use std::collections::{HashMap, HashSet};
use std::ffi::OsString;
use std::path::PathBuf;

use lazy_static::lazy_static;
use structopt::clap::AppSettings::{ColorAlways, ColoredHelp, DeriveDisplayOrder};
use structopt::{clap, StructOpt};
use syntect::highlighting::Theme as SyntaxTheme;
use syntect::parsing::SyntaxSet;

use crate::git_config::{GitConfig, GitConfigEntry};
use crate::options;
use crate::utils::bat::assets::HighlightingAssets;
use crate::utils::bat::output::PagingMode;

// No Default trait as this ignores `default_value = ..`
#[derive(StructOpt)]
#[structopt(
    name = "delta",
    about = "A viewer for git and diff output",
    setting(ColorAlways),
    setting(ColoredHelp),
    setting(DeriveDisplayOrder),
    after_help = "\
GIT CONFIG
----------

By default, delta takes settings from a section named \"delta\" in git config files, if one is
present. The git config file to use for delta options will usually be ~/.gitconfig, but delta
follows the rules given in https://git-scm.com/docs/git-config#FILES. Most delta options can be
given in a git config file, using the usual option names but without the initial '--'. An example
is

[delta]
    line-numbers = true
    zero-style = dim syntax

FEATURES
--------
A feature is a named collection of delta options in git config. An example is:

[delta \"my-delta-feature\"]
    syntax-theme = Dracula
    plus-style = bold syntax \"#002800\"

To activate those options, you would use:

delta --features my-delta-feature

A feature name may not contain whitespace. You can activate multiple features:

[delta]
    features = my-highlight-styles-colors-feature my-line-number-styles-feature

If more than one feature sets the same option, the last one wins.

STYLES
------

All options that have a name like --*-style work the same way. It is very similar to how
colors/styles are specified in a gitconfig file:
https://git-scm.com/docs/git-config#Documentation/git-config.txt-color

Here is an example:

--minus-style 'red bold ul \"#ffeeee\"'

That means: For removed lines, set the foreground (text) color to 'red', make it bold and
            underlined, and set the background color to '#ffeeee'.

See the COLORS section below for how to specify a color. In addition to real colors, there are 4
special color names: 'auto', 'normal', 'raw', and 'syntax'.

Here is an example of using special color names together with a single attribute:

--minus-style 'syntax bold auto'

That means: For removed lines, syntax-highlight the text, and make it bold, and do whatever delta
            normally does for the background.

The available attributes are: 'blink', 'bold', 'dim', 'hidden', 'italic', 'reverse', 'strike',
and 'ul' (or 'underline').

The attribute 'omit' is supported by commit-style, file-style, and hunk-header-style, meaning to
remove the element entirely from the output.

A complete description of the style string syntax follows:

- If the input that delta is receiving already has colors, and you want delta to output those
  colors unchanged, then use the special style string 'raw'. Otherwise, delta will strip any colors
  from its input.

- A style string consists of 0, 1, or 2 colors, together with an arbitrary number of style
  attributes, all separated by spaces.

- The first color is the foreground (text) color. The second color is the background color.
  Attributes can go in any position.

- This means that in order to specify a background color you must also specify a foreground (text)
  color.

- If you want delta to choose one of the colors automatically, then use the special color 'auto'.
  This can be used for both foreground and background.

- If you want the foreground/background color to be your terminal's foreground/background color,
  then use the special color 'normal'.

- If you want the foreground text to be syntax-highlighted according to its language, then use the
  special foreground color 'syntax'. This can only be used for the foreground (text).

- The minimal style specification is the empty string ''. This means: do not apply any colors or
  styling to the element in question.

COLORS
------

There are four ways to specify a color (this section applies to foreground and background colors
within a style string):

1. CSS color name

   Any of the 140 color names used in CSS: https://www.w3schools.com/colors/colors_groups.asp

2. RGB hex code

   An example of using an RGB hex code is:
   --file-style=\"#0e7c0e\"

3. ANSI color name

   There are 8 ANSI color names:
   black, red, green, yellow, blue, magenta, cyan, white.

   In addition, all of them have a bright form:
   brightblack, brightred, brightgreen, brightyellow, brightblue, brightmagenta, brightcyan, brightwhite.

   An example of using an ANSI color name is:
   --file-style=\"green\"

   Unlike RGB hex codes, ANSI color names are just names: you can choose the exact color that each
   name corresponds to in the settings of your terminal application (the application you use to
   enter commands at a shell prompt). This means that if you use ANSI color names, and you change
   the color theme used by your terminal, then delta's colors will respond automatically, without
   needing to change the delta command line.

   \"purple\" is accepted as a synonym for \"magenta\". Color names and codes are case-insensitive.

4. ANSI color number

   An example of using an ANSI color number is:
   --file-style=28

   There are 256 ANSI color numbers: 0-255. The first 16 are the same as the colors described in
   the \"ANSI color name\" section above. See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit.
   Specifying colors like this is useful if your terminal only supports 256 colors (i.e. doesn\'t
   support 24-bit color).


