package merrors

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

type testReasonedError struct {
	error
	reason string
}

func (e testReasonedError) Reason() string {
	return e.reason
}

func TestReasonUsesReasonedError(t *testing.T) {
	err := testReasonedError{
		error:  InvalidArgument("value is invalid"),
		reason: "amount_below_minimum",
	}
	reason, ok := Reason(err)
	if !ok {
		t.Fatalf("expected reason")
	}
	if reason != "amount_below_minimum" {
		t.Fatalf("reason mismatch: got=%q", reason)
	}
}

func TestInvalidArgumentSupportsBrokenArgumentName(t *testing.T) {
	t.Run("without argument name keeps old behavior", func(t *testing.T) {
		err := InvalidArgument("value is missing")
		expected := "invalidArgError: value is missing"
		if err.Error() != expected {
			t.Fatalf("unexpected error message: %s", err)
		}
		if !errors.Is(err, ErrInvalidArg) {
			t.Fatalf("error should wrap ErrInvalidArg")
		}
	})

	t.Run("single argument name", func(t *testing.T) {
		err := InvalidArgument("value is missing", "bot_token_env")
		expected := `invalidArgError: broken argument "bot_token_env": value is missing`
		if err.Error() != expected {
			t.Fatalf("unexpected error message: %s", err)
		}
	})

	t.Run("multiple argument names", func(t *testing.T) {
		err := InvalidArgument("value mismatch", "bot_token_env", "chat_id_env", " ")
		expected := `invalidArgError: broken arguments "bot_token_env", "chat_id_env": value mismatch`
		if err.Error() != expected {
			t.Fatalf("unexpected error message: %s", err)
		}
	})
}

func TestInvalidArgumentWithNamesfSupportsBrokenArgumentName(t *testing.T) {
	err := InvalidArgumentWithNamesf([]string{"gateway.supported_assets.currency"}, "asset[%d] %s", 2, "is invalid")
	expected := `invalidArgError: broken argument "gateway.supported_assets.currency": asset[2] is invalid`
	if err.Error() != expected {
		t.Fatalf("unexpected error message: %s", err)
	}
	if !errors.Is(err, ErrInvalidArg) {
		t.Fatalf("error should wrap ErrInvalidArg")
	}
}

func TestInvalidArgumentWrapSupportsBrokenArgumentName(t *testing.T) {
	base := Define("root cause")
	err := InvalidArgumentWrap(base, "value is missing", "bot_token_env")
	if !strings.Contains(err.Error(), `invalidArgError: broken argument "bot_token_env": value is missing`) {
		t.Fatalf("wrapped error should include broken argument name: %s", err)
	}
	if !errors.Is(err, ErrInvalidArg) || !errors.Is(err, base) {
		t.Fatalf("wrapped error should preserve all error layers")
	}
}

func TestInternalWrapAllPreservesAllCauses(t *testing.T) {
	first := Define("first cause")
	second := Define("second cause")
	err := InternalWrapAll("combined failure", first, nil, second)
	if !strings.Contains(err.Error(), "internal: combined failure") {
		t.Fatalf("wrapped error should include context: %s", err)
	}
	if !errors.Is(err, ErrInternal) || !errors.Is(err, first) || !errors.Is(err, second) {
		t.Fatalf("wrapped error should preserve all error layers")
	}
}

func TestOpaqueWrapPreservesCauseWithoutExposingItsText(t *testing.T) {
	cause := DataConflict("restricted storage key")
	err := OpaqueWrap(ErrInternal, cause, "safe persistence failure")

	if got, want := err.Error(), "internal: safe persistence failure"; got != want {
		t.Fatalf("opaque error mismatch: got=%q want=%q", got, want)
	}
	if !errors.Is(err, ErrInternal) || !errors.Is(err, ErrDataConflict) {
		t.Fatalf("opaque error did not preserve classifications: %v", err)
	}
}

func TestOperationalWrapsPreserveClassificationAndCause(t *testing.T) {
	cause := Define("dependency failure")
	tests := []struct {
		name string
		err  error
		kind error
	}{
		{name: "failed precondition", err: FailedPreconditionWrap(cause, "AA capability unavailable"), kind: ErrFailedPrecondition},
		{name: "service unavailable", err: ServiceUnavailableWrap(cause, "Arbitrum RPC unavailable"), kind: ErrServiceUnavailable},
		{name: "data conflict", err: DataConflictWrap(cause, "managed wallet replay differs"), kind: ErrDataConflict},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if !errors.Is(tt.err, tt.kind) || !errors.Is(tt.err, cause) {
				t.Fatalf("wrapped error should preserve classification and cause: %s", tt.err)
			}
		})
	}
}