local config_file = ''
local config_dir = ''

---
-- Find config file and set global variables
--
-- @return string
local function find_config_file()
    if config_file ~= '' then
    	return config_file
    end

    local scandir = require('plenary.scandir').scan_dir
    local Path = require('plenary.path')

    local current_dir = Path:new('.')
    while config_file == '' do
    	local files = scandir(current_dir.filename, { depth = 1 })
	for _, file in ipairs(files) do
	    if string.find(file, 'rclone.conf') then
		config_file = file
		config_dir = current_dir.filename

		return config_file
	    end
	end

	--if current_dir:is_root() then
	if current_dir.filename == '/' then
	    -- set to 'rclone config file' output
	    local handle = io.popen('rclone config file', 'r')
	    handle:read() -- advance one line because we want the second line only
	    local output = handle:read();
	    handle:close()

	    config_file = output
	    local config_file_path = Path:new(config_file)
	    config_dir = config_file_path:parent().filename

	    return config_file
	end

	current_dir = current_dir:parent()
    end
end

---
-- Get rclone config as JSON
-- and parse to table
--
-- @return string
local function get_config()
    local handle = io.popen('rclone config dump --config=' .. find_config_file(), 'r')
    local config = handle:read('*all');
    handle:close()

    return vim.fn.json_decode(config)
end

---
-- Get the desired remote config from the config file
--
-- @param remote string
--
-- @return string
-- @return table
-- @return nil
local function get_remote_config(remote)
    local config = get_config()
    local target_remote = nil
    local target_config = nil

    if remote then
	if config[remote] then
	    target_remote = remote
	    target_config = config[remote]
	else
	    print("Couldn't find remote: \"" .. remote .. '"')
	    return
	end
    else
        local config_length = 0
	for _, _ in pairs(config) do
	    config_length = config_length + 1
        end

	if config_length == 0 then
	    print('No remotes defined in config file at "' .. find_config_file() .. '"')
	    return
	end

	if config_length == 1 then
	    for remote_name, remote_config in pairs(config) do
		target_remote = remote_name
		target_config = remote_config
	    end
	else
	    for remote_name, remote_config in pairs(config) do
		if remote_config.vim_rclone_default then
		    target_remote = remote_name
		    target_config = remote_config
		end
	    end

	    if target_remote == nil then
		print('No default remote specified')
		return
	    end
	end
    end


    if target_config.vim_rclone_local_path == nil or target_config.vim_rclone_local_path == '' or
	target_config.vim_rclone_remote_path == nil or target_config.vim_rclone_remote_path == '' then
	print('No local and or remote path set for remote "' .. target_remote .. '"')
	return
    end

    return target_remote, target_config
end

---
-- Build the local path
--
-- @param config table
--
-- @return string
local function prepare_cmd_local_path(config)
    local Path = require('plenary.path')
    local local_path = Path:new(config.vim_rclone_local_path)

    local_path._cwd = config_dir -- set cwd to config dir to resolve path correctly
    local_path = local_path:absolute()
    local_path = local_path:gsub('%./', '') -- remove wrongly kept ./ for relative paths

    return local_path
end

---
-- Add remote path
--
-- @param config table
-- @param remote string
--
-- @return string
local function build_cmd_remote_path(config, remote)
    return remote .. ':' .. config.vim_rclone_remote_path
end

---
-- Add config location path
--
-- @return string
local function build_cmd_config()
    return '--config=' .. find_config_file()
end

---
-- Add exclude patterns
--
-- @param local_path string
--
-- @return string
local function build_cmd_exclude(local_path)
    local Path = require('plenary.path')
    local cmd = ''

    -- TODO: add configurable default exclude patterns
    local configurable_default_exclude_patterns = {'.git/', '.gitignore', '.rcloneignore'}
    for _, pattern in pairs(configurable_default_exclude_patterns) do
    	cmd = cmd .. ' --exclude=' .. pattern
    end

