package configuration

import (
	"context"
	"errors"
	"strings"
	"testing"

	"go.maximumdirect.net/configkit"
)

func mapping(label string, values map[string]any) configkit.Input {
	return configkit.Input{Source: configkit.Mapping(label, values)}
}

func TestLoadIdentifiedResourceLists(t *testing.T) {
	for _, header := range []bool{false, true} {
		values := map[string]any{
			"backends": []any{map[string]any{"id": "local", "endpoint": "https://example.invalid/v1"}},
			"collections": map[string]any{"team": map[string]any{
				"backends": []any{map[string]any{"id": "local", "endpoint": "https://example.invalid/v1"}},
			}},
		}
		if header {
			values["version"] = "2"
		}
		loaded, err := load(mapping("identified resources", values), nil)
		if err != nil {
			t.Fatalf("load identified resources with header %t: %v", header, err)
		}
		if loaded.result.Config.Backends[0].ID != "local" || loaded.result.Config.Collections["team"].Backends[0].ID != "local" {
			t.Fatal("identified root and collection resources were not retained")
		}
	}
}

func TestIdentifiedResourcesComposeAcrossNamespacesAndKinds(t *testing.T) {
	resources := func() map[string]any {
		return map[string]any{
			"backends": []any{
				map[string]any{"id": "shared", "endpoint": "https://example.invalid/v1"},
				map[string]any{"id": "child", "extends": map[string]any{"id": "shared"}},
			},
			"profiles": []any{
				map[string]any{"id": "shared", "model": "model"},
				map[string]any{"id": "child", "extends": map[string]any{"id": "shared"}},
			},
			"prompts": []any{
				map[string]any{"id": "shared", "messages": []any{map[string]any{"role": "user", "content": "inherited"}},
					"output": map[string]any{"format": "text", "validation_mode": "basic"}},
				map[string]any{"id": "child", "extends": map[string]any{"id": "shared"}},
			},
		}
	}
	values := resources()
	values["collections"] = map[string]any{"*": resources(), "123": resources()}
	state, err := load(mapping("identified namespaces", values), nil)
	if err != nil {
		t.Fatal(err)
	}
	for _, prefix := range []string{"", "*/", "123/"} {
		backend, err := state.registry.GetBackend(prefix + "child")
		if err != nil || backend.ID != prefix+"child" || backend.Endpoint != "https://example.invalid/v1" {
			t.Fatalf("inherited backend %q = %+v, %v", prefix, backend, err)
		}
		profile, err := state.GetProfileIdentity(context.Background(), prefix+"child")
		if err != nil || profile != prefix+"child" {
			t.Fatalf("inherited profile %q = %q, %v", prefix, profile, err)
		}
		definition, _, err := state.prompt(prefix + "child")
		if err != nil || definition.ID != prefix+"child" || len(definition.Templates) != 1 || definition.Templates[0].Content != "inherited" {
			t.Fatalf("inherited prompt %q = %+v, %v", prefix, definition, err)
		}
	}
}

func TestIdentifiedResourcesRejectInvalidInheritance(t *testing.T) {
	for _, kind := range []string{"backends", "profiles", "prompts"} {
		for name, records := range map[string][]any{
			"missing": {map[string]any{"id": "child", "extends": map[string]any{"id": "missing"}}},
			"self":    {map[string]any{"id": "child", "extends": map[string]any{"id": "child"}}},
			"cycle": {
				map[string]any{"id": "first", "extends": map[string]any{"id": "second"}},
				map[string]any{"id": "second", "extends": map[string]any{"id": "first"}},
			},
		} {
			t.Run(kind+"/"+name, func(t *testing.T) {
				_, err := load(mapping("invalid inheritance", map[string]any{kind: records}), nil)
				var loadErr *configkit.LoadError
				if !errors.As(err, &loadErr) {
					t.Fatalf("load error = %v, want an upstream inheritance diagnostic", err)
				}
				for _, diagnostic := range loadErr.Diagnostics() {
					if diagnostic.Code == configkit.CodeInheritanceMissing || diagnostic.Code == configkit.CodeInheritanceCycle {
						return
					}
				}
				t.Fatalf("missing inheritance diagnostic: %+v", loadErr.Diagnostics())
			})
		}
	}
}

