--
-- Licensed to the Apache Software Foundation (ASF) under one or more
-- contributor license agreements.  See the NOTICE file distributed with
-- this work for additional information regarding copyright ownership.
-- The ASF licenses this file to You under the Apache License, Version 2.0
-- (the "License"); you may not use this file except in compliance with
-- the License.  You may obtain a copy of the License at
--
--     http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
--
local expr = require("resty.expr.v1")
local core = require("apisix.core")
local schema_plugin = require("apisix.admin.plugins").check_schema
local upstreams = require("apisix.admin.upstreams")
local utils = require("apisix.admin.utils")
local tostring = tostring
local type = type
local loadstring = loadstring


local _M = {
    version = 0.2,
}


local function check_conf(id, conf, need_id)
    if not conf then
        return nil, {error_msg = "missing configurations"}
    end

    id = id or conf.id
    if need_id and not id then
        return nil, {error_msg = "missing route id"}
    end

    if not need_id and id then
        return nil, {error_msg = "wrong route id, do not need it"}
    end

    if need_id and conf.id and tostring(conf.id) ~= tostring(id) then
        return nil, {error_msg = "wrong route id"}
    end

    conf.id = id

    core.log.info("schema: ", core.json.delay_encode(core.schema.route))
    core.log.info("conf  : ", core.json.delay_encode(conf))

    if conf.host and conf.hosts then
        return nil, {error_msg = "only one of host or hosts is allowed"}
    end

    if conf.remote_addr and conf.remote_addrs then
        return nil, {error_msg = "only one of remote_addr or remote_addrs is "
                                 .. "allowed"}
    end

    local ok, err = core.schema.check(core.schema.route, conf)
    if not ok then
        return nil, {error_msg = "invalid configuration: " .. err}
    end

    local upstream_conf = conf.upstream
    if upstream_conf then
        local ok, err = upstreams.check_upstream_conf(upstream_conf)
        if not ok then
            return nil, {error_msg = err}
        end
    end

    local upstream_id = conf.upstream_id
    if upstream_id then
        local key = "/upstreams/" .. upstream_id
        local res, err = core.etcd.get(key)
        if not res then
            return nil, {error_msg = "failed to fetch upstream info by "
                                     .. "upstream id [" .. upstream_id .. "]: "
                                     .. err}
        end

        if res.status ~= 200 then
            return nil, {error_msg = "failed to fetch upstream info by "
                                     .. "upstream id [" .. upstream_id .. "], "
                                     .. "response code: " .. res.status}
        end
    end

    local service_id = conf.service_id
    if service_id then
        local key = "/services/" .. service_id
        local res, err = core.etcd.get(key)
        if not res then
            return nil, {error_msg = "failed to fetch service info by "
                                     .. "service id [" .. service_id .. "]: "
                                     .. err}
        end

        if res.status ~= 200 then
            return nil, {error_msg = "failed to fetch service info by "
                                     .. "service id [" .. service_id .. "], "
                                     .. "response code: " .. res.status}
        end
    end

    local plugin_config_id = conf.plugin_config_id
    if plugin_config_id then
        local key = "/plugin_configs/" .. plugin_config_id
        local res, err = core.etcd.get(key)
        if not res then
            return nil, {error_msg = "failed to fetch plugin config info by "
                                     .. "plugin config id [" .. plugin_config_id .. "]: "
                                     .. err}
        end

        if res.status ~= 200 then
            return nil, {error_msg = "failed to fetch plugin config info by "
                                     .. "plugin config id [" .. plugin_config_id .. "], "
                                     .. "response code: " .. res.status}
        end
    end

    if conf.plugins then
        local ok, err = schema_plugin(conf.plugins)
        if not ok then
            return nil, {error_msg = err}
        end
    end

    if conf.vars then
        ok, err = expr.new(conf.vars)
        if not ok then
            return nil, {error_msg = "failed to validate the 'vars' expression: " .. err}
        end
    end

