package copyx_test

import (
	"errors"
	"reflect"
	"strings"
	"sync"
	"testing"

	"git.yuntuo.hk/k2safe/go-omni/copyx"
)

type checkSource struct{ Rows []checkSourceRow }
type checkSourceRow struct{ Value string }
type checkTarget struct{ Rows []checkTargetRow }
type checkTargetRow struct{ Value int }
type recursiveSource struct {
	Children []*recursiveSource
	Value    string
}
type recursiveTarget struct {
	Children []*recursiveTarget
	Value    int
}
type recursiveCompatible struct {
	Children []*recursiveCompatible
	Value    string
}

func TestCheckTypesAndEmptyCollections(t *testing.T) {
	err := copyx.Check[checkSource, checkTarget]()
	var field *copyx.Error
	if !errors.Is(err, copyx.ErrType) || !errors.As(err, &field) || field.Path != "$.Rows[].Value" {
		t.Fatal(err)
	}
	for _, rows := range [][]checkSourceRow{nil, {}, {{Value: "42"}}} {
		out := checkTarget{Rows: []checkTargetRow{{Value: 99}}}
		if err := copyx.Copy(&out, checkSource{rows}); !errors.Is(err, copyx.ErrType) {
			t.Fatalf("rows %v: %v", rows, err)
		}
		if len(out.Rows) != 1 || out.Rows[0].Value != 99 {
			t.Fatal("partial target committed")
		}
	}
	if err := copyx.Check[map[string]checkSourceRow, map[string]checkTargetRow](); !errors.Is(err, copyx.ErrType) {
		t.Fatal(err)
	}
	var dst map[string]checkTargetRow
	if err := copyx.Copy(&dst, map[string]checkSourceRow{}); !errors.Is(err, copyx.ErrType) {
		t.Fatal(err)
	}
	var array [0]checkTargetRow
	if err := copyx.Copy(&array, [0]checkSourceRow{}); !errors.Is(err, copyx.ErrType) {
		t.Fatal(err)
	}
	if err := copyx.Check[map[string]int, map[int]int](); !errors.Is(err, copyx.ErrType) {
		t.Fatal(err)
	}
	if err := copyx.Check[[2]int, [3]int](); !errors.Is(err, copyx.ErrType) {
		t.Fatal(err)
	}
	if err := copyx.Check[*recursiveSource, *recursiveTarget](); !errors.Is(err, copyx.ErrType) {
		t.Fatal(err)
	}
	if err := copyx.Check[*recursiveSource, *recursiveCompatible](copyx.WithDeepCopy()); err != nil {
		t.Fatal(err)
	}
}
func TestCheckRulesAndConverterBoundaries(t *testing.T) {
	type from struct {
		Name  string
		Extra bool
	}
	type to struct {
		Label string
		Keep  int
	}
	options := []copyx.Option{copyx.WithStrictFields(), copyx.WithFieldNames[from, to](map[string]string{"Name": "Label"}), copyx.WithIgnoreSource[from, to]("Extra"), copyx.WithIgnoreTarget[from, to]("Keep")}
	if err := copyx.Check[from, to](options...); err != nil {
		t.Fatal(err)
	}
	if err := copyx.Check[from, to](); !errors.Is(err, copyx.ErrField) {
		t.Fatal(err)
	}
	type short struct{ Name string }
	if err := copyx.Check[from, short](copyx.WithStrictFields()); !errors.Is(err, copyx.ErrField) {
		t.Fatal(err)
	}
	if err := copyx.Check[checkSource, checkTarget](copyx.WithConverter(func(string) (int, error) { panic("check must not execute converters") })); err != nil {
		t.Fatal(err)
	}
	if err := copyx.Check[struct{ Value any }, struct{ Value int }](); !errors.Is(err, copyx.ErrDynamicType) {
		t.Fatal(err)
	}
	if err := copyx.Check[any, int](copyx.WithConverter(func(any) (int, error) { panic("not called") })); err != nil {
