refactor telescope command (#398)

* refactor telescope command

* addd telescope default options support

* fix variable name wrong

* convert command line string to lua type

* add comment.

* update readme for use theme in commandline

* enhance complete in commandline

* enhance complete in commandline

* enhance covert commandline options

lua/telescope/command.lua

@@ -0,0 +1,96 @@
+local themes = require('telescope.themes')
+local builtin = require('telescope.builtin')
+local extensions = require('telescope._extensions').manager
+local config = require('telescope.config')
+local command = {}
+
+-- convert command line string arguments to
+-- lua number boolean type and nil value
+local function convert_user_opts(user_opts)
+  local default_opts = config.values
+
+  local _switch = {
+    ['boolean'] = function(key,val)
+      if val == 'false' then
+        user_opts[key] = false
+      end
+      user_opts[key] = true
+    end,
+    ['number'] = function(key,val)
+      user_opts[key] = tonumber(val)
+    end,
+    ['string'] = function(key,val)
+      if val == 'nil' then
+        user_opts[key] = nil
+      end
+      if val == '""' then
+        user_opts[key] = ''
+      end
+      if val == '"' then
+        user_opts[key] = ''
+      end
+    end
+  }
+
+  local _switch_metatable = {
+    __index = function(_,k)
+      print(string.format('Type of %s does not match',k))
+    end
+  }
+
+  setmetatable(_switch,_switch_metatable)
+
+  for key,val in pairs(user_opts) do
+    if default_opts[key]  == nil then
+      print('[Telescope] argument not exists in default options')
+      return
+    end
+    _switch[type(default_opts[key])](key,val)
+  end
+end
+
+-- receive the viml command args
+-- it should be a table value like
+-- {
+--   cmd = 'find_files',
+--   theme = 'dropdown',
+--   extension_type  = 'command'
+--   opts = {
+--      cwd = '***',
+-- }
+function command.run_command(args)
+  local user_opts = args or {}
+  if next(user_opts) == nil and not user_opts.cmd then
+    print('[Telescope] your command miss args')
+    return
+  end
+
+  local cmd = user_opts.cmd
+  local opts = user_opts.opts or {}
+  local extension_type = user_opts.extension_type or ''
+  local theme = user_opts.theme or ''
+
+  if next(opts) ~= nil then
+    convert_user_opts(opts)
+  end
+
+  if string.len(theme) > 0 then
+    opts = themes[theme](opts)
+  end
+
+  if string.len(extension_type) > 0 and extension_type ~= '"' then
+    extensions[cmd][extension_type](opts)
+    return
+  end
+
+  if builtin[cmd] then
+    builtin[cmd](opts)
+    return
+  end
+
+  if rawget(extensions,cmd) then
+    extensions[cmd][cmd](opts)
+  end
+end
+
+return command