LINE NUMBERS
------------

To display line numbers, use --line-numbers.

Line numbers are displayed in two columns. Here's what it looks like by default:

 1  ⋮ 1  │ unchanged line
 2  ⋮    │ removed line
    ⋮ 2  │ added line

In that output, the line numbers for the old (minus) version of the file appear in the left column,
and the line numbers for the new (plus) version of the file appear in the right column. In an
unchanged (zero) line, both columns contain a line number.

The following options allow the line number display to be customized:

--line-numbers-left-format:  Change the contents of the left column
--line-numbers-right-format: Change the contents of the right column
--line-numbers-left-style:   Change the style applied to the left column
--line-numbers-right-style:  Change the style applied to the right column
--line-numbers-minus-style:  Change the style applied to line numbers in minus lines
--line-numbers-zero-style:   Change the style applied to line numbers in unchanged lines
--line-numbers-plus-style:   Change the style applied to line numbers in plus lines

Options --line-numbers-left-format and --line-numbers-right-format allow you to change the contents
of the line number columns. Their values are arbitrary format strings, which are allowed to contain
the placeholders {nm} for the line number associated with the old version of the file and {np} for
the line number associated with the new version of the file. The placeholders support a subset of
the string formatting syntax documented here: https://doc.rust-lang.org/std/fmt/#formatting-parameters.
Specifically, you can use the alignment and width syntax.

For example, the default value of --line-numbers-left-format is '{nm:^4}⋮'. This means that the
left column should display the minus line number (nm), center-aligned, padded with spaces to a
width of 4 characters, followed by a unicode dividing-line character (⋮).

Similarly, the default value of --line-numbers-right-format is '{np:^4}│'. This means that the
right column should display the plus line number (np), center-aligned, padded with spaces to a
width of 4 characters, followed by a unicode dividing-line character (│).

Use '<' for left-align, '^' for center-align, and '>' for right-align.


If something isn't working correctly, or you have a feature request, please open an issue at
https://github.com/dandavison/delta/issues.
"
)]
pub struct Opt {
    /// Use default colors appropriate for a light terminal background. For more control, see the
    /// style options and --syntax-theme.
    #[structopt(long = "light")]
    pub light: bool,

    /// Use default colors appropriate for a dark terminal background. For more control, see the
    /// style options and --syntax-theme.
    #[structopt(long = "dark")]
    pub dark: bool,

    /// Display line numbers next to the diff. See LINE NUMBERS section.
    #[structopt(short = "n", long = "line-numbers")]
    pub line_numbers: bool,

    /// Display a side-by-side diff view instead of the traditional view.
    #[structopt(short = "s", long = "side-by-side")]
    pub side_by_side: bool,

    #[structopt(long = "diff-highlight")]
    /// Emulate diff-highlight (https://github.com/git/git/tree/master/contrib/diff-highlight)
    pub diff_highlight: bool,

    #[structopt(long = "diff-so-fancy")]
    /// Emulate diff-so-fancy (https://github.com/so-fancy/diff-so-fancy)
    pub diff_so_fancy: bool,

    #[structopt(long = "navigate")]
    /// Activate diff navigation: use n to jump forwards and N to jump backwards. To change the
    /// file labels used see --file-modified-label, --file-removed-label, --file-added-label,
    /// --file-renamed-label.
    pub navigate: bool,

    #[structopt(long = "relative-paths")]
    /// Output all file paths relative to the current directory so that they
    /// resolve correctly when clicked on or used in shell commands.
    pub relative_paths: bool,

    #[structopt(long = "hyperlinks")]
    /// Render commit hashes, file names, and line numbers as hyperlinks,
    /// according to the hyperlink spec for terminal emulators:
    /// https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda. By
    /// default, file names and line numbers link to the local file using a file
    /// URL, whereas commit hashes link to the commit in GitHub, if the remote
    /// repository is hosted by GitHub. See --hyperlinks-file-link-format for
    /// full control over the file URLs emitted. Hyperlinks are supported by
    /// several common terminal emulators. To make them work, you must use less
    /// version >= 581 with the -R flag (or use -r with older less versions, but
    /// this will break e.g. --navigate). If you use tmux, then you will also
    /// need a patched fork of tmux (see https://github.com/dandavison/tmux).
    pub hyperlinks: bool,

    #[structopt(long = "keep-plus-minus-markers")]
    /// Prefix added/removed lines with a +/- character, exactly as git does. By default, delta
    /// does not emit any prefix, so code can be copied directly from delta's output.
    pub keep_plus_minus_markers: bool,

    /// Display the active values for all Delta options. Style options are displayed with
    /// foreground and background colors. This can be used to experiment with colors by combining
    /// this option with other options such as --minus-style, --zero-style, --plus-style, --light,
    /// --dark, etc.
    #[structopt(long = "show-config")]
    pub show_config: bool,