func TestIdentifiedResourcesRejectInvalidLocalIDs(t *testing.T) {
	for _, kind := range []string{"backends", "profiles", "prompts"} {
		for _, test := range []struct {
			name   string
			record map[string]any
		}{
			{name: "missing", record: map[string]any{}},
			{name: "null", record: map[string]any{"id": nil}},
			{name: "non-string", record: map[string]any{"id": 42}},
			{name: "blank", record: map[string]any{"id": " "}},
			{name: "slash", record: map[string]any{"id": "not/local"}},
		} {
			t.Run(kind+"/"+test.name, func(t *testing.T) {
				_, err := load(mapping("invalid resource ID", map[string]any{kind: []any{test.record}}), nil)
				var loadErr *configkit.LoadError
				if !errors.As(err, &loadErr) || len(loadErr.Diagnostics()) == 0 {
					t.Fatalf("load error = %v, want a path-aware error", err)
				}
			})
		}
	}
}

func TestIdentifiedResourcesRejectDuplicateStrictPeers(t *testing.T) {
	for _, kind := range []string{"backends", "profiles", "prompts"} {
		for _, namespace := range []string{"", "*"} {
			t.Run(kind+"/"+namespace, func(t *testing.T) {
				values := func() map[string]any {
					records := []any{map[string]any{"id": "duplicate"}}
					if namespace == "" {
						return map[string]any{kind: records}
					}
					return map[string]any{"collections": map[string]any{namespace: map[string]any{kind: records}}}
				}
				_, err := load(configkit.Input{Source: configkit.NoSource()}, []configkit.Underlay{{Inputs: []configkit.Input{
					mapping("first", values()), mapping("second", values()),
				}}})
				var loadErr *configkit.LoadError
				if !errors.As(err, &loadErr) {
					t.Fatalf("load error = %v, want an upstream duplicate diagnostic", err)
				}
				for _, diagnostic := range loadErr.Diagnostics() {
					if diagnostic.Code == configkit.CodeComposeConflict {
						return
					}
				}
				t.Fatalf("missing duplicate conflict: %+v", loadErr.Diagnostics())
			})
		}
	}
}

func TestFinalIdentitiesAreCheckedAfterApplicationResolution(t *testing.T) {
	for _, kind := range []string{"backends", "profiles", "prompts"} {
		for _, namespace := range []string{"", "*"} {
			t.Run(kind+"/"+namespace, func(t *testing.T) {
				definition := configurationDefinition(&loaded{})
				definition.Resolve = func(config *document, resolution *configkit.Resolution) error {
					path := configkit.Keys(kind)
					if namespace == "" {
						switch kind {
						case "backends":
							config.Backends = []backendConfig{{ID: "same"}, {ID: "same"}}
						case "profiles":
							config.Profiles = []profileConfig{{ID: "same"}, {ID: "same"}}
						case "prompts":
							config.Prompts = []promptConfig{{ID: "same"}, {ID: "same"}}
						}
					} else {
						collection := collectionConfig{}
						switch kind {
						case "backends":
							collection.Backends = []backendConfig{{ID: "same"}, {ID: "same"}}
						case "profiles":
							collection.Profiles = []profileConfig{{ID: "same"}, {ID: "same"}}
						case "prompts":
							collection.Prompts = []promptConfig{{ID: "same"}, {ID: "same"}}
						}
						config.Collections = map[string]collectionConfig{namespace: collection}
						path = configkit.Keys("collections", namespace, kind)
					}
					resolution.RecordNormalization(path, "supply resolved records")
					return nil
				}
				input := configkit.Input{Source: configkit.NoSource()}
				if namespace != "" {
					input = mapping("existing collection", map[string]any{"collections": map[string]any{
						namespace: map[string]any{kind: []any{}},
					}})
				}
				_, err := configkit.LoadLayered(input, configkit.LayeredOptions[document]{Definition: definition})
				var loadErr *configkit.LoadError
				if !errors.As(err, &loadErr) {
					t.Fatalf("load error = %v, want a final identity diagnostic", err)
				}
				for _, diagnostic := range loadErr.Diagnostics() {
					if diagnostic.Code == configkit.CodeSequenceConflict {
						return
					}
				}
				t.Fatalf("missing final identity conflict: %+v", loadErr.Diagnostics())
			})
		}
	}
}

