//! init: generate a local agent-manager.yaml for the current directory,
//! based on the detected technology stack or an explicit template
//! (issue #52: 'am init --template web|python|rust|cli').

use super::*;
use crate::context;
use anyhow::{anyhow, Context, Result};
use std::path::{Path, PathBuf};

/// Generate a local config file in dir; refuses to overwrite unless force.
/// `template` renders a pre-filled config for a stack ('am init --template');
/// None falls back on the automatic stack detection. Returns the written path.
pub fn generate(dir: &Path, force: bool, template: Option<&str>) -> Result<PathBuf> {
    let target = dir.join(crate::config::LOCAL_CONFIG_NAME);
    if target.exists() && !force {
        return Err(anyhow!(
            "{} already exists — use --force to overwrite it",
            target.display()
        ));
    }
    let project = dir
        .file_name()
        .map(|n| n.to_string_lossy().to_string())
        .unwrap_or_else(|| "project".to_string());
    let dir_str = dir.to_string_lossy().to_string();
    let content = if let Some(t) = template {
        crate::templates::render(t, &project, &dir_str)?
    } else {
        let ctx = context::detect(dir);
        let agents = context::recommended_agents(&ctx.stack);
        let members = agents
            .iter()
            .map(|a| a.to_string())
            .collect::<Vec<_>>()
            .join(", ");
        let stack = if ctx.stack.is_empty() {
            crate::i18n::tr("aucune détectée").to_string()
        } else {
            ctx.stack.join(", ")
        };
        format!(
            "# Généré par 'am init' le {date}
# Pile détectée : {stack}
version: \"1.0\"
groups:
  dev: [{members}]
agents: []
",
            date = crate::installers::now_rfc3339(),
        )
    };
    std::fs::write(&target, content)
        .with_context(|| format!("cannot write {}", target.display()))?;
    Ok(target)
}

pub fn run(app: &App, force: bool, template: Option<&str>) -> Result<i32> {
    // 'am init --template list' prints the available templates.
    if template == Some("list") {
        println!("available templates:");
        for (name, desc) in crate::templates::TEMPLATES {
            println!("  {name:<8} {desc}");
        }
        return Ok(0);
    }
    if app.dry_run() {
        app.log.dry(format!(
            "would generate {} in the current directory",
            crate::config::LOCAL_CONFIG_NAME
        ));
        return Ok(0);
    }
    let cwd = std::env::current_dir().context("cannot determine the current directory")?;
    let ctx = context::detect(&cwd);
    let path = generate(&cwd, force, template)?;
    match template {
        Some(t) => app.log.success(&format!(
            "wrote {} (template: {t})",
            path.display()
        )),
        None => app.log.success(&format!(
            "wrote {} (stack: {})",
            path.display(),
            if ctx.stack.is_empty() {
                crate::i18n::tr("aucune détectée").to_string()
            } else {
                ctx.stack.join(", ")
            }
        )),
    }
    app.log.info(&format!(
        "group 'dev' prêt : am start group:dev — ajustez ensuite la config générée"
    ));
    Ok(0)
}