    /// List supported languages and associated file extensions.
    #[structopt(long = "list-languages")]
    pub list_languages: bool,

    /// List available syntax-highlighting color themes.
    #[structopt(long = "list-syntax-themes")]
    pub list_syntax_themes: bool,

    /// Show all available syntax-highlighting themes, each with an example of highlighted diff output.
    /// If diff output is supplied on standard input then this will be used for the demo. For
    /// example: `git show | delta --show-syntax-themes`.
    #[structopt(long = "show-syntax-themes")]
    pub show_syntax_themes: bool,

    /// Show available delta themes, each with an example of highlighted diff
    /// output. A delta theme is a delta named feature (see --features) that
    /// sets either `light` or `dark`. See
    /// https://github.com/dandavison/delta#custom-color-themes. If diff output
    /// is supplied on standard input then this will be used for the demo. For
    /// example: `git show | delta --show-themes`. By default shows dark or
    /// light themes only, according to whether delta is in dark or light mode
    /// (as set by the user or inferred from BAT_THEME). To control the themes
    /// shown, use --dark or --light, or both, on the command line together with
    /// this option.
    #[structopt(long = "show-themes")]
    pub show_themes: bool,

    /// Show available named colors. In addition to named colors, arbitrary
    /// colors can be specified using RGB hex codes. See COLORS section.
    #[structopt(long = "show-colors")]
    pub show_colors: bool,

    /// Parse ANSI color escape sequences in input and display them as git style
    /// strings. Example usage: git show --color=always | delta --parse-ansi
    /// This can be used to help identify input style strings to use with map-styles.
    #[structopt(long = "parse-ansi")]
    pub parse_ansi: bool,

    #[structopt(long = "no-gitconfig")]
    /// Do not take any settings from git config. See GIT CONFIG section.
    pub no_gitconfig: bool,

    #[structopt(long = "raw")]
    /// Do not alter the input in any way. This is mainly intended for testing delta.
    pub raw: bool,

    #[structopt(long = "color-only")]
    /// Do not alter the input structurally in any way, but color and highlight hunk lines
    /// according to your delta configuration. This is mainly intended for other tools that use
    /// delta.
    pub color_only: bool,

    ////////////////////////////////////////////////////////////////////////////////////////////
    #[structopt(long = "features")]
    /// Name of delta features to use (space-separated). A feature is a named collection of delta
    /// options in ~/.gitconfig. See FEATURES section. The environment variable DELTA_FEATURES can
    /// be set to a space-separated list of feature names. If this is preceded with a space, the
    /// features from the environment variable will be added to those specified in git config. E.g.
    /// DELTA_FEATURES=+side-by-side can be used to activate side-by-side temporarily.
    pub features: Option<String>,

    #[structopt(long = "syntax-theme")]
    /// The code syntax-highlighting theme to use. Use --show-syntax-themes to demo available
    /// themes. Defaults to the value of the BAT_THEME environment variable, if that contains a
    /// valid theme name. --syntax-theme=none disables all syntax highlighting.
    pub syntax_theme: Option<String>,

    #[structopt(long = "minus-style", default_value = "normal auto")]
    /// Style (foreground, background, attributes) for removed lines. See STYLES section.
    pub minus_style: String,

    #[structopt(long = "zero-style", default_value = "syntax normal")]
    /// Style (foreground, background, attributes) for unchanged lines. See STYLES section.
    pub zero_style: String,

    #[structopt(long = "plus-style", default_value = "syntax auto")]
    /// Style (foreground, background, attributes) for added lines. See STYLES section.
    pub plus_style: String,

    #[structopt(long = "minus-emph-style", default_value = "normal auto")]
    /// Style (foreground, background, attributes) for emphasized sections of removed lines. See
    /// STYLES section.
    pub minus_emph_style: String,

    #[structopt(long = "minus-non-emph-style", default_value = "minus-style")]
    /// Style (foreground, background, attributes) for non-emphasized sections of removed lines
    /// that have an emphasized section. See STYLES section.
    pub minus_non_emph_style: String,

    #[structopt(long = "plus-emph-style", default_value = "syntax auto")]
    /// Style (foreground, background, attributes) for emphasized sections of added lines. See
    /// STYLES section.
    pub plus_emph_style: String,

    #[structopt(long = "plus-non-emph-style", default_value = "plus-style")]
    /// Style (foreground, background, attributes) for non-emphasized sections of added lines that
    /// have an emphasized section. See STYLES section.
    pub plus_non_emph_style: String,

    #[structopt(long = "commit-style", default_value = "raw")]
    /// Style (foreground, background, attributes) for the commit hash line. See STYLES section.
    /// The style 'omit' can be used to remove the commit hash line from the output.
    pub commit_style: String,

