build.rs

use std::collections::BTreeMap;
use std::env;
use std::fs;
use std::path::Path;
use std::process::Command;

fn main() {
    generate_version();
    embed_themes();
}

/// Inject build-time version info as environment variables.
fn generate_version() {
    let version = env::var("CARGO_PKG_VERSION").unwrap_or_else(|_| "0.0.0".to_string());

    let commit = Command::new("git")
        .args(["rev-parse", "--short", "HEAD"])
        .output()
        .ok()
        .and_then(|o| {
            if o.status.success() {
                String::from_utf8(o.stdout)
                    .ok()
                    .map(|s| s.trim().to_string())
            } else {
                None
            }
        })
        .unwrap_or_else(|| "unknown".to_string());

    let build_time = chrono::Utc::now().to_rfc3339();

    let channel = env::var("FORESTAGE_CHANNEL").unwrap_or_else(|_| "alpha".to_string());
    let tag = env::var("FORESTAGE_TAG").unwrap_or_else(|_| format!("{version}-{commit}"));

    let long_version = format!("{tag} ({commit}, {channel})");

    println!("cargo:rustc-env=FORESTAGE_VERSION={version}");
    println!("cargo:rustc-env=FORESTAGE_COMMIT={commit}");
    println!("cargo:rustc-env=FORESTAGE_BUILD_TIME={build_time}");
    println!("cargo:rustc-env=FORESTAGE_CHANNEL={channel}");
    println!("cargo:rustc-env=FORESTAGE_TAG={tag}");
    println!("cargo:rustc-env=FORESTAGE_LONG_VERSION={long_version}");

    println!("cargo:rerun-if-changed=.git/HEAD");
    println!("cargo:rerun-if-env-changed=FORESTAGE_CHANNEL");
    println!("cargo:rerun-if-env-changed=FORESTAGE_TAG");
}

/// Embed all persona theme YAMLs at compile time using raw string literals.
///
/// Generates a Rust source file containing a function that returns a HashMap
/// of theme slug to YAML content. Uses `r#"..."#` raw strings to avoid
/// escaping issues with newlines, quotes, and backslashes in YAML content.
fn embed_themes() {
    let out_dir = env::var("OUT_DIR").expect("OUT_DIR not set");
    let themes_dir = Path::new("personas/themes");

    let mut themes: BTreeMap<String, String> = BTreeMap::new();

    if themes_dir.is_dir() {
        let mut entries: Vec<_> = fs::read_dir(themes_dir)
            .expect("failed to read personas/themes/")
            .filter_map(Result::ok)
            .filter(|e| {
                e.path()
                    .extension()
                    .is_some_and(|ext| ext == "yaml" || ext == "yml")
            })
            .collect();
        entries.sort_by_key(fs::DirEntry::file_name);

        for entry in entries {
            let path = entry.path();
            let slug = path
                .file_stem()
                .expect("no stem")
                .to_string_lossy()
                .to_string();
            let content = fs::read_to_string(&path)
                .unwrap_or_else(|e| panic!("failed to read {}: {e}", path.display()));
            themes.insert(slug, content);

            // Rebuild when individual theme files change
            println!("cargo:rerun-if-changed={}", path.display());
        }
    }

    let mut code = String::from(
        "/// Auto-generated by build.rs — do not edit.\n\
         pub fn embedded_themes() -> std::collections::HashMap<&'static str, &'static str> {\n\
         \x20   let mut m = std::collections::HashMap::new();\n",
    );

    for (slug, content) in &themes {
        // Use raw string literals to avoid all escaping issues.
        // r#"..."# handles newlines, quotes, backslashes natively.
        // Only fails if content contains the sequence "# — theme YAML never does.
        assert!(
            !content.contains("\"#"),
            "theme {slug} contains raw string delimiter sequence"
        );
        code.push_str(&format!("    m.insert(\"{slug}\", r#\"{content}\"#);\n"));
    }

    code.push_str("    m\n}\n");

    let dest = Path::new(&out_dir).join("themes_embedded.rs");
    fs::write(&dest, code).expect("failed to write themes_embedded.rs");

    // Also rebuild if themes directory itself changes (files added/removed)
    println!("cargo:rerun-if-changed=personas/themes");
}