local http = require("httpclient")

local M = {}
-- 微信支付统一下单
local url_pay = "https://api.mch.weixin.qq.com/pay/unifiedorder"


-- 纯文本方式取中间内容（不使用正则）
function extract_between(text, start_str, end_str)
    local start_pos = string.find(text, start_str, 1, true)
    if not start_pos then return nil end

    local from = start_pos + #start_str
    local end_pos = string.find(text, end_str, from, true)
    if not end_pos then return nil end

    return string.sub(text, from, end_pos - 1)
end


-- 验签
M.sign = function(data,key)
    local sign_str = ""
    local keys = {}
    for k,_ in pairs(data) do
        table.insert(keys, k)
    end
    table.sort(keys)
    for i,k in ipairs(keys) do
        if i > 1 then
            sign_str = sign_str .. "&"
        end
        sign_str = sign_str .. k .. "=" .. data[k]
    end
    sign_str = sign_str .. "&key=" .. key
    return string.upper(codec.md5(sign_str))
end

-- 微信支付统一下单
M.unified_order = function(appid,mch_id,openid,key,body,out_trade_no,total_fee,notify_url)
    function xml_make(data)
        local xml_data = "<xml>"
        for k,v in pairs(data) do
            xml_data = xml_data .. "<" .. k .. ">" .. v .. "</" .. k .. ">"
        end
        xml_data = xml_data .. "</xml>"
        return xml_data
    end
    local data = {
        appid = appid,
        body = body,
        mch_id = mch_id,
        nonce_str = fw.make_software_guid(),
        notify_url = notify_url,
        openid = openid,
        out_trade_no = out_trade_no,
        spbill_create_ip = request.remote_ipaddress(),
        total_fee = total_fee,
        trade_type = "JSAPI",
    }
    data.sign = M.sign(data,key)

    -- 生成XML
    local xml_data = xml_make(data)
    --  print("================xml_request=================")
    --  print(appid,"|",mch_id,"|",openid,"|",key,"|",body,"|",out_trade_no,"|",total_fee,"|",notify_url)
    --  print(xml_data) 
    
    local result,res = http.post(url_pay,{
        ["Content-Type"] = "text/xml", 
    }, xml_data)
    if not result then 
        return false,"request error"..res
    end
    --  print("============res=============")
    --  print(res)

    -- 取中间文本
    local result_code = extract_between(res,"<result_code><![CDATA[","]]></result_code>")
    if result_code ~= "SUCCESS" then
        return false,extract_between(res,"<err_code_des><![CDATA[","]]></err_code_des>")
    end

    local prepay_id = extract_between(res,"<prepay_id><![CDATA[","]]></prepay_id>")

    local result_data = {
        appId = appid,
        nonceStr = fw.make_software_guid(), 
        package = "prepay_id=" .. prepay_id,
        signType = "MD5",
        timeStamp =  string.format("%d",os.time())
    }
    result_data["paySign"] = M.sign(result_data,key)
    return true,result_data
end



return M