    #[structopt(long = "commit-decoration-style", default_value = "")]
    /// Style (foreground, background, attributes) for the commit hash decoration. See STYLES
    /// section. The style string should contain one of the special attributes 'box', 'ul'
    /// (underline), 'ol' (overline), or the combination 'ul ol'.
    pub commit_decoration_style: String,

    /// The regular expression used to identify the commit line when parsing git output.
    #[structopt(long = "commit-regex", default_value = r"^commit ")]
    pub commit_regex: String,

    #[structopt(long = "file-style", default_value = "blue")]
    /// Style (foreground, background, attributes) for the file section. See STYLES section. The
    /// style 'omit' can be used to remove the file section from the output.
    pub file_style: String,

    #[structopt(long = "file-decoration-style", default_value = "blue ul")]
    /// Style (foreground, background, attributes) for the file decoration. See STYLES section. The
    /// style string should contain one of the special attributes 'box', 'ul' (underline), 'ol'
    /// (overline), or the combination 'ul ol'.
    pub file_decoration_style: String,

    /// Format string for commit hyperlinks (requires --hyperlinks). The
    /// placeholder "{commit}" will be replaced by the commit hash. For example:
    /// --hyperlinks-commit-link-format='https://mygitrepo/{commit}/'
    #[structopt(long = "hyperlinks-commit-link-format")]
    pub hyperlinks_commit_link_format: Option<String>,

    /// Format string for file hyperlinks (requires --hyperlinks). The
    /// placeholders "{path}" and "{line}" will be replaced by the absolute file
    /// path and the line number, respectively. The default value of this option
    /// creates hyperlinks using standard file URLs; your operating system
    /// should open these in the application registered for that file type.
    /// However, these do not make use of the line number. In order for the link
    /// to open the file at the correct line number, you could use a custom URL
    /// format such as "file-line://{path}:{line}" and register an application
    /// to handle the custom "file-line" URL scheme by opening the file in your
    /// editor/IDE at the indicated line number. See
    /// https://github.com/dandavison/open-in-editor for an example.
    #[structopt(long = "hyperlinks-file-link-format", default_value = "file://{path}")]
    pub hyperlinks_file_link_format: String,

    #[structopt(long = "hunk-header-style", default_value = "line-number syntax")]
    /// Style (foreground, background, attributes) for the hunk-header. See STYLES section. Special
    /// attributes 'file' and 'line-number' can be used to include the file path, and number of
    /// first hunk line, in the hunk header. The style 'omit' can be used to remove the hunk header
    /// section from the output.
    pub hunk_header_style: String,

    #[structopt(long = "hunk-header-file-style", default_value = "blue")]
    /// Style (foreground, background, attributes) for the file path part of the hunk-header. See
    /// STYLES section. The file path will only be displayed if hunk-header-style contains the
    /// 'file' special attribute.
    pub hunk_header_file_style: String,

    #[structopt(long = "hunk-header-line-number-style", default_value = "blue")]
    /// Style (foreground, background, attributes) for the line number part of the hunk-header. See
    /// STYLES section. The line number will only be displayed if hunk-header-style contains the
    /// 'line-number' special attribute.
    pub hunk_header_line_number_style: String,

    #[structopt(long = "hunk-header-decoration-style", default_value = "blue box")]
    /// Style (foreground, background, attributes) for the hunk-header decoration. See STYLES
    /// section. The style string should contain one of the special attributes 'box', 'ul'
    /// (underline), 'ol' (overline), or the combination 'ul ol'.
    pub hunk_header_decoration_style: String,

    #[structopt(long = "merge-conflict-begin-symbol", default_value = "▼")]
    /// A string that is repeated to form the line marking the beginning of a merge conflict region.
    pub merge_conflict_begin_symbol: String,

    #[structopt(long = "merge-conflict-end-symbol", default_value = "▲")]
    /// A string that is repeated to form the line marking the end of a merge conflict region.
    pub merge_conflict_end_symbol: String,

    #[structopt(
        long = "merge-conflict-ours-diff-header-style",
        default_value = "normal"
    )]
    /// Style (foreground, background, attributes) for the header above the diff between the
    /// ancestral commit and 'our' branch. See STYLES section.
    pub merge_conflict_ours_diff_header_style: String,

    #[structopt(
        long = "merge-conflict-ours-diff-header-decoration-style",
        default_value = "box"
    )]
    /// Style (foreground, background, attributes) for the decoration of the header above the diff
    /// between the ancestral commit and 'our' branch.  See STYLES section. The style string should
    /// contain one of the special attributes 'box', 'ul' (underline), 'ol' (overline), or the
    /// combination 'ul ol'.
    pub merge_conflict_ours_diff_header_decoration_style: String,

    #[structopt(
        long = "merge-conflict-theirs-diff-header-style",
        default_value = "normal"
    )]
    /// Style (foreground, background, attributes) for the header above the diff between the
    /// ancestral commit and 'their' branch. See STYLES section.
    pub merge_conflict_theirs_diff_header_style: String,

