//! `swarmctl agent agents-md` — read an agent's `AGENTS.md` and edit it with
//! a diff, through swarm-controller's `/api/agents/{name}/agents-md` routes.
//!
//! The read is the copy the agent's harness last published, so it works
//! while the agent is stopped. An edit is applied by the harness to the file
//! itself, so it needs the agent running.

use std::path::Path;

use anyhow::{Context as _, Result};
use swarm_controller_api::agents_md::{AgentsMdEdit, AgentsMdSaved, AgentsMdView};

use crate::agent::{parse_ident, send};
use crate::remote::Target;

fn runtime() -> Result<tokio::runtime::Runtime> {
    tokio::runtime::Builder::new_current_thread()
        .enable_all()
        .build()
        .context("starting a tokio runtime for the controller request")
}

/// The agent's `AGENTS.md` path. The name is checked first, so it cannot
/// reshape the URI.
fn member(agent: &str) -> Result<String> {
    let agent = parse_ident(agent, "agent name")?;
    Ok(format!("/api/agents/{agent}/agents-md"))
}

/// Run `swarmctl agent agents-md get`: the text on stdout, unchanged, and its
/// revision on stderr, so stdout redirected to a file is the file.
pub(crate) fn get(target: &Target, agent: &str) -> Result<()> {
    let uri = member(agent)?;
    let view: AgentsMdView = runtime()?.block_on(send(
        target,
        hyper::Method::GET,
        &uri,
        None::<&()>,
        "agents-md-get",
    ))?;
    eprintln!("revision {}", view.revision);
    print!("{}", view.content);
    Ok(())
}

/// Run `swarmctl agent agents-md apply`: send the diff in `diff_file`, made
/// against `base`, and print the file's new revision.
pub(crate) fn apply(target: &Target, agent: &str, base: &str, diff_file: &Path) -> Result<()> {
    let uri = member(agent)?;
    let diff = std::fs::read_to_string(diff_file)
        .with_context(|| format!("reading the diff {}", diff_file.display()))?;
    let edit = AgentsMdEdit {
        base_revision: base.to_owned(),
        diff,
    };
    let saved: AgentsMdSaved = runtime()?.block_on(send(
        target,
        hyper::Method::PUT,
        &uri,
        Some(&edit),
        "agents-md-apply",
    ))?;
    println!(
        "applied; {agent}'s AGENTS.md is at revision {}",
        saved.revision
    );
    Ok(())
}