path: root/src/options.rs

//! CLI option parsing.

use std::{
    env,
    ffi::OsStr,
    fmt::Display,
    path::{Path, PathBuf},
};

use clap::{crate_authors, crate_description, Arg, Command};
use const_format::formatcp;
use crossterm::tty::IsTty;
use itertools::Itertools;

use crate::{
    display::style::BackgroundColor,
    exit_codes::EXIT_BAD_ARGUMENTS,
    parse::guess_language::{language_override_from_name, LanguageOverride},
    version::VERSION,
};

pub(crate) const DEFAULT_BYTE_LIMIT: usize = 1_000_000;
// Chosen experimentally: this is sufficiently many for all the sample
// files (the highest is slow_1.rs/slow_2.rs at 1.3M nodes), but
// small enough to terminate in ~5 seconds like the test file in #306.
pub(crate) const DEFAULT_GRAPH_LIMIT: usize = 3_000_000;
pub(crate) const DEFAULT_PARSE_ERROR_LIMIT: usize = 0;

pub(crate) const DEFAULT_TAB_WIDTH: usize = 4;

pub(crate) const USAGE: &str = concat!(env!("CARGO_BIN_NAME"), " [OPTIONS] OLD-PATH NEW-PATH");

#[derive(Debug, Clone, Copy)]
pub(crate) enum ColorOutput {
    Always,
    Auto,
    Never,
}

#[derive(Debug, Clone)]
pub(crate) struct DisplayOptions {
    pub(crate) background_color: BackgroundColor,
    pub(crate) use_color: bool,
    pub(crate) display_mode: DisplayMode,
    pub(crate) print_unchanged: bool,
    pub(crate) tab_width: usize,
    pub(crate) terminal_width: usize,
    pub(crate) num_context_lines: u32,
    pub(crate) syntax_highlight: bool,
    pub(crate) sort_paths: bool,
}

pub(crate) const DEFAULT_TERMINAL_WIDTH: usize = 80;

impl Default for DisplayOptions {
    fn default() -> Self {
        Self {
            background_color: BackgroundColor::Dark,
            use_color: false,
            display_mode: DisplayMode::SideBySide,
            print_unchanged: true,
            tab_width: 8,
            terminal_width: DEFAULT_TERMINAL_WIDTH,
            num_context_lines: 3,
            syntax_highlight: true,
            sort_paths: false,
        }
    }
}

#[derive(Debug, Clone)]
pub(crate) struct DiffOptions {
    pub(crate) graph_limit: usize,
    pub(crate) byte_limit: usize,
    pub(crate) parse_error_limit: usize,
    pub(crate) check_only: bool,
    pub(crate) ignore_comments: bool,
    pub(crate) strip_cr: bool,
}

impl Default for DiffOptions {
    fn default() -> Self {
        Self {
            graph_limit: DEFAULT_GRAPH_LIMIT,
            byte_limit: DEFAULT_BYTE_LIMIT,
            parse_error_limit: DEFAULT_PARSE_ERROR_LIMIT,
            check_only: false,
            ignore_comments: false,
            strip_cr: false,
        }
    }
}

fn app() -> clap::Command<'static> {
    Command::new("Difftastic")
        .override_usage(USAGE)
        .version(env!("CARGO_PKG_VERSION"))
        .long_version(VERSION.as_str())
        .about(crate_description!())
        .author(crate_authors!())
        .after_long_help(concat!(
            "You can compare two files with difftastic by specifying them as arguments.\n\n",
            "$ ",
            env!("CARGO_BIN_NAME"),
            " old.js new.js\n\n",
            "You can also use directories as arguments. Difftastic will walk both directories and compare files with matching names.\n\n",
            "$ ",
            env!("CARGO_BIN_NAME"),
            " old/ new/\n\n",
            "If you have a file with conflict markers, you can pass it as a single argument. Difftastic will diff the two conflicting file states.\n\n",
            "$ ",
            env!("CARGO_BIN_NAME"),
            " file_with_conflicts.js\n\n",
            "Difftastic can also be invoked with 7 arguments in the format that GIT_EXTERNAL_DIFF expects.\n\n",
            "See the full manual at: https://difftastic.wilfred.me.uk/")
        )
        .arg(
            Arg::new("dump-syntax")
                .long("dump-syntax")
                .takes_value(true)
                .value_name("PATH")
                .long_help(
                    "Parse a single file with tree-sitter and display the difftastic syntax tree.",
                ).help_heading("DEBUG OPTIONS"),
        )
        .arg(
            Arg::new("dump-syntax-dot")
                .long("dump-syntax-dot")
                .takes_value(true)
                .value_name("PATH")
                .long_help(
                    "Parse a single file with tree-sitter and display the difftastic syntax tree, as a DOT graph.",
                ).help_heading("DEBUG OPTIONS"),
        )
        .arg(
            Arg::new("dump-ts")
                .long("dump-ts")
                .takes_value(true)
                .value_name("PATH")
                .long_help(
                    "Parse a single file with tree-sitter and display the tree-sitter parse tree.",
                ).help_heading("DEBUG OPTIONS"),
        )
        .arg(
            Arg::new("context")
                .long("context")
                .takes_value(true)
                .value_name("LINES")
                .long_help("The number of contextual lines to show around changed lines.")
                .default_value("3")