package telemetry

import (
	"strings"
	"testing"
	"time"
	"unicode/utf8"

	"doormile/models"
)

var now = time.Date(2026, 9, 29, 18, 0, 0, 0, time.UTC)

// The exact shape core/agent.py publishes after a task.
const engineTask = `{"kind":"task","ts":"2026-09-29T17:59:58.123456","agent_id":"EXCEPTION_AGENT",
 "task_id":"3f2c9a","task_type":"handle_stall","status":"completed","error":null,"duration_ms":412}`

func TestParseTaskReadsTheEngineShape(t *testing.T) {
	run, err := ParseTask([]byte(engineTask), now)
	if err != nil {
		t.Fatal(err)
	}
	if run.Agentid != "EXCEPTION_AGENT" || run.Tasktype != "handle_stall" || run.Status != "completed" || run.Durationms != 412 {
		t.Errorf("parsed %+v", run)
	}
	if run.Taskid == nil || *run.Taskid != "3f2c9a" {
		t.Errorf("task id = %v", run.Taskid)
	}
	if !run.Receivedat.Equal(now) {
		t.Errorf("receivedat = %v, want the backend's clock", run.Receivedat)
	}
	if run.Occurredat == nil || run.Occurredat.Format("15:04:05") != "17:59:58" {
		t.Errorf("occurredat = %v", run.Occurredat)
	}
}

func TestParseTaskKeepsAFailureAndItsError(t *testing.T) {
	run, err := ParseTask([]byte(`{"agent_id":"DISPATCH_AGENT","task_id":"x","status":"FAILED","error":"boom","duration_ms":5}`), now)
	if err != nil || run.Status != "failed" || run.Error != "boom" {
		t.Fatalf("got %+v, %v", run, err)
	}
}

// A run attributed to the wrong agent is worse than a missing one.
func TestParseTaskRefusesWhatItCannotAttribute(t *testing.T) {
	cases := map[string]string{
		"not json":          `{nope`,
		"no agent":          `{"status":"completed"}`,
		"blank agent":       `{"agent_id":"  ","status":"completed"}`,
		"no status":         `{"agent_id":"A"}`,
		"agent id too long": `{"agent_id":"` + strings.Repeat("A", 65) + `","status":"completed"}`,
	}
	for name, body := range cases {
		if _, err := ParseTask([]byte(body), now); err != ErrInvalid {
			t.Errorf("%s: want ErrInvalid, got %v", name, err)
		}
	}
}

func TestParseTaskCleansUpEdgeValues(t *testing.T) {
	long := strings.Repeat("é", 1500) // 3000 bytes of two-byte runes
	run, err := ParseTask([]byte(`{"agent_id":"A","status":"completed","duration_ms":-40,"ts":"garbage","error":"`+long+`"}`), now)
	if err != nil {
		t.Fatal(err)
	}
	if run.Durationms != 0 {
		t.Errorf("negative duration kept: %d", run.Durationms)
	}
	if run.Taskid != nil {
		t.Error("an absent task id must be stored as null, not an empty string")
	}
	if run.Occurredat != nil {
		t.Error("an unparseable engine time must be null, not guessed")
	}
	if len(run.Error) > maxErrorLen || !utf8.ValidString(run.Error) {
		t.Errorf("error not truncated safely: %d bytes, valid=%v", len(run.Error), utf8.ValidString(run.Error))
	}
}

func TestParseAgent(t *testing.T) {
	st, err := ParseAgent([]byte(`{"kind":"agent","agent_id":"JARVIS","status":"idle","current_task":null,"tasks_completed":12,"tasks_failed":1}`), now)
	if err != nil {
		t.Fatal(err)
	}
	if st.AgentID != "JARVIS" || st.Status != "idle" || st.TasksCompleted != 12 || st.TasksFailed != 1 || !st.LastSeenAt.Equal(now) {
		t.Errorf("parsed %+v", st)
	}
	if _, err := ParseAgent([]byte(`{"status":"idle"}`), now); err != ErrInvalid {
		t.Error("an agent event with no id was accepted")
	}
}

