#[path = "commands/diff.rs"]

pub mod rad_diff;

use std::ffi::OsString;

use anyhow::anyhow;

use radicle::git;

use radicle::rad;

use radicle_surf as surf;

use crate::git::pretty_diff::ToPretty as _;

use crate::git::Rev;

use crate::terminal as term;

use crate::terminal::args::{Args, Error, Help};

use crate::terminal::highlight::Highlighter;

pub const HELP: Help = Help {

    name: "diff",

    description: "Show changes between commits",

    version: env!("RADICLE_VERSION"),

    usage: r#"

Usage

    rad diff [<commit>] [--staged] [<option>...]

    rad diff <commit> [<commit>] [<option>...]

    This command is meant to operate as closely as possible to `git diff`,

    except its output is optimized for human-readability.

Options

    --unified, -U   Context lines to show (default: 5)

    --staged        View staged changes

    --color         Force color output

    --help          Print help

"#,

};

pub struct Options {

    pub commits: Vec<Rev>,

    pub staged: bool,

    pub unified: usize,

    pub color: bool,

}

impl Args for Options {

    fn from_args(args: Vec<OsString>) -> anyhow::Result<(Self, Vec<OsString>)> {

        use lexopt::prelude::*;

        let mut parser = lexopt::Parser::from_args(args);

        let mut commits = Vec::new();

        let mut staged = false;

        let mut unified = 5;

        let mut color = false;

        while let Some(arg) = parser.next()? {

            match arg {

                Long("unified") | Short('U') => {

                    let val = parser.value()?;

                    unified = term::args::number(&val)?;

                }

                Long("staged") | Long("cached") => staged = true,

                Long("color") => color = true,

                Long("help") | Short('h') => return Err(Error::Help.into()),

                Value(val) => {

                    let rev = term::args::rev(&val)?;

                    commits.push(rev);

                }

                _ => return Err(anyhow::anyhow!(arg.unexpected())),

            }

        }

        Ok((

            Options {

                commits,

                staged,

                unified,

                color,

            },

            vec![],

        ))

    }

}

pub fn run(options: Options, _ctx: impl term::Context) -> anyhow::Result<()> {

    let repo = rad::repo()?;

    let oids = options

        .commits

        .into_iter()

        .map(|rev| {

            repo.revparse_single(rev.as_str())

                .map_err(|e| anyhow!("unknown object {rev}: {e}"))

                .and_then(|o| {

                    o.into_commit()

                        .map_err(|_| anyhow!("object {rev} is not a commit"))

                })

        })

        .collect::<Result<Vec<_>, _>>()?;

    let mut opts = git::raw::DiffOptions::new();

    opts.patience(true)

        .minimal(true)

        .context_lines(options.unified as u32);

    let mut find_opts = git::raw::DiffFindOptions::new();

    find_opts.exact_match_only(true);

    find_opts.all(true);

    let mut diff = match oids.as_slice() {

        [] => {

            if options.staged {

                let head = repo.head()?.peel_to_tree()?;

                // HEAD vs. index.

                repo.diff_tree_to_index(Some(&head), None, Some(&mut opts))

            } else {

                // Working tree vs. index.

                repo.diff_index_to_workdir(None, None)

            }

        }

        [commit] => {

            let commit = commit.tree()?;

            if options.staged {

                // Commit vs. index.

                repo.diff_tree_to_index(Some(&commit), None, Some(&mut opts))

            } else {

                // Commit vs. working tree.

                repo.diff_tree_to_workdir(Some(&commit), Some(&mut opts))

            }

        }

        [left, right] => {

            // Commit vs. commit.

            let left = left.tree()?;

            let right = right.tree()?;

            repo.diff_tree_to_tree(Some(&left), Some(&right), Some(&mut opts))

        }

        _ => {

            anyhow::bail!("Too many commits given. See `rad diff --help` for usage.");

        }

    }?;

    diff.find_similar(Some(&mut find_opts))?;

    term::Paint::force(options.color);

    let diff = surf::diff::Diff::try_from(diff)?;

    let mut hi = Highlighter::default();

    let pretty = diff.pretty(&mut hi, &(), &repo);

    crate::pager::run(pretty)?;

    Ok(())

}

        "diff" => {

            term::run_command_args::<rad_diff::Options, _>(

                rad_diff::HELP,

                rad_diff::run,

                args.to_vec(),

            );

        }