{ lib, pkgs }:
let
  datasourceUid = "vm-datasource-uid";

  # Helper to create a panel with common defaults
  mkPanel = { id, title, type, gridPos, targets, options ? { }, fieldConfig ? { }, ... }@args:
    {
      inherit id title type gridPos targets;
      datasource = { uid = datasourceUid; type = "prometheus"; };
      options = options;
      fieldConfig = {
        defaults = fieldConfig.defaults or { };
        overrides = fieldConfig.overrides or [ ];
      };
    } // (builtins.removeAttrs args [ "id" "title" "type" "gridPos" "targets" "options" "fieldConfig" ]);

  # Dashboard definition
  dashboard = {
    uid = "smart-disk-health";
    title = "S.M.A.R.T Disk Health";
    description = "S.M.A.R.T metrics and RAID array status";
    tags = [ "disk" "smart" "storage" "nas" ];
    timezone = "browser";
    editable = false;
    refresh = "5m";
    schemaVersion = 39;
    version = 1;

    # Variables
    templating.list = [
      {
        name = "host";
        label = "Host";
        type = "query";
        datasource = { uid = datasourceUid; type = "prometheus"; };
        query = "label_values(smart_health_passed, instance)";
        regex = "";
        sort = 1;
        refresh = 1;
        includeAll = true;
        multi = false;
        current = { selected = true; text = "All"; value = "$__all"; };
      }
    ];

    # Panels
    panels = [
      # === OVERVIEW ROW ===
      {
        id = 1;
        type = "row";
        title = "Overview";
        collapsed = false;
        gridPos = { x = 0; y = 0; w = 24; h = 1; };
        panels = [ ];
      }

      # Alert Status - Shows firing disk alerts
      {
        id = 5;
        title = "Alert Status";
        type = "alertlist";
        gridPos = { x = 0; y = 1; w = 6; h = 5; };
        options = {
          alertInstanceLabelFilter = "";
          alertName = "Disk";
          dashboardAlerts = false;
          groupBy = [ ];
          groupMode = "default";
          maxItems = 20;
          sortOrder = 1;
          stateFilter = {
            "error" = true;
            firing = true;
            noData = false;
            normal = false;
            pending = false;
          };
          viewMode = "list";
        };
      }

      # Health Status - Stat panel
      (mkPanel {
        id = 2;
        title = "Disk Health Status";
        type = "stat";
        gridPos = { x = 6; y = 1; w = 6; h = 5; };
        targets = [{
          expr = ''smart_health_passed{instance=~"$host"}'';
          legendFormat = "{{device}}";
          refId = "A";
        }];
        options = {
          reduceOptions = { values = false; calcs = [ "lastNotNull" ]; fields = ""; };
          orientation = "horizontal";
          textMode = "auto";
          colorMode = "background";
          graphMode = "none";
        };
        fieldConfig = {
          defaults = {
            mappings = [
              { type = "value"; options."1" = { text = "PASSED"; color = "green"; index = 0; }; }
              { type = "value"; options."0" = { text = "FAILED"; color = "red"; index = 1; }; }
            ];
            thresholds = {
              mode = "absolute";
              steps = [
                { color = "red"; value = null; }
                { color = "green"; value = 1; }
              ];
            };
          };
        };
      })

      # Temperature Gauge
      (mkPanel {
        id = 3;
        title = "Disk Temperatures";
        type = "gauge";
        gridPos = { x = 12; y = 1; w = 6; h = 8; };
        targets = [{
          expr = ''smart_temperature_celsius{instance=~"$host"}'';
          legendFormat = "{{device}}";
          refId = "A";
        }];
        options = {
          reduceOptions = { values = false; calcs = [ "lastNotNull" ]; fields = ""; };
          orientation = "auto";
          showThresholdLabels = false;
          showThresholdMarkers = true;
        };
        fieldConfig = {
          defaults = {
            unit = "celsius";
            min = 0;
            max = 70;
            thresholds = {
              mode = "absolute";
              steps = [
                { color = "green"; value = null; }
                { color = "yellow"; value = 45; }
                { color = "red"; value = 55; }
              ];
            };
          };
        };
      })

