package sourcerefs

import (
	"context"
	"reflect"
	"strings"
	"testing"
	"unicode/utf8"

	"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"
)

func TestValidatorOwnsSourceAndRangeValidation(t *testing.T) {
	value := validList()
	result, err := New(Options{}).Validate(context.Background(), request(document(), value))
	if err != nil || !result.Approved {
		t.Fatalf("valid result = %#v, %v", result, err)
	}
	value.Occurrences[0].SourceRefs = []source.SourceRef{
		{SourceID: "foreign", StartUnitID: 1, EndUnitID: 1},
		{SourceID: "session", StartUnitID: 99, EndUnitID: 99},
		{SourceID: "session", StartUnitID: 2, EndUnitID: 1},
	}
	result, err = New(Options{}).Validate(context.Background(), request(document(), value))
	if err != nil || result.Approved || result.ReasonCode != ReasonCode {
		t.Fatalf("invalid result = %#v, %v", result, err)
	}
	for _, index := range []string{"occurrences[0].source_refs[0]", "occurrences[0].source_refs[1]", "occurrences[0].source_refs[2]"} {
		if !strings.Contains(result.Message, index) {
			t.Fatalf("validation message = %q, missing %q", result.Message, index)
		}
	}
}

func TestValidatorEnforcesChunkOnlyDuringExtraction(t *testing.T) {
	doc := document()
	chunk := &source.Chunk{ID: "chunk-0", SourceID: doc.ID, Units: append([]source.SourceUnit(nil), doc.Units[:2]...)}
	contained := validList()
	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Stage: string(pipeline.StageExtract), Source: doc, Chunk: chunk, Value: contained})
	if err != nil || !result.Approved {
		t.Fatalf("contained evidence = %#v, %v", result, err)
	}

	crossesChunk := validList()
	crossesChunk.Occurrences[0].SourceRefs = []source.SourceRef{{SourceID: doc.ID, StartUnitID: 2, EndUnitID: 3}}
	result, err = New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Stage: string(pipeline.StageExtract), Source: doc, Chunk: chunk, Value: crossesChunk})
	if err != nil || result.Approved || !strings.Contains(result.Message, "outside the current extraction chunk") {
		t.Fatalf("out-of-chunk evidence = %#v, %v", result, err)
	}

	noncontiguousChunk := &source.Chunk{ID: "chunk-1", SourceID: doc.ID, Units: []source.SourceUnit{doc.Units[0], doc.Units[2]}}
	spansMissingUnit := validList()
	spansMissingUnit.Occurrences[0].SourceRefs = []source.SourceRef{{SourceID: doc.ID, StartUnitID: 1, EndUnitID: 3}}
	result, err = New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Stage: string(pipeline.StageExtract), Source: doc, Chunk: noncontiguousChunk, Value: spansMissingUnit})
	if err != nil || result.Approved || !strings.Contains(result.Message, "outside the current extraction chunk") {
		t.Fatalf("partially contained evidence = %#v, %v", result, err)
	}

	multiRange := validList()
	multiRange.Occurrences[0].SourceRefs = []source.SourceRef{{SourceID: doc.ID, StartUnitID: 1, EndUnitID: 2}, {SourceID: doc.ID, StartUnitID: 3, EndUnitID: 4}}
	result, err = New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Source: doc, Value: multiRange})
	if err != nil || !result.Approved {
		t.Fatalf("post-merge evidence = %#v, %v", result, err)
	}
}

func TestValidatorRequiresChunkDuringExtractionAndDefersShape(t *testing.T) {
	_, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Stage: string(pipeline.StageExtract), Source: document(), Value: validList()})
	if err == nil || !strings.Contains(err.Error(), "requires the current extraction chunk") {
		t.Fatalf("Validate() error = %v", err)
	}
	malformed := dnd.ItemOccurrenceList{Occurrences: []dnd.ItemOccurrence{{ItemID: "item", Name: "Ring"}}}
	result, err := New(Options{}).Validate(context.Background(), request(document(), malformed))
	if err != nil || !result.Approved {
		t.Fatalf("shape deferral = %#v, %v", result, err)
	}
}

func TestValidatorBoundsDiagnosticsAndRegistration(t *testing.T) {
	value := dnd.ItemOccurrenceList{Occurrences: make([]dnd.ItemOccurrence, 24)}
	for index := range value.Occurrences {
		value.Occurrences[index] = dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindDiscovered, SourceRefs: []source.SourceRef{{SourceID: "foreign", StartUnitID: index + 1, EndUnitID: index + 1}}}
	}
	result, err := New(Options{}).Validate(context.Background(), request(document(), value))
	if err != nil || result.Approved || result.ReasonCode != ReasonCode || len([]byte(result.Message)) > 4096 || !utf8.ValidString(result.Message) || !strings.Contains(result.Message, "occurrences[0].source_refs[0]") || !strings.Contains(result.Message, "additional issue(s) omitted") {
		t.Fatalf("Validate() = %#v, %v", result, err)
	}
	before := validList()
	copy := before
	if _, err := New(Options{}).Validate(context.Background(), request(document(), before)); err != nil || !reflect.DeepEqual(before, copy) {
		t.Fatal("Validate() mutated input")
	}
	if got := New(Options{}).CheckpointFingerprints(); !reflect.DeepEqual(got, []pipeline.CheckpointFingerprint{{Name: "policy", Value: policy}}) {
		t.Fatalf("CheckpointFingerprints() = %#v", got)
	}
	registry := pipeline.NewValidatorRegistry()
	if err := Register(registry); err != nil {
		t.Fatal(err)
	}
	if got, ok := registry.Spec(Key); !ok || !reflect.DeepEqual(got, Spec()) {
		t.Fatalf("registry spec = %#v, %t", got, ok)
	}
	if _, err := DecodeOptions(map[string]any{"unexpected": true}); err == nil {
		t.Fatal("DecodeOptions() accepted unknown option")
	}
}

func request(doc *source.SourceDocument, value dnd.ItemOccurrenceList) contracts.TypedValidationRequest[dnd.ItemOccurrenceList] {
	return contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Source: doc, Value: value}
}

func document() *source.SourceDocument {
	return &source.SourceDocument{ID: "session", Units: []source.SourceUnit{{ID: 1}, {ID: 2}, {ID: 3}, {ID: 4}}}
}

func validList() dnd.ItemOccurrenceList {
	return dnd.ItemOccurrenceList{Occurrences: []dnd.ItemOccurrence{{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindAcquired, To: "party", SourceRefs: []source.SourceRef{{SourceID: "session", StartUnitID: 1, EndUnitID: 2}}}}}
}
