-- Copyright (C) 2013 Jiale Zhi (calio), Cloudflare Inc.
-- require "luacov"

local type          = type
local byte          = string.byte
local sub           = string.sub
local format        = string.format
local log           = ngx.log
local ERR           = ngx.ERR

local EQUAL         = byte("=")
local SEMICOLON     = byte(";")
local SPACE         = byte(" ")
local HTAB          = byte("\t")


local ok, new_tab = pcall(require, "table.new")
if not ok then
    new_tab = function (narr, nrec) return {} end
end

local _M = new_tab(0, 2)

_M._VERSION = '0.01'


local mt = { __index = _M }


local function get_cookie_table(text_cookie)
    if type(text_cookie) ~= "string" then
        log(ERR, format("expect text_cookie to be \"string\" but found %s",
                type(text_cookie)))
        return {}
    end

    local EXPECT_KEY    = 1
    local EXPECT_VALUE  = 2
    local EXPECT_SP     = 3

    local n = 0
    local len = #text_cookie

    for i=1, len do
        if byte(text_cookie, i) == SEMICOLON then
            n = n + 1
        end
    end

    local cookie_table  = new_tab(0, n + 1)

    local state = EXPECT_SP
    local i = 1
    local j = 1
    local key, value

    while j <= len do
        if state == EXPECT_KEY then
            if byte(text_cookie, j) == EQUAL then
                key = sub(text_cookie, i, j - 1)
                state = EXPECT_VALUE
                i = j + 1
            end
        elseif state == EXPECT_VALUE then
            if byte(text_cookie, j) == SEMICOLON
                    or byte(text_cookie, j) == SPACE
                    or byte(text_cookie, j) == HTAB
            then
                value = sub(text_cookie, i, j - 1)
                cookie_table[key] = value

                key, value = nil, nil
                state = EXPECT_SP
                i = j + 1
            end
        elseif state == EXPECT_SP then
            if byte(text_cookie, j) ~= SPACE
                and byte(text_cookie, j) ~= HTAB
            then
                state = EXPECT_KEY
                i = j
                j = j - 1
            end
        end
        j = j + 1
    end

    if key ~= nil and value == nil then
        cookie_table[key] = sub(text_cookie, i)
    end

    return cookie_table
end

function _M.new(self)
    local _cookie = ngx.var.http_cookie
    if not _cookie then
        return nil, "no cookie found in current request"
    end
    return setmetatable({ _cookie = _cookie }, mt)
end

function _M.get(self, key)
    if self.cookie_table == nil then
        self.cookie_table = get_cookie_table(self._cookie)
    end

    return self.cookie_table[key]
end

function _M.get_all(self)
    local err

    if self.cookie_table == nil then
        self.cookie_table = get_cookie_table(self._cookie)
    end

    return self.cookie_table
end

return _M