// The NATS callback must never block: a full buffer drops and counts.
func TestEnqueueDropsInsteadOfBlocking(t *testing.T) {
	r := &Recorder{runs: make(chan models.AIAgentRun, 1), now: func() time.Time { return now }}
	if !r.Enqueue(models.AIAgentRun{Agentid: "A"}) {
		t.Fatal("first run refused")
	}
	done := make(chan bool)
	go func() { done <- r.Enqueue(models.AIAgentRun{Agentid: "B"}) }()
	select {
	case ok := <-done:
		if ok || r.dropped.Load() != 1 {
			t.Errorf("full buffer: accepted=%v dropped=%d", ok, r.dropped.Load())
		}
	case <-time.After(time.Second):
		t.Fatal("Enqueue blocked on a full buffer")
	}
}

func TestHandlersIgnoreBadInputAndMissingRedis(t *testing.T) {
	r := &Recorder{runs: make(chan models.AIAgentRun, 4), now: func() time.Time { return now }}
	r.HandleTask([]byte(`{bad`))
	r.HandleAgent([]byte(`{"agent_id":"A","status":"idle"}`)) // rdb nil: must not panic
	if len(r.runs) != 0 {
		t.Error("an invalid task event was enqueued")
	}
	r.HandleTask([]byte(engineTask))
	if len(r.runs) != 1 {
		t.Error("a valid task event was not enqueued")
	}
}

func TestSummariseRuns(t *testing.T) {
	s := SummariseRuns([]AgentRunStats{
		{Agentid: "B", Runs: 3, Failed: 1},
		{Agentid: "A", Runs: 10, Failed: 0},
		{Agentid: "C", Runs: 3, Failed: 2},
	})
	if s.Total != 16 || s.Failed != 3 {
		t.Errorf("totals %d/%d", s.Total, s.Failed)
	}
	var order []string
	for _, a := range s.PerAgent {
		order = append(order, a.Agentid)
	}
	if strings.Join(order, ",") != "A,B,C" {
		t.Errorf("order %v, want busiest first then by id", order)
	}
	if empty := SummariseRuns(nil); empty.PerAgent == nil || empty.Total != 0 {
		t.Error("no runs must summarise to an empty list, not null")
	}
}

func TestSummariseDecisions(t *testing.T) {
	s := SummariseDecisions([]DecisionCount{
		{Decisiontype: "miler_assignment", Outcome: "success", Count: 7},
		{Decisiontype: "stall_response", Outcome: "pending", Count: 2},
		{Decisiontype: "miler_assignment", Outcome: "pending", Count: 3},
	})
	if s.Total != 12 || len(s.ByType) != 2 {
		t.Fatalf("summary %+v", s)
	}
	first := s.ByType[0]
	if first.Decisiontype != "miler_assignment" || first.Total != 10 || first.Outcomes["success"] != 7 || first.Outcomes["pending"] != 3 {
		t.Errorf("miler_assignment rolled up wrong: %+v", first)
	}
}

func TestClampDays(t *testing.T) {
	for in, want := range map[int]int{0: 7, -3: 7, 1: 1, 7: 7, 30: 30, 90: RetentionDays} {
		if got := ClampDays(in); got != want {
			t.Errorf("ClampDays(%d) = %d, want %d", in, got, want)
		}
	}
}

// aiagentruns is created by AutoMigrate, so its columns are timestamptz. The
// recorder must stamp a true instant; utils.DBNow (IST digits labelled UTC) is
// 5h30m off as an instant and made the Phase 4 end-to-end run read a 20:57 IST
// run back as 02:27 the next day.
func TestRecorderStampsARealInstant(t *testing.T) {
	r := NewRecorder(nil, nil)
	if d := r.now().Sub(time.Now()); d > time.Minute || d < -time.Minute {
		t.Fatalf("recorder clock is %v off real time; it must not use utils.DBNow", d)
	}
}