func TestIdentifiedResourceLayerOperations(t *testing.T) {
	base := mapping("base profiles", map[string]any{"profiles": []any{
		map[string]any{"id": "first", "model": "original", "service_tier": "standard"},
		map[string]any{"id": "second", "model": "retained"},
	}})
	for _, test := range []struct {
		name    string
		mode    string
		records []any
		models  map[string]string
	}{
		{name: "whole record upsert", records: []any{map[string]any{"id": "first", "model": "updated"}}, models: map[string]string{"first": "updated", "second": "retained"}},
		{name: "empty upsert", records: []any{}, models: map[string]string{"first": "original", "second": "retained"}},
		{name: "append", mode: "append", records: []any{map[string]any{"id": "third", "model": "added"}}, models: map[string]string{"first": "original", "second": "retained", "third": "added"}},
		{name: "replace", mode: "replace", records: []any{map[string]any{"id": "third", "model": "replacement"}}, models: map[string]string{"third": "replacement"}},
		{name: "clear", mode: "replace", records: []any{}, models: map[string]string{}},
	} {
		t.Run(test.name, func(t *testing.T) {
			values := map[string]any{"profiles": test.records}
			if test.mode != "" {
				values["config"] = map[string]any{"sequences": []any{map[string]any{
					"destination": []any{"profiles"}, "mode": test.mode,
				}}}
			}
			state, err := load(mapping("overlay profiles", values), []configkit.Underlay{{Inputs: []configkit.Input{base}}})
			if err != nil {
				t.Fatal(err)
			}
			profiles := indexedProfiles(&state.result.Config)
			if len(profiles) != len(test.models) {
				t.Fatalf("profiles = %+v, want IDs and models %+v", profiles, test.models)
			}
			for id, model := range test.models {
				profile, ok := profiles[id]
				if !ok || profile.Model == nil || *profile.Model != model {
					t.Fatalf("profile %q = %+v, want model %q", id, profile, model)
				}
			}
			if test.name == "whole record upsert" && profiles["first"].ServiceTier != nil {
				t.Fatalf("upsert retained a displaced field: %+v", profiles["first"])
			}
		})
	}
}

func TestIdentifiedResourceLayersRejectDisplacedParentAndDuplicateAppend(t *testing.T) {
	base := mapping("base", map[string]any{"profiles": []any{
		map[string]any{"id": "shared", "model": "original"},
	}})
	for _, test := range []struct {
		name   string
		values map[string]any
		code   configkit.Code
	}{
		{
			name: "self extension cannot recover displaced record",
			values: map[string]any{"profiles": []any{
				map[string]any{"id": "shared", "extends": map[string]any{"id": "shared"}},
			}},
			code: configkit.CodeInheritanceCycle,
		},
		{
			name: "append cannot duplicate an identity",
			values: map[string]any{
				"config":   map[string]any{"sequences": []any{map[string]any{"destination": []any{"profiles"}, "mode": "append"}}},
				"profiles": []any{map[string]any{"id": "shared", "model": "other"}},
			},
			code: configkit.CodeSequenceConflict,
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			_, err := load(mapping("overlay", test.values), []configkit.Underlay{{Inputs: []configkit.Input{base}}})
			var loadErr *configkit.LoadError
			if !errors.As(err, &loadErr) {
				t.Fatalf("load error = %v, want structured diagnostic", err)
			}
			for _, diagnostic := range loadErr.Diagnostics() {
				if diagnostic.Code == test.code {
					return
				}
			}
			t.Fatalf("missing %s diagnostic: %+v", test.code, loadErr.Diagnostics())
		})
	}
}

func TestLoadChecksOptionalConfigurationVersion(t *testing.T) {
	for _, test := range []struct {
		name    string
		version any
		include bool
		valid   bool
	}{
		{name: "string two", version: "2", include: true, valid: true},
		{name: "integer two", version: int64(2), include: true, valid: true},
		{name: "omitted", valid: true},
		{name: "explicit null", include: true},
		{name: "unsupported string", version: "1", include: true},
	} {
		t.Run(test.name, func(t *testing.T) {
			values := map[string]any{}
			if test.include {
				values["version"] = test.version
			}
			loaded, err := load(mapping("main", values), nil)
			if test.valid {
				if err != nil {
					t.Fatalf("load accepted version: %v", err)
				}
				if test.include && (loaded.result.Config.Version == nil || *loaded.result.Config.Version != "2") {
					t.Fatalf("typed version = %v, want 2", loaded.result.Config.Version)
				}
				if !test.include && loaded.result.Config.Version != nil {
					t.Fatalf("omitted version = %q, want nil", *loaded.result.Config.Version)
				}
				return
			}
			var loadErr *configkit.LoadError
			if err == nil || !errors.As(err, &loadErr) {
				t.Fatalf("load error = %v, want ConfigKit load error", err)
			}
			found := false
			for _, diagnostic := range loadErr.Diagnostics() {
				if diagnostic.Path.String() == "/version" && diagnostic.Message == "unsupported configuration specification version" {
					found = true
				}
			}
			if !found {
				t.Fatalf("load diagnostics = %+v, want safe version diagnostic", loadErr.Diagnostics())
			}
		})
	}
}

