package shape

import (
	"context"
	"fmt"
	"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 TestValidatorAcceptsEveryOccurrenceRuleAndNormalizableWhitespace(t *testing.T) {
	quantity := 1
	value := dnd.ItemOccurrenceList{Occurrences: []dnd.ItemOccurrence{{ItemID: "item", Name: "  Hidden Cache  ", Kind: dnd.ItemOccurrenceKindDiscovered, From: " ", To: " ", SourceRefs: refs(1, 1)},
		{ItemID: "item", Name: "Gold Pieces", Kind: dnd.ItemOccurrenceKindAcquired, Quantity: &quantity, To: " party ", SourceRefs: refs(2, 2)},
		{ItemID: "item", Name: "Torch", Kind: dnd.ItemOccurrenceKindLost, From: " party ", SourceRefs: refs(3, 3)},
		{ItemID: "item", Name: "Potion", Kind: dnd.ItemOccurrenceKindConsumed, From: " Aria ", SourceRefs: refs(4, 4)},
		{ItemID: "item", Name: "Moonblade", Kind: dnd.ItemOccurrenceKindTransferred, From: "Aria", To: "Borin", SourceRefs: refs(5, 5)},
	}}
	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Value: value})
	if err != nil || !result.Approved {
		t.Fatalf("Validate() = %#v, %v", result, err)
	}
	empty, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Value: dnd.ItemOccurrenceList{Occurrences: []dnd.ItemOccurrence{}}})
	if err != nil || !empty.Approved {
		t.Fatalf("empty list result = %#v, %v", empty, err)
	}
}

func TestValidatorRejectsOwnedSemanticBoundaries(t *testing.T) {
	valid := validList()
	zero := 0
	negative := -1
	tests := []struct {
		name  string
		value dnd.ItemOccurrenceList
		want  string
	}{
		{"missing occurrences", dnd.ItemOccurrenceList{}, "occurrences must be present"},
		{"blank name", listWith(dnd.ItemOccurrence{ItemID: "item", Name: " \t", Kind: dnd.ItemOccurrenceKindDiscovered, SourceRefs: refs(1, 1)}), "name must not be empty"},
		{"unsupported kind", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: "unknown", SourceRefs: refs(1, 1)}), "kind is unsupported"},
		{"discovered holder", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindDiscovered, From: "Aria", SourceRefs: refs(1, 1)}), "incompatible"},
		{"acquired without holder", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindAcquired, SourceRefs: refs(1, 1)}), "incompatible"},
		{"lost destination", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindLost, From: "Aria", To: "Borin", SourceRefs: refs(1, 1)}), "incompatible"},
		{"consumed without holder", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindConsumed, SourceRefs: refs(1, 1)}), "incompatible"},
		{"party transfer from", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindTransferred, From: "party", To: "Borin", SourceRefs: refs(1, 1)}), "incompatible"},
		{"party transfer to", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindTransferred, From: "Aria", To: " PARTY ", SourceRefs: refs(1, 1)}), "incompatible"},
		{"case equivalent transfer", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindTransferred, From: "Aria", To: "aria", SourceRefs: refs(1, 1)}), "incompatible"},
		{"unicode equivalent transfer", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindTransferred, From: "Åria", To: "Åria", SourceRefs: refs(1, 1)}), "incompatible"},
		{"zero quantity", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindAcquired, Quantity: &zero, To: "party", SourceRefs: refs(1, 1)}), "quantity must be positive"},
		{"negative quantity", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindAcquired, Quantity: &negative, To: "party", SourceRefs: refs(1, 1)}), "quantity must be positive"},
		{"missing source refs", listWith(dnd.ItemOccurrence{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindDiscovered}), "source_refs must contain"},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Value: test.value})
			if err != nil || result.Approved || result.ReasonCode != ReasonCode || !strings.Contains(result.Message, test.want) {
				t.Fatalf("Validate() = %#v, %v; want %q", result, err, test.want)
			}
		})
	}
	if result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Value: valid}); err != nil || !result.Approved {
		t.Fatalf("valid result = %#v, %v", result, err)
	}
}

