config_dir .. "/" .. file,
          env.defaults_toml)
      else
        util.write_file(writer.conf.config_dir .. "/" .. file, lang[name])
      end
    end
  end
  -- Create capsule and gemlog directories
  util.make_dir(env.capsules.main.capsule_dir)
  util.make_dir(env.capsules.main.gemlog_dir)
end


writer.docs.parse_config = [[
  Read the config and template files, and load the values into a table.
  ]]
function writer.parse_config(config_file)
  local lines = util.split_lines(config_file)
  local config_group = env.toml_vars.general
  local line_cap = ""
  writer.conf.capsules = {}
  for l = 1, #lines do
    -- Config group
    if string.sub(lines[l], 1, 1) == "[" then
      for tv, label in pairs(env.toml_vars) do
        if string.find(lines[l], label) ~= nil then config_group = label end
      end
      if config_group == env.toml_vars.capsules then
        local _, lb_sep = string.find(lines[l], "%[" .. config_group .. "%.")
        local rb_sep, _ = string.find(lines[l], "%]")
        if lb_sep ~= nil then
          line_cap = string.sub(lines[l], lb_sep + 1, rb_sep - 1)
          writer.conf.capsules[line_cap] = {}
        end
      end

    -- Config variables (ignore comments)
    elseif (string.sub(lines[l], 1, 1) ~= "#") and
      (string.find(lines[l], "=") ~= nil) then
      local eq_sep, _ = string.find(lines[l], " = ")
      local qt_sep, _ = string.find(lines[l], "\"")
      local k = string.sub(lines[l], 1, eq_sep - 1)
      local val = string.sub(lines[l], eq_sep + 4, string.len(lines[l]) - 1)
      if qt_sep == nil then
        val = string.sub(lines[l], eq_sep + 3, string.len(lines[l]))
      end
      -- Load settings by key and their values to the config table
      if config_group == env.toml_vars.general then
        writer.conf[k] = val
      elseif config_group == env.toml_vars.capsules then
        -- Convert boolean values
        if (val == "\"true\"") or (val == "\"false\"") then
          writer.conf.capsules[line_cap][k] = util.to_bool(val)
        else
          writer.conf.capsules[line_cap][k] = val
        end
      end
    end
  end

  -- If the main capsule id is not the app default, update the id
  if (writer.conf.cap_id == env.general.main_capsule) and
    (writer.conf.main_capsule ~= env.general.main_capsule) then
    writer.conf.cap_id = writer.conf.main_capsule
  end
  -- Add an alias to the selected capsule's table
  writer.conf.cap = writer.conf.capsules[writer.conf.cap_id]

  -- Fill in the remaining defaults
  for k, v in pairs(env.defaults) do
    if writer.conf[k] == nil then
      writer.conf[k] = env.defaults[k]
    end
  end

  -- Replace shell variables in paths to make them usable
  for c_id, _ in pairs(writer.conf.capsules) do
    writer.conf.capsules[c_id]["capsule_dir"] = util.replace_shell_vars(
      writer.conf.capsules[c_id]["capsule_dir"])
    writer.conf.capsules[c_id]["gemlog_dir"] = util.replace_shell_vars(
      writer.conf.capsules[c_id]["gemlog_dir"])
    -- Create capsule and gemlog directories
    util.make_dir(writer.conf.capsules[c_id]["capsule_dir"])
    util.make_dir(writer.conf.capsules[c_id]["gemlog_dir"])
  end

  -- Set lang
  lang = require("lang." .. writer.conf.app_lang)

  -- Custom templates override lang defaults (ignore config)
  for name, file in pairs(env.defaults.config_files) do
    if name ~= "config" then
      local template = util.read_file(writer.conf.config_dir .. "/" .. file)
      if template ~= "" then lang[name] = template end
    end
  end
end


writer.docs.load_config = [[
  Check whether there is an existing config and load it if found. Exit if a
  capsule is not found.
  ]]
function writer.load_config(cap_id)
  writer.conf.config_dir = util.replace_shell_vars(env.defaults.config_dir)
  local config_file = util.read_file(writer.conf.config_dir .. "/" ..
    env.defaults.config_files.config)
  local config_new = false

  -- No config found
  if (config_file == "") and (not config_new) then
    writer.gen_config()
    config_new = true
  end

