-- Colorize a string in the given color
--
-- Colorizes a string in a given hexadecimal color coded color. The string will
-- be returned including a reset color escape (assumably white text color)
--
-- @param color   The hexadecimal value for the color you want to use
-- @param string  The string that has to be colorized
-- @return string The colorized string
local colorize = function (color, string)
    local c = minetest.get_color_escape_sequence('#'..string.upper(color))
    local r = minetest.get_color_escape_sequence('#FFFFFF')
    return c..string..r
end


-- Validate a new value
--
-- 1. Check if setting is valid at all
-- 2. If `show` has to be set, validate for 'true' or 'false' string
-- 3. Validate against a simple regex
-- 4. If all of the above was not `nil`, return `true`
--
-- @param setting   The setting the value is for
-- @param new_value The new value that has to be validated
-- @return bool     If the new value for the setting is valid or not
local validate = function (setting, new_value)
    local valid_values = {
        runtime = '^[^%c]+$',
        offset = '^%-?[0-9]+,%-?[0-9]+$',
        ingame_time = '^[^%c]+$',
        current_time = '^[^%c]+$',
        font_color = '^[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]$',
        start = '^[^%c]+$',
        show = '^$', -- unmatchable, see below
        locale = '^$', -- currently unsupported and not settable by user
        position = '^%-?[0-9]+,%-?[0-9]+$',
        format = '^[^%c]+$',
        alignment = '^%-?[0-9]+,%-?[0-9]+$'
    }

    if valid_values[setting] == nil then return false end

    -- Check if `new_value` for setting `show` is either 'true' or 'false' and
    -- return true in both cases (because either 'true' or 'false' are valid).
    if setting == 'show' and new_value == 'true' then return true end
    if setting == 'show' and new_value == 'false' then return true end

    if new_value:match(valid_values[setting]) == nil then return false end
    return true
end


-- Show help to the player
--
-- @param player The player to show the help to
local show_help = function (player)
    local help = colorize('729fcf', 'Mtimer Help')..'\n'
    local name = player:get_player_name()

    help = help..'  '..colorize('73d216', '/mtimer help')..' = '
    help = help..'Show this messaget\n'

    help = help..'  '..colorize('73d216', '/mtimer show')..' = '
    help = help..'List the current configuration\n'

    help = help..'  '..colorize('73d216', '/mtimer set setting value')..' = '
    help = help..'Set '..colorize('73d216', 'setting')..' to '
    help = help..colorize('73d216', 'value')

    minetest.chat_send_player(name, help)
end


-- Show the configuration to the player
--
-- Gathers all settable variables and prints them to the player
--
-- @param player The player object of the player to print to
local show_configuration = function (player)
    local name = player:get_player_name()
    local result_string = colorize('729fcf', 'MTimer Configuration')..'\n'
    local font_color = player:get_attribute('mtimer:font_color')

    local configuration = {
        runtime = player:get_attribute('mtimer:runtime'),
        offset = player:get_attribute('mtimer:offset'),
        ingame_time = player:get_attribute('mtimer:ingame_time'),
        current_time = player:get_attribute('mtimer:current_time'),
        font_color = colorize(font_color, font_color),
        start = player:get_attribute('mtimer:start'),
        show = player:get_attribute('mtimer:show'),
        locale = player:get_attribute('mtimer:locale'),
        position = player:get_attribute('mtimer:position'),
        format = player:get_attribute('mtimer:format'),
        alignment = player:get_attribute('mtimer:alignment')
    }

    for setting,value in pairs(configuration) do
        local s = colorize('73d216', setting)
        result_string = result_string..'  '..s..' = '..value..'\n'
    end

    minetest.chat_send_player(name, result_string)
end


local set = function (player, payload)
    local name = player:get_player_name()
    local setting = payload:match('[%a_]+')
    local new_value = payload:gsub('^[%a_]+ ', '')
    local old_value = player:get_attribute('mtimer:'..setting)
    local status = ''

    if old_value == nil then
        minetest.chat_send_player(name, colorize('ef2929', 'Unknown setting!'))
        show_configuration(player)
        return
    end

    if validate(setting, new_value) == false then
        minetest.chat_send_player(name, colorize('ef2929', 'Invalid value!'))
        show_configuration(player)
        return
    end

    status = status..colorize('729fcf', '[MTimer]')..' '
    status = status..'Setting '..colorize('73d216', setting)..' to '
    status = status..colorize('75507b', new_value)

    print('[MTimer] '..name..' sets `'..setting..'` to `'..new_value..'`')
    minetest.chat_send_player(name, status)
    player:set_attribute('mtimer:'..setting, new_value)
    mtimer_update(player)
end


-- Register the chat command that will be used to interact with MTimer.
--
-- The chat command has three actions:
--
-- help   Show help to the user via the regular chat
-- show   Show the current configuration to the user
-- set    Set the given setting to the given value
minetest.register_chatcommand('mtimer', {
    params = '<help>, <show>, <set setting value>',
    description = 'Manage MTimer display',
    func = function(name, parameters)
        local player = minetest.get_player_by_name(name)
        local action = parameters:match('%a+')
        local payload = parameters:gsub('^%a+ ', '')
        if action == 'help' then show_help(player) end
        if action == 'show' then show_configuration(player) end
        if action == 'set' and payload ~= nil then set(player, payload) end
    end
})