package requests

import (
	"encoding/json"
	"testing"
	"time"
)

func TestFlexibleDate_UnmarshalJSON_DateOnly(t *testing.T) {
	var fd FlexibleDate
	err := fd.UnmarshalJSON([]byte(`"2025-11-27"`))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	want := time.Date(2025, 11, 27, 0, 0, 0, 0, time.UTC)
	if !fd.Time.Equal(want) {
		t.Errorf("got %v, want %v", fd.Time, want)
	}
}

func TestFlexibleDate_UnmarshalJSON_RFC3339(t *testing.T) {
	var fd FlexibleDate
	err := fd.UnmarshalJSON([]byte(`"2025-11-27T15:30:00Z"`))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	want := time.Date(2025, 11, 27, 15, 30, 0, 0, time.UTC)
	if !fd.Time.Equal(want) {
		t.Errorf("got %v, want %v", fd.Time, want)
	}
}

func TestFlexibleDate_UnmarshalJSON_Null(t *testing.T) {
	var fd FlexibleDate
	err := fd.UnmarshalJSON([]byte(`null`))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if !fd.Time.IsZero() {
		t.Errorf("expected zero time, got %v", fd.Time)
	}
}

func TestFlexibleDate_UnmarshalJSON_EmptyString(t *testing.T) {
	var fd FlexibleDate
	err := fd.UnmarshalJSON([]byte(`""`))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if !fd.Time.IsZero() {
		t.Errorf("expected zero time, got %v", fd.Time)
	}
}

func TestFlexibleDate_UnmarshalJSON_Invalid(t *testing.T) {
	var fd FlexibleDate
	err := fd.UnmarshalJSON([]byte(`"not-a-date"`))
	if err == nil {
		t.Fatal("expected error for invalid date, got nil")
	}
}

func TestFlexibleDate_MarshalJSON_Valid(t *testing.T) {
	fd := FlexibleDate{Time: time.Date(2025, 11, 27, 15, 30, 0, 0, time.UTC)}
	data, err := fd.MarshalJSON()
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	var s string
	if err := json.Unmarshal(data, &s); err != nil {
		t.Fatalf("result is not a JSON string: %v", err)
	}
	want := "2025-11-27T15:30:00Z"
	if s != want {
		t.Errorf("got %q, want %q", s, want)
	}
}

func TestFlexibleDate_MarshalJSON_Zero(t *testing.T) {
	fd := FlexibleDate{}
	data, err := fd.MarshalJSON()
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if string(data) != "null" {
		t.Errorf("got %s, want null", string(data))
	}
}

func TestFlexibleDate_ToTimePtr_Valid(t *testing.T) {
	fd := &FlexibleDate{Time: time.Date(2025, 11, 27, 0, 0, 0, 0, time.UTC)}
	ptr := fd.ToTimePtr()
	if ptr == nil {
		t.Fatal("expected non-nil pointer")
	}
	if !ptr.Equal(fd.Time) {
		t.Errorf("got %v, want %v", *ptr, fd.Time)
	}
}

func TestFlexibleDate_ToTimePtr_Zero(t *testing.T) {
	fd := &FlexibleDate{}
	ptr := fd.ToTimePtr()
	if ptr != nil {
		t.Errorf("expected nil, got %v", *ptr)
	}
}

func TestFlexibleDate_ToTimePtr_NilReceiver(t *testing.T) {
	var fd *FlexibleDate
	ptr := fd.ToTimePtr()
	if ptr != nil {
		t.Errorf("expected nil for nil receiver, got %v", *ptr)
	}
}

func TestFlexibleDate_RoundTrip(t *testing.T) {
	original := FlexibleDate{Time: time.Date(2025, 6, 15, 10, 0, 0, 0, time.UTC)}
	data, err := original.MarshalJSON()
	if err != nil {
		t.Fatalf("marshal error: %v", err)
	}
	var restored FlexibleDate
	if err := restored.UnmarshalJSON(data); err != nil {
		t.Fatalf("unmarshal error: %v", err)
	}
	if !original.Time.Equal(restored.Time) {
		t.Errorf("round-trip mismatch: original %v, restored %v", original.Time, restored.Time)
	}
}
