labmcp/internal/monitoring/handlers.go

package monitoring

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"
	"time"

	"git.t-juice.club/torjus/labmcp/internal/mcp"
)

// AlertSummary queries Alertmanager for active (non-silenced) alerts and returns
// a short summary string. Returns empty string if there are no alerts or if
// Alertmanager is unreachable.
func AlertSummary(am *AlertmanagerClient) string {
	active := true
	silenced := false
	inhibited := false
	alerts, err := am.ListAlerts(context.Background(), AlertFilters{
		Active:    &active,
		Silenced:  &silenced,
		Inhibited: &inhibited,
	})
	if err != nil || len(alerts) == 0 {
		return ""
	}

	// Count by severity
	severities := make(map[string]int)
	for _, a := range alerts {
		sev := a.Labels["severity"]
		if sev == "" {
			sev = "unknown"
		}
		severities[sev]++
	}

	var parts []string
	// Show critical first if present
	if n, ok := severities["critical"]; ok {
		parts = append(parts, fmt.Sprintf("%d critical", n))
		delete(severities, "critical")
	}
	if n, ok := severities["warning"]; ok {
		parts = append(parts, fmt.Sprintf("%d warning", n))
		delete(severities, "warning")
	}
	for sev, n := range severities {
		parts = append(parts, fmt.Sprintf("%d %s", n, sev))
	}

	return fmt.Sprintf("ALERT STATUS: %d active alert(s) firing (%s). Use list_alerts for details. Let the user know about this.",
		len(alerts), strings.Join(parts, ", "))
}

// HandlerOptions configures which handlers are registered.
type HandlerOptions struct {
	// EnableSilences enables the create_silence tool, which is a write operation.
	// Disabled by default as a safety measure.
	EnableSilences bool
}

// RegisterHandlers registers all monitoring tool handlers on the MCP server.
func RegisterHandlers(server *mcp.Server, prom *PrometheusClient, am *AlertmanagerClient, opts HandlerOptions) {
	server.RegisterTool(listAlertsTool(), makeListAlertsHandler(am))
	server.RegisterTool(getAlertTool(), makeGetAlertHandler(am))
	server.RegisterTool(searchMetricsTool(), makeSearchMetricsHandler(prom))
	server.RegisterTool(getMetricMetadataTool(), makeGetMetricMetadataHandler(prom))
	server.RegisterTool(queryTool(), makeQueryHandler(prom))
	server.RegisterTool(listTargetsTool(), makeListTargetsHandler(prom))
	server.RegisterTool(listSilencesTool(), makeListSilencesHandler(am))
	if opts.EnableSilences {
		server.RegisterTool(createSilenceTool(), makeCreateSilenceHandler(am))
	}
}

// Tool definitions

func listAlertsTool() mcp.Tool {
	return mcp.Tool{
		Name:        "list_alerts",
		Description: "List alerts from Alertmanager with optional filters",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"state": {
					Type:        "string",
					Description: "Filter by alert state: 'active', 'suppressed', or 'unprocessed'",
					Enum:        []string{"active", "suppressed", "unprocessed"},
				},
				"severity": {
					Type:        "string",
					Description: "Filter by severity label (e.g., 'critical', 'warning')",
				},
				"receiver": {
					Type:        "string",
					Description: "Filter by receiver name",
				},
			},
		},
	}
}

func getAlertTool() mcp.Tool {
	return mcp.Tool{
		Name:        "get_alert",
		Description: "Get full details for a specific alert by fingerprint",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"fingerprint": {
					Type:        "string",
					Description: "Alert fingerprint identifier",
				},
			},
			Required: []string{"fingerprint"},
		},
	}
}

func searchMetricsTool() mcp.Tool {
	return mcp.Tool{
		Name:        "search_metrics",
		Description: "Search Prometheus metric names with optional substring filter, enriched with metadata (type, help text)",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"query": {
					Type:        "string",
					Description: "Substring to filter metric names (e.g., 'cpu', 'memory', 'node_'). Empty returns all metrics.",
				},
				"limit": {
					Type:        "integer",
					Description: "Maximum number of results (default: 50)",
					Default:     50,
				},
			},
		},
	}
}

func getMetricMetadataTool() mcp.Tool {
	return mcp.Tool{
		Name:        "get_metric_metadata",
		Description: "Get type, help text, and unit for a specific Prometheus metric",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"metric": {
					Type:        "string",
					Description: "Metric name (e.g., 'node_cpu_seconds_total')",
				},
			},
			Required: []string{"metric"},
		},
	}
}

