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
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152

use std::{ffi::OsString, marker::PhantomData, path::PathBuf, process::exit, str::FromStr};

use clap::{Parser, Subcommand};
use console::style;
use nu_ansi_term::{Color, Style};
use reedline::{
    default_emacs_keybindings, DefaultHinter, DefaultPrompt, Emacs, IdeMenu, KeyModifiers,
    MenuBuilder, Prompt, Reedline, ReedlineEvent, ReedlineMenu, Signal, Span,
};
use shlex::Shlex;

pub struct ClapEditor<C: Parser + Send + Sync + 'static> {
    rl: Reedline,
    prompt: Box<dyn Prompt>,
    c_phantom: PhantomData<C>,
}

impl<C: Parser + Send + Sync + 'static> Default for ClapEditor<C> {
    fn default() -> Self {
        Self::new()
    }
}

struct ReedCompleter<C: Parser + Send + Sync + 'static> {
    c_phantom: PhantomData<C>,
}

impl<C: Parser + Send + Sync + 'static> reedline::Completer for ReedCompleter<C> {
    fn complete(&mut self, line: &str, pos: usize) -> Vec<reedline::Suggestion> {
        let cmd = C::command();
        let mut cmd = clap_complete::dynamic::shells::CompleteCommand::augment_subcommands(cmd);
        let args = Shlex::new(line);
        let mut args = std::iter::once("".to_owned())
            .chain(args)
            .map(OsString::from)
            .collect::<Vec<_>>();
        if line.ends_with(' ') {
            args.push(OsString::new());
        }
        let arg_index = args.len() - 1;
        let span = Span::new(pos - args[arg_index].len(), pos);
        let Ok(candidates) = clap_complete::dynamic::complete(
            &mut cmd,
            args,
            arg_index,
            PathBuf::from_str(".").ok().as_deref(),
        ) else {
            return vec![];
        };
        candidates
            .into_iter()
            .map(|c| reedline::Suggestion {
                value: c.0.to_string_lossy().into_owned(),
                description: c.1.map(|x| x.to_string()),
                style: None,
                extra: None,
                span,
                append_whitespace: true,
            })
            .collect()
    }
}

impl<C: Parser + Send + Sync + 'static> ClapEditor<C> {
    fn construct(prompt: Box<dyn Prompt>, hook: impl FnOnce(Reedline) -> Reedline) -> Self {
        let completion_menu = Box::new(
            IdeMenu::default()
                .with_default_border()
                .with_name("completion_menu"),
        );
        let mut keybindings = default_emacs_keybindings();
        keybindings.add_binding(
            KeyModifiers::NONE,
            reedline::KeyCode::Tab,
            ReedlineEvent::UntilFound(vec![
                ReedlineEvent::Menu("completion_menu".to_string()),
                ReedlineEvent::MenuNext,
            ]),
        );

        let rl = Reedline::create()
            .with_completer(Box::new(ReedCompleter::<C> {
                c_phantom: PhantomData,
            }))
            .with_menu(ReedlineMenu::EngineCompleter(completion_menu))
            .with_hinter(Box::new(
                DefaultHinter::default().with_style(Style::new().italic().fg(Color::DarkGray)),
            ))
            .with_edit_mode(Box::new(Emacs::new(keybindings)));

        let rl = hook(rl);
        ClapEditor {
            rl,
            prompt,
            c_phantom: PhantomData,
        }
    }

    /// Creates a new `ClapEditor` with the default prompt.
    pub fn new() -> Self {
        Self::construct(Box::new(DefaultPrompt::default()), |e| e)
    }

    /// Creates a new `ClapEditor` with the given prompt.
    pub fn new_with_prompt(
        prompt: Box<dyn Prompt>,
        hook: impl FnOnce(Reedline) -> Reedline,
    ) -> Self {
        Self::construct(prompt, hook)
    }

    pub fn get_editor(&mut self) -> &mut Reedline {
        &mut self.rl
    }

    pub fn read_command(&mut self) -> Option<C> {
        let line = match self.rl.read_line(&*self.prompt) {
            Ok(Signal::Success(buffer)) => buffer,
            Ok(Signal::CtrlC | Signal::CtrlD) => {
                // Drop the `rl` in order to save the history
                _ = std::mem::replace(&mut self.rl, Reedline::create());
                exit(0);
            }
            _ => return None,
        };
        if line.trim().is_empty() {
            return None;
        }

        // _ = self.rl.add_history_entry(line.as_str());

        match shlex::split(&line) {
            Some(split) => {
                match C::try_parse_from(std::iter::once("").chain(split.iter().map(String::as_str)))
                {
                    Ok(c) => Some(c),
                    Err(e) => {
                        e.print().unwrap();
                        None
                    }
                }
            }
            None => {
                println!(
                    "{} input was not valid and could not be processed",
                    style("error:").red().bold()
                );
                None
            }
        }
    }
}