using DistTestCore.Codex;
using DistTestCore.Metrics;
using KubernetesWorkflow;
using System.Text;

namespace DistTestCore
{
    public class PrometheusStarter
    {
        private readonly TestLifecycle lifecycle;
        private readonly WorkflowCreator workflowCreator;

        public PrometheusStarter(TestLifecycle lifecycle, WorkflowCreator workflowCreator)
        {
            this.lifecycle = lifecycle;
            this.workflowCreator = workflowCreator;
        }

        public IMetricsAccessFactory CollectMetricsFor(CodexSetup codexSetup, RunningContainers containers)
        {
            if (!codexSetup.MetricsEnabled) return new MetricsUnavailableAccessFactory();

            Log($"Starting metrics server for {containers.Describe()}");
            var startupConfig = new StartupConfig();
            startupConfig.Add(new PrometheusStartupConfig(GeneratePrometheusConfig(containers.Containers)));

            var workflow = workflowCreator.CreateWorkflow();
            var runningContainers = workflow.Start(1, Location.Unspecified, new PrometheusContainerRecipe(), startupConfig);
            if (runningContainers.Containers.Length != 1) throw new InvalidOperationException("Expected only 1 Prometheus container to be created.");

            Log("Metrics server started.");

            return new CodexNodeMetricsAccessFactory(runningContainers);
        }

        private string GeneratePrometheusConfig(RunningContainer[] nodes)
        {
            var config = "";
            config += "global:\n";
            config += "  scrape_interval: 30s\n";
            config += "  scrape_timeout: 10s\n";
            config += "\n";
            config += "scrape_configs:\n";
            config += "  - job_name: services\n";
            config += "    metrics_path: /metrics\n";
            config += "    static_configs:\n";
            config += "      - targets:\n";

            foreach (var node in nodes)
            {
                var ip = node.Pod.Ip;
                var port = node.Recipe.GetPortByTag(CodexContainerRecipe.MetricsPortTag).Number;
                config += $"          - '{ip}:{port}'\n";
            }

            var bytes = Encoding.ASCII.GetBytes(config);
            return Convert.ToBase64String(bytes);
        }

        private void Log(string msg)
        {
            lifecycle.Log.Log(msg);
        }
    }
}