  -- Config found, read the configuration and load the values to an
  -- associative table, writer.conf.
  if (config_file ~= "") and (not config_new) then
    -- Check capsule id exists, abort if no valid capsule found
    if (cap_id == nil) or (string.find(cap_id, " ") ~= nil) then
      writer.conf.cap_id = env.general.main_capsule
    else
      writer.conf.cap_id = cap_id
    end
    local cap_label = "%[" .. env.toml_vars.capsules .. "%." ..
      tostring(cap_id) .. "%]"
    if (string.find(config_file, cap_label) == nil) and
      (writer.conf.cap_id ~= env.general.main_capsule) then
      print(lang.errs.invalid_cap_id)
      os.exit()
    end

    writer.parse_config(config_file)
  end
end


writer.docs.add_gemtext = [[
  Given a title and mode, create a new gemtext file. Supported modes: page,
  post.
  ]]
function writer.add_gemtext(title, mode)
  local file_name = title
  local post_title = title
  if ((title == "") or (title == nil)) and (mode == "post") then
    file_name = os.date(writer.conf.post_slug_date_format) .. "-" ..
      writer.conf.post_slug .. writer.conf.post_ext
    post_title = writer.conf.post_slug
  elseif ((title == "") or (title == nil)) and (mode == "page") then
    file_name = writer.conf.page_slug .. writer.conf.post_ext
    post_title = writer.conf.page_slug
  else
    -- Strip punctuation from the title and convert to file name
    local delim = "delim-" .. tostring(math.random(90000000000))
    file_name = string.gsub(file_name, " ", delim)
    if mode == "post" then
      file_name = os.date(writer.conf.post_slug_date_format) .. "-" ..
        string.gsub(file_name, "%p", "") .. writer.conf.post_ext
    else
      file_name = string.gsub(file_name, "%p", "") .. writer.conf.post_ext
    end
    file_name = string.lower(string.gsub(file_name, delim, "-"))
  end

  local text = lang.post
  local file_path = writer.conf.cap.gemlog_dir .. "/" .. file_name
  if mode == "page" then
    text = lang.page
    file_path = writer.conf.cap.capsule_dir .. "/" .. file_name
  end
  text = string.gsub(text, lang.tpl_vars.post.date,
    os.date(writer.conf.post_date_format))
  text = string.gsub(text, lang.tpl_vars.post.author, writer.conf.cap.author)
  text = string.gsub(text, lang.tpl_vars.post.title, post_title)

  util.write_file(file_path, text)
  return file_name
end


writer.docs.get_posts = [[
  Get a list of gemlog posts and return the file names and their contents in a
  table.
  ]]
function writer.get_posts()
  local ls = util.ls_grep(writer.conf.cap.gemlog_dir, writer.conf.post_ext)
  local posts = {}
  local n = 0
  local files_list = util.split_str(ls)
  for f = 1, #files_list do
    if files_list[f] ~= writer.conf.cap.index_page then
      n = n + 1
      posts[n] = { files_list[f], util.read_file(writer.conf.cap.gemlog_dir ..
        "/" .. files_list[f]) }
    end
  end
  return posts
end


writer.docs.get_posts_meta = [[
  Extract gemlog posts metadata and return them as an associative table.
  ]]
function writer.get_posts_meta()
  local meta = {}
  local posts = writer.get_posts()
  for e = 1, #posts do
    meta[e] = {}
    if string.find(posts[e][2], "# ") == nil then
      meta[e]["title"] = posts[e][1]
      meta[e]["content"] = posts[e][2]
    else
      meta[e]["title"] = util.extract_str(posts[e][2], "# ", "\n")
      hi1, hi2 = string.find(posts[e][2], "# ")
      meta[e]["content"] = string.sub(posts[e][2], hi1,
        string.len(posts[e][2]))
    end
    if string.find(posts[e][2], "author: ") == nil then
      meta[e]["author"] = writer.conf.cap.author
    else
      meta[e]["author"] = util.extract_str(posts[e][2], "author: ", "\n")
    end
    if string.find(posts[e][2], "date: ") == nil then
      meta[e]["date"] = util.extract_file_date(writer.conf.cap.gemlog_dir,
        posts[e][1])
      if (meta[e]["date"] == "") or (meta[e]["date"] == nil) then
        meta[e]["date"] = os.date(writer.conf.post_date_format)
      end
    else
      meta[e]["date"] = util.extract_str(posts[e][2], "date: ", "\n")
    end
    if string.find(posts[e][2], "summary: ") == nil then
      meta[e]["summary"] = meta[e]["title"]
    else
      meta[e]["summary"] = util.extract_str(posts[e][2], "summary: ", "\n")
    end
    if string.find(posts[e][2], "tags: ") == nil then
      meta[e]["tags"] = ""
    else
      meta[e]["tags"] = util.extract_str(posts[e][2], "tags: ", "\n")
    end
    meta[e]["url"] =  writer.conf.cap.log_url .. "/" .. posts[e][1]
  end
  return meta
end


