package cli

import (
	"encoding/json"
	"fmt"
	"text/tabwriter"
	"time"

	"github.com/spf13/cobra"

	"gitea.mynodes.xyz/ilker/llmgw/internal/control/adminapi"
)

func newFabricTestCmd(client func() *ctlClient, asJSON *bool) *cobra.Command {
	var (
		fabric  string
		seconds int
	)
	c := &cobra.Command{
		Use:   "fabric-test NODE-A NODE-B",
		Short: "Measure RDMA bandwidth between two nodes, rail by rail",
		Long: `Runs ib_write_bw from each of NODE-A's adapters on a fabric to the same
adapter on NODE-B — mlx5_0 to mlx5_0, and so on, the way NCCL pairs them —
one rail at a time, and grades each against its link's rate: ok at 80% or
more, slow at 50%, fail below or when nothing got through.

Every check on one node can pass while two nodes still cannot reach each
other: a cable into the wrong switch, a partition key, a RoCE network with no
route. A replica spanning them then hangs on its first all-reduce. Run this
before placing one.

It goes through the agents, so it needs no ssh between nodes. perftest is
installed on a node the first time it is asked. The traffic is real and
takes a few seconds a rail; run it when the fabric is quiet.`,
		Example: `  llmgw ctl fabric-test gpu01 gpu02
  llmgw ctl fabric-test gpu01 gpu02 --fabric ib-compute --seconds 10`,
		Args: cobra.ExactArgs(2),
		RunE: func(cmd *cobra.Command, args []string) error {
			body, _ := json.Marshal(map[string]any{"a": args[0], "b": args[1], "fabric": fabric, "seconds": seconds})
			cl := client()
			// Rails one after another, each for its seconds and a settle; the
			// client's usual timeout is for questions, not measurements.
			cl.http.Timeout = 30 * time.Minute
			var v adminapi.FabricTestView
			if err := cl.post(cmd.Context(), "/api/v1/fabric-test", body, &v); err != nil {
				return err
			}
			if *asJSON {
				return json.NewEncoder(cmd.OutOrStdout()).Encode(v)
			}
			out := cmd.OutOrStdout()
			fmt.Fprintf(out, "%s → %s on %s, %s\n\n", v.A, v.B, v.Fabric, v.Took)
			w := tabwriter.NewWriter(out, 0, 0, 2, ' ', 0)
			fmt.Fprintln(w, "RAIL\tLINK\tMEASURED\tVERDICT\tDETAIL")
			for _, r := range v.Rails {
				link := "-"
				if r.RateGbps > 0 {
					link = fmt.Sprintf("%d Gb/s", r.RateGbps)
				}
				fmt.Fprintf(w, "%s → %s\t%s\t%.1f Gb/s\t%s\t%s\n", r.A, r.B, link, r.Gbps, r.Verdict, r.Detail)
			}
			_ = w.Flush()
			for _, n := range v.Notes {
				fmt.Fprintf(out, "\nnote: %s\n", n)
			}
			if !v.OK {
				return fmt.Errorf("not every rail passed")
			}
			return nil
		},
	}
	c.Flags().StringVar(&fabric, "fabric", "", "the fabric to test (default: the one the two nodes share)")
	c.Flags().IntVar(&seconds, "seconds", 3, "how long each rail runs, up to 30")
	return c
}