local string = string
local table = table
local pairs = pairs


local message = {}

function message.build(context)
    local messages = context.rule.messages
    local mode = context.mode or "affirmative"
    local template = context.template or "standard"
    local parent = context.parent
    local message = messages[mode][template]

    if
        context.message and
            (not parent or (parent and not parent._message) or
                (parent and parent._message and parent.message ~= context.message))
     then
        message = context.message
    end

    context.placeholder = context.placeholder or context.name or tostring(context.input)

    if context.translator then
        message = context.translator(message)
    end

    for property in string.gmatch(message, "{{(%a+)}}") do
        message = string.gsub(message, "{{" .. property .. "}}", '"' .. tostring(context[property]) .. '"')
    end

    context._message = message

    return message
end

function message.get_messages(context, level)
    local messages = {}

    while (#context.children == 1 and level > 1) do
        context = context.children[1]
    end

    if (context.mode == "negative" or context.result == false) then
        table.insert(messages, {level = level, content = message.build(context)})
    end

    for index = 1, #context.children do
        local childConstraint = context.children[index]
        local childLevel = (level + 1)
        local childMessages = message.get_messages(childConstraint, childLevel)
        for _, message in pairs(childMessages) do
            table.insert(messages, message)
        end
    end

    return messages
end

function message.new(context)
    return {
        get_full = function()
            local messages = {}
            for _, message in pairs(message.get_messages(context, 1)) do
                local prefix = ""

                if message.level > 1 then
                    prefix = string.rep(" ", (message.level - 1)) .. "- "
                end

                table.insert(messages, prefix .. message.content)
            end

            return table.concat(messages, "\n")
        end,
        get_single = function()
            local current = context
            while #current.children == 1 do
                current = current.children[1]
            end

            return message.build(current)
        end
    }
end

return message