    #[structopt(
        long = "merge-conflict-theirs-diff-header-decoration-style",
        default_value = "box"
    )]
    /// Style (foreground, background, attributes) for the decoration of the header above the diff
    /// between the ancestral commit and 'their' branch.  See STYLES section. The style string should
    /// contain one of the special attributes 'box', 'ul' (underline), 'ol' (overline), or the
    /// combination 'ul ol'.
    pub merge_conflict_theirs_diff_header_decoration_style: String,

    #[structopt(long = "map-styles")]
    /// A string specifying a mapping styles encountered in raw input to desired
    /// output styles. An example is
    /// --map-styles='bold purple => red "#eeeeee", bold cyan => syntax "#eeeeee"'
    pub map_styles: Option<String>,

    /// Format string for git blame commit metadata. Available placeholders are
    /// "{timestamp}", "{author}", and "{commit}".
    #[structopt(
        long = "blame-format",
        default_value = "{timestamp:<15} {author:<15.14} {commit:<8}"
    )]
    pub blame_format: String,

    /// Separator between the commit metadata and code sections of a line of git blame output.
    #[structopt(long = "blame-separator", default_value = "│")]
    pub blame_separator: String,

    #[structopt(long = "blame-separator-style")]
    /// Style (foreground, background, attributes) for the separator between the commit metadata and
    /// code sections of a line of `git blame` output.
    pub blame_separator_style: Option<String>,

    #[structopt(long = "blame-code-style")]
    /// Style (foreground, background, attributes) for the code section of a line of `git blame`
    /// output. By default the code will be syntax-highlighted with the same background color as the
    /// blame format section of the line (the background color is determined by blame-palette). E.g.
    /// setting this option to 'syntax' will syntax-highlight the code with no background color.
    pub blame_code_style: Option<String>,

    /// Background colors used for git blame lines (space-separated string).
    /// Lines added by the same commit are painted with the same color; colors
    /// are recycled as needed.
    #[structopt(long = "blame-palette")]
    pub blame_palette: Option<String>,

    /// Format of `git blame` timestamp in raw git output received by delta.
    #[structopt(
        long = "blame-timestamp-format",
        default_value = "%Y-%m-%d %H:%M:%S %z"
    )]
    pub blame_timestamp_format: String,

    #[structopt(long = "grep-match-line-style")]
    /// Style (foreground, background, attributes) for matching lines of code in
    /// grep output. See STYLES section. Defaults to plus-style.
    pub grep_match_line_style: Option<String>,

    #[structopt(long = "grep-match-word-style")]
    /// Style (foreground, background, attributes) for the specific matching
    /// substrings within a matching line of code in grep output. See STYLES
    /// section. Defaults to plus-style.
    pub grep_match_word_style: Option<String>,

    #[structopt(long = "grep-context-line-style")]
    /// Style (foreground, background, attributes) for non-matching lines of
    /// code in grep output. See STYLES section. Defaults to zero-style.
    pub grep_context_line_style: Option<String>,

    #[structopt(long = "grep-file-style")]
    /// Style (foreground, background, attributes) for file paths in grep
    /// output. See STYLES section. Defaults to hunk-header-file-path-style.
    pub grep_file_style: Option<String>,

    #[structopt(long = "grep-line-number-style")]
    /// Style (foreground, background, attributes) for line numbers in grep
    /// output. See STYLES section. Defaults to hunk-header-line-number-style.
    pub grep_line_number_style: Option<String>,

    #[structopt(long = "grep-separator-symbol", default_value = ":")]
    /// Symbol used in grep output to separate file path (and line number) from
    /// the line of file contents. Defaults to ":" for both match and context
    /// lines, since many terminal emulators recognize constructs like
    /// "/path/to/file:7:". However, standard grep output uses "-" for context
    /// lines: set this option to "keep" to keep the original separator symbols.
    pub grep_separator_symbol: String,

    /// Default language used for syntax highlighting when this cannot be
    /// inferred from a filename. It will typically make sense to set this in
    /// per-repository git config (.git/config)
    #[structopt(long = "default-language")]
    pub default_language: Option<String>,

    #[structopt(long = "inline-hint-style", default_value = "blue")]
    /// Style (foreground, background, attributes) for content added by delta to
    /// the original diff such as special characters to highlight tabs, and the
    /// symbols used to indicate wrapped lines. See STYLES section.
    pub inline_hint_style: String,

    /// The regular expression used to decide what a word is for the within-line highlight
    /// algorithm. For less fine-grained matching than the default try --word-diff-regex="\S+"
    /// --max-line-distance=1.0 (this is more similar to `git --word-diff`).
    #[structopt(long = "word-diff-regex", default_value = r"\w+")]
    pub tokenization_regex: String,

    /// The maximum distance between two lines for them to be inferred to be homologous. Homologous
    /// line pairs are highlighted according to the deletion and insertion operations transforming
    /// one into the other.
    #[structopt(long = "max-line-distance", default_value = "0.6")]
    pub max_line_distance: f64,