func TestLoadRejectsMalformedHeadersAndLegacyResourceMappings(t *testing.T) {
	for name, values := range map[string]map[string]any{
		"boolean header":    {"version": true},
		"fractional header": {"version": 2.5},
		"sequence header":   {"version": []any{2}},
		"backend mapping":   {"backends": map[string]any{"local": map[string]any{"endpoint": "https://example.invalid/v1"}}},
		"profile mapping":   {"profiles": map[string]any{"local": map[string]any{}}},
		"prompt mapping":    {"prompts": map[string]any{"local": map[string]any{}}},
	} {
		t.Run(name, func(t *testing.T) {
			_, err := load(mapping(name, values), nil)
			var loadErr *configkit.LoadError
			if !errors.As(err, &loadErr) || len(loadErr.Diagnostics()) == 0 {
				t.Fatalf("load error = %v, want structured rejection", err)
			}
		})
	}
}

func TestNestedConfigRemainsApplicationData(t *testing.T) {
	state, err := load(mapping("nested config", map[string]any{
		"config": map[string]any{},
		"profiles": []any{map[string]any{"id": "example", "extra_params": map[string]any{
			"config": map[string]any{"imports": "provider data"},
		}}},
	}), nil)
	if err != nil {
		t.Fatal(err)
	}
	profile, err := state.GetProfile(context.Background(), "example")
	if err != nil || profile.ResolvedTarget.ExtraParams["config"].(map[string]any)["imports"] != "provider data" {
		t.Fatalf("nested application data = %+v, %v", profile, err)
	}
}

func TestLoadConsumesAcceptedUnderlayVersionAndValidatesHeaderlessPayload(t *testing.T) {
	underlay := mapping("declared underlay", map[string]any{
		"version": int64(2),
	})
	loaded, err := load(mapping("headerless main", map[string]any{}), []configkit.Underlay{{Inputs: []configkit.Input{underlay}}})
	if err != nil {
		t.Fatalf("load accepted non-main declaration: %v", err)
	}
	if loaded.result.Config.Version != nil {
		t.Fatalf("consumed non-main declaration remained in effective payload: %q", *loaded.result.Config.Version)
	}

	invalidFragment := mapping("headerless prompt fragment", map[string]any{
		"prompts": []any{map[string]any{"id": "incomplete", "description": "still validated"}},
	})
	if _, err := load(configkit.Input{Source: configkit.NoSource()}, []configkit.Underlay{{Inputs: []configkit.Input{invalidFragment}}}); err == nil || !strings.Contains(err.Error(), "at least one message is required") {
		t.Fatalf("headerless fragment validation error = %v, want final prompt validation", err)
	}
}