func queryTool() mcp.Tool {
	return mcp.Tool{
		Name:        "query",
		Description: "Execute an instant PromQL query against Prometheus. Supports aggregations like avg_over_time(metric[1h]), rate(), sum(), etc.",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"promql": {
					Type:        "string",
					Description: "PromQL expression to evaluate (e.g., 'up', 'rate(http_requests_total[5m])', 'avg_over_time(node_load1[1h])')",
				},
			},
			Required: []string{"promql"},
		},
	}
}

func listTargetsTool() mcp.Tool {
	return mcp.Tool{
		Name:        "list_targets",
		Description: "List Prometheus scrape targets with health status, grouped by job",
		InputSchema: mcp.InputSchema{
			Type:       "object",
			Properties: map[string]mcp.Property{},
		},
	}
}

func listSilencesTool() mcp.Tool {
	return mcp.Tool{
		Name:        "list_silences",
		Description: "List active and pending alert silences from Alertmanager",
		InputSchema: mcp.InputSchema{
			Type:       "object",
			Properties: map[string]mcp.Property{},
		},
	}
}

func createSilenceTool() mcp.Tool {
	return mcp.Tool{
		Name:        "create_silence",
		Description: `Create a new silence in Alertmanager. IMPORTANT: Always confirm with the user before creating a silence, showing them the matchers, duration, and reason.`,
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"matchers": {
					Type:        "string",
					Description: `JSON array of matchers, e.g. [{"name":"alertname","value":"TargetDown","isRegex":false}]`,
				},
				"duration": {
					Type:        "string",
					Description: "Silence duration in Go duration format (e.g., '2h', '30m', '1h30m')",
				},
				"author": {
					Type:        "string",
					Description: "Author of the silence",
				},
				"comment": {
					Type:        "string",
					Description: "Reason for the silence",
				},
			},
			Required: []string{"matchers", "duration", "author", "comment"},
		},
	}
}

// Handler constructors

func makeListAlertsHandler(am *AlertmanagerClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		filters := AlertFilters{}

		if state, ok := args["state"].(string); ok && state != "" {
			switch state {
			case "active":
				active := true
				filters.Active = &active
				silenced := false
				filters.Silenced = &silenced
				inhibited := false
				filters.Inhibited = &inhibited
			case "suppressed":
				active := false
				filters.Active = &active
			case "unprocessed":
				unprocessed := true
				filters.Unprocessed = &unprocessed
			}
		}

		if severity, ok := args["severity"].(string); ok && severity != "" {
			filters.Filter = append(filters.Filter, fmt.Sprintf(`severity="%s"`, severity))
		}

		if receiver, ok := args["receiver"].(string); ok && receiver != "" {
			filters.Receiver = receiver
		}

		alerts, err := am.ListAlerts(ctx, filters)
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("failed to list alerts: %w", err)), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(formatAlerts(alerts))},
		}, nil
	}
}

func makeGetAlertHandler(am *AlertmanagerClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		fingerprint, _ := args["fingerprint"].(string)
		if fingerprint == "" {
			return mcp.ErrorContent(fmt.Errorf("fingerprint is required")), nil
		}

		// Fetch all alerts and find the one matching the fingerprint
		alerts, err := am.ListAlerts(ctx, AlertFilters{})
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("failed to fetch alerts: %w", err)), nil
		}

		for _, a := range alerts {
			if a.Fingerprint == fingerprint {
				return mcp.CallToolResult{
					Content: []mcp.Content{mcp.TextContent(formatAlerts([]Alert{a}))},
				}, nil
			}
		}

		return mcp.ErrorContent(fmt.Errorf("alert with fingerprint '%s' not found", fingerprint)), nil
	}
}

func makeSearchMetricsHandler(prom *PrometheusClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		query, _ := args["query"].(string)
		limit := 50
		if l, ok := args["limit"].(float64); ok && l > 0 {
			limit = int(l)
		}

		// Get all metric names
		allNames, err := prom.LabelValues(ctx, "__name__")
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("failed to fetch metric names: %w", err)), nil
		}

		// Filter by substring
		var matched []string
		queryLower := strings.ToLower(query)
		for _, name := range allNames {
			if query == "" || strings.Contains(strings.ToLower(name), queryLower) {
				matched = append(matched, name)
				if len(matched) >= limit {
					break
				}
			}
		}

