package engine

import (
	"errors"
	"reflect"
	"strings"
	"testing"
)

type ordinarySequenceItem struct {
	ID string `yaml:"id"`
}

type ordinarySequenceRecord struct {
	ID       string                 `yaml:"id"`
	Children []ordinarySequenceItem `yaml:"children"`
}

type ordinarySequenceConfig struct {
	Items   []ordinarySequenceItem `yaml:"items"`
	Catalog struct {
		Items []ordinarySequenceItem `yaml:"items"`
	} `yaml:"catalog"`
	Records []ordinarySequenceRecord `yaml:"records"`
}

func TestOrdinaryLoadAcceptsDeclarationsWithoutImports(t *testing.T) {
	result, err := testLoad[ordinarySequenceConfig](Bytes("catalog.yml", []byte(`configkit:
  sequences:
    - destination: [items]
      key: id
items:
  - id: prompt
`)))
	if err != nil {
		t.Fatal(err)
	}
	if !reflect.DeepEqual(result.Config.Items, []ordinarySequenceItem{{ID: "prompt"}}) {
		t.Fatalf("items = %#v", result.Config.Items)
	}
	if _, ok := result.Metadata().Lookup(Keys("configkit")); ok {
		t.Fatal("collection controls reached application metadata")
	}
	items, ok := result.Metadata().Lookup(Keys("items"))
	if !ok || !items.Explicit || len(items.Origin.Locations) != 1 {
		t.Fatalf("items metadata = %#v, %v", items, ok)
	}
}

func TestOrdinaryLoadKeepsDisabledImportRejection(t *testing.T) {
	_, err := testLoad[ordinarySequenceConfig](Bytes("disabled.yml", []byte(`configkit:
  imports: [{path: fragment.yml}]
  sequences: [{destination: [items], key: id}]
`)))
	if err == nil {
		t.Fatal("source with disabled imports succeeded")
	}
	var loadError *LoadError
	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 || loadError.Diagnostics()[0].Code != CodeImportDisabled {
		t.Fatalf("error = %#v", err)
	}
}

func TestOrdinaryLoadValidatesSingletonCollectionIdentity(t *testing.T) {
	_, err := testLoad[ordinarySequenceConfig](Bytes("missing-identity.yml", []byte(`configkit:
  sequences:
    - destination: [items]
      key: id
items: [{}]
`)))
	if err == nil {
		t.Fatal("singleton sequence without identity succeeded")
	}
	var loadError *LoadError
	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 || loadError.Diagnostics()[0].Code != CodeComposeInvalid {
		t.Fatalf("error = %#v", err)
	}
}

func TestOrdinaryLoadCombinesImportedCollectionPeers(t *testing.T) {
	tests := []struct {
		name     string
		second   string
		want     []ordinarySequenceItem
		wantCode Code
	}{
		{name: "distinct identities", second: "items: [{id: second}]\n", want: []ordinarySequenceItem{{ID: "first"}, {ID: "second"}}},
		{name: "duplicate peer identity", second: "items: [{id: first}]\n", wantCode: CodeComposeConflict},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			directory := t.TempDir()
			mainPath := writeImportFile(t, directory, "main.yml", `configkit:
  imports:
    - path: first.yml
    - path: second.yml
  sequences:
    - destination: [items]
      key: id
      mode: append
`)
			writeImportFile(t, directory, "first.yml", "items: [{id: first}]\n")
			writeImportFile(t, directory, "second.yml", test.second)

			result, err := testLoad[ordinarySequenceConfig](File(mainPath), Options[ordinarySequenceConfig]{Imports: true})
			if test.wantCode != "" {
				if result != nil || err == nil {
					t.Fatalf("result, err = %#v, %v", result, err)
				}
				var loadError *LoadError
				if !errors.As(err, &loadError) || len(loadError.Diagnostics()) == 0 || loadError.Diagnostics()[0].Code != test.wantCode {
					t.Fatalf("error = %#v", err)
				}
				return
			}
			if err != nil {
				var loadError *LoadError
				if errors.As(err, &loadError) {
					t.Fatalf("diagnostics = %#v", loadError.Diagnostics())
				}
				t.Fatal(err)
			}
			if !reflect.DeepEqual(result.Config.Items, test.want) {
				t.Fatalf("items = %#v, want %#v", result.Config.Items, test.want)
			}
			inline, err := testLoad[ordinarySequenceConfig](Bytes("inline.yml", []byte(`configkit:
  sequences:
    - destination: [items]
      key: id
      mode: append
items: [{id: first}, {id: second}]
`)))
			if err != nil {
				t.Fatal(err)
			}
			if !reflect.DeepEqual(result.Config.Items, inline.Config.Items) {
				t.Fatalf("imported items %#v differ from inline items %#v", result.Config.Items, inline.Config.Items)
			}
		})
	}
}

func TestImportedCollectionDeclarationsUseRelativePlacement(t *testing.T) {
	directory := t.TempDir()
	mainPath := writeImportFile(t, directory, "main.yml", `configkit:
  imports:
    - path: first.yml
      destination: [catalog]
    - path: second.yml
      destination: [catalog]
`)
	fragment := `configkit:
  sequences:
    - destination: [items]
      key: id
      mode: append
items: [{id: ITEM}]
`
	writeImportFile(t, directory, "first.yml", strings.ReplaceAll(fragment, "ITEM", "first"))
	writeImportFile(t, directory, "second.yml", strings.ReplaceAll(fragment, "ITEM", "second"))

	result, err := testLoad[ordinarySequenceConfig](File(mainPath), Options[ordinarySequenceConfig]{Imports: true})
	if err != nil {
		t.Fatal(err)
	}
	want := []ordinarySequenceItem{{ID: "first"}, {ID: "second"}}
	if !reflect.DeepEqual(result.Config.Catalog.Items, want) {
		t.Fatalf("catalog items = %#v, want %#v", result.Config.Catalog.Items, want)
	}
}

func TestSequenceItemSourceAppliesItsCollectionDeclarations(t *testing.T) {
	directory := t.TempDir()
	mainPath := writeImportFile(t, directory, "main.yml", `configkit:
  imports:
    - path: item.yml
      destination: [records]
      placement: sequence-item
`)
	writeImportFile(t, directory, "item.yml", `configkit:
  sequences:
    - destination: [children]
      key: id
      mode: append
id: parent
children: [{id: child}]
`)
	result, err := testLoad[ordinarySequenceConfig](File(mainPath), Options[ordinarySequenceConfig]{Imports: true})
	if err != nil {
		t.Fatal(err)
	}
	want := []ordinarySequenceRecord{{ID: "parent", Children: []ordinarySequenceItem{{ID: "child"}}}}
	if !reflect.DeepEqual(result.Config.Records, want) {
		t.Fatalf("records = %#v, want %#v", result.Config.Records, want)
	}
}

func TestOrdinaryLoadAllowsDeclarationsWithoutValues(t *testing.T) {
	result, err := testLoad[ordinarySequenceConfig](Bytes("policy.yml", []byte(`configkit:
  sequences:
    - destination: [items]
      key: id
`)))
	if err != nil {
		t.Fatal(err)
	}
	if result.Config.Items != nil {
		t.Fatalf("items = %#v, want absent", result.Config.Items)
	}
}