func TestLoadComposesLiteralKeysAndEffectivePresence(t *testing.T) {
	base := mapping("defaults", map[string]any{
		"version":  int64(2),
		"backends": []any{map[string]any{"id": "local.v1", "endpoint": "http://localhost:8080/v1", "concurrency_limit": 2}},
		"collections": map[string]any{"base": map[string]any{
			"release_version": "",
			"backends":        []any{map[string]any{"id": "local.v1", "endpoint": "http://localhost:8080/v1", "concurrency_limit": 3}},
			"profiles": []any{
				map[string]any{"id": "one", "backend": "local.v1", "temperature": 0.8, "top_p": 0.9, "api_key_required": true,
					"extra_params": map[string]any{"provider": map[string]any{"first": 1, "second": 2}}},
				map[string]any{"id": "child.v1", "extends": map[string]any{"id": "one"}},
				map[string]any{"id": "namespaced", "backend": "base/local.v1", "model": "collection-model"},
			},
		}, "invoice": map[string]any{
			"release_version": "r7",
			"prompts": []any{
				map[string]any{"id": "summary",
					"messages": []any{map[string]any{"role": "user", "content": "Summarize."}},
					"output":   map[string]any{"format": "text", "validation_mode": "basic"},
				},
				map[string]any{"id": "version",
					"messages": []any{map[string]any{"role": "user", "content": "Nested ID."}},
					"output":   map[string]any{"format": "text", "validation_mode": "basic"},
				},
			},
		}},
	})
	overlay := mapping("operator", map[string]any{
		"backends": []any{map[string]any{"id": "local.v1", "endpoint": "http://localhost:8080/v1", "concurrency_limit": 2, "queue_capacity": 0}},
		"collections": map[string]any{"base": map[string]any{"profiles": []any{map[string]any{"id": "child.v1", "extends": map[string]any{"id": "one"},
			"temperature": 0, "top_p": nil, "api_key_required": false,
			"extra_params": map[string]any{"provider": map[string]any{"second": 3}},
		}}}},
	})
	loaded, err := load(mapping("main", map[string]any{"version": "2"}), []configkit.Underlay{
		{Inputs: []configkit.Input{base}}, {Inputs: []configkit.Input{overlay}},
	})
	if err != nil {
		var loadErr *configkit.LoadError
		if errors.As(err, &loadErr) {
			t.Fatalf("load: %v; diagnostics: %+v", err, loadErr.Diagnostics())
		}
		t.Fatal(err)
	}
	profile := loaded.result.Config.Collections["base"].Profiles[1]
	if profile.Temperature == nil || *profile.Temperature != 0 || profile.TopP != nil || profile.APIKeyRequired == nil || *profile.APIKeyRequired {
		t.Fatalf("effective values were not retained: %+v", profile)
	}
	if loaded.profiles["base/child.v1"]["temperature"] != fieldValue || loaded.profiles["base/child.v1"]["top_p"] != fieldNull || loaded.profiles["base/child.v1"]["api_key_required"] != fieldValue {
		t.Fatalf("effective presence was lost: %+v", loaded.profiles["base/child.v1"])
	}
	provider := profile.ExtraParams["provider"].(map[string]any)
	if provider["first"] != int64(1) || provider["second"] != int64(3) {
		t.Fatalf("recursive overlay failed: %+v", provider)
	}
	backend := loaded.result.Config.Backends[0]
	if backend.QueueCapacity == nil || *backend.QueueCapacity != 0 || loaded.backends["local.v1"]["queue_capacity"] != fieldValue {
		t.Fatalf("explicit zero queue capacity was lost: %+v", backend)
	}
	if _, err := loaded.registry.GetBackend("base/local.v1"); err != nil {
		t.Fatalf("collection backend was not indexed by its full ID: %v", err)
	}
	collectionProfile, exists := loaded.indexedProfiles["base/namespaced"]
	if !exists || collectionProfile.ID != "base/namespaced" || collectionProfile.ResolvedTarget == nil || collectionProfile.ResolvedTarget.BackendID != "base/local.v1" {
		t.Fatalf("collection profile snapshot = %+v, exists %t", collectionProfile, exists)
	}
	if loaded.result.Config.Collections["invoice"].Prompts[0].Messages[0].Content == nil {
		t.Fatal("literal prompt content was not decoded")
	}
	if loaded.result.Config.Version == nil || *loaded.result.Config.Version != "2" ||
		loaded.result.Config.Collections["base"].ReleaseVersion == nil || *loaded.result.Config.Collections["base"].ReleaseVersion != "" ||
		loaded.result.Config.Collections["invoice"].ReleaseVersion == nil || *loaded.result.Config.Collections["invoice"].ReleaseVersion != "r7" {
		t.Fatalf("root or collection version metadata was not retained: %+v", loaded.result.Config)
	}
	if _, _, err := loaded.prompt("invoice/version"); err != nil {
		t.Fatalf("resource named version was not indexed under its qualified identity: %v", err)
	}
}

func TestLoadRejectsInvalidCollectionAndResourceKeys(t *testing.T) {
	for _, test := range []struct {
		name    string
		values  map[string]any
		message string
	}{
		{
			name:    "namespace with separator",
			values:  map[string]any{"collections": map[string]any{"bad/name": map[string]any{}}},
			message: "collection namespace must be nonblank and contain no slash",
		},
		{
			name: "root resource with separator",
			values: map[string]any{"backends": []any{
				map[string]any{"id": "bad/name", "endpoint": "https://example.test/v1"},
			}},
			message: "backend ID must be a nonblank local key without a slash",
		},
		{
			name: "collection resource with separator",
			values: map[string]any{"collections": map[string]any{"good": map[string]any{
				"prompts": []any{map[string]any{"id": "bad/name",
					"messages": []any{map[string]any{"role": "user", "content": "Hello."}},
					"output":   map[string]any{"format": "text", "validation_mode": "basic"},
				}},
			}}},
			message: "prompt ID must be a nonblank local key without a slash",
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			_, err := load(mapping("invalid names", test.values), nil)
			var loadErr *configkit.LoadError
			if err == nil || !errors.As(err, &loadErr) {
				t.Fatalf("load error = %v, want ConfigKit validation error", err)
			}
			for _, diagnostic := range loadErr.Diagnostics() {
				if diagnostic.Message == test.message {
					return
				}
			}
			t.Fatalf("load diagnostics = %+v, want message %q", loadErr.Diagnostics(), test.message)
		})
	}
}

