package itemevents

import (
	"context"
	"reflect"
	"testing"

	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared/diagnostics"
)

func TestNormalizeTrimsCanonicalizesAndClones(t *testing.T) {
	doc := &source.SourceDocument{ID: "session", Units: []source.SourceUnit{{ID: 30}, {ID: 10}}}
	quantity := 4
	input := dnd.ItemEventList{Events: []dnd.ItemEvent{{
		Name: "  Gold  Pieces  ", Kind: dnd.ItemEventKindTransferred, Quantity: &quantity, From: "  Borin  ", To: "  Aria  ",
		SourceRefs: []source.SourceRef{{SourceID: doc.ID, StartUnitID: 10, EndUnitID: 10}, {SourceID: doc.ID, StartUnitID: 30, EndUnitID: 30}, {SourceID: doc.ID, StartUnitID: 30, EndUnitID: 30}},
	}}}
	result := normalize(t, doc, input)
	got := result.Value.Events[0]
	if got.Name != "Gold  Pieces" || got.From != "Borin" || got.To != "Aria" || got.Quantity == input.Events[0].Quantity ||
		!reflect.DeepEqual(got.SourceRefs, []source.SourceRef{{SourceID: doc.ID, StartUnitID: 30, EndUnitID: 30}, {SourceID: doc.ID, StartUnitID: 10, EndUnitID: 10}}) {
		t.Fatalf("normalized event = %#v", got)
	}
	if !hasWarning(result.Warnings, ReasonCodeDisplayNormalized) || !hasWarning(result.Warnings, ReasonCodeSourceRefsNormalized) {
		t.Fatalf("warnings = %#v", result.Warnings)
	}
	second := normalize(t, doc, result.Value)
	if !reflect.DeepEqual(second.Value, result.Value) || len(second.Warnings) != 0 {
		t.Fatalf("second normalization = %#v; want idempotent output without warnings", second)
	}
	*got.Quantity = 99
	got.SourceRefs[0].StartUnitID = 999
	if quantity != 4 || input.Events[0].SourceRefs[1].StartUnitID != 30 {
		t.Fatalf("Normalize() aliased input: %#v", input)
	}
}

func TestNormalizeOrdersAndCollapsesExactDuplicatesOnly(t *testing.T) {
	doc := &source.SourceDocument{ID: "session", Units: []source.SourceUnit{{ID: 30}, {ID: 10}, {ID: 20}}}
	ref := func(unit int) source.SourceRef {
		return source.SourceRef{SourceID: doc.ID, StartUnitID: unit, EndUnitID: unit}
	}
	quantity := 2
	duplicate := dnd.ItemEvent{Name: "  Potion ", Kind: dnd.ItemEventKindAcquired, Quantity: &quantity, To: " Aria ", SourceRefs: []source.SourceRef{ref(30)}}
	input := dnd.ItemEventList{Events: []dnd.ItemEvent{
		{Name: "Later", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(20)}},
		duplicate,
		{Name: "Potion", Kind: dnd.ItemEventKindAcquired, Quantity: &quantity, To: "Aria", SourceRefs: []source.SourceRef{ref(30)}},
		{Name: "Potion", Kind: dnd.ItemEventKindAcquired, Quantity: &quantity, To: "Borin", SourceRefs: []source.SourceRef{ref(30)}},
		{Name: "Potion", Kind: dnd.ItemEventKindAcquired, Quantity: &quantity, To: "Aria", SourceRefs: []source.SourceRef{{SourceID: doc.ID, StartUnitID: 999, EndUnitID: 999}}},
	}}
	result := normalize(t, doc, input)
	got := result.Value.Events
	if len(got) != 4 || got[0].Name != "Potion" || got[0].To != "Aria" || got[1].To != "Borin" || got[2].Name != "Later" || got[3].SourceRefs[0].StartUnitID != 999 {
		t.Fatalf("normalized events = %#v", got)
	}
	if !hasWarning(result.Warnings, ReasonCodeEventsReordered) || !hasWarning(result.Warnings, ReasonCodeDuplicateCollapsed) {
		t.Fatalf("warnings = %#v", result.Warnings)
	}
}

