local string_dist = require 'string_distance'

assert(debug and debug.getinfo)

--------------------------------------------------------------------------------
-- Error handler

local ErrorHandler = setmetatable({}, {__call = function (c, ...) return c.new(...) end})
      ErrorHandler.__index = ErrorHandler

function ErrorHandler.new (module_name)
	return setmetatable({module_name = module_name, registered = {}}, ErrorHandler)
end

function ErrorHandler:register (f)
    assert(type(self) == 'table')
	assert(type(f) == 'function')
	self.registered[f] = true
end

local ERROR_MODES = { ['internal'] = true, ['external'] = true }

function ErrorHandler:getErrorFunc (mode, name)

    -- Parameter fixing
	local mode  =  mode or 'internal'
    local name  =  name or (mode == 'external' and '') or mode
    if name ~= '' then  name = '/'..name  end

    -- Error checking
    assert(ERROR_MODES[mode])
	assert(type(name) == 'string')

    -- Create error funcs.
    if mode == 'internal' then
        return function (format_msg, ...)
            error(('[%s%s]: '..format_msg):format(self.module_name, name, ...), 2)
        end
    elseif mode == 'external' then
        return function (format_msg, ...)
            local level = 2
            while self.registered[debug.getinfo(level, 'f').func] do
                level = level + 1
            end
            error(('[%s%s]: '..format_msg):format(self.module_name, name, ...), level)
        end
    end
    assert(false)
end

--------------------------------------------------------------------------------

return {
    ErrorHandler  =  ErrorHandler
}