func TestLoadInterpretsBackendNormalizationAndNullDefault(t *testing.T) {
	loaded, err := load(mapping("backend", map[string]any{"backends": []any{
		map[string]any{"id": "local", "endpoint": " HTTP://localhost:8080/v1 ", "api_key_env": " TOKEN_NAME ",
			"concurrency_limit": 2, "queue_capacity": nil},
	}}), nil)
	if err != nil {
		t.Fatal(err)
	}
	backend, err := loaded.GetBackend("local")
	if err != nil || backend.Endpoint != "http://localhost:8080/v1" ||
		backend.APIKeyEnv != "TOKEN_NAME" || backend.QueueCapacity != 1024 {
		t.Fatalf("backend normalization/default was not applied: %+v", backend)
	}
	composed := loaded.result.Config.Backends[0]
	if composed.Endpoint == nil || *composed.Endpoint != " HTTP://localhost:8080/v1 " ||
		composed.APIKeyEnv == nil || *composed.APIKeyEnv != " TOKEN_NAME " || composed.QueueCapacity != nil {
		t.Fatalf("composed backend was changed: %+v", composed)
	}
	if loaded.backends["local"]["queue_capacity"] != fieldNull {
		t.Fatalf("explicit null was not retained: %+v", loaded.backends["local"])
	}
	field, found := loaded.result.Metadata().Lookup(configkit.Keys("backends").Index(0).Key("endpoint"))
	if !found || field.Origin.Operation == configkit.ChangeNormalization || len(field.Origin.Locations) == 0 {
		t.Fatalf("endpoint origin was not preserved: %+v", field)
	}
}

func TestLoadBackendSmokeTestsOmissionAndNull(t *testing.T) {
	for _, test := range []struct {
		name       string
		smokeTests any
		include    bool
		inherited  bool
	}{
		{name: "omitted"},
		{name: "null", smokeTests: nil, include: true, inherited: true},
	} {
		t.Run(test.name, func(t *testing.T) {
			backend := map[string]any{"id": "local", "endpoint": "https://backend.example/v1"}
			if test.include {
				backend["smoke_tests"] = test.smokeTests
			}
			main := mapping("backend", map[string]any{
				"backends": []any{backend},
			})
			var underlays []configkit.Underlay
			if test.inherited {
				underlays = []configkit.Underlay{{Inputs: []configkit.Input{mapping("defaults", map[string]any{
					"backends": []any{map[string]any{"id": "local",
						"endpoint":    "https://backend.example/v1",
						"smoke_tests": map[string]any{"default_profile": "inherited-profile"},
					}},
				})}}}
			}
			loaded, err := load(main, underlays)
			if err != nil {
				t.Fatal(err)
			}
			if got := loaded.result.Config.Backends[0].SmokeTests; got != nil {
				t.Fatalf("smoke_tests = %+v, want nil", got)
			}
			selected, err := loaded.registry.GetBackend("local")
			if err != nil {
				t.Fatal(err)
			}
			if selected.SmokeTests != nil {
				t.Fatalf("indexed smoke_tests = %+v, want nil", selected.SmokeTests)
			}
		})
	}
}

