local http = require("httpclient")
local codec = require("fastweb.codec")
local base64 = require("base64")
local openssl = require("openssl")
local M = {}

local url_get_access_token = "https://qyapi.weixin.qq.com/cgi-bin/gettoken"
local url_send_message = "https://qyapi.weixin.qq.com/cgi-bin/message/send"
local url_get_userid_by_mobile = "https://qyapi.weixin.qq.com/cgi-bin/user/getuserid"
local url_get_userids = "https://qyapi.weixin.qq.com/cgi-bin/user/list_id"


-- 验证签名
M.verify_signature = function(token,timestamp,nonce,echostr)
    local params = {token, timestamp, nonce, echostr}
    table.sort(params, function(a, b) return tostring(a) < tostring(b) end)
    return string.lower(codec.sha1(table.concat(params)))
end

-- 解密数据
M.decrypt_data = function(qywx_aeskey,data)

    -- 16随机数+4字节消息长度+消息体+接收ID
    local function parse_decrypted_msg(data)
        -- data: string, decrypted_echostr
        if #data < 20 then
            return nil, "data too short"
        end
        -- 跳过16字节随机数
        local msg_len_bytes = data:sub(17, 20)
        local b1, b2, b3, b4 = msg_len_bytes:byte(1, 4)
        local msg_len = b1 * 2^24 + b2 * 2^16 + b3 * 2^8 + b4
        local msg_start = 21
        local msg_end = 20 + msg_len
        local msg = data:sub(msg_start, msg_end)
        return msg
    end
 
    local cipher = openssl.cipher.new("aes-256-cbc")
    cipher:init(base64.decode(qywx_aeskey), "0123456789abcdef", false)
    local plaintext = cipher:update(data)
    plaintext =  parse_decrypted_msg(plaintext)
    return plaintext
end


-- 获取access_token
M.get_access_token = function(corpid,corpsecret)

    local url = url_get_access_token .. "?corpid=" .. corpid .. "&corpsecret=" .. corpsecret
    local result,err = http.get(url,{
        ["Content-Type"] = "application/json"
    })
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true,data.access_token
    end
    return false,data.errmsg
end
-- 获取userid
M.get_userid_by_mobile = function(access_token,mobile)
    local url = url_get_userid_by_mobile .. "?access_token=" .. access_token .. "&mobile=" .. mobile
    local result,err = http.post(url,{
        ["Content-Type"] = "application/json"
    },cjson.encode({
        mobile = mobile
    }))
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true,data.userid
    end
    return false,data.errmsg
end
-- 获取用户列表
M.get_userids = function(access_token)
    local url = url_get_userids .. "?access_token=" .. access_token
    local result,err = http.post(url,{
        ["Content-Type"] = "application/json"
    },cjson.encode({
        limit = 1000
    }))
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true,data.dept_user
    end
    return false,data.errmsg
end
-- 上传临时文件
M.upload_temp_file = function(access_token,data,type_str)
    local function make_upload_temp_data(data)
        local boundary = "----WebKitFormBoundary7MA4YWxkTrZu0gW"
        local body = ""
        
        local filename = ""
        if type_str == "image" then
            filename = tostring(os.time())..".png"
        elseif type_str == "video" then
            filename = tostring(os.time())..".mp4"
        end

        -- 构造 multipart 数据
        body = body .. "--" .. boundary .. "\r\n"
        body = body .. "Content-Disposition: form-data; name=\"media\"; filename=\""..filename.."\"\r\n"
        body = body .. "Content-Type: application/octet-stream\r\n\r\n" .. data .. "\r\n"
        body = body .. "--" .. boundary .. "--\r\n"
        
        return body
    end
    local body = make_upload_temp_data(data)
    local url = "https://qyapi.weixin.qq.com/cgi-bin/media/upload?access_token=" .. access_token.."&type="..type_str
    local result,err = http.post(url,{
        ["Content-Type"] = "multipart/form-data; boundary=--WebKitFormBoundary7MA4YWxkTrZu0gW",
        ["Content-Length"] = #body
    },body)
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true,data.media_id
    end 
    return false,data.errmsg
end
-- 发送消息 
M.send_message = function(access_token,userid,agentid,message)
    local url = url_send_message .. "?access_token=" .. access_token
    local result,err = http.post(url,{
        ["Content-Type"] = "application/json"
    },cjson.encode({
        touser = userid,
        msgtype = "text",
        agentid = agentid,
        text = {
            content = message
        }
    }))
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true
    end 
    return false,data.errmsg
end
-- 发送图片消息
M.send_image_message = function(access_token,userid,agentid,image_filepath)
    local file = io.open(image_filepath, "rb")
    if not file then
        return false, "cannot open file: " .. tostring(image_filepath)
    end
    local data = file:read("*a")
    file:close()
    local ok, media_id = M.upload_temp_file(access_token, data,"image")
    if not ok then
        return false, "upload_temp_file_failed:"..media_id
    end
    local url = url_send_message .. "?access_token=" .. access_token
    local result, err = http.post(url, {
        ["Content-Type"] = "application/json"
    }, cjson.encode({
        touser = userid,
        msgtype = "image",
        agentid = agentid,
        image = {
            media_id = media_id,
        }
    }))
    if not result then
        return false, err
    end
    local resp = cjson.decode(err)
    if resp.errcode == 0 then
        return true
    end
    return false, resp.errmsg
end
-- 发送视频消息
M.send_video_message = function(access_token,userid,agentid,title,video_filepath)
    local file = io.open(video_filepath, "rb")
    if not file then
        return false, "cannot open file: " .. tostring(video_filepath)
    end
    local data = file:read("*a")
    file:close()
    local ok, media_id = M.upload_temp_file(access_token, data,"video")
    if not ok then
        return false, "upload_temp_file_failed:"..media_id
    end
    local url = url_send_message .. "?access_token=" .. access_token
    local result, err = http.post(url, {
        ["Content-Type"] = "application/json"
    }, cjson.encode({
        touser = userid,
        msgtype = "video",
        agentid = agentid,
        video = {
            media_id = media_id,
            title = title
        }
    }))
    if not result then
        return false, err
    end
    local resp = cjson.decode(err)
    if resp.errcode == 0 then
        return true
    end
    return false, resp.errmsg
end
-- 发送卡片消息
M.send_card_message = function(access_token,userid,agentid,message)
    local url = url_send_message .. "?access_token=" .. access_token
    local result,err = http.post(url,{
        ["Content-Type"] = "application/json"
    },cjson.encode({
        touser = userid,
        msgtype = "news",
        agentid = agentid,
        news = {
            articles = {
                message
            }
        }
    }))
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true
    end 
    return false,data.errmsg
end
-- 发送卡片消息
M.send_template_card_message = function(access_token,userid,agentid,message)
    local url = url_send_message .. "?access_token=" .. access_token
    local result,err = http.post(url,{
        ["Content-Type"] = "application/json"
    },cjson.encode({
        touser = userid,
        msgtype = "template_card",
        agentid = agentid,
        template_card = message
    }))
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true
    end 
    return false,data.errmsg
end
-- 发送MMD消息
M.send_markdown_message = function(access_token,userid,agentid,message)
    local url = url_send_message .. "?access_token=" .. access_token
    local result,err = http.post(url,{
        ["Content-Type"] = "application/json"
    },cjson.encode({
        touser = userid,
        msgtype = "markdown",
        agentid = agentid,
        markdown = {
            content = message 
        }
    }))
    if not result then
        return false,err
    end
    local data = cjson.decode(err)
    if data.errcode == 0 then
        return true
    end 
    return false,data.errmsg
end
return M