func TestValidatorProvidesActionableContextualHolderGuidance(t *testing.T) {
	tests := []struct {
		name         string
		occurrence   dnd.ItemOccurrence
		wantGuidance []string
	}{
		{
			name:         "discovered",
			occurrence:   dnd.ItemOccurrence{ItemID: "item:sha256:opaque", Name: "Ring", Kind: dnd.ItemOccurrenceKindDiscovered, From: "Aria", SourceRefs: refs(1, 2)},
			wantGuidance: []string{"For `discovered` occurrences", "both `from` and `to` to JSON null"},
		},
		{
			name:         "acquired",
			occurrence:   dnd.ItemOccurrence{ItemID: "item:sha256:opaque", Name: "Ring", Kind: dnd.ItemOccurrenceKindAcquired, From: "Merchant", To: "party", SourceRefs: refs(1, 2)},
			wantGuidance: []string{"For `acquired` occurrences", "`from` to JSON null", "named party member gaining possession"},
		},
		{
			name:         "lost",
			occurrence:   dnd.ItemOccurrence{ItemID: "item:sha256:opaque", Name: "Ring", Kind: dnd.ItemOccurrenceKindLost, From: "party", To: "Merchant", SourceRefs: refs(1, 2)},
			wantGuidance: []string{"For `lost` occurrences", "named party member losing possession", "`to` to JSON null"},
		},
		{
			name:         "consumed",
			occurrence:   dnd.ItemOccurrence{ItemID: "item:sha256:opaque", Name: "Ring", Kind: dnd.ItemOccurrenceKindConsumed, SourceRefs: refs(1, 2)},
			wantGuidance: []string{"For `consumed` occurrences", "named party member consuming the item", "`to` to JSON null"},
		},
		{
			name:         "transferred",
			occurrence:   dnd.ItemOccurrence{ItemID: "item:sha256:opaque", Name: "Ring", Kind: dnd.ItemOccurrenceKindTransferred, From: "party", To: "Borin", SourceRefs: refs(1, 2)},
			wantGuidance: []string{"For `transferred` occurrences", "two distinct named party members", "never use `party`"},
		},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Value: listWith(test.occurrence)})
			if err != nil || result.Approved {
				t.Fatalf("Validate() = %#v, %v; want rejection", result, err)
			}
			for _, fragment := range append(test.wantGuidance, "item \"Ring\"", "source units 1-2") {
				if !strings.Contains(result.CorrectionGuidance, fragment) {
					t.Fatalf("CorrectionGuidance = %q, want %q", result.CorrectionGuidance, fragment)
				}
			}
			for _, forbidden := range []string{test.occurrence.ItemID, "sha256", Key, ReasonCode, "occurrences[0]"} {
				if strings.Contains(result.CorrectionGuidance, forbidden) {
					t.Fatalf("CorrectionGuidance leaked implementation identifier %q: %q", forbidden, result.CorrectionGuidance)
				}
			}
			if !strings.Contains(result.Message, "expected") || !strings.Contains(result.Message, "got from") {
				t.Fatalf("operator message = %q, want expected and observed holders", result.Message)
			}
		})
	}
}

func TestValidatorGroupsRepeatedHolderCorrectionsAndRetainsDistinctRules(t *testing.T) {
	value := dnd.ItemOccurrenceList{Occurrences: []dnd.ItemOccurrence{
		{ItemID: "item-1", Name: "Silver Pieces", Kind: dnd.ItemOccurrenceKindAcquired, From: "Orc", To: "party", SourceRefs: refs(1, 1)},
		{ItemID: "item-2", Name: "Torch", Kind: dnd.ItemOccurrenceKindAcquired, From: "Chest", To: "Aria", SourceRefs: refs(2, 2)},
		{ItemID: "item-3", Name: "Potion", Kind: dnd.ItemOccurrenceKindConsumed, SourceRefs: refs(3, 3)},
	}}
	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Value: value})
	if err != nil || result.Approved {
		t.Fatalf("Validate() = %#v, %v; want rejection", result, err)
	}
	if strings.Count(result.CorrectionGuidance, "For `acquired` occurrences") != 1 || strings.Count(result.CorrectionGuidance, "For `consumed` occurrences") != 1 {
		t.Fatalf("CorrectionGuidance = %q, want one rule per affected kind", result.CorrectionGuidance)
	}
	for _, fragment := range []string{"item \"Silver Pieces\"", "source unit 1", "item \"Torch\"", "source unit 2", "item \"Potion\"", "source unit 3"} {
		if !strings.Contains(result.CorrectionGuidance, fragment) {
			t.Fatalf("CorrectionGuidance = %q, want contextual fragment %q", result.CorrectionGuidance, fragment)
		}
	}
}

func TestValidatorAggregatesBoundedIndexedDiagnosticsAndRegistration(t *testing.T) {
	value := dnd.ItemOccurrenceList{Occurrences: make([]dnd.ItemOccurrence, 24)}
	for index := range value.Occurrences {
		value.Occurrences[index] = dnd.ItemOccurrence{ItemID: "item", Name: fmt.Sprintf("Item %d", index), Kind: "unsupported"}
	}
	result, err := New(Options{}).Validate(context.Background(), contracts.TypedValidationRequest[dnd.ItemOccurrenceList]{Value: value})
	if err != nil || result.Approved || result.ReasonCode != ReasonCode || len([]byte(result.Message)) > 4096 || !utf8.ValidString(result.Message) || !strings.Contains(result.Message, "occurrences[0]") || !strings.Contains(result.Message, "additional issue(s) omitted") {
		t.Fatalf("Validate() = %#v, %v", result, err)
	}
	if len([]byte(result.CorrectionGuidance)) > 4096 || !utf8.ValidString(result.CorrectionGuidance) || !strings.Contains(result.CorrectionGuidance, "additional issue(s) omitted") {
		t.Fatalf("CorrectionGuidance = %q, want bounded aggregate", result.CorrectionGuidance)
	}
	if value.Occurrences[0].Name != "Item 0" {
		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 validList() dnd.ItemOccurrenceList {
	return dnd.ItemOccurrenceList{Occurrences: []dnd.ItemOccurrence{{ItemID: "item", Name: "Ring", Kind: dnd.ItemOccurrenceKindAcquired, To: "party", SourceRefs: refs(1, 1)}}}
}

func listWith(occurrence dnd.ItemOccurrence) dnd.ItemOccurrenceList {
	return dnd.ItemOccurrenceList{Occurrences: []dnd.ItemOccurrence{occurrence}}
}

func refs(start, end int) []source.SourceRef {
	return []source.SourceRef{{SourceID: "session", StartUnitID: start, EndUnitID: end}}
}