writer.docs.gen_index_page = [[
  Generate a gemlog index page listing all gemlog posts.
  ]]
function writer.gen_index_page()
  local index_text = util.replace_vars(lang.index, lang.tpl_vars.log,
    writer.conf.cap)
  local posts_text = ""
  -- Reverse insert links to log posts, newest first
  for e = #writer.posts, 1, -1 do
    local post_date = util.split_str(writer.posts[e]["date"], "(.*)[T]")[1]
    -- If post date cannot be extracted, revert to current date
    if post_date == nil then
      post_date = os.date(writer.conf.post_date_format)
    end
    -- Get post filename from the url
    local fi1, fi2 = string.find(writer.posts[e]["url"],
      writer.conf.post_file_pattern)
    posts_text = posts_text .. "\n=> " ..
      string.sub(writer.posts[e]["url"], fi1 + 1, fi2) .. " " ..
      post_date .. "    " .. writer.posts[e]["title"]
  end
  index_text = string.gsub(index_text, lang.tpl_vars.index.posts,
    posts_text)
  util.write_file(writer.conf.cap.gemlog_dir .. "/" ..
    writer.conf.cap.index_page, index_text)
end


writer.docs.gen_atom_feed = [[
  Generate an Atom feed of gemlog posts.
  ]]
function writer.gen_atom_feed()
  local feed_meta = {
    date = os.date(writer.conf.post_date_format),
    url = writer.conf.cap.url .. "/" .. writer.conf.cap.atom_feed,
  }
  local feed_text = util.replace_vars(lang.atom_header, lang.tpl_vars.log,
    writer.conf.cap)
  feed_text = util.replace_vars(feed_text, lang.tpl_vars.feed, feed_meta)
  local feed_post = ""
  -- Reverse insert log posts, newest first
  for e = #writer.posts, 1, -1 do
    feed_post = lang.atom_entry
    writer.posts[e]["content"] = util.replace_feed_entities(
      writer.posts[e]["content"])
    feed_post = util.replace_vars(feed_post, lang.tpl_vars.post,
      writer.posts[e])
    feed_text = feed_text .. feed_post
  end
  feed_text = feed_text .. lang.atom_footer
  feed_text = util.replace_feed_entities(feed_text, "post")

  util.write_file(writer.conf.cap.gemlog_dir .. "/" ..
    writer.conf.cap.atom_feed, feed_text)
end


writer.docs.publish = [[
  Transfer a capsule's contents to a remote location.
  ]]
function writer.publish()
  if writer.conf.cap.transfer_mode == "rsync" then
    os.execute(writer.conf.cap.rsync_exec .. " " ..
      writer.conf.cap.rsync_options .. " " .. writer.conf.cap.capsule_dir ..
      "/ " .. writer.conf.cap.rsync_dest .. "/")
  else
    os.execute(writer.conf.cap.scp_exec .. " -r " ..
      writer.conf.cap.capsule_dir .. "/* " .. writer.conf.cap.scp_target)
  end
end



local cli = {}
cli.docs = {}


cli.docs.handle_args = [[
  Match command-line options to the respective application functions, passing
  any additional arguments to the functions.
  ]]
function cli.handle_args(args)
  if (args[1] ~= lang.opts.help) and (args[1] ~= lang.opts.version) then
    writer.load_config(args[2])
  end

  if (args[1] == lang.opts.index) or (args[1] == lang.opts.publish) then
    writer.posts = writer.get_posts_meta()
    if writer.conf.cap.gen_index_page then writer.gen_index_page() end
    if writer.conf.cap.gen_atom_feed then writer.gen_atom_feed() end
  end

  if args[1] == lang.opts.config then
    writer.load_config()
    print(lang.msgs.load_config .. writer.conf.config_dir)

  elseif (args[1] == lang.opts.post) or (args[1] == lang.opts.page) then
    local file_name = ""
    if args[3] ~= nil then
      file_name = writer.add_gemtext(args[3], args[1])
    else
      file_name = writer.add_gemtext(args[2], args[1])
    end
    print(lang.msgs.add_gemtext .. file_name)

  elseif args[1] == lang.opts.index then
    print(lang.msgs.index)

  elseif args[1] == lang.opts.publish then
    writer.publish()
    print(lang.msgs.publish)

  elseif args[1] == lang.opts.help then
    print(env.app.exec_name .. lang.msgs.help)

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


cli.handle_args(arg)