package provider

import (
	"errors"
	"fmt"
	"testing"
)

// sdkError simulates an underlying provider SDK error type, so tests can
// assert errors.As reaches through the wrapper to it.
type sdkError struct{ code int }

func (e *sdkError) Error() string { return fmt.Sprintf("sdk error %d", e.code) }

func TestError_IsAndAs(t *testing.T) {
	t.Parallel()
	underlying := &sdkError{code: 429}
	err := Wrap(ErrQuotaExceeded, "create", "gcp-eu", "zones/z/instances/x", underlying)

	if !errors.Is(err, ErrQuotaExceeded) {
		t.Error("errors.Is(err, ErrQuotaExceeded) = false, want true")
	}
	if errors.Is(err, ErrNotFound) {
		t.Error("errors.Is(err, ErrNotFound) = true, want false")
	}

	var sdk *sdkError
	if !errors.As(err, &sdk) {
		t.Fatal("errors.As(err, &sdk) = false, want true")
	}
	if sdk.code != 429 {
		t.Errorf("recovered sdkError.code = %d, want 429", sdk.code)
	}
}

func TestError_WrapWithNilUnderlying(t *testing.T) {
	t.Parallel()
	err := Wrap(ErrPermanent, "get", "mock", "id", nil)
	if !errors.Is(err, ErrPermanent) {
		t.Error("errors.Is(err, ErrPermanent) = false, want true")
	}
	if err.Error() == "" {
		t.Error("Error() returned an empty string")
	}
}

func TestClass(t *testing.T) {
	t.Parallel()
	tests := []struct {
		name string
		err  error
		want error
	}{
		{"nil returns nil", nil, nil},
		{"wrapped not found", Wrap(ErrNotFound, "get", "mock", "id", nil), ErrNotFound},
		{"wrapped quota", Wrap(ErrQuotaExceeded, "create", "gcp", "id", nil), ErrQuotaExceeded},
		{"wrapped permanent", Wrap(ErrPermanent, "create", "gcp", "id", nil), ErrPermanent},
		{"wrapped transient", Wrap(ErrTransient, "create", "gcp", "id", nil), ErrTransient},
		{"unclassified defaults to transient", errors.New("boom"), ErrTransient},
		{"further-wrapped preserves classification", fmt.Errorf("outer: %w", Wrap(ErrQuotaExceeded, "create", "gcp", "id", nil)), ErrQuotaExceeded},
	}
	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			t.Parallel()
			if got := Class(tc.err); got != tc.want {
				t.Errorf("Class(%v) = %v, want %v", tc.err, got, tc.want)
			}
		})
	}
}