// Copyright 2022 Google LLC

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

// https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

package dev.cel.common;

import static com.google.common.collect.ImmutableList.toImmutableList;

import com.google.auto.value.AutoValue;

import com.google.common.base.Joiner;

import com.google.errorprone.annotations.CheckReturnValue;

import com.google.errorprone.annotations.Immutable;

import dev.cel.common.internal.SafeStringFormatter;

import java.util.Collection;

import java.util.Optional;

import java.util.PrimitiveIterator;

/**

* Encapulates a {@link CelSourceLocation} and message representing an error within an expression.

*/

@AutoValue

@Immutable

@SuppressWarnings("UnicodeEscape") // Suppressed to distinguish half-width and full-width chars.

public abstract class CelIssue {

private static final Joiner JOINER = Joiner.on('\n');

/** Severity of a CelIssue. */

public enum Severity {

ERROR,

WARNING,

INFORMATION,

DEPRECATED;

}

// Package-private default constructor to prevent unexpected extensions outside of this codebase.

CelIssue() {}

public abstract Severity getSeverity();

public abstract CelSourceLocation getSourceLocation();

public abstract String getMessage();

public abstract long getExprId();

public static Builder newBuilder() {

return new AutoValue_CelIssue.Builder();

}

/**

* Build {@link CelIssue} from the given expression id, {@link CelSourceLocation}, format string,

* and arguments.

*/

public static CelIssue formatError(

long exprId, CelSourceLocation sourceLocation, String message) {

return newBuilder()

.setExprId(exprId)

.setSeverity(Severity.ERROR)

.setSourceLocation(sourceLocation)

.setMessage(message)

.build();

}

/**

* Build {@link CelIssue} from the given {@link CelSourceLocation}, format string, and arguments.

*/

public static CelIssue formatError(CelSourceLocation sourceLocation, String message) {

return formatError(0L, sourceLocation, message);

}

/** Build {@link CelIssue} from the given line, column, format string, and arguments. */

public static CelIssue formatError(int line, int column, String message) {

return formatError(CelSourceLocation.of(line, column), message);

}

// Halfwidth '.' and '^'.

private static final char DOT = '\u002e';

private static final char HAT = '\u005e';

// Fullwidth '.' and '^'.

private static final char WIDE_DOT = '\uff0e';

private static final char WIDE_HAT = '\uff3e';

/** Returns a human-readable error with all issues joined in a single string. */

public static String toDisplayString(Collection<CelIssue> issues, Source source) {

return JOINER.join(

issues.stream().map(iss -> iss.toDisplayString(source)).collect(toImmutableList()));

}

/** Returns a string representing this error that is suitable for displaying to humans. */

public String toDisplayString(Source source) {

// Based onhttps://github.com/google/cel-go/blob/v0.5.1/common/error.go#L42.

String result =

SafeStringFormatter.format(

"%s: %s:%d:%d: %s",

getSeverity(),

source.getDescription(),

getSourceLocation().getLine(),

getSourceLocation().getColumn() + 1,

getMessage());

if (!CelSourceLocation.NONE.equals(getSourceLocation())) {

Optional<String> optionalSnippet = source.getSnippet(getSourceLocation().getLine());

if (optionalSnippet.isPresent()) {

StringBuilder builder = new StringBuilder();

String snippet = optionalSnippet.get().replace('\t', ' ');

builder.append(result).append("\n | ").append(snippet).append("\n | ");

PrimitiveIterator.OfInt codePoints = snippet.codePoints().iterator();

for (int index = 0;

index < getSourceLocation().getColumn() && codePoints.hasNext();

index++) {

int codePoint = codePoints.nextInt();

if (codePoint > 0x7f) {

// We make a naive assumption that all characters above 0xff are fullwidth.

// Unfortunately,

// as of Java 8, there is nothing in the Character class to determine width.

builder.append(WIDE_DOT);

} else {

builder.append(DOT);

}

}

if (codePoints.hasNext() && codePoints.nextInt() > 0x7f) {

// See above.

builder.append(WIDE_HAT);

} else {

builder.append(HAT);

}

result = builder.toString();

}

}

return result;

}

/** Builder for configuring {@link CelIssue}. */

@AutoValue.Builder

public abstract static class Builder {

public abstract Builder setSeverity(Severity severity);

public abstract Builder setSourceLocation(CelSourceLocation location);

public abstract Builder setMessage(String message);

public abstract Builder setExprId(long exprId);

@CheckReturnValue

public abstract CelIssue build();

}

}