{ config, pkgs, lib, ... }:

{
  services.prometheus = {
    enable = true;
    retentionTime = "14d";
    listenAddress = "[::1]";
    scrapeConfigs = [
      {
        job_name = "hedgedoc";
        scrape_interval = "15s";
        scheme = "https";
        static_configs = [{ targets = ["md.berlin.ccc.de:443"]; }];
      }
      {
        job_name = "synapse";
        scrape_interval = "15s";
        static_configs = [{ targets = ["matrix.berlin.ccc.de:9009"]; }];
      }
      {
        job_name = "node";
        scrape_interval = "15s";
        static_configs = [
          {
            targets = [
              "matrix.${config.networking.domain}:${toString config.services.prometheus.exporters.node.port}"
              "md.${config.networking.domain}:${toString config.services.prometheus.exporters.node.port}"
              "postgres.${config.networking.domain}:${toString config.services.prometheus.exporters.node.port}"
              "monitoring:${toString config.services.prometheus.exporters.node.port}"
            ];
          }
        ];
      }
      {
        job_name = "nginx";
        scrape_interval = "15s";
        static_configs = [
          {
            targets = [
              "monitoring:${toString config.services.prometheus.exporters.nginx.port}"
              "matrix:${toString config.services.prometheus.exporters.nginx.port}"
            ];
          }
        ];
      }
    ];
    ruleFiles = [
      # https://github.com/element-hq/synapse/tree/master/contrib/prometheus
      (pkgs.writeText "prom-synapse-rules.yaml" ''
        groups:
        - name: synapse
          rules:
          - record: 'synapse_federation_client_sent'
            labels:
              type: "EDU"
            expr: 'synapse_federation_client_sent_edus_total + 0'
          - record: 'synapse_federation_client_sent'
            labels:
              type: "PDU"
            expr: 'synapse_federation_client_sent_pdu_destinations_count_total + 0'
          - record: 'synapse_federation_client_sent'
            labels:
              type: "Query"
            expr: 'sum(synapse_federation_client_sent_queries) by (job)'
          - record: 'synapse_federation_server_received'
            labels:
              type: "EDU"
            expr: 'synapse_federation_server_received_edus_total + 0'
          - record: 'synapse_federation_server_received'
            labels:
              type: "PDU"
            expr: 'synapse_federation_server_received_pdus_total + 0'
          - record: 'synapse_federation_server_received'
            labels:
              type: "Query"
            expr: 'sum(synapse_federation_server_received_queries) by (job)'
          - record: 'synapse_federation_transaction_queue_pending'
            labels:
              type: "EDU"
            expr: 'synapse_federation_transaction_queue_pending_edus + 0'
          - record: 'synapse_federation_transaction_queue_pending'
            labels:
              type: "PDU"
            expr: 'synapse_federation_transaction_queue_pending_pdus + 0'
      '')
    ];
  };
}