    if conf.filter_func then
        local func, err = loadstring("return " .. conf.filter_func)
        if not func then
            return nil, {error_msg = "failed to load 'filter_func' string: "
                                     .. err}
        end

        if type(func()) ~= "function" then
            return nil, {error_msg = "'filter_func' should be a function"}
        end
    end

    if conf.script then
        local obj, err = loadstring(conf.script)
        if not obj then
            return nil, {error_msg = "failed to load 'script' string: "
                                     .. err}
        end

        if type(obj()) ~= "table" then
            return nil, {error_msg = "'script' should be a Lua object"}
        end
    end

    return need_id and id or true
end


function _M.put(id, conf, sub_path, args)
    local id, err = check_conf(id, conf, true)
    if not id then
        return 400, err
    end

    local key = "/routes/" .. id

    local ok, err = utils.inject_conf_with_prev_conf("route", key, conf)
    if not ok then
        return 500, {error_msg = err}
    end

    local res, err = core.etcd.set(key, conf, args.ttl)
    if not res then
        core.log.error("failed to put route[", key, "] to etcd: ", err)
        return 500, {error_msg = err}
    end

    return res.status, res.body
end


function _M.get(id)
    local key = "/routes"
    if id then
        key = key .. "/" .. id
    end

    local res, err = core.etcd.get(key, not id)
    if not res then
        core.log.error("failed to get route[", key, "] from etcd: ", err)
        return 500, {error_msg = err}
    end

    return res.status, res.body
end


function _M.post(id, conf, sub_path, args)
    local id, err = check_conf(id, conf, false)
    if not id then
        return 400, err
    end

    local key = "/routes"
    -- core.log.info("key: ", key)
    utils.inject_timestamp(conf)
    local res, err = core.etcd.push("/routes", conf, args.ttl)
    if not res then
        core.log.error("failed to post route[", key, "] to etcd: ", err)
        return 500, {error_msg = err}
    end

    return res.status, res.body
end


function _M.delete(id)
    if not id then
        return 400, {error_msg = "missing route id"}
    end

    local key = "/routes/" .. id
    -- core.log.info("key: ", key)
    local res, err = core.etcd.delete(key)
    if not res then
        core.log.error("failed to delete route[", key, "] in etcd: ", err)
        return 500, {error_msg = err}
    end

    return res.status, res.body
end


function _M.patch(id, conf, sub_path, args)
    if not id then
        return 400, {error_msg = "missing route id"}
    end

    if not conf then
        return 400, {error_msg = "missing new configuration"}
    end

    if not sub_path or sub_path == "" then
        if type(conf) ~= "table"  then
            return 400, {error_msg = "invalid configuration"}
        end
    end

    local key = "/routes"
    if id then
        key = key .. "/" .. id
    end

    local res_old, err = core.etcd.get(key)
    if not res_old then
        core.log.error("failed to get route [", key, "] in etcd: ", err)
        return 500, {error_msg = err}
    end

    if res_old.status ~= 200 then
        return res_old.status, res_old.body
    end
    core.log.info("key: ", key, " old value: ",
                  core.json.delay_encode(res_old, true))

    local node_value = res_old.body.node.value
    local modified_index = res_old.body.node.modifiedIndex

    if sub_path and sub_path ~= "" then
        local code, err, node_val = core.table.patch(node_value, sub_path, conf)
        node_value = node_val
        if code then
            return code, err
        end
    else
        node_value = core.table.merge(node_value, conf);
    end

    utils.inject_timestamp(node_value, nil, conf)

    core.log.info("new conf: ", core.json.delay_encode(node_value, true))

    local id, err = check_conf(id, node_value, true)
    if not id then
        return 400, err
    end

    local res, err = core.etcd.atomic_set(key, node_value, args.ttl, modified_index)
    if not res then
        core.log.error("failed to set new route[", key, "] to etcd: ", err)
        return 500, {error_msg = err}
    end

    return res.status, res.body
end


return _M