package emission_test

import (
	"os"
	"path/filepath"
	"sort"
	"testing"

	"gopkg.in/yaml.v3"

	"github.com/netkingdom/flex-auth/internal/emission"
	"github.com/netkingdom/flex-auth/pkg/api"
)

func deny(id, tenant string) api.DecisionEnvelope {
	return api.DecisionEnvelope{
		ID:       id,
		Effect:   api.DecisionEffectDeny,
		Resource: api.ResourceRef{ID: "t1", Type: "tenant", System: "tenant-engine"},
		Binding:  &api.DecisionBinding{Tenant: tenant},
	}
}

func readEvents(t *testing.T, dir string) []map[string]any {
	t.Helper()
	data, err := os.ReadFile(filepath.Join(dir, "outbox.jsonl"))
	if err != nil {
		t.Fatal(err)
	}
	var events []map[string]any
	for _, line := range splitLines(data) {
		var e struct {
			Event map[string]any `json:"event"`
		}
		if err := yaml.Unmarshal(line, &e); err != nil {
			t.Fatal(err)
		}
		events = append(events, e.Event)
	}
	return events
}

func splitLines(data []byte) [][]byte {
	var lines [][]byte
	start := 0
	for i, b := range data {
		if b == '\n' {
			lines = append(lines, data[start:i])
			start = i + 1
		}
	}
	return lines
}

func TestCommittedEventsCarryAuditCoreRequiredFields(t *testing.T) {
	dir := t.TempDir()
	outbox, err := emission.Open(dir, "flex-auth.tenant-engine")
	if err != nil {
		t.Fatal(err)
	}
	// Identical checks share a content-digest decision id.
	if err := outbox.AppendBatch([]api.DecisionEnvelope{deny("decision:aa", ""), deny("decision:aa", "tenant:acme")}); err != nil {
		t.Fatal(err)
	}
	outbox.Close()

	events := readEvents(t, dir)
	if len(events) != 2 {
		t.Fatalf("events = %d; want 2", len(events))
	}
	// audit-core normalize() rejects an event missing any of these.
	for _, event := range events {
		for _, key := range []string{"id", "type", "source", "subject", "tenant", "correlation_id", "occurred_at", "data"} {
			if value, ok := event[key]; !ok || value == "" || value == nil {
				t.Fatalf("event missing %q: %v", key, event)
			}
		}
		if event["type"] != "flex-auth.decision.deny" || event["correlation_id"] != "decision:aa" {
			t.Fatalf("event = %v", event)
		}
	}
	if events[0]["id"] == events[1]["id"] {
		t.Fatal("two decisions share an event id; audit-core idempotency would merge them")
	}
	if events[0]["tenant"] != emission.PlatformTenant || events[1]["tenant"] != "tenant:acme" {
		t.Fatalf("tenants = %v, %v", events[0]["tenant"], events[1]["tenant"])
	}
}

func TestCountsSurviveRestartAndTornTailIsDropped(t *testing.T) {
	dir := t.TempDir()
	outbox, err := emission.Open(dir, "flex-auth.test")
	if err != nil {
		t.Fatal(err)
	}
	if err := outbox.Append(deny("decision:1", "")); err != nil {
		t.Fatal(err)
	}
	outbox.Close()

	// A crash mid-write leaves a line with no newline.
	f, _ := os.OpenFile(filepath.Join(dir, "outbox.jsonl"), os.O_APPEND|os.O_WRONLY, 0)
	f.WriteString(`{"seq":2,"event":{"type":"flex-auth.decision.de`)
	f.Close()

	outbox, err = emission.Open(dir, "flex-auth.test")
	if err != nil {
		t.Fatalf("reopen with torn tail: %v", err)
	}
	if err := outbox.Append(deny("decision:3", "")); err != nil {
		t.Fatal(err)
	}
	outbox.Close()

	outbox, err = emission.Open(dir, "flex-auth.test")
	if err != nil {
		t.Fatalf("reopen after append past torn tail: %v", err)
	}
	defer outbox.Close()
	if got := outbox.Status().Committed["flex-auth.decision.deny"]; got != 2 {
		t.Fatalf("committed deny = %d; want 2 (torn write never counted)", got)
	}
}

func TestReleasedUncommittedIsReportedPerClass(t *testing.T) {
	outbox, err := emission.Open(t.TempDir(), "flex-auth.test")
	if err != nil {
		t.Fatal(err)
	}
	defer outbox.Close()
	outbox.NoteReleasedUncommitted(api.DecisionEffectRedact)
	status := outbox.Status()
	if status.ReleasedUncommitted["flex-auth.decision.redact"] != 1 {
		t.Fatalf("status = %+v", status)
	}
	if len(status.Committed) != len(api.DecisionEffects()) {
		t.Fatalf("status must report every class, zero included: %+v", status.Committed)
	}
}

// cadence.yaml must classify exactly the effect vocabulary, so a new effect
// cannot ship unclassified (FLEX-WP-0031-T03 gate).
func TestCadenceClassifiesEveryEffect(t *testing.T) {
	data, err := os.ReadFile(filepath.Join("..", "..", "cadence.yaml"))
	if err != nil {
		t.Fatal(err)
	}
	var cadence struct {
		Classes map[string]struct {
			Action        string `yaml:"action"`
			EvidenceClass string `yaml:"evidence_class"`
		} `yaml:"classes"`
	}
	if err := yaml.Unmarshal(data, &cadence); err != nil {
		t.Fatal(err)
	}
	var declared, want []string
	for name, class := range cadence.Classes {
		if class.EvidenceClass != "load-bearing" {
			continue
		}
		declared = append(declared, name)
		if class.Action != emission.Class(api.DecisionEffect(name)) {
			t.Errorf("class %q action = %q; want %q", name, class.Action, emission.Class(api.DecisionEffect(name)))
		}
	}
	for _, effect := range api.DecisionEffects() {
		want = append(want, string(effect))
	}
	sort.Strings(declared)
	sort.Strings(want)
	if len(declared) != len(want) {
		t.Fatalf("cadence.yaml load-bearing classes %v; want the effect vocabulary %v", declared, want)
	}
	for i := range want {
		if declared[i] != want[i] {
			t.Fatalf("cadence.yaml load-bearing classes %v; want %v", declared, want)
		}
	}
}