package valid

import (
	"errors"
	"strings"
	"testing"

	"code.nochebuena.dev/go/xerrors"
	playground "github.com/go-playground/validator/v10"
)

type testUser struct {
	Name  string `validate:"required"`
	Email string `validate:"required,email"`
	Age   int    `validate:"min=18,max=120"`
}

// ---------------------------------------------------------------
// Constructor tests
// ---------------------------------------------------------------

func TestNew_Defaults(t *testing.T) {
	v := New()
	if v == nil {
		t.Fatal("New() returned nil")
	}
}

func TestNew_WithMessageProvider(t *testing.T) {
	called := false
	mp := &testMP{fn: func(field, tag, param string) string {
		called = true
		return "custom: " + field
	}}

	v := New(WithMessageProvider(mp))
	_ = v.Struct(testUser{}) // triggers validation failure (missing Name/Email)
	if !called {
		t.Error("custom MessageProvider was not called")
	}
}

// ---------------------------------------------------------------
// Struct validation tests
// ---------------------------------------------------------------

func TestValidator_Struct_Valid(t *testing.T) {
	v := New()
	u := testUser{Name: "Alice", Email: "alice@example.com", Age: 25}
	if err := v.Struct(u); err != nil {
		t.Errorf("expected nil, got %v", err)
	}
}

func TestValidator_Struct_MissingRequired(t *testing.T) {
	v := New()
	u := testUser{Email: "a@b.com", Age: 20} // Name is missing
	err := v.Struct(u)
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	var xe *xerrors.Err
	if !errors.As(err, &xe) {
		t.Fatalf("expected *xerrors.Err, got %T", err)
	}
	if xe.Code() != xerrors.ErrInvalidInput {
		t.Errorf("code = %s, want %s", xe.Code(), xerrors.ErrInvalidInput)
	}
	if xe.Fields()["field"] != "Name" {
		t.Errorf("field = %v, want Name", xe.Fields()["field"])
	}
}

func TestValidator_Struct_InvalidEmail(t *testing.T) {
	v := New()
	u := testUser{Name: "Bob", Email: "not-an-email", Age: 25}
	err := v.Struct(u)
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	var xe *xerrors.Err
	if !errors.As(err, &xe) {
		t.Fatalf("expected *xerrors.Err, got %T", err)
	}
	if xe.Fields()["tag"] != "email" {
		t.Errorf("tag = %v, want email", xe.Fields()["tag"])
	}
}

func TestValidator_Struct_BelowMin(t *testing.T) {
	v := New()
	u := testUser{Name: "Carol", Email: "carol@example.com", Age: 10}
	err := v.Struct(u)
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	var xe *xerrors.Err
	if !errors.As(err, &xe) {
		t.Fatalf("expected *xerrors.Err, got %T", err)
	}
	if xe.Code() != xerrors.ErrInvalidInput {
		t.Errorf("code = %s, want %s", xe.Code(), xerrors.ErrInvalidInput)
	}
}

func TestValidator_Struct_AboveMax(t *testing.T) {
	v := New()
	u := testUser{Name: "Dave", Email: "dave@example.com", Age: 200}
	err := v.Struct(u)
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	var xe *xerrors.Err
	if !errors.As(err, &xe) {
		t.Fatalf("expected *xerrors.Err, got %T", err)
	}
	if xe.Code() != xerrors.ErrInvalidInput {
		t.Errorf("code = %s, want %s", xe.Code(), xerrors.ErrInvalidInput)
	}
}

func TestValidator_Struct_NotAStruct(t *testing.T) {
	v := New()
	err := v.Struct("not a struct")
	if err == nil {
		t.Fatal("expected error, got nil")
	}

	var xe *xerrors.Err
	if !errors.As(err, &xe) {
		t.Fatalf("expected *xerrors.Err, got %T", err)
	}
	if xe.Code() != xerrors.ErrInternal {
		t.Errorf("code = %s, want %s", xe.Code(), xerrors.ErrInternal)
	}
}

func TestValidator_Struct_ErrorCode(t *testing.T) {
	v := New()
	u := testUser{} // all fields fail
	err := v.Struct(u)

