strip_path = require("strip_path")

local uuid = require "resty.jit-uuid"
uuid.seed()

local cjson = require "cjson"

-- Upyun upload parameters
local upyun_operator = ngx.var.$upyun_operator
local upyun_passwd = ngx.var.upyun_passwd

local upyun_expiration = 1800
local upyun_method = "POST"

local function calculate_authorization(bucket, remote_dir, local_filename_with_path)

    -- Get filename with extension without path
    local upyun_filename = strip_path.strip_path(local_filename_with_path)
    ngx.log(ngx.INFO, "UPYUN FILENAME -> ", upyun_filename)

    -- Connect upyun save key
    local upyun_save_key = "/" .. remote_dir .. "/" .. upyun_filename
    ngx.log(ngx.INFO, "UPYUN SAVE KEY -> ", upyun_save_key)

    -- Get RFC1123 data
    local upyun_date = ngx.http_time(ngx.time()) -- RFC1123 date
    ngx.log(ngx.INFO, "UPYUN DATE RFC1123 FORMAT -> ", upyun_date)

    -- Generate upyun UCT time
    local upyun_utc_time = os.time(os.date("!*t"))
    ngx.log(ngx.INFO, "UPYUN UTC TIME -> ", upyun_utc_time)

    -- Calculate upyun file expiration
    local upyun_file_expiration = upyun_utc_time + upyun_expiration
    ngx.log(ngx.INFO, "UPYUN FILE EXPIRATION -> ", upyun_file_expiration)

    local upyun_policy_json = string.format("{\"bucket\":\"%s\",\"save-key\":\"%s\",\"expiration\":\"%s\",\"date\":\"%s\"}", bucket, upyun_save_key,upyun_file_expiration,upyun_date)

    ngx.log(ngx.INFO, "UPYUN POLICY JSON -> ", upyun_policy_json)

    -- Calculate upyun policy
    local upyun_policy = ngx.encode_base64(upyun_policy_json)
    ngx.say("UPYUN POLICY -> ", upyun_policy)

    ---- Calculate MD5 passwd
    local upyun_md5_passwd = ngx.md5(upyun_passwd)
    ngx.log(ngx.INFO, "UPYUN MD5 PASSWD -> ", upyun_md5_passwd)

    ---- Connect to be signed string
    local upyun_to_be_signed_string = upyun_method .. "&" .. "/" .. bucket .. "&" .. upyun_date .. "&" .. upyun_policy
    ngx.log(ngx.INFO, "UPYUN TO BE SIGNED STRING -> ", upyun_to_be_signed_string)

    -- Calculate upyun token hmac sha1
    local upyun_token_hmac_sha1 = ngx.hmac_sha1(upyun_md5_passwd, upyun_to_be_signed_string)
    --ngx.log(ngx.INFO, "UPYUN TOKEN HMAC SHA1 -> ", upyun_token_hmac_sha1)

    -- Calculate upyun signature
    local upyun_signature = ngx.encode_base64(upyun_token_hmac_sha1)
    ngx.log(ngx.INFO, "UPYUN SIGNATURE -> ", upyun_signature)

    -- Connect upyun upload file authorization
    local upyun_upload_file_authorization = string.format("UPYUN %s:%s", upyun_operator, upyun_signature)
    ngx.log(ngx.INFO, "UPYUN UPLOAD FILE AUTHORIZATION -> ", upyun_upload_file_authorization)

    return upyun_upload_file_authorization
end