func TestNormalizeUsesEveryCanonicalTieBreaker(t *testing.T) {
	doc := testDocument()
	ref := func(unit int) source.SourceRef {
		return source.SourceRef{SourceID: doc.ID, StartUnitID: unit, EndUnitID: unit}
	}
	quantity := 1
	tests := []struct {
		name    string
		earlier dnd.ItemEvent
		later   dnd.ItemEvent
	}{
		{"evidence position", dnd.ItemEvent{Name: "Z", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "A", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(20)}}},
		{"normalized name", dnd.ItemEvent{Name: "A", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "B", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}},
		{"exact name", dnd.ItemEvent{Name: "A", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "a", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}},
		{"kind", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindAcquired, To: "Aria", SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}},
		{"from presence", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, From: "Aria", SourceRefs: []source.SourceRef{ref(10)}}},
		{"from comparison", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "A", To: "Z", SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "B", To: "Z", SourceRefs: []source.SourceRef{ref(10)}}},
		{"exact from", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "A", To: "Z", SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "a", To: "Z", SourceRefs: []source.SourceRef{ref(10)}}},
		{"to presence", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, To: "Aria", SourceRefs: []source.SourceRef{ref(10)}}},
		{"to comparison", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "A", To: "A", SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "A", To: "B", SourceRefs: []source.SourceRef{ref(10)}}},
		{"exact to", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "A", To: "A", SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindTransferred, From: "A", To: "a", SourceRefs: []source.SourceRef{ref(10)}}},
		{"quantity", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, Quantity: &quantity, SourceRefs: []source.SourceRef{ref(10)}}},
		{"reference sequence", dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10)}}, dnd.ItemEvent{Name: "Item", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{ref(10), ref(20)}}},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result := normalize(t, doc, dnd.ItemEventList{Events: []dnd.ItemEvent{test.later, test.earlier}})
			if len(result.Value.Events) != 2 || !reflect.DeepEqual(result.Value.Events[0], test.earlier) || !reflect.DeepEqual(result.Value.Events[1], test.later) {
				t.Fatalf("normalized events = %#v; want %#v then %#v", result.Value.Events, test.earlier, test.later)
			}
		})
	}
}

func TestNormalizePreservesEmptyAndMalformedCandidates(t *testing.T) {
	for _, input := range []dnd.ItemEventList{{}, {Events: []dnd.ItemEvent{}}} {
		result := normalize(t, nil, input)
		if (result.Value.Events == nil) != (input.Events == nil) {
			t.Fatalf("empty representation changed: %#v", result.Value)
		}
	}
	malformed := dnd.ItemEventList{Events: []dnd.ItemEvent{
		{Name: "  Coin  ", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{{SourceID: "session", StartUnitID: 99, EndUnitID: 99}}},
		{Name: "Coin", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{{SourceID: "session", StartUnitID: 99, EndUnitID: 99}}},
	}}
	result := normalize(t, testDocument(), malformed)
	if len(result.Value.Events) != 2 || result.Value.Events[0].Name != "Coin" || result.Value.Events[1].Name != "Coin" {
		t.Fatalf("malformed candidates were not safely retained: %#v", result.Value)
	}
}

func TestNormalizeDoesNotInferOrConvertInventoryMeaning(t *testing.T) {
	doc := testDocument()
	quantity := 25
	input := dnd.ItemEventList{Events: []dnd.ItemEvent{
		{Name: "  gold pieces  ", Kind: dnd.ItemEventKindDiscovered, Quantity: &quantity, SourceRefs: []source.SourceRef{{SourceID: doc.ID, StartUnitID: 10, EndUnitID: 10}}},
		{Name: "  gp  ", Kind: dnd.ItemEventKindAcquired, Quantity: &quantity, To: " party ", SourceRefs: []source.SourceRef{{SourceID: doc.ID, StartUnitID: 20, EndUnitID: 20}}},
		{Name: "  potion of healing  ", Kind: dnd.ItemEventKindTransferred, Quantity: &quantity, From: " Aria ", To: " Borin ", SourceRefs: []source.SourceRef{{SourceID: doc.ID, StartUnitID: 30, EndUnitID: 30}}},
	}}
	result := normalize(t, doc, input)
	got := make(map[string]dnd.ItemEvent, len(result.Value.Events))
	for _, event := range result.Value.Events {
		got[event.Name] = event
	}
	if event := got["gold pieces"]; event.Kind != dnd.ItemEventKindDiscovered || event.Quantity == nil || *event.Quantity != 25 {
		t.Fatalf("discovery event was inferred or converted: %#v", event)
	}
	if event := got["gp"]; event.Kind != dnd.ItemEventKindAcquired || event.Quantity == nil || *event.Quantity != 25 || event.To != "party" {
		t.Fatalf("acquisition event was inferred or denomination-converted: %#v", event)
	}
	if event := got["potion of healing"]; event.Kind != dnd.ItemEventKindTransferred || event.From != "Aria" || event.To != "Borin" || event.Quantity == nil || *event.Quantity != 25 {
		t.Fatalf("transfer event was inferred, aliased, singularized, or ledger-adjusted: %#v", event)
	}
}

