package engine

import (
	"fmt"
	"reflect"
	"strings"
	"testing"
)

func TestBroadPartialCLIOverrideRetainsUnchangedMetadata(t *testing.T) {
	type child struct {
		Name string `yaml:"name"`
	}
	type record struct {
		Count   int     `yaml:"count"`
		Zero    int     `yaml:"zero"`
		Enabled bool    `yaml:"enabled"`
		Items   []child `yaml:"items"`
		Maybe   *child  `yaml:"maybe"`
	}
	type config struct {
		Records map[string]record `yaml:"records"`
	}
	var body strings.Builder
	body.WriteString("records:\n")
	updates := make(map[string]any)
	for index := range 96 {
		name := fmt.Sprintf("key/%d~", index)
		fmt.Fprintf(&body, "  %s: {count: 9, zero: 0, enabled: false, items: [{name: old}], maybe: {name: old}}\n", name)
		if index%2 == 0 {
			updates[name] = map[string]any{"count": 0, "items": []any{}, "maybe": nil}
		}
	}
	input := parseDocumentForDecode(t, body.String())
	schema := mustSchemaFor[config](t)
	decoded, issues := decodeConfiguration(schema, reflect.ValueOf(config{}), input)
	if len(issues) != 0 {
		t.Fatal(issues)
	}
	batch, diagnostics := preparePostStructuralOverrides(overridePreparationInput{root: input}, nil,
		[]Override{{Path: Keys("records"), Value: updates, Flag: "--records"}}, nil, defaultImportLimits())
	if len(diagnostics) != 0 {
		t.Fatal(diagnostics)
	}
	result, issues := applyDecodedOverrides(schema, decoded, batch, decodeContext{})
	if len(issues) != 0 {
		t.Fatal(issues)
	}
	for index := range 96 {
		name := fmt.Sprintf("key/%d~", index)
		path := Keys("records", name)
		value := result.value.Interface().(config).Records[name]
		for _, key := range []string{"zero", "enabled"} {
			pointer := path.Key(key).String()
			if _, explicit := result.presence[pointer]; !explicit || result.origins[pointer].Layer != LayerBase {
				t.Fatalf("retained explicit field lost metadata at %s", pointer)
			}
		}
		if index%2 != 0 {
			if value.Count != 9 || len(value.Items) != 1 || value.Maybe == nil || result.origins[path.Key("count").String()].Layer != LayerBase {
				t.Fatalf("omitted record changed at %s", path)
			}
			continue
		}
		if value.Count != 0 || len(value.Items) != 0 || value.Maybe != nil {
			t.Fatalf("CLI replacement failed at %s: %#v", path, value)
		}
		for _, removed := range []Path{path.Key("items").Index(0), path.Key("items").Index(0).Key("name"), path.Key("maybe").Key("name")} {
			_, present := result.presence[removed.String()]
			_, origin := result.origins[removed.String()]
			if present || origin {
				t.Fatalf("removed descendant kept metadata at %s", removed)
			}
		}
		for _, key := range []string{"count", "items", "maybe"} {
			pointer := path.Key(key).String()
			if presence, ok := result.presence[pointer]; !ok || presence.location.SourceID != batch.overrides[0].source.ID || result.origins[pointer].Layer != LayerCLI {
				t.Fatalf("CLI field lost metadata at %s", pointer)
			}
		}
	}
}