//! Embedded project templates for 'am init --template' (issue #52).
//! Each template renders an agent-manager.yaml pre-filled for a stack:
//! a dev group, a default profile and project hooks. Variables {project}
//! and {dir} are substituted at render time.

use anyhow::{bail, Result};

/// (name, description) of every available template.
pub const TEMPLATES: &[(&str, &str)] = &[
    ("web", "frontend/web full-stack : node, npm, tests, serveur local"),
    ("python", "python : uv/pip, pytest, ruff, mypy"),
    ("rust", "rust : cargo, clippy, tests, rustfmt"),
    ("cli", "générique CLI : commandes shell, scripts, git"),
];

/// The four embedded templates.
const WEB: &str = r#"# Généré par 'am init --template web' — projet {project}
# Répertoire : {dir}
version: "1.0"
groups:
  dev: [claude-code, opencode, gemini-cli]
profiles:
  dev:
    agent: claude-code
    env:
      NODE_ENV: development
      CI: "1"
    args: []
settings:
  hooks:
    on_install: ["npm install"]
    on_start: ["npm run dev"]
agents: []
"#;

const PYTHON: &str = r#"# Généré par 'am init --template python' — projet {project}
# Répertoire : {dir}
version: "1.0"
groups:
  dev: [claude-code, codex, aider]
profiles:
  dev:
    agent: claude-code
    env:
      PYTHONUNBUFFERED: "1"
      PYTHONDONTWRITEBYTECODE: "1"
    args: []
settings:
  hooks:
    on_install: ["uv sync --all-extras"]
    on_start: ["uv run pytest -q"]
agents: []
"#;

const RUST: &str = r#"# Généré par 'am init --template rust' — projet {project}
# Répertoire : {dir}
version: "1.0"
groups:
  dev: [claude-code, codex, jcode]
profiles:
  dev:
    agent: claude-code
    env:
      CARGO_TERM_COLOR: always
      RUST_BACKTRACE: "1"
    args: []
settings:
  hooks:
    on_install: ["cargo fetch"]
    on_start: ["cargo test"]
agents: []
"#;

const CLI: &str = r#"# Généré par 'am init --template cli' — projet {project}
# Répertoire : {dir}
version: "1.0"
groups:
  dev: [claude-code, opencode]
profiles:
  dev:
    agent: claude-code
    env: {}
    args: []
agents: []
"#;

fn template_of(name: &str) -> Option<&'static str> {
    match name {
        "web" => Some(WEB),
        "python" => Some(PYTHON),
        "rust" => Some(RUST),
        "cli" => Some(CLI),
        _ => None,
    }
}

/// Render a template for a project. `project` is the project name (used in
/// the header comment), `dir` the absolute directory path. Unknown template
/// names fail with the available list.
pub fn render(name: &str, project: &str, dir: &str) -> Result<String> {
    let Some(tpl) = template_of(name) else {
        let list = TEMPLATES
            .iter()
            .map(|(n, _)| *n)
            .collect::<Vec<_>>()
            .join(", ");
        bail!("unknown template '{name}' — available: {list}");
    };
    Ok(tpl.replace("{project}", project).replace("{dir}", dir))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn renders_all_templates_with_substitution() {
        for (name, _) in TEMPLATES {
            let out = render(name, "mon-app", "/work/mon-app").unwrap();
            assert!(out.contains("mon-app"), "{name}: project substituted");
            assert!(out.contains("/work/mon-app"), "{name}: dir substituted");
            assert!(!out.contains("{project}"), "{name}: no leftover var");
            assert!(!out.contains("{dir}"), "{name}: no leftover var");
            // The rendered config must parse and validate.
            let cfg: crate::config::Config = serde_yaml::from_str(&out).unwrap_or_else(|e| {
                panic!("{name}: invalid YAML: {e}\n{out}")
            });
            assert!(crate::config::validate(&cfg).is_empty(), "{name}: invalid config");
            assert!(!cfg.groups.is_empty(), "{name}: a dev group is expected");
        }
    }

    #[test]
    fn unknown_template_fails_with_list() {
        let err = render("cobol", "x", "/tmp").unwrap_err();
        assert!(err.to_string().contains("web"), "{err}");
    }
}