use std::path::PathBuf;

use clap::Parser;
use git_repository::{objs::tree::EntryMode, traverse::tree::Recorder, Commit, Repository};
use terminal_size::{Height, Width};
use textplots::{Chart, Plot, Shape};

#[derive(Debug, Parser)]
struct Args {
    /// Path to a git repository.
    #[arg(default_value = ".")]
    repo: PathBuf,
    #[arg(long)]
    width: Option<u32>,
    #[arg(long)]
    height: Option<u32>,
}

fn count_lines(repo: &Repository, commit: &Commit) -> anyhow::Result<usize> {
    let mut lines = 0;
    let mut recorder = Recorder::default();
    commit.tree()?.traverse().breadthfirst(&mut recorder)?;
    for entry in recorder.records {
        if matches!(entry.mode, EntryMode::Blob | EntryMode::BlobExecutable) {
            let object = repo.find_object(entry.oid)?;
            let data = object.detach().data;
            let text = String::from_utf8(data)?;
            lines += text.lines().count();
        }
    }
    Ok(lines)
}

fn main() -> anyhow::Result<()> {
    let args = Args::parse();
    let (Width(width), Height(height)) =
        terminal_size::terminal_size().unwrap_or((Width(80), Height(24)));
    let width = args.width.unwrap_or(width as u32 - 12) * 2;
    let height = args.height.unwrap_or(height as u32 - 6) * 4;

    let mut repo = git_repository::discover(args.repo)?;
    repo.object_cache_size(Some(100 * 1024 * 1024));
    let commit = repo.head_commit()?;

    let mut lines = vec![];
    for ancestor in commit.ancestors().all()? {
        let ancestor = repo.find_object(ancestor.unwrap())?.try_into_commit()?;
        let line_count = count_lines(&repo, &ancestor)?;
        println!("{} {line_count}", ancestor.id);
        lines.push(line_count);
    }

    let xmax = lines.len();
    let ymax = lines.iter().copied().max().unwrap_or(0);
    let lines = lines
        .into_iter()
        .rev()
        .enumerate()
        .map(|(i, l)| (i as f32, l as f32))
        .collect::<Vec<_>>();

    let mut chart = Chart::new_with_y_range(width, height, 0_f32, xmax as f32, 0_f32, ymax as f32);
    chart.lineplot(&Shape::Lines(&lines)).nice();

    Ok(())
}