-- 仅允许 GET 请求
if ngx.req.get_method() ~= "GET" then
    ngx.status = ngx.HTTP_NOT_ALLOWED
    ngx.header["Content-Type"] = "application/json"
    ngx.say('{"error":"Method not allowed, only GET is supported."}')
    return ngx.exit(ngx.HTTP_NOT_ALLOWED)
end

-- 固定的设备映射表
local device_list = {
    { deviceId = "400500001", deviceName = "主所牵引变压器"},
    { deviceId = "400500002", deviceName = "主所供电变压器"},
    { deviceId = "400500002", deviceName = "主所供电变压器"},
    { deviceId = "400500003", deviceName = "动力变压器"},
    { deviceId = "400500003", deviceName = "动力变压器"},
    { deviceId = "400500004", deviceName = "牵引变压器"},
    { deviceId = "400500004", deviceName = "牵引变压器"},
    { deviceId = "400500005", deviceName = "断路器1"},
    { deviceId = "400500005", deviceName = "断路器1"},
    { deviceId = "400500006", deviceName = "断路器"},
    { deviceId = "400500006", deviceName = "断路器"},
    { deviceId = "400500007", deviceName = "隔离开关"},
    { deviceId = "400500007", deviceName = "隔离开关"},
    { deviceId = "400500008", deviceName = "手动隔离开关"},
    { deviceId = "400500008", deviceName = "手动隔离开关"},
    { deviceId = "400500009", deviceName = "电容"},
    { deviceId = "400500009", deviceName = "电容"},
    { deviceId = "400500010", deviceName = "避雷器接地"},
    { deviceId = "400500010", deviceName = "避雷器接地"},
    { deviceId = "400500011", deviceName = "手车"},
    { deviceId = "400500011", deviceName = "手车"},
    { deviceId = "400500012", deviceName = "箭头"},
    { deviceId = "400500012", deviceName = "箭头"},
    { deviceId = "400500013", deviceName = "备自投"},
    { deviceId = "400500013", deviceName = "备自投"},
    { deviceId = "400500014", deviceName = "避雷器"},
    { deviceId = "400500014", deviceName = "避雷器"},
    { deviceId = "400500015", deviceName = "互感器"},
    { deviceId = "400500015", deviceName = "互感器"},
    { deviceId = "400500016", deviceName = "互感器1"},
    { deviceId = "400500016", deviceName = "互感器1"},
    { deviceId = "400500017", deviceName = "互感器2"},
    { deviceId = "400500017", deviceName = "互感器2"},
    { deviceId = "400500018", deviceName = "接地"},
    { deviceId = "400500018", deviceName = "接地"},
    { deviceId = "400500019", deviceName = "本所遥控权限"},
    { deviceId = "400500019", deviceName = "本所遥控权限"},
    { deviceId = "400500020", deviceName = "软压板"},
    { deviceId = "400500020", deviceName = "软压板"},
    { deviceId = "400501001", deviceName = "233kV交流母线"},
    { deviceId = "400501002", deviceName = "27.5KV交流母线"},
    { deviceId = "400501003", deviceName = "228V交流母线"},
    { deviceId = "400501004", deviceName = "233kV交流馈线"},
    { deviceId = "400501005", deviceName = "27.5kV交流馈线"},
    { deviceId = "400501006", deviceName = "228V交流馈线"},
    { deviceId = "400501007", deviceName = "回流母线"},
    { deviceId = "400501008", deviceName = "电分相"},
    { deviceId = "400500022", deviceName = "主所牵引变压器"},
    { deviceId = "400500023", deviceName = "主所供电变压器"},
    { deviceId = "400500024", deviceName = "动力变压器"},
    { deviceId = "400500025", deviceName = "牵引变压器"},
    { deviceId = "400500026", deviceName = "断路器1"},
    { deviceId = "400500027", deviceName = "断路器"},
    { deviceId = "400500028", deviceName = "隔离开关"},
    { deviceId = "400500029", deviceName = "手动隔离开关"},
    { deviceId = "400500030", deviceName = "电容"},
    { deviceId = "400500031", deviceName = "避雷器接地"},
    { deviceId = "400500032", deviceName = "手车"},
    { deviceId = "400500033", deviceName = "箭头"},
    { deviceId = "400500034", deviceName = "备自投"},
    { deviceId = "400500035", deviceName = "避雷器"},
    { deviceId = "400500036", deviceName = "互感器"},
    { deviceId = "400500037", deviceName = "互感器1"},
    { deviceId = "400500038", deviceName = "互感器2"},
    { deviceId = "400500039", deviceName = "接地"},
    { deviceId = "400500040", deviceName = "本所遥控权限"},
    { deviceId = "400500041", deviceName = "软压板"},
    { deviceId = "400501009", deviceName = "233kV交流母线"},
    { deviceId = "400501010", deviceName = "27.5KV交流母线"},
    { deviceId = "400501011", deviceName = "228V交流母线"},
    { deviceId = "400501012", deviceName = "233kV交流馈线"},
    { deviceId = "400501013", deviceName = "27.5kV交流馈线"},
    { deviceId = "400501014", deviceName = "228V交流馈线"},
    { deviceId = "400501015", deviceName = "回流母线"},
    { deviceId = "400501016", deviceName = "电分相"}
}

-- 获取查询参数 ?count=xx
local count = tonumber(ngx.var.arg_count) or #device_list
if count > #device_list then
    count = #device_list
end

-- 构造返回数据
local devices = {}
for i = 1, count do
    local device = device_list[i]
    table.insert(devices, {
        dataId = device.deviceId,
        id = device.deviceId,
        dataName = device.deviceName,
        value = math.random(0, 1),
    })
end

-- 输出 JSON
ngx.header.content_type = "application/json; charset=utf-8"
local cjson = require("cjson.safe")
ngx.say(cjson.encode(devices))