      # RAID Status - Stat panel
      (mkPanel {
        id = 4;
        title = "RAID Array Status";
        type = "stat";
        gridPos = { x = 18; y = 1; w = 6; h = 8; };
        targets = [{
          expr = ''mdadm_array_state{instance=~"$host"}'';
          legendFormat = "{{array}}";
          refId = "A";
        }];
        options = {
          reduceOptions = { values = false; calcs = [ "lastNotNull" ]; fields = ""; };
          orientation = "horizontal";
          textMode = "auto";
          colorMode = "background";
          graphMode = "none";
        };
        fieldConfig = {
          defaults = {
            mappings = [
              { type = "value"; options."1" = { text = "Healthy"; color = "green"; index = 0; }; }
              { type = "value"; options."0" = { text = "Degraded"; color = "red"; index = 1; }; }
            ];
            thresholds = {
              mode = "absolute";
              steps = [
                { color = "red"; value = null; }
                { color = "green"; value = 1; }
              ];
            };
          };
        };
      })

      # Sector Health Table - Promoted to overview for visibility
      (mkPanel {
        id = 13;
        title = "Sector Health";
        type = "table";
        gridPos = { x = 0; y = 6; w = 12; h = 4; };
        targets = [
          {
            expr = ''smart_reallocated_sector_ct{instance=~"$host"}'';
            legendFormat = "{{device}}";
            refId = "A";
            format = "table";
            instant = true;
          }
          {
            expr = ''smart_current_pending_sector{instance=~"$host"}'';
            legendFormat = "{{device}}";
            refId = "B";
            format = "table";
            instant = true;
          }
          {
            expr = ''smart_offline_uncorrectable{instance=~"$host"}'';
            legendFormat = "{{device}}";
            refId = "C";
            format = "table";
            instant = true;
          }
        ];
        options = {
          showHeader = true;
          cellHeight = "sm";
        };
        transformations = [
          { id = "merge"; options = { }; }
          {
            id = "organize";
            options = {
              excludeByName = { Time = true; __name__ = true; instance = true; job = true; serial = true; };
              renameByName = {
                device = "Device";
                "Value #A" = "Reallocated Sectors";
                "Value #B" = "Pending Sectors";
                "Value #C" = "Offline Uncorrectable";
              };
            };
          }
        ];
        fieldConfig = {
          defaults = {
            thresholds = {
              mode = "absolute";
              steps = [
                { color = "green"; value = null; }
                { color = "yellow"; value = 1; }
                { color = "red"; value = 10; }
              ];
            };
            custom = { displayMode = "color-background-solid"; };
          };
        };
      })

      # === DETAILED METRICS ROW ===
      {
        id = 10;
        type = "row";
        title = "Detailed Metrics";
        collapsed = false;
        gridPos = { x = 0; y = 10; w = 24; h = 1; };
        panels = [ ];
      }

      # Temperature Time Series
      (mkPanel {
        id = 11;
        title = "Temperature Over Time";
        type = "timeseries";
        gridPos = { x = 0; y = 11; w = 12; h = 8; };
        targets = [{
          expr = ''smart_temperature_celsius{instance=~"$host"}'';
          legendFormat = "{{device}}";
          refId = "A";
        }];
        options = {
          legend = { displayMode = "list"; placement = "bottom"; showLegend = true; };
          tooltip = { mode = "multi"; sort = "desc"; };
        };
        fieldConfig = {
          defaults = {
            unit = "celsius";
            custom = {
              drawStyle = "line";
              lineInterpolation = "smooth";
              fillOpacity = 10;
              pointSize = 5;
              showPoints = "auto";
            };
            thresholds = {
              mode = "absolute";
              steps = [
                { color = "green"; value = null; }
                { color = "yellow"; value = 45; }
                { color = "red"; value = 55; }
              ];
            };
          };
        };
      })

      # Power On Hours
      (mkPanel {
        id = 12;
        title = "Power On Hours";
        type = "stat";
        gridPos = { x = 12; y = 11; w = 12; h = 8; };
        targets = [{
          expr = ''smart_power_on_hours{instance=~"$host"}'';
          legendFormat = "{{device}}";
          refId = "A";
        }];
        options = {
          reduceOptions = { values = false; calcs = [ "lastNotNull" ]; fields = ""; };
          orientation = "horizontal";
          textMode = "value_and_name";
          colorMode = "none";
          graphMode = "none";
        };
        fieldConfig = {
          defaults = {
            unit = "h";
          };
        };
      })