    /// Style (foreground, background, attributes) for line numbers in the old (minus) version of
    /// the file. See STYLES and LINE NUMBERS sections.
    #[structopt(long = "line-numbers-minus-style", default_value = "auto")]
    pub line_numbers_minus_style: String,

    /// Style (foreground, background, attributes) for line numbers in unchanged (zero) lines. See
    /// STYLES and LINE NUMBERS sections.
    #[structopt(long = "line-numbers-zero-style", default_value = "auto")]
    pub line_numbers_zero_style: String,

    /// Style (foreground, background, attributes) for line numbers in the new (plus) version of
    /// the file. See STYLES and LINE NUMBERS sections.
    #[structopt(long = "line-numbers-plus-style", default_value = "auto")]
    pub line_numbers_plus_style: String,

    /// Format string for the left column of line numbers. A typical value would be "{nm:^4}⋮"
    /// which means to display the line numbers of the minus file (old version), center-aligned,
    /// padded to a width of 4 characters, followed by a dividing character. See the LINE NUMBERS
    /// section.
    #[structopt(long = "line-numbers-left-format", default_value = "{nm:^4}⋮")]
    pub line_numbers_left_format: String,

    /// Format string for the right column of line numbers. A typical value would be "{np:^4}│ "
    /// which means to display the line numbers of the plus file (new version), center-aligned,
    /// padded to a width of 4 characters, followed by a dividing character, and a space. See the
    /// LINE NUMBERS section.
    #[structopt(long = "line-numbers-right-format", default_value = "{np:^4}│")]
    pub line_numbers_right_format: String,

    /// Style (foreground, background, attributes) for the left column of line numbers. See STYLES
    /// and LINE NUMBERS sections.
    #[structopt(long = "line-numbers-left-style", default_value = "auto")]
    pub line_numbers_left_style: String,

    /// Style (foreground, background, attributes) for the right column of line numbers. See STYLES
    /// and LINE NUMBERS sections.
    #[structopt(long = "line-numbers-right-style", default_value = "auto")]
    pub line_numbers_right_style: String,

    /// How often a line should be wrapped if it does not fit. Zero means to never wrap. Any content
    /// which does not fit will be truncated. A value of "unlimited" means a line will be wrapped
    /// as many times as required.
    #[structopt(long = "wrap-max-lines", default_value = "2")]
    pub wrap_max_lines: String,

    /// Symbol added to the end of a line indicating that the content has been wrapped
    /// onto the next line and continues left-aligned.
    #[structopt(long = "wrap-left-symbol", default_value = "↵")]
    pub wrap_left_symbol: String,

    /// Symbol added to the end of a line indicating that the content has been wrapped
    /// onto the next line and continues right-aligned.
    #[structopt(long = "wrap-right-symbol", default_value = "↴")]
    pub wrap_right_symbol: String,

    /// Threshold for right-aligning wrapped content. If the length of the remaining wrapped
    /// content, as a percentage of width, is less than this quantity it will be right-aligned.
    /// Otherwise it will be left-aligned.
    #[structopt(long = "wrap-right-percent", default_value = "37.0")]
    pub wrap_right_percent: String,

    /// Symbol displayed in front of right-aligned wrapped content.
    #[structopt(long = "wrap-right-prefix-symbol", default_value = "…")]
    pub wrap_right_prefix_symbol: String,

    #[structopt(long = "navigate-regex")]
    /// A regexp to use in the less pager when navigating (auto-generated when unspecified)
    pub navigate_regex: Option<String>,

    #[structopt(long = "file-modified-label", default_value = "")]
    /// Text to display in front of a modified file path.
    pub file_modified_label: String,

    #[structopt(long = "file-removed-label", default_value = "removed:")]
    /// Text to display in front of a removed file path.
    pub file_removed_label: String,

    #[structopt(long = "file-added-label", default_value = "added:")]
    /// Text to display in front of a added file path.
    pub file_added_label: String,

    #[structopt(long = "file-copied-label", default_value = "copied:")]
    /// Text to display in front of a copied file path.
    pub file_copied_label: String,

    #[structopt(long = "file-renamed-label", default_value = "renamed:")]
    /// Text to display in front of a renamed file path.
    pub file_renamed_label: String,

    #[structopt(long = "right-arrow", default_value = "⟶  ")]
    /// Text to display with a changed value such as a diff heading, a rename, or a chmod.
    pub right_arrow: String,

    #[structopt(long = "hunk-label", default_value = "")]
    /// Text to display in front of a hunk header.
    pub hunk_label: String,

    #[structopt(long = "max-line-length", default_value = "512")]
    /// Truncate lines longer than this. To prevent any truncation, set to zero. Note that
    /// delta will be slow on very long lines (e.g. minified .js) if truncation is disabled.
    /// When wrapping lines it is automatically set to fit at least all visible characters.
    pub max_line_length: usize,

