/*
 * Copyright 2018 Confluent Inc.
 *
 * Licensed under the Confluent Community License (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.confluent.io/confluent-community-license
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations under the License.
 */

package io.confluent.ksql.cli.console;

import com.google.common.collect.ImmutableMap;
import io.confluent.ksql.util.CliUtils;
import io.confluent.ksql.util.ErrorMessageUtil;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Map;
import java.util.Objects;
import java.util.function.Predicate;
import org.jline.reader.History;
import org.jline.reader.LineReader;
import org.jline.reader.LineReader.Option;
import org.jline.reader.LineReaderBuilder;
import org.jline.reader.impl.DefaultExpander;
import org.jline.reader.impl.DefaultParser;
import org.jline.reader.impl.history.DefaultHistory;
import org.jline.terminal.Terminal;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class JLineReader implements io.confluent.ksql.cli.console.LineReader {

  private static final Logger LOGGER = LoggerFactory.getLogger(JLineReader.class);

  private static final String DEFAULT_PROMPT = "ksql> ";

  private final DefaultHistory history;

  private final LineReader lineReader;
  private final String prompt;
  private final Terminal terminal;

  JLineReader(
      final Terminal terminal,
      final Path historyFilePath,
      final Predicate<String> cliLinePredicate
  ) {
    this.terminal = Objects.requireNonNull(terminal, "terminal");
    this.lineReader = build(terminal, historyFilePath, cliLinePredicate);

    this.history = new DefaultHistory(this.lineReader);

    this.prompt = DEFAULT_PROMPT;
  }

  @Override
  public Iterable<? extends History.Entry> getHistory() {
    return lineReader.getHistory();
  }

  @Override
  public String readLine() {
    final String line = lineReader.readLine(prompt);

    addToHistory(line);
    return line;
  }

  private void addToHistory(final String line) {
    try {
      history.add(line);
      history.save();
    } catch (final IOException e) {
      LOGGER.error("Error saving history file", e);
      terminal.writer()
          .println("Error saving history file:" + ErrorMessageUtil.buildErrorMessage(e));
    }
  }

  private static LineReader build(
      final Terminal terminal,
      final Path historyFilePath,
      final Predicate<String> cliLinePredicate
  ) {
    final DefaultParser parser = new DefaultParser();
    parser.setEofOnEscapedNewLine(true);
    parser.setEofOnUnclosedQuote(true);
    parser.setQuoteChars(new char[]{'\''});
    parser.setEscapeChars(new char[]{'\\'});

    final LineReader lineReader = LineReaderBuilder.builder()
        .appName("KSQL")
        .variable(LineReader.SECONDARY_PROMPT_PATTERN, ">")
        .option(Option.HISTORY_IGNORE_DUPS, true)
        .option(Option.HISTORY_IGNORE_SPACE, false)
        .option(Option.HISTORY_INCREMENTAL, false)
        .option(Option.DISABLE_EVENT_EXPANSION, false)
        .expander(new KsqlExpander())
        .parser(new TrimmingParser(new KsqlLineParser(parser, cliLinePredicate)))
        .terminal(terminal)
        .build();

    if (Files.exists(historyFilePath) || CliUtils.createFile(historyFilePath)) {
      lineReader.setVariable(LineReader.HISTORY_FILE, historyFilePath);
      LOGGER.info("Command history saved at: " + historyFilePath);
    } else {
      terminal.writer().println(String.format(
          "WARNING: Unable to create command history file '%s', command history will not be saved.",
          historyFilePath
      ));
    }

    return lineReader;
  }

  private static class KsqlExpander extends DefaultExpander {

    private static final String EXPANDED_CS =
        "CREATE STREAM s (field1 type1, field2 type2) "
            + "WITH (KAFKA_TOPIC='topic-name', VALUE_FORMAT='json');";

    private static final String EXPANDED_CT =
        "CREATE TABLE t (field1 type1, field2 type2) "
            + "WITH (KAFKA_TOPIC='topic-name', VALUE_FORMAT='json', KEY='field1');";

    private static final Map<String, String> shortcuts = ImmutableMap.of(
        "cs", EXPANDED_CS,
        "ct", EXPANDED_CT,
        "csas", "CREATE STREAM s AS SELECT ",
        "ctas", "CREATE TABLE t AS SELECT ",
        "ii", "INSERT INTO x SELECT "
    );

    /**
     * Override the default JLine 'expandHistory' behavior so that history-referencing expressions
     * such as '!42' or '!!' will only be processed and replaced if they occur at the beginning of
     * an input line, even if the input line spans multiple terminal lines.
     */
    @Override
    public String expandHistory(final History history, final String line) {
      if (line.startsWith("!") || line.startsWith("^")) {
        return super.expandHistory(history, line);
      }

      return line;
    }

    @Override
    public String expandVar(final String word) {
      return shortcuts.getOrDefault(word.toLowerCase(), word);
    }
  }
}