		// Fetch metadata for matched metrics
		metadata, err := prom.Metadata(ctx, "")
		if err != nil {
			// Non-fatal: proceed without metadata
			metadata = nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(formatMetricSearch(matched, metadata))},
		}, nil
	}
}

func makeGetMetricMetadataHandler(prom *PrometheusClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		metric, _ := args["metric"].(string)
		if metric == "" {
			return mcp.ErrorContent(fmt.Errorf("metric is required")), nil
		}

		metadata, err := prom.Metadata(ctx, metric)
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("failed to fetch metadata: %w", err)), nil
		}

		metas := metadata[metric]
		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(formatMetricMetadata(metric, metas))},
		}, nil
	}
}

func makeQueryHandler(prom *PrometheusClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		promql, _ := args["promql"].(string)
		if promql == "" {
			return mcp.ErrorContent(fmt.Errorf("promql is required")), nil
		}

		data, err := prom.Query(ctx, promql, time.Time{})
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("query failed: %w", err)), nil
		}

		var result string
		switch data.ResultType {
		case "vector":
			result = formatInstantVector(data.Result)
		case "scalar":
			if len(data.Result) > 0 && len(data.Result[0].Value) >= 2 {
				if v, ok := data.Result[0].Value[1].(string); ok {
					result = fmt.Sprintf("**Scalar result:** %s", v)
				}
			}
			if result == "" {
				result = "Scalar query returned no value."
			}
		default:
			result = fmt.Sprintf("Result type: %s\n\n%s", data.ResultType, formatInstantVector(data.Result))
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(result)},
		}, nil
	}
}

func makeListTargetsHandler(prom *PrometheusClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		data, err := prom.Targets(ctx)
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("failed to fetch targets: %w", err)), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(formatTargets(data))},
		}, nil
	}
}

func makeListSilencesHandler(am *AlertmanagerClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		silences, err := am.ListSilences(ctx)
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("failed to fetch silences: %w", err)), nil
		}

		// Filter to active/pending only
		var filtered []Silence
		for _, s := range silences {
			if s.Status != nil && (s.Status.State == "active" || s.Status.State == "pending") {
				filtered = append(filtered, s)
			}
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(formatSilences(filtered))},
		}, nil
	}
}

func makeCreateSilenceHandler(am *AlertmanagerClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		matchersJSON, _ := args["matchers"].(string)
		if matchersJSON == "" {
			return mcp.ErrorContent(fmt.Errorf("matchers is required")), nil
		}

		durationStr, _ := args["duration"].(string)
		if durationStr == "" {
			return mcp.ErrorContent(fmt.Errorf("duration is required")), nil
		}

		author, _ := args["author"].(string)
		if author == "" {
			return mcp.ErrorContent(fmt.Errorf("author is required")), nil
		}

		comment, _ := args["comment"].(string)
		if comment == "" {
			return mcp.ErrorContent(fmt.Errorf("comment is required")), nil
		}

		// Parse matchers
		var matchers []Matcher
		if err := parseJSON(matchersJSON, &matchers); err != nil {
			return mcp.ErrorContent(fmt.Errorf("invalid matchers JSON: %w", err)), nil
		}

		// Parse duration
		duration, err := time.ParseDuration(durationStr)
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("invalid duration: %w", err)), nil
		}

		now := time.Now()
		silence := Silence{
			Matchers:  matchers,
			StartsAt:  now,
			EndsAt:    now.Add(duration),
			CreatedBy: author,
			Comment:   comment,
		}

		id, err := am.CreateSilence(ctx, silence)
		if err != nil {
			return mcp.ErrorContent(fmt.Errorf("failed to create silence: %w", err)), nil
		}

		var sb strings.Builder
		sb.WriteString("Silence created successfully.\n\n")
		sb.WriteString(fmt.Sprintf("**ID:** %s\n", id))
		sb.WriteString(fmt.Sprintf("**Expires:** %s\n", silence.EndsAt.Format(time.RFC3339)))
		sb.WriteString(fmt.Sprintf("**Author:** %s\n", author))
		sb.WriteString(fmt.Sprintf("**Comment:** %s\n", comment))

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(sb.String())},
		}, nil
	}
}

// parseJSON is a helper to unmarshal JSON from a string.
func parseJSON(s string, v interface{}) error {
	return json.Unmarshal([]byte(s), v)
}