config.lua

local M = {}

-- helper function to use default value if the user vaule is nil
local if_nil = function(value, default_value)
	return value ~= nil and value or default_value
end

-- default_langugages_config table contains key & value
-- key: the language name
-- value: a table with the following elements
-- index1 single_line_comment
-- index2 multiline comment
-- index3 prefer_multicomment
local default_langugages_config = {
	default = { "//", { "/*", "*/" }, false },
	fish = { '#', {}, false },
	go = { "//", { "/*", "*/" }, false },
	lua = { "--", { "--[[", "--]]" }, false },
	ruby = { '#', {}, false },
	sh = { '#', {}, false },
	toml = { '#', {}, false },
	typescript = { "//", { "/*", "*/" }, false },
	vim = { '"', {}, false },
	yaml = { '#', {}, false },
}

local default_options = {
	append_space = true,
}

-- The config structure contains the following:
-- key: the language name
-- value: is a table that has the following keys/values
-- single_line_comment: string
-- multiline_comment: table that has opening/closing comment strings (optional)
-- prefer_multiline: boolean
-- example:
-- { "go"= { single_line_comment= "//", multiline_comment= { "/*", "*/"} , prefer_multiline= false } }
M.set_languages = function(config)
	local user_config = {}
	config = config == nil and {} or config

	for k, v in pairs(config) do
		local key = k
		local value = {}

		if v.single_line_comment == nil then
			error("single_line_comment parameter cannot be nil for language " .. key)
		end

		local default_sign_line_comment = default_langugages_config[key] and default_langugages_config[key][1] or nil
		table.insert(value, if_nil(v.single_line_comment, default_sign_line_comment))

		local default_multiline_comment = default_langugages_config[key] and default_langugages_config[key][2] or nil
		table.insert(value, if_nil(v.multiline_comment, default_multiline_comment))

		local default_prefer_multiline = default_langugages_config[key] and default_langugages_config[key][3] or false
		table.insert(value, if_nil(v.prefer_multiline, default_prefer_multiline))

		user_config[key] = value
	end

	return vim.tbl_deep_extend("keep", user_config, default_langugages_config)
end

-- Set other options
-- @param config table
M.set_opts = function(config)
	local user_config = {}
	config = config == nil and {} or config

	for k, v in pairs(config) do
		local key = k
		local value = {}

    -- append_space append an additional space after a comment string
		local default_append_space = default_options[key] and default_options[key] or true
		table.insert(value, if_nil(v.append_space, default_append_space))

		user_config[key] = value
	end

	return vim.tbl_deep_extend("keep", user_config, default_options)
end

return M