1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

//! Helper that helps with interactive editing, including multi-line parsing and validation,
//! and auto-completion for file name during creating external table.

use datafusion::sql::parser::{DFParser, Statement};
use rustyline::completion::Completer;
use rustyline::completion::FilenameCompleter;
use rustyline::completion::Pair;
use rustyline::error::ReadlineError;
use rustyline::highlight::Highlighter;
use rustyline::hint::Hinter;
use rustyline::validate::ValidationContext;
use rustyline::validate::ValidationResult;
use rustyline::validate::Validator;
use rustyline::Context;
use rustyline::Helper;
use rustyline::Result;

#[derive(Default)]
pub struct CliHelper {
    completer: FilenameCompleter,
}

impl Highlighter for CliHelper {}

impl Hinter for CliHelper {
    type Hint = String;
}

/// returns true if the current position is after the open quote for
/// creating an external table.
fn is_open_quote_for_location(line: &str, pos: usize) -> bool {
    let mut sql = line[..pos].to_string();
    sql.push('\'');
    if let Ok(stmts) = DFParser::parse_sql(&sql) {
        if let Some(Statement::CreateExternalTable(_)) = stmts.back() {
            return true;
        }
    }
    false
}

impl Completer for CliHelper {
    type Candidate = Pair;

    fn complete(
        &self,
        line: &str,
        pos: usize,
        ctx: &Context<'_>,
    ) -> std::result::Result<(usize, Vec<Pair>), ReadlineError> {
        if is_open_quote_for_location(line, pos) {
            self.completer.complete(line, pos, ctx)
        } else {
            Ok((0, Vec::with_capacity(0)))
        }
    }
}

impl Validator for CliHelper {
    fn validate(&self, ctx: &mut ValidationContext<'_>) -> Result<ValidationResult> {
        let input = ctx.input().trim_end();
        if let Some(sql) = input.strip_suffix(';') {
            match DFParser::parse_sql(sql) {
                Ok(statements) if statements.is_empty() => Ok(ValidationResult::Invalid(
                    Some("  🤔 You entered an empty statement".to_string()),
                )),
                Ok(statements) if statements.len() > 1 => Ok(ValidationResult::Invalid(
                    Some("  🤔 You entered more than one statement".to_string()),
                )),
                Ok(_statements) => Ok(ValidationResult::Valid(None)),
                Err(err) => Ok(ValidationResult::Invalid(Some(format!(
                    "  🤔 Invalid statement: {}",
                    err
                )))),
            }
        } else if input.starts_with('\\') {
            // command
            Ok(ValidationResult::Valid(None))
        } else {
            Ok(ValidationResult::Incomplete)
        }
    }
}

impl Helper for CliHelper {}