// Copyright (c) 2026, Pim van Pelt <pim@ipng.ch>

package prober

import (
	"context"
	"fmt"
	"net"
	"time"

	"git.ipng.ch/ipng/vpp-maglev/internal/config"
	"git.ipng.ch/ipng/vpp-maglev/internal/health"
)

// ProbeFunc is the signature for a health check probe.
type ProbeFunc func(ctx context.Context, cfg ProbeConfig) health.ProbeResult

// ProbeConfig holds all parameters needed to execute a single probe.
type ProbeConfig struct {
	Target           net.IP        // backend address to probe
	Port             uint16        // destination port (used by TCP and HTTP probers)
	ProbeSrc         net.IP        // source address to bind; nil lets the OS choose
	HealthCheckNetns string        // network namespace name; sockets are created inside it
	Timeout          time.Duration
	HTTP             *config.HTTPParams // non-nil for type http/https
	TCP              *config.TCPParams  // non-nil for type tcp
}

// ForType returns the ProbeFunc registered for the given healthcheck type.
// Returns a failing stub for unknown types.
func ForType(t string) ProbeFunc {
	switch t {
	case "icmp":
		return ICMPProbe
	case "tcp":
		return TCPProbe
	case "http":
		return HTTPProbe
	case "https":
		return HTTPSProbe
	default:
		return func(_ context.Context, _ ProbeConfig) health.ProbeResult {
			return health.ProbeResult{
				OK:     false,
				Layer:  health.LayerUnknown,
				Code:   "UNKNOWN",
				Detail: fmt.Sprintf("unknown probe type %q", t),
			}
		}
	}
}