use crate::bare::GitBare;
use crate::error::{GitError, GitResult};
use crate::pb::GetDiffStatsRequest;

impl GitBare {
    pub fn get_diff_stats(&self, request: GetDiffStatsRequest) -> GitResult<crate::pb::DiffStats> {
        let base = match request.base.and_then(|s| s.selector) {
            Some(crate::pb::object_selector::Selector::Oid(oid)) => oid.hex,
            Some(crate::pb::object_selector::Selector::Revision(name)) => name.revision,
            None => "HEAD".into(),
        };
        let head = match request.head.and_then(|s| s.selector) {
            Some(crate::pb::object_selector::Selector::Oid(oid)) => oid.hex,
            Some(crate::pb::object_selector::Selector::Revision(name)) => name.revision,
            None => "HEAD".into(),
        };
        diff_stats_for_range(self, &base, &head, request.options.as_ref())
    }
}

pub(crate) fn diff_stats_for_range(
    repo: &GitBare,
    base: &str,
    head: &str,
    options: Option<&crate::pb::DiffOptions>,
) -> GitResult<crate::pb::DiffStats> {
    let mut args = vec![
        "--git-dir".to_string(),
        repo.bare_dir.to_string_lossy().into_owned(),
        "diff".into(),
        "--shortstat".into(),
    ];
    push_diff_options(&mut args, options);
    args.push(base.to_string());
    args.push(head.to_string());
    if let Some(options) = options
        && !options.pathspec.is_empty()
    {
        args.push("--".into());
        args.extend(options.pathspec.iter().cloned());
    }

    let result = duct::cmd("git", &args)
        .stdout_capture()
        .stderr_capture()
        .unchecked()
        .run()?;
    if !result.status.success() {
        return Err(GitError::CommandFailed {
            status_code: result.status.code(),
            stderr: String::from_utf8_lossy(&result.stderr).into_owned(),
        });
    }

    Ok(parse_shortstat(&String::from_utf8_lossy(&result.stdout)))
}

pub(crate) fn parse_shortstat(output: &str) -> crate::pb::DiffStats {
    let mut stats = crate::pb::DiffStats::default();
    for part in output.trim().split(',') {
        let part = part.trim();
        if let Some(n) = part
            .strip_suffix(" insertion(+)")
            .or_else(|| part.strip_suffix(" insertions(+)"))
        {
            stats.additions = n.trim().parse().unwrap_or(0);
        } else if let Some(n) = part
            .strip_suffix(" deletion(-)")
            .or_else(|| part.strip_suffix(" deletions(-)"))
        {
            stats.deletions = n.trim().parse().unwrap_or(0);
        } else if let Some(n) = part
            .strip_suffix(" file changed")
            .or_else(|| part.strip_suffix(" files changed"))
        {
            stats.changed_files = n.trim().parse().unwrap_or(0);
        }
    }
    stats
}

pub(crate) fn push_diff_options(args: &mut Vec<String>, options: Option<&crate::pb::DiffOptions>) {
    let Some(options) = options else {
        return;
    };

    if options.rename_detection {
        args.push("-M".into());
    }
    if options.copy_detection {
        args.push("-C".into());
    }

    match crate::pb::diff_options::WhitespaceMode::try_from(options.whitespace_mode)
        .unwrap_or(crate::pb::diff_options::WhitespaceMode::DiffWhitespaceModeDefault)
    {
        crate::pb::diff_options::WhitespaceMode::DiffWhitespaceModeIgnoreAll => {
            args.push("-w".into())
        }
        crate::pb::diff_options::WhitespaceMode::DiffWhitespaceModeIgnoreChange => {
            args.push("-b".into())
        }
        crate::pb::diff_options::WhitespaceMode::DiffWhitespaceModeIgnoreEol => {
            args.push("--ignore-space-at-eol".into());
        }
        _ => {}
    }
}