/*
 * 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
 *
 *     http://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 io.trino.sql.tree;

import com.google.common.collect.ImmutableList;

import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.regex.Pattern;

import static com.google.common.base.Preconditions.checkArgument;
import static java.util.Locale.ENGLISH;
import static java.util.Objects.requireNonNull;

public class Identifier
        extends Expression
{
    private static final Pattern NAME_PATTERN = Pattern.compile("[a-zA-Z_]([a-zA-Z0-9_])*");

    private final String value;
    private final boolean delimited;

    public Identifier(NodeLocation location, String value, boolean delimited)
    {
        this(Optional.of(location), value, delimited);
    }

    public Identifier(String value, boolean delimited)
    {
        this(Optional.empty(), value, delimited);
    }

    public Identifier(String value)
    {
        this(Optional.empty(), value, !NAME_PATTERN.matcher(value).matches());
    }

    private Identifier(Optional<NodeLocation> location, String value, boolean delimited)
    {
        super(location);
        this.value = requireNonNull(value, "value is null");
        this.delimited = delimited;

        checkArgument(!value.isEmpty(), "value is empty");
        checkArgument(delimited || NAME_PATTERN.matcher(value).matches(), "value contains illegal characters: %s", value);
    }

    public String getValue()
    {
        return value;
    }

    public boolean isDelimited()
    {
        return delimited;
    }

    public String getCanonicalValue()
    {
        if (isDelimited()) {
            return value;
        }

        return value.toUpperCase(ENGLISH);
    }

    @Override
    public <R, C> R accept(AstVisitor<R, C> visitor, C context)
    {
        return visitor.visitIdentifier(this, context);
    }

    @Override
    public List<Node> getChildren()
    {
        return ImmutableList.of();
    }

    @Override
    public boolean equals(Object o)
    {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        Identifier that = (Identifier) o;
        return Objects.equals(value, that.value);
    }

    @Override
    public int hashCode()
    {
        return value.hashCode();
    }

    @Override
    public boolean shallowEquals(Node other)
    {
        if (!sameClass(this, other)) {
            return false;
        }

        Identifier that = (Identifier) other;
        return Objects.equals(value, that.value) && delimited == that.delimited;
    }
}

@@ -583,16 +583,98 @@
 .tree;%0A%0A
+import com.google.common.base.CharMatcher;%0Aimport com.google.common.base.Strings;%0A
 import c
@@ -713,16 +713,16 @@
 leList;%0A
-
 %0Aimport 
@@ -793,40 +793,8 @@
 nal;
-%0Aimport java.util.regex.Pattern;
 %0A%0Aim
@@ -857,16 +857,68 @@
 gument;%0A
+import static com.google.common.base.Verify.verify;%0A
 import s
@@ -1080,73 +1080,358 @@
 nal 
-Pattern NAME_PATT
+CharMatcher FIRST_CHAR_DISALLOWED_MATCH
 ER
-N
  = 
-Pattern.compile(%22%5Ba-zA-Z_%5D(%5Ba-zA-Z0-9_%5D)*%22
+CharMatcher.inRange('0', '9')%0A            .precomputed();%0A%0A    private static final CharMatcher ALLOWED_CHARS_MATCHER = CharMatcher.inRange('a', 'z')%0A            .or(CharMatcher.inRange('A', 'Z'))%0A            .or(CharMatcher.is('_'))%0A            .or(CharMatcher.inRange('0', '9'))%0A            .precomputed(
 );%0A%0A
@@ -1849,44 +1849,31 @@
 e, !
-NAME_PATTERN.matcher(value).matches(
+isValidIdentifier(value
 ));%0A
@@ -2195,44 +2195,31 @@
  %7C%7C 
-NAME_PATTERN.matcher(value).matches(
+isValidIdentifier(value
 ), %22
@@ -3393,16 +3393,16 @@
  other;%0A
-
         
@@ -3479,11 +3479,469 @@
 d;%0A    %7D
+%0A%0A    private static boolean isValidIdentifier(String value)%0A    %7B%0A        verify(!Strings.isNullOrEmpty(value), %22Identifier cannot be empty or null%22);%0A%0A        if (FIRST_CHAR_DISALLOWED_MATCHER.matches(value.charAt(0))) %7B%0A            return false;%0A        %7D%0A%0A        // We've already checked that first char does not contain digits,%0A        // so to avoid copying we are checking whole string.%0A        return ALLOWED_CHARS_MATCHER.matchesAllOf(value);%0A    %7D
 %0A%7D%0A

Remove regex usage from Identifier validation