		t.Fatal(err)
	}
	if err := copyx.Check[*int, int](); err != nil {
		t.Fatal(err)
	} // Actual nil remains a runtime error.
	var src *int
	dst := 1
	if err := copyx.Copy(&dst, src); !errors.Is(err, copyx.ErrNil) || dst != 1 {
		t.Fatal(err)
	}
	var empty []int
	if err := copyx.Copy(&empty, []any{}); err != nil || empty == nil {
		t.Fatal("dynamic emptiness changed", err)
	}
	if err := copyx.Check[sync.Mutex, sync.Mutex](); !errors.Is(err, copyx.ErrUnsupported) {
		t.Fatal(err)
	}
	option := copyx.WithConverter(func(v []int) ([]int, error) { return v, nil })
	if err := copyx.Check[[]int, []int](copyx.WithDeepCopy(), option); err != nil {
		t.Fatal(err)
	}
	if _, err := copyx.Clone([]int{1}, option); !errors.Is(err, copyx.ErrSharedReference) {
		t.Fatal("type check bypassed graph audit", err)
	}
}
func TestCopierCheckConcurrentAndOptionsIsolation(t *testing.T) {
	good, _ := copyx.New(copyx.WithConverter(func(string) (int, error) { return 42, nil }))
	bad, _ := copyx.New()
	var wg sync.WaitGroup
	for i := 0; i < 24; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			for j := 0; j < 20; j++ {
				if err := good.Check(reflect.TypeFor[checkSource](), reflect.TypeFor[checkTarget]()); err != nil {
					t.Error(err)
				}
				if err := bad.Check(reflect.TypeFor[checkSource](), reflect.TypeFor[checkTarget]()); !errors.Is(err, copyx.ErrType) {
					t.Error(err)
				}
				var target checkTarget
				if err := good.Copy(&target, checkSource{Rows: []checkSourceRow{}}); err != nil || target.Rows == nil {
					t.Error(err)
				}
			}
		}()
	}
	wg.Wait()
	if err := good.Check(nil, reflect.TypeFor[int]()); err == nil {
		t.Fatal("nil type accepted")
	}
	var absent *copyx.Copier
	if err := absent.Check(reflect.TypeFor[int](), reflect.TypeFor[int]()); err == nil {
		t.Fatal("nil copier accepted")
	}
	if err := copyx.Check[int, string](); err == nil || !strings.Contains(err.Error(), "int -> string") {
		t.Fatal(err)
	}
}
func BenchmarkTypeCheck(b *testing.B) {
	c, _ := copyx.New(copyx.WithConverter(func(string) (int, error) { return 1, nil }))
	from, to := reflect.TypeFor[checkSource](), reflect.TypeFor[checkTarget]()
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		if err := c.Check(from, to); err != nil {
			b.Fatal(err)
		}
	}
}

func TestEmptyTypeCheckPreservesAbsentValueSemantics(t *testing.T) {
	var callback func()
	if out, err := copyx.Clone(callback); err != nil || out != nil {
		t.Fatal(err)
	}
	if out, err := copyx.Clone([]func(){}); err != nil || out == nil || len(out) != 0 {
		t.Fatal(err)
	}
	if _, err := copyx.Clone([]func(){func() {}}); !errors.Is(err, copyx.ErrUnsupported) {
		t.Fatal(err)
	}
	if err := copyx.Check[[]func(), []func()](copyx.WithDeepCopy()); !errors.Is(err, copyx.ErrUnsupported) {
		t.Fatal("preflight must report potentially non-nil handles", err)
	}
	type from struct {
		Ignored *int
		Value   string
	}
	type to struct {
		Ignored *int
		Value   int
	}
	var dst []to
	if err := copyx.Copy(&dst, []from{}, copyx.WithDeepCopy()); !errors.Is(err, copyx.ErrType) {
		t.Fatal(err)
	}
}