    /// How to extend the background color to the end of the line in side-by-side mode. Can
    /// be ansi (default) or spaces (default if output is not to a terminal). Has no effect
    /// if --width=variable is given.
    #[structopt(long = "line-fill-method")]
    pub line_fill_method: Option<String>,

    /// The width of underline/overline decorations. Examples: "72" (exactly 72 characters),
    /// "-2" (auto-detected terminal width minus 2). An expression such as "74-2" is also valid
    /// (equivalent to 72 but may be useful if the caller has a variable holding the value "74").
    /// Use --width=variable to extend decorations and background colors to the end of the text
    /// only. Otherwise background colors extend to the full terminal width.
    #[structopt(short = "w", long = "width")]
    pub width: Option<String>,

    /// Width allocated for file paths in a diff stat section. If a relativized
    /// file path exceeds this width then the diff stat will be misaligned.
    #[structopt(long = "diff-stat-align-width", default_value = "48")]
    pub diff_stat_align_width: usize,

    /// The number of spaces to replace tab characters with. Use --tabs=0 to pass tab characters
    /// through directly, but note that in that case delta will calculate line widths assuming tabs
    /// occupy one character's width on the screen: if your terminal renders tabs as more than than
    /// one character wide then delta's output will look incorrect.
    #[structopt(long = "tabs", default_value = "4")]
    pub tab_width: usize,

    /// Whether to emit 24-bit ("true color") RGB color codes. Options are auto, always, and never.
    /// "auto" means that delta will emit 24-bit color codes if the environment variable COLORTERM
    /// has the value "truecolor" or "24bit". If your terminal application (the application you use
    /// to enter commands at a shell prompt) supports 24 bit colors, then it probably already sets
    /// this environment variable, in which case you don't need to do anything.
    #[structopt(long = "true-color", default_value = "auto")]
    pub true_color: String,

    /// Deprecated: use --true-color.
    #[structopt(long = "24-bit-color")]
    pub _24_bit_color: Option<String>,

    /// Whether to examine ANSI color escape sequences in raw lines received from Git and handle
    /// lines colored in certain ways specially. This is on by default: it is how Delta supports
    /// Git's --color-moved feature. Set this to "false" to disable this behavior.
    #[structopt(long = "inspect-raw-lines", default_value = "true")]
    pub inspect_raw_lines: String,

    #[structopt(long)]
    /// Which pager to use. The default pager is `less`. You can also change pager
    /// by setting the environment variables DELTA_PAGER, BAT_PAGER, or PAGER
    /// (and that is their order of priority). This option overrides all environment
    /// variables above.
    pub pager: Option<String>,

    /// Whether to use a pager when displaying output. Options are: auto, always, and never.
    #[structopt(long = "paging", default_value = "auto")]
    pub paging_mode: String,

    /// First file to be compared when delta is being used in diff mode: `delta file_1 file_2` is
    /// equivalent to `diff -u file_1 file_2 | delta`.
    #[structopt(parse(from_os_str))]
    pub minus_file: Option<PathBuf>,

    /// Second file to be compared when delta is being used in diff mode.
    #[structopt(parse(from_os_str))]
    pub plus_file: Option<PathBuf>,

    /// Style for removed empty line marker (used only if --minus-style has no background color)
    #[structopt(
        long = "--minus-empty-line-marker-style",
        default_value = "normal auto"
    )]
    pub minus_empty_line_marker_style: String,

    /// Style for added empty line marker (used only if --plus-style has no background color)
    #[structopt(long = "--plus-empty-line-marker-style", default_value = "normal auto")]
    pub plus_empty_line_marker_style: String,

    /// Style for whitespace errors. Defaults to color.diff.whitespace if that is set in git
    /// config, or else 'magenta reverse'.
    #[structopt(long = "whitespace-error-style", default_value = "auto auto")]
    pub whitespace_error_style: String,

    #[structopt(long = "line-buffer-size", default_value = "32")]
    /// Size of internal line buffer. Delta compares the added and removed versions of nearby lines
    /// in order to detect and highlight changes at the level of individual words/tokens.
    /// Therefore, nearby lines must be buffered internally before they are painted and emitted.
    /// Increasing this value might improve highlighting of some large diff hunks. However, setting
    /// this to a high value will adversely affect delta's performance when entire files are
    /// added/removed.
    pub line_buffer_size: usize,

    #[structopt(long = "minus-color")]
    /// Deprecated: use --minus-style='normal my_background_color'.
    pub deprecated_minus_background_color: Option<String>,

    #[structopt(long = "minus-emph-color")]
    /// Deprecated: use --minus-emph-style='normal my_background_color'.
    pub deprecated_minus_emph_background_color: Option<String>,

    #[structopt(long = "plus-color")]
    /// Deprecated: Use --plus-style='syntax my_background_color' to change the background color
    /// while retaining syntax-highlighting.
    pub deprecated_plus_background_color: Option<String>,