    -- add .gitignore patterns
    local gitignore = Path:new(local_path .. '/.gitignore')
    if gitignore:exists() then
        cmd = cmd .. ' --exclude-from=' .. gitignore.filename
    end

    -- add .rcloneignore patterns
    local rcloneignore = Path:new(local_path .. '/.rcloneignore')
    if rcloneignore:exists() then
    	cmd = cmd .. ' --exclude-from=' .. rcloneignore.filename
    end

    return cmd:gsub('^%s?', '') -- ltrim
end

---
-- Add logging
--
-- @return string
local function build_cmd_logging()
    local log_level = 'INFO'
    local cmd = ''

    cmd = '--log-level=' .. log_level
    cmd = cmd .. ' --log-file=' .. vim.fn.stdpath('data') .. '/rclone_nvim/rclone.log'

    return cmd
end

---
-- Call the 'rclone copy' command with config values
-- 'rclone copy <args>'
--
-- @return any
local function copy(options)
    local remote, config = get_remote_config(options.remote)
    if remote == nil then
	return
    end

    local local_path = prepare_cmd_local_path(config)

    local cmd =
	'rclone copy ' ..
	local_path .. ' ' ..
	build_cmd_remote_path(config, remote) .. ' ' ..
	build_cmd_config() .. ' ' ..
	build_cmd_exclude(local_path) .. ' ' ..
	build_cmd_logging()

    if options['--dry-run'] then
      print(cmd)
    else
      os.execute(cmd)
    end

    print("Copied!")

    return config
end

---
-- Call the 'rclone copy' command with config values for the current file
-- 'rclone copy <args>'
--
-- @return any
local function copyFile(options)
    local remote, config = get_remote_config(options.remote)
    if remote == nil then
	return
    end

    local local_path = prepare_cmd_local_path(config)

    -- build relative path to file for local and remote
    local Path = require('plenary.path')
    local local_file_path = Path:new(vim.fn.expand('%')):absolute()
    local local_file_path_relative = local_file_path:gsub(local_path:gsub('([^%w])', '%%%1'), '')
    local local_file_path_relative_parent = Path:new(local_file_path_relative):parent().filename

    local cmd =
	'rclone copy ' ..
	local_path .. local_file_path_relative .. ' ' ..
	build_cmd_remote_path(config, remote) .. local_file_path_relative_parent .. ' ' ..
	build_cmd_config() .. ' ' ..
	build_cmd_exclude(local_path) .. ' ' ..
	build_cmd_logging()

    if options['--dry-run'] then
      print(cmd)
    else
      os.execute(cmd)
    end

    print("Copied file!")

    return config
end

---
-- Call the 'rclone sync' command with config values
-- 'rclone sync <args>'
--
-- @return any
local function sync(options)
    local remote, config = get_remote_config(options.remote)
    if remote == nil then
	return
    end

    local local_path = prepare_cmd_local_path(config)

    local cmd =
	'rclone sync ' ..
	local_path .. ' ' ..
	build_cmd_remote_path(config, remote) .. ' ' ..
	build_cmd_config() .. ' ' ..
	build_cmd_exclude(local_path) .. ' ' ..
	build_cmd_logging()

    if options['--dry-run'] then
      print(cmd)
    else
      os.execute(cmd)
    end

    print("Synced!")

    return config
end

-- Table for dynamic command access
local commands = {
  copy = copy,
  copyFile = copyFile,
  sync = sync,
}

---
-- Parse args and run specified command
local function run(cmd, ...)
  local args = { ... }
  if cmd == nil then
    print('No command supplied!')
    return
  end

  if commands[cmd] == nil then
    print('Command "' .. cmd .. '" does not exist.')
    return
  end

  local options = {}
  for _, arg in ipairs(args) do
    if arg:find('%-%-') == 1 then
      options[arg] = true
    elseif arg:find('=', 1) == nil then
      options['remote'] = arg
    else
      local param = vim.split(arg, '=')
      local key = table.remove(param, 1)
      param = table.concat(param, '=')

      options[key] = param
    end
  end

  commands[cmd](options)
end

return {
  run = run,
}