func TestLoadMergesBackendSmokeTestsAndRetainsFallbacks(t *testing.T) {
	base := mapping("defaults", map[string]any{
		"backends": []any{map[string]any{"id": "catalog",
			"endpoint": "https://backend.example/v1",
			"smoke_tests": map[string]any{
				"default_profile": "catalog-profile",
				"reachability":    map[string]any{"endpoint": " https://probe.example/ready?check=1 "},
				"authentication": map[string]any{
					"kind":     " OPENROUTER_KEY ",
					"endpoint": "https://probe.example/key?scope=current",
				},
			},
		}},
	})
	overlay := mapping("operator", map[string]any{
		"backends": []any{map[string]any{"id": "local", "extends": map[string]any{"id": "catalog"},
			"smoke_tests": map[string]any{
				"default_profile": "not-yet-listed",
				"authentication":  map[string]any{"kind": " NONE ", "endpoint": nil},
			},
		}},
	})
	loaded, err := load(configkit.Input{Source: configkit.NoSource()}, []configkit.Underlay{
		{Inputs: []configkit.Input{base}},
		{Inputs: []configkit.Input{overlay}},
	})
	if err != nil {
		t.Fatalf("load effective diagnostic metadata: %v", err)
	}
	selected, err := loaded.registry.GetBackend("local")
	if err != nil {
		t.Fatal(err)
	}
	metadata := selected.SmokeTests
	if selected.Endpoint != "https://backend.example/v1" {
		t.Fatalf("effective backend endpoint = %q", selected.Endpoint)
	}
	if metadata == nil || metadata.DefaultProfile == nil || *metadata.DefaultProfile != "not-yet-listed" {
		t.Fatalf("default profile overlay was not retained: %+v", metadata)
	}
	if metadata.Reachability == nil || metadata.Reachability.Endpoint == nil ||
		*metadata.Reachability.Endpoint != "https://probe.example/ready?check=1" {
		t.Fatalf("full reachability destination was not normalized: %+v", metadata.Reachability)
	}
	if metadata.Authentication == nil || metadata.Authentication.Kind == nil || *metadata.Authentication.Kind != "none" ||
		metadata.Authentication.Endpoint != nil {
		t.Fatalf("authentication overlay or null fallback was not retained: %+v", metadata.Authentication)
	}
}

func TestLoadRejectsInvalidFinalBackendSmokeTests(t *testing.T) {
	for _, test := range []struct {
		name string
		data map[string]any
		path string
	}{
		{
			name: "blank default profile",
			data: map[string]any{"default_profile": " \t "},
			path: "/backends/0/smoke_tests/default_profile",
		},
		{
			name: "authentication kind required",
			data: map[string]any{"authentication": map[string]any{}},
			path: "/backends/0/smoke_tests/authentication/kind",
		},
		{
			name: "unknown authentication kind",
			data: map[string]any{"authentication": map[string]any{"kind": "bearer"}},
			path: "/backends/0/smoke_tests/authentication/kind",
		},
		{
			name: "non-http reachability URL",
			data: map[string]any{"reachability": map[string]any{"endpoint": "ftp://probe.example/ready"}},
			path: "/backends/0/smoke_tests/reachability/endpoint",
		},
		{
			name: "blank authentication URL",
			data: map[string]any{"authentication": map[string]any{"kind": "none", "endpoint": "  "}},
			path: "/backends/0/smoke_tests/authentication/endpoint",
		},
		{
			name: "relative authentication URL",
			data: map[string]any{"authentication": map[string]any{"kind": "none", "endpoint": "/key"}},
			path: "/backends/0/smoke_tests/authentication/endpoint",
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			_, err := load(mapping("backend", map[string]any{
				"backends": []any{map[string]any{"id": "local",
					"endpoint":    "https://backend.example/v1",
					"smoke_tests": test.data,
				}},
			}), nil)
			var loadError *configkit.LoadError
			if !errors.As(err, &loadError) {
				t.Fatalf("expected final-value validation error, got %v", err)
			}
			for _, diagnostic := range loadError.Diagnostics() {
				if diagnostic.Path.String() == test.path {
					return
				}
			}
			t.Fatalf("expected diagnostic at %s, got %+v", test.path, loadError.Diagnostics())
		})
	}
}

func TestLoadDefaultsAbsentQueueCapacity(t *testing.T) {
	underlay := mapping("defaults", map[string]any{"backends": []any{
		map[string]any{"id": "local", "endpoint": "http://localhost:8080/v1", "api_key_env": "OLD_KEY"},
	}})
	loaded, err := load(mapping("backend", map[string]any{"backends": []any{
		map[string]any{"id": "local", "endpoint": "http://localhost:8080/v1", "concurrency_limit": 1},
	}}), []configkit.Underlay{{Inputs: []configkit.Input{underlay}}})
	if err != nil {
		t.Fatal(err)
	}
	backend, err := loaded.GetBackend("local")
	if err != nil || backend.APIKeyEnv != "" || backend.QueueCapacity != 1024 || loaded.result.Config.Backends[0].QueueCapacity != nil || loaded.backends["local"]["queue_capacity"] != fieldAbsent {
		t.Fatalf("absent queue capacity did not receive its default: %+v", backend)
	}
}