    #[structopt(long = "plus-emph-color")]
    /// Deprecated: Use --plus-emph-style='syntax my_background_color' to change the background
    /// color while retaining syntax-highlighting.
    pub deprecated_plus_emph_background_color: Option<String>,

    #[structopt(long = "highlight-removed")]
    /// Deprecated: use --minus-style='syntax'.
    pub deprecated_highlight_minus_lines: bool,

    #[structopt(long = "commit-color")]
    /// Deprecated: use --commit-style='my_foreground_color'
    /// --commit-decoration-style='my_foreground_color'.
    pub deprecated_commit_color: Option<String>,

    #[structopt(long = "file-color")]
    /// Deprecated: use --file-style='my_foreground_color'
    /// --file-decoration-style='my_foreground_color'.
    pub deprecated_file_color: Option<String>,

    #[structopt(long = "hunk-style")]
    /// Deprecated: synonym of --hunk-header-decoration-style.
    pub deprecated_hunk_style: Option<String>,

    #[structopt(long = "hunk-color")]
    /// Deprecated: use --hunk-header-style='my_foreground_color'
    /// --hunk-header-decoration-style='my_foreground_color'.
    pub deprecated_hunk_color: Option<String>,

    #[structopt(long = "theme")]
    /// Deprecated: use --syntax-theme.
    pub deprecated_theme: Option<String>,

    #[structopt(skip)]
    pub computed: ComputedValues,

    #[structopt(skip)]
    pub git_config: Option<GitConfig>,

    #[structopt(skip)]
    pub git_config_entries: HashMap<String, GitConfigEntry>,
}

#[derive(Default, Clone, Debug)]
pub struct ComputedValues {
    pub available_terminal_width: usize,
    pub stdout_is_term: bool,
    pub background_color_extends_to_terminal_width: bool,
    pub decorations_width: Width,
    pub inspect_raw_lines: InspectRawLines,
    pub is_light_mode: bool,
    pub paging_mode: PagingMode,
    pub syntax_set: SyntaxSet,
    pub syntax_theme: Option<SyntaxTheme>,
    pub true_color: bool,
}

#[derive(Clone, Debug, PartialEq)]
pub enum Width {
    Fixed(usize),
    Variable,
}

impl Default for Width {
    fn default() -> Self {
        Width::Variable
    }
}

#[derive(Clone, Debug, PartialEq)]
pub enum InspectRawLines {
    True,
    False,
}

impl Default for InspectRawLines {
    fn default() -> Self {
        InspectRawLines::False
    }
}

impl Default for PagingMode {
    fn default() -> Self {
        PagingMode::Never
    }
}

impl Opt {
    pub fn from_args_and_git_config(
        git_config: Option<GitConfig>,
        assets: HighlightingAssets,
    ) -> Self {
        Self::from_clap_and_git_config(Self::clap().get_matches(), git_config, assets)
    }

    pub fn from_iter_and_git_config<I>(iter: I, git_config: Option<GitConfig>) -> Self
    where
        I: IntoIterator,
        I::Item: Into<OsString> + Clone,
    {
        let assets = HighlightingAssets::new();
        Self::from_clap_and_git_config(Self::clap().get_matches_from(iter), git_config, assets)
    }

    fn from_clap_and_git_config(
        arg_matches: clap::ArgMatches,
        mut git_config: Option<GitConfig>,
        assets: HighlightingAssets,
    ) -> Self {
        let mut opt = Opt::from_clap(&arg_matches);
        options::rewrite::apply_rewrite_rules(&mut opt, &arg_matches);
        options::set::set_options(&mut opt, &mut git_config, &arg_matches, assets);
        opt.git_config = git_config;
        opt
    }

    #[allow(dead_code)]
    pub fn get_option_names<'a>() -> HashMap<&'a str, &'a str> {
        itertools::chain(
            Self::clap()
                .p
                .opts
                .iter()
                .map(|opt| (opt.b.name, opt.s.long.unwrap())),
            Self::clap()
                .p
                .flags
                .iter()
                .map(|opt| (opt.b.name, opt.s.long.unwrap())),
        )
        .filter(|(name, _)| !IGNORED_OPTION_NAMES.contains(name))
        .collect()
    }
}

// Option names to exclude when listing options to process for various purposes. These are
// (1) Deprecated options
// (2) Pseudo-flag commands such as --list-languages
lazy_static! {
    static ref IGNORED_OPTION_NAMES: HashSet<&'static str> = vec![
        "deprecated-file-color",
        "deprecated-hunk-style",
        "deprecated-minus-background-color",
        "deprecated-minus-emph-background-color",
        "deprecated-hunk-color",
        "deprecated-plus-emph-background-color",
        "deprecated-plus-background-color",
        "deprecated-highlight-minus-lines",
        "deprecated-theme",
        "deprecated-commit-color",
        "list-languages",
        "list-syntax-themes",
        "show-config",
        "show-syntax-themes",
    ]
    .into_iter()
    .collect();
}
