use std::process::Command;

use anyhow::Context as _;

trait SuccessExt {
    fn success(&mut self) -> anyhow::Result<()>;
}

impl SuccessExt for Command {
    fn success(&mut self) -> anyhow::Result<()> {
        if !self.status()?.success() {
            anyhow::bail!("Command returned unsuccessfully");
        }
        Ok(())
    }
}

pub struct RenderedTree {
    repo_dir: std::path::PathBuf,
    dot_file: std::path::PathBuf,
    svg_file: std::path::PathBuf,
}

pub async fn render(
    _ctx: &crate::Context,
    tree: &crate::tree::Tree,
) -> anyhow::Result<RenderedTree> {
    let repo_dir = std::path::PathBuf::from("render-git");

    if repo_dir.is_dir() {
        log::info!("Found old {repo_dir:?} repository, removing...");
        std::fs::remove_dir_all(&repo_dir).context("Failed to remove stale render repository")?;
    }

    std::fs::create_dir(&repo_dir).context("Failed creating directory for rendered graph")?;

    let dot_file = repo_dir.join("techtree.dot");
    let svg_file = repo_dir.join("techtree.svg");

    let dot_source = tree.to_dot();
    std::fs::write(&dot_file, dot_source.as_bytes())
        .context("Failed to write `dot` source file")?;

    Command::new("dot")
        .args(["-T", "svg"])
        .arg("-o")
        .arg(&svg_file)
        .arg(&dot_file)
        .success()
        .context("Failed to generate svg graph from dot source")?;

    Ok(RenderedTree {
        repo_dir,
        dot_file,
        svg_file,
    })
}

pub async fn publish(ctx: &crate::Context, rendered: &RenderedTree) -> anyhow::Result<()> {
    Command::new("git")
        .arg("-C")
        .arg(&rendered.repo_dir)
        .arg("init")
        .arg("--initial-branch=render")
        .arg("--quiet")
        .success()
        .context("Failed to initialize render repository")?;

    Command::new("git")
        .arg("-C")
        .arg(&rendered.repo_dir)
        .args(["config", "user.email", "git@fa-fo.de"])
        .success()
        .context("Failed to configure identity for render repo")?;

    Command::new("git")
        .arg("-C")
        .arg(&rendered.repo_dir)
        .args(["config", "user.name", "Forgejo Actions"])
        .success()
        .context("Failed to configure identity for render repo")?;

    Command::new("git")
        .arg("-C")
        .arg(&rendered.repo_dir)
        .arg("add")
        .arg(rendered.dot_file.strip_prefix(&rendered.repo_dir).unwrap())
        .arg(rendered.svg_file.strip_prefix(&rendered.repo_dir).unwrap())
        .success()
        .context("Failed to add generated graph files to git index")?;

    Command::new("git")
        .arg("-C")
        .arg(&rendered.repo_dir)
        .arg("commit")
        .args(["-m", &format!("Updated techtree at {}", ctx.timestamp)])
        .success()
        .context("Failed to add generated graph files to git index")?;

    Command::new("git")
        .arg("-C")
        .arg(&rendered.repo_dir)
        .arg("push")
        .arg("--force")
        .arg("--quiet")
        .arg(ctx.repo_auth_url.to_string())
        .arg("HEAD:refs/heads/render")
        .status()
        .context("Failed to push rendered graph to forgejo repository")?;

    Ok(())
}