func TestLoadCapturesProfilePresence(t *testing.T) {
	loaded, err := load(mapping("profile", map[string]any{"profiles": []any{
		map[string]any{"id": "local", "temperature": 0, "top_p": nil, "api_key_required": false},
	}}), nil)
	if err != nil {
		t.Fatal(err)
	}
	profile := loaded.result.Config.Profiles[0]
	if profile.Temperature == nil || *profile.Temperature != 0 || profile.TopP != nil || profile.APIKeyRequired == nil || *profile.APIKeyRequired {
		t.Fatalf("profile values were not preserved: %+v", profile)
	}
	fields := loaded.profiles["local"]
	if fields["temperature"] != fieldValue || fields["top_p"] != fieldNull || fields["api_key_required"] != fieldValue || fields["model"] != fieldAbsent {
		t.Fatalf("profile presence was not preserved: %+v", fields)
	}
}

func TestLoadRejectsStrictGroupConflict(t *testing.T) {
	_, err := load(configkit.Input{Source: configkit.NoSource()}, []configkit.Underlay{{Inputs: []configkit.Input{
		mapping("first", map[string]any{"profiles": []any{map[string]any{"id": "shared", "model": "one"}}}),
		mapping("second", map[string]any{"profiles": []any{map[string]any{"id": "shared", "model": "one"}}}),
	}}})
	var loadError *configkit.LoadError
	if !errors.As(err, &loadError) {
		t.Fatalf("expected ConfigKit load error, got %v", err)
	}
}

func TestLoadValidatesOnlyFinalDomainValues(t *testing.T) {
	underlay := mapping("defaults", map[string]any{
		"backends": []any{map[string]any{"id": "local", "endpoint": "not a URL"}},
		"profiles": []any{map[string]any{"id": "partial", "backend": "local"}},
	})
	main := mapping("operator", map[string]any{"backends": []any{map[string]any{"id": "local", "endpoint": "http://localhost:8080/v1"}}})
	loaded, err := load(main, []configkit.Underlay{{Inputs: []configkit.Input{underlay}}})
	if err != nil {
		t.Fatalf("replaced lower-layer domain value should not fail: %v", err)
	}
	if loaded.result.Config.Profiles[0].Model != nil {
		t.Fatal("unused partial profile unexpectedly gained a model")
	}

	_, err = load(configkit.Input{Source: configkit.NoSource()}, []configkit.Underlay{{Inputs: []configkit.Input{
		mapping("invalid", map[string]any{"backends": []any{map[string]any{"id": "unused", "endpoint": "not a URL"}}}),
	}}})
	var loadError *configkit.LoadError
	if !errors.As(err, &loadError) {
		t.Fatalf("expected path-aware effective backend failure, got %v", err)
	}
	if diagnostics := loadError.Diagnostics(); len(diagnostics) != 1 || diagnostics[0].Path.String() != "/backends/0/endpoint" {
		t.Fatalf("expected endpoint diagnostic, got %+v", diagnostics)
	}
}

func TestLoadValidatesOnlyFinalBackendSmokeTestValues(t *testing.T) {
	underlay := mapping("defaults", map[string]any{
		"backends": []any{map[string]any{"id": "local",
			"endpoint": "https://backend.example/v1",
			"smoke_tests": map[string]any{
				"default_profile": " ",
				"reachability":    map[string]any{"endpoint": "ftp://invalid.example/"},
				"authentication":  map[string]any{"kind": "unsupported"},
			},
		}},
	})
	main := mapping("operator", map[string]any{
		"backends": []any{map[string]any{"id": "local", "endpoint": "https://backend.example/v1",
			"smoke_tests": map[string]any{
				"default_profile": "dangling-profile",
				"reachability":    map[string]any{"endpoint": nil},
				"authentication":  map[string]any{"kind": "none"},
			},
		}},
	})
	loaded, err := load(main, []configkit.Underlay{{Inputs: []configkit.Input{underlay}}})
	if err != nil {
		t.Fatalf("replaced lower metadata should not fail: %v", err)
	}
	selected, err := loaded.registry.GetBackend("local")
	if err != nil {
		t.Fatal(err)
	}
	if selected.SmokeTests == nil || selected.SmokeTests.DefaultProfile == nil ||
		*selected.SmokeTests.DefaultProfile != "dangling-profile" {
		t.Fatalf("final dangling default profile was not retained: %+v", selected.SmokeTests)
	}
}

func TestLoadKeepsSyntaxErrorsFromLowerTiers(t *testing.T) {
	_, err := load(mapping("operator", map[string]any{"backends": []any{map[string]any{"id": "local", "endpoint": "http://localhost:8080"}}}),
		[]configkit.Underlay{{Inputs: []configkit.Input{{Source: configkit.Bytes("broken", []byte("backends: ["))}}}})
	var loadError *configkit.LoadError
	if !errors.As(err, &loadError) {
		t.Fatalf("expected lower-tier parsing error, got %v", err)
	}
}