package enemyevents

import (
	"encoding/json"
	"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"
)

func validList() dnd.EnemyEventList {
	return dnd.EnemyEventList{Events: []dnd.EnemyEvent{
		{Name: "Ashfang", Kind: dnd.EnemyEventKindEngaged, SourceRefs: refs(1, 2)},
		{Name: "Ashfang", Kind: dnd.EnemyEventKindFled, SourceRefs: refs(5, 6)},
	}}
}

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

func TestCodecRoundTripAndIdentity(t *testing.T) {
	codec := New()
	value := validList()
	content, err := codec.Encode(value)
	if err != nil {
		t.Fatalf("Encode() error = %v", err)
	}
	decoded, err := codec.Decode(content)
	if err != nil || !reflect.DeepEqual(decoded, value) {
		t.Fatalf("Decode() = %#v, %v; want %#v", decoded, err, value)
	}

	schema := codec.Schema()
	if codec.Kind() != dnd.EnemyEventListKind || codec.MediaType() != MediaType || schema.ID != SchemaID || schema.Name != SchemaName || schema.Version != SchemaVersion || !json.Valid(schema.JSONSchema) {
		t.Fatalf("codec identity/schema = %q/%q %#v", codec.Kind(), codec.MediaType(), schema)
	}
	registry := pipeline.NewArtifactCodecRegistry()
	if err := pipeline.RegisterArtifactCodec(registry, codec); err != nil {
		t.Fatal(err)
	}
	spec, ok := registry.Spec(dnd.EnemyEventListKind)
	if !ok || spec.SchemaDigest != contracts.DigestArtifactSchema(schema) {
		t.Fatalf("registered spec = %#v, %t", spec, ok)
	}
}

func TestCodecRejectsStrictJSONAndMissingRequiredFields(t *testing.T) {
	validJSON := `{"events":[{"name":"Ashfang","kind":"engaged","source_refs":[{"source_id":"session","start_unit_id":1,"end_unit_id":1}]}]}`
	tests := []struct {
		name, raw, want string
	}{
		{"invalid JSON", `{`, "decode dnd enemy event list"},
		{"unknown root field", `{"events":[],"unexpected":true}`, "unknown field"},
		{"unknown event field", strings.Replace(validJSON, `"kind":"engaged"`, `"kind":"engaged","unexpected":true`, 1), "unknown field"},
		{"missing events", `{}`, "events must be present"},
		{"missing name", strings.Replace(validJSON, `"name":"Ashfang",`, "", 1), "events[0].name must be present"},
		{"missing kind", strings.Replace(validJSON, `"kind":"engaged",`, "", 1), "events[0].kind must be present"},
		{"missing refs", strings.Replace(validJSON, `,"source_refs":[{"source_id":"session","start_unit_id":1,"end_unit_id":1}]`, "", 1), "events[0].source_refs must be present"},
		{"missing source ID", strings.Replace(validJSON, `"source_id":"session",`, "", 1), "source_refs[0].source_id must be present"},
		{"trailing JSON", `{"events":[]} {}`, "multiple JSON values"},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			if _, err := New().Decode([]byte(test.raw)); err == nil || !strings.Contains(err.Error(), test.want) {
				t.Fatalf("Decode() error = %v, want %q", err, test.want)
			}
		})
	}
}

func TestCodecDefensivelyOwnsValuesAndDefersSemanticValidation(t *testing.T) {
	codec := New()
	candidate := dnd.EnemyEventList{Events: []dnd.EnemyEvent{{
		Name: " ", Kind: "unsupported", SourceRefs: []source.SourceRef{{SourceID: "", StartUnitID: 0, EndUnitID: -1}},
	}}}
	content, err := codec.EncodeCandidate(candidate)
	if err != nil {
		t.Fatal(err)
	}
	decoded, err := codec.Decode(content)
	if err != nil || !reflect.DeepEqual(decoded, candidate) {
		t.Fatalf("Decode() = %#v, %v; want semantic candidate preservation", decoded, err)
	}
	decoded.Events[0].SourceRefs[0].SourceID = "changed"
	if candidate.Events[0].SourceRefs[0].SourceID != "" {
		t.Fatal("Decode() retained caller-owned source references")
	}

	first := codec.Schema()
	first.JSONSchema[0] = '['
	if second := codec.Schema(); !json.Valid(second.JSONSchema) || second.JSONSchema[0] == '[' {
		t.Fatal("Schema() returned shared bytes")
	}
}