package api_test

import (
	"bytes"
	"encoding/json"
	"net/http"
	"strconv"
	"testing"
)

// postGrouped posts a firing webhook whose group labels are exactly the given
// map, unlike postWebhook, which only ever groups by alertname.
func postGrouped(t *testing.T, s *ts, fingerprint, startsAt string, groupLabels map[string]string) {
	t.Helper()
	labels := map[string]string{}
	for k, v := range groupLabels {
		labels[k] = v
	}
	payload := map[string]any{
		"version": "4", "status": "firing",
		"groupKey":    fingerprint,
		"groupLabels": groupLabels,
		"alerts": []map[string]any{
			amAlert(fingerprint, groupLabels["alertname"], "firing", startsAt, zeroTime, labels),
		},
	}
	data, _ := json.Marshal(payload)
	resp, err := http.Post(s.URL+"/api/integrations/"+s.ingestKey+"/alertmanager",
		"application/json", bytes.NewReader(data))
	if err != nil {
		t.Fatalf("post webhook: %v", err)
	}
	resp.Body.Close()
}

func similar(t *testing.T, s *ts, id int) []map[string]any {
	t.Helper()
	var out []map[string]any
	decode(t, s.req(t, http.MethodGet, "/api/incidents/"+strconv.Itoa(id)+"/similar", nil), &out)
	return out
}

// Same alert on another instance is the same problem; a resolution note left on
// the first one is what the second one should be shown.
func TestSimilar_IgnoresVolatileLabelsAndLeadsWithResolutionNote(t *testing.T) {
	s := newTS(t)
	postGrouped(t, s, "fp-a", "2026-05-20T10:00:00Z",
		map[string]string{"alertname": "DiskFull", "instance": "web-1", "job": "node"})
	s.req(t, http.MethodPost, "/api/incidents/1/resolve",
		map[string]string{"resolution": "rotated the logs"}).Body.Close()

	postGrouped(t, s, "fp-b", "2026-05-21T10:00:00Z",
		map[string]string{"alertname": "DiskFull", "instance": "web-2", "job": "node"})

	got := similar(t, s, 2)
	if len(got) != 1 || int(got[0]["id"].(float64)) != 1 {
		t.Fatalf("expected incident 1 as the only similar one, got %v", got)
	}
	notes := got[0]["resolution_notes"].([]any)
	if len(notes) != 1 || notes[0].(map[string]any)["detail"] != "rotated the logs" {
		t.Fatalf("expected the resolution note, got %v", notes)
	}
}

// A different stable label (job) is a different problem, and an incident nobody
// wrote a note on has nothing to show.
func TestSimilar_DifferentSignatureOrNoNotesIsExcluded(t *testing.T) {
	s := newTS(t)
	postGrouped(t, s, "fp-1", "2026-05-20T10:00:00Z",
		map[string]string{"alertname": "DiskFull", "job": "node"})
	s.req(t, http.MethodPost, "/api/incidents/1/notes", map[string]string{"content": "checked"}).Body.Close()
	s.req(t, http.MethodPost, "/api/incidents/1/resolve", nil).Body.Close()

	postGrouped(t, s, "fp-2", "2026-05-20T11:00:00Z",
		map[string]string{"alertname": "DiskFull", "job": "db"})
	s.req(t, http.MethodPost, "/api/incidents/2/resolve", nil).Body.Close()

	postGrouped(t, s, "fp-3", "2026-05-21T10:00:00Z",
		map[string]string{"alertname": "DiskFull", "job": "db"})

	// Incident 3 matches 2 by signature, but 2 has no notes.
	if got := similar(t, s, 3); len(got) != 0 {
		t.Fatalf("expected nothing similar to incident 3, got %v", got)
	}
}

// An open incident is not "earlier experience" yet, and the incident itself is
// never its own match.
func TestSimilar_OpenIncidentsAreNotListed(t *testing.T) {
	s := newTS(t)
	postGrouped(t, s, "fp-o1", "2026-05-20T10:00:00Z", map[string]string{"alertname": "Flap"})
	s.req(t, http.MethodPost, "/api/incidents/1/notes",
		map[string]any{"content": "still open", "pinned": true}).Body.Close()
	postGrouped(t, s, "fp-o2", "2026-05-21T10:00:00Z", map[string]string{"alertname": "Flap"})

	if got := similar(t, s, 2); len(got) != 0 {
		t.Fatalf("expected an open incident not to be listed, got %v", got)
	}
}