	var xe *xerrors.Err
	if !errors.As(err, &xe) {
		t.Fatalf("errors.As failed: %T", err)
	}
	if xe.Code() != xerrors.ErrInvalidInput {
		t.Errorf("Code() = %s, want %s", xe.Code(), xerrors.ErrInvalidInput)
	}
}

func TestValidator_Struct_Fields(t *testing.T) {
	v := New()
	u := testUser{} // missing Name triggers required
	err := v.Struct(u)

	var xe *xerrors.Err
	errors.As(err, &xe)
	fields := xe.Fields()
	if _, ok := fields["field"]; !ok {
		t.Error("Fields() missing 'field' key")
	}
	if _, ok := fields["tag"]; !ok {
		t.Error("Fields() missing 'tag' key")
	}
}

func TestValidator_Struct_Unwrap(t *testing.T) {
	v := New()
	u := testUser{} // triggers validation error
	err := v.Struct(u)

	var xe *xerrors.Err
	errors.As(err, &xe)

	// The wrapped error must be a playground.ValidationErrors.
	cause := errors.Unwrap(xe)
	if cause == nil {
		t.Fatal("Unwrap returned nil")
	}
	var ve playground.ValidationErrors
	if !errors.As(cause, &ve) {
		t.Errorf("Unwrap should return validator.ValidationErrors, got %T", cause)
	}
}

func TestValidator_Struct_SpanishMessages(t *testing.T) {
	v := New(WithMessageProvider(SpanishMessages))
	u := testUser{Email: "a@b.com", Age: 20} // missing Name

	err := v.Struct(u)
	if err == nil {
		t.Fatal("expected error")
	}

	if !strings.Contains(err.Error(), "obligatorio") {
		t.Errorf("expected Spanish message, got: %s", err.Error())
	}
}

func TestValidator_Struct_EnglishMessage_Required(t *testing.T) {
	v := New()
	u := testUser{Email: "a@b.com", Age: 20} // missing Name

	err := v.Struct(u)
	if err == nil {
		t.Fatal("expected error")
	}

	if !strings.Contains(err.Error(), "required") {
		t.Errorf("expected English 'required' message, got: %s", err.Error())
	}
}

// ---------------------------------------------------------------
// MessageProvider tests
// ---------------------------------------------------------------

func TestDefaultMessages_AllTags(t *testing.T) {
	mp := DefaultMessages
	tags := []struct {
		tag   string
		param string
	}{
		{"required", ""},
		{"email", ""},
		{"min", "5"},
		{"max", "100"},
		{"unknown_rule", ""},
	}
	for _, tt := range tags {
		msg := mp.Message("Field", tt.tag, tt.param)
		if msg == "" {
			t.Errorf("DefaultMessages.Message(%q) returned empty string", tt.tag)
		}
	}
}

func TestSpanishMessages_AllTags(t *testing.T) {
	mp := SpanishMessages
	tags := []struct {
		tag   string
		param string
	}{
		{"required", ""},
		{"email", ""},
		{"min", "5"},
		{"max", "100"},
		{"unknown_rule", ""},
	}
	for _, tt := range tags {
		msg := mp.Message("Campo", tt.tag, tt.param)
		if msg == "" {
			t.Errorf("SpanishMessages.Message(%q) returned empty string", tt.tag)
		}
	}
}

func TestWithMessageProvider_CustomImpl(t *testing.T) {
	mp := &testMP{fn: func(field, tag, param string) string {
		return "CUSTOM:" + field + ":" + tag
	}}
	v := New(WithMessageProvider(mp))
	u := testUser{Email: "a@b.com", Age: 20} // missing Name

	err := v.Struct(u)
	if err == nil {
		t.Fatal("expected error")
	}
	if !strings.Contains(err.Error(), "CUSTOM:") {
		t.Errorf("expected custom message prefix, got: %s", err.Error())
	}
}

// ---------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------

type testMP struct {
	fn func(field, tag, param string) string
}

func (m *testMP) Message(field, tag, param string) string {
	return m.fn(field, tag, param)
}