func TestNormalizerContractAndBoundedWarnings(t *testing.T) {
	normalizer := New(Options{})
	if spec := ModuleSpec(); spec.Key != Key || spec.Stage != pipeline.StageNormalize || spec.ArtifactKind != dnd.ItemEventListKind || len(spec.ReferenceSlots) != 0 ||
		!reflect.DeepEqual(spec.Requires, []string{"merged"}) || !reflect.DeepEqual(spec.Provides, []string{"normalized"}) {
		t.Fatalf("ModuleSpec() = %#v", spec)
	}
	if metadata := normalizer.ManifestMetadata(); !reflect.DeepEqual(metadata, map[string]any{"normalization_policy": normalizationPolicy}) {
		t.Fatalf("ManifestMetadata() = %#v", metadata)
	}
	if fingerprints := normalizer.CheckpointFingerprints(); !reflect.DeepEqual(fingerprints, []pipeline.CheckpointFingerprint{{Name: "normalization_policy", Value: normalizationPolicy}}) {
		t.Fatalf("CheckpointFingerprints() = %#v", fingerprints)
	}
	registry := pipeline.NewNormalizerRegistry()
	if err := Register(registry); err != nil {
		t.Fatalf("Register() error = %v", err)
	}
	if _, err := DecodeOptions(map[string]any{"unexpected": true}); err == nil {
		t.Fatal("DecodeOptions() accepted unknown option")
	}

	count := diagnostics.MaxWarnings + 5
	doc := &source.SourceDocument{ID: "session", Units: make([]source.SourceUnit, count)}
	input := dnd.ItemEventList{Events: make([]dnd.ItemEvent, count)}
	for index := range input.Events {
		doc.Units[index].ID = index + 1
		input.Events[index] = dnd.ItemEvent{Name: "  Coin  ", Kind: dnd.ItemEventKindDiscovered, SourceRefs: []source.SourceRef{{SourceID: doc.ID, StartUnitID: count - index, EndUnitID: count - index}}}
	}
	result := normalize(t, doc, input)
	if len(result.Warnings) != diagnostics.MaxWarnings || result.Warnings[len(result.Warnings)-1].ReasonCode != ReasonCodeWarningsOmitted {
		t.Fatalf("warnings = %#v", result.Warnings)
	}
}

func normalize(t *testing.T, doc *source.SourceDocument, input dnd.ItemEventList) contracts.TypedNormalizeResult[dnd.ItemEventList] {
	t.Helper()
	result, err := New(Options{}).Normalize(context.Background(), contracts.TypedNormalizeRequest[dnd.ItemEventList]{Source: doc, MergeOutput: contracts.MergeArtifact[dnd.ItemEventList]{Value: input}})
	if err != nil {
		t.Fatalf("Normalize() error = %v", err)
	}
	return result
}

func testDocument() *source.SourceDocument {
	return &source.SourceDocument{ID: "session", Units: []source.SourceUnit{{ID: 10}, {ID: 20}, {ID: 30}}}
}

func hasWarning(warnings []contracts.Warning, reason string) bool {
	for _, warning := range warnings {
		if warning.ReasonCode == reason {
			return true
		}
	}
	return false
}