package npcs

import (
	"context"
	"reflect"
	"strings"
	"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/npcs/identity"
)

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

func TestNormalizeNamesEvidenceAndIDs(t *testing.T) {
	input := dnd.NPCList{NPCs: []dnd.NPC{{
		ID: "wrong", Name: "  Lady\tAsh  ", SourceRefs: []source.SourceRef{
			{SourceID: "b", StartUnitID: 2, EndUnitID: 3},
			{SourceID: "a", StartUnitID: 4, EndUnitID: 4},
			{SourceID: "b", StartUnitID: 2, EndUnitID: 3},
		},
	}}}
	result, err := New(Options{}).Normalize(context.Background(), normalizeRequest(input))
	if err != nil {
		t.Fatalf("Normalize() error = %v", err)
	}
	want := dnd.NPC{ID: identity.DeriveID("Lady Ash"), Name: "Lady Ash", SourceRefs: []source.SourceRef{{SourceID: "a", StartUnitID: 4, EndUnitID: 4}, {SourceID: "b", StartUnitID: 2, EndUnitID: 3}}}
	if !reflect.DeepEqual(result.Value.NPCs[0], want) {
		t.Fatalf("NPC = %#v, want %#v", result.Value.NPCs[0], want)
	}
	for _, reason := range []string{ReasonCodeNPCFieldsNormalized, ReasonCodeSourceReferencesNormalized, ReasonCodeNPCIDRecomputed} {
		if !hasWarning(result.Warnings, reason, "npcs[0]") {
			t.Fatalf("warnings = %#v, want %s", result.Warnings, reason)
		}
	}
}

func TestNormalizeConsolidatesCanonicalNamesOnlyAndUnionsEvidence(t *testing.T) {
	input := dnd.NPCList{NPCs: []dnd.NPC{
		{Name: " Captain Vale ", SourceRefs: []source.SourceRef{{SourceID: "a", StartUnitID: 1, EndUnitID: 1}}},
		{Name: "captain vale", SourceRefs: []source.SourceRef{{SourceID: "b", StartUnitID: 2, EndUnitID: 2}}},
		{Name: "The Captain", SourceRefs: []source.SourceRef{{SourceID: "c", StartUnitID: 3, EndUnitID: 3}}},
	}}
	result, err := New(Options{}).Normalize(context.Background(), normalizeRequest(input))
	if err != nil {
		t.Fatalf("Normalize() error = %v", err)
	}
	if len(result.Value.NPCs) != 2 || result.Value.NPCs[0].Name != "Captain Vale" || result.Value.NPCs[1].Name != "The Captain" {
		t.Fatalf("NPCs = %#v, want name-only stable consolidation", result.Value.NPCs)
	}
	if refs := result.Value.NPCs[0].SourceRefs; len(refs) != 2 || refs[0].SourceID != "a" || refs[1].SourceID != "b" {
		t.Fatalf("source refs = %#v, want evidence union", refs)
	}
	if !hasWarning(result.Warnings, ReasonCodeDuplicateNPCCollapsed, "npcs[0]") {
		t.Fatalf("warnings = %#v, want duplicate collapse", result.Warnings)
	}
}

func TestNormalizePreservesInvalidCandidatesAndDoesNotAliasInput(t *testing.T) {
	input := dnd.NPCList{NPCs: []dnd.NPC{{Name: " ", SourceRefs: []source.SourceRef{{SourceID: "source", StartUnitID: 0, EndUnitID: -1}}}}}
	before := dnd.NPCList{NPCs: []dnd.NPC{{Name: " ", SourceRefs: []source.SourceRef{{SourceID: "source", StartUnitID: 0, EndUnitID: -1}}}}}
	result, err := New(Options{}).Normalize(context.Background(), normalizeRequest(input))
	if err != nil || !reflect.DeepEqual(input, before) {
		t.Fatalf("Normalize() = %#v, %v; input mutated to %#v", result, err, input)
	}
	if result.Value.NPCs[0].Name != "" || result.Value.NPCs[0].SourceRefs[0].EndUnitID != -1 {
		t.Fatalf("candidate = %#v, want invalid semantics preserved", result.Value.NPCs[0])
	}
	result.Value.NPCs[0].SourceRefs[0].SourceID = "changed"
	if input.NPCs[0].SourceRefs[0].SourceID != "source" {
		t.Fatal("output aliases input evidence")
	}
}

func TestNormalizeHandlesNilAndCanceledCalls(t *testing.T) {
	normalizer := New(Options{})
	result, err := normalizer.Normalize(context.Background(), normalizeRequest(dnd.NPCList{NPCs: nil}))
	if err != nil || result.Value.NPCs != nil {
		t.Fatalf("nil list result = %#v, error = %v", result.Value, err)
	}
	canceled, cancel := context.WithCancel(context.Background())
	cancel()
	if _, err := normalizer.Normalize(canceled, normalizeRequest(dnd.NPCList{})); err == nil || !strings.Contains(err.Error(), "context error") {
		t.Fatalf("canceled Normalize() error = %v", err)
	}
}

func normalizeRequest(value dnd.NPCList) contracts.TypedNormalizeRequest[dnd.NPCList] {
	return contracts.TypedNormalizeRequest[dnd.NPCList]{MergeOutput: contracts.MergeArtifact[dnd.NPCList]{Value: value}}
}

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