      # === RAID DETAILS ROW ===
      {
        id = 20;
        type = "row";
        title = "RAID Details";
        collapsed = false;
        gridPos = { x = 0; y = 19; w = 24; h = 1; };
        panels = [ ];
      }

      # RAID Devices
      (mkPanel {
        id = 21;
        title = "RAID Array Devices";
        type = "stat";
        gridPos = { x = 0; y = 20; w = 12; h = 4; };
        targets = [
          {
            expr = ''mdadm_array_devices_active{instance=~"$host"}'';
            legendFormat = "{{array}} Active";
            refId = "A";
          }
          {
            expr = ''mdadm_array_devices_total{instance=~"$host"}'';
            legendFormat = "{{array}} Total";
            refId = "B";
          }
        ];
        options = {
          reduceOptions = { values = false; calcs = [ "lastNotNull" ]; fields = ""; };
          orientation = "horizontal";
          textMode = "value_and_name";
          colorMode = "value";
          graphMode = "none";
        };
        fieldConfig = {
          defaults = {
            unit = "short";
          };
        };
      })

      # UDMA CRC Errors
      (mkPanel {
        id = 22;
        title = "UDMA CRC Errors";
        type = "timeseries";
        gridPos = { x = 12; y = 20; w = 12; h = 4; };
        targets = [{
          expr = ''smart_udma_crc_error_count{instance=~"$host"}'';
          legendFormat = "{{device}}";
          refId = "A";
        }];
        options = {
          legend = { displayMode = "list"; placement = "bottom"; showLegend = true; };
          tooltip = { mode = "multi"; sort = "desc"; };
        };
        fieldConfig = {
          defaults = {
            unit = "short";
            custom = {
              drawStyle = "line";
              lineInterpolation = "stepAfter";
              fillOpacity = 0;
              pointSize = 5;
              showPoints = "auto";
            };
          };
        };
      })

      # Last Update Timestamp
      (mkPanel {
        id = 30;
        title = "Last Metrics Update";
        type = "stat";
        gridPos = { x = 0; y = 24; w = 6; h = 5; };
        targets = [{
          expr = ''time() - disk_metrics_last_update{instance=~"$host"}'';
          legendFormat = "Age";
          refId = "A";
        }];
        options = {
          reduceOptions = { values = false; calcs = [ "lastNotNull" ]; fields = ""; };
          orientation = "horizontal";
          textMode = "value";
          colorMode = "value";
          graphMode = "none";
        };
        fieldConfig = {
          defaults = {
            unit = "s";
            thresholds = {
              mode = "absolute";
              steps = [
                { color = "green"; value = null; }
                { color = "yellow"; value = 1800; }
                { color = "red"; value = 3600; }
              ];
            };
          };
        };
      })

      # Device Activity Status
      (mkPanel {
        id = 31;
        title = "Device Activity";
        type = "stat";
        gridPos = { x = 6; y = 24; w = 18; h = 5; };
        targets = [{
          expr = ''smart_device_active{instance=~"$host"}'';
          legendFormat = "{{device}}";
          refId = "A";
        }];
        options = {
          reduceOptions = { values = false; calcs = [ "lastNotNull" ]; fields = ""; };
          orientation = "horizontal";
          textMode = "auto";
          colorMode = "background";
          graphMode = "none";
        };
        fieldConfig = {
          defaults = {
            mappings = [
              { type = "value"; options."1" = { text = "Active"; color = "green"; index = 0; }; }
              { type = "value"; options."0" = { text = "Standby"; color = "blue"; index = 1; }; }
            ];
            thresholds = {
              mode = "absolute";
              steps = [
                { color = "blue"; value = null; }
                { color = "green"; value = 1; }
              ];
            };
          };
        };
      })
    ];
  };
in
pkgs.writeText "smart-dashboard.json" (builtins.toJSON dashboard)