use std::path::{Path, PathBuf};
use std::{env, fs};

use base64::{engine::general_purpose, Engine as _};

/// Work out where the workspace dir is
fn workspace_dir() -> PathBuf {
    let output = std::process::Command::new(env!("CARGO"))
        .arg("locate-project")
        .arg("--workspace")
        .arg("--message-format=plain")
        .output()
        .unwrap()
        .stdout;
    let cargo_path = Path::new(std::str::from_utf8(&output).unwrap().trim());
    cargo_path.parent().unwrap().to_path_buf()
}

// We do this here so it's only actually run and checked once at build time.
fn determine_git_rev() -> Option<String> {
    let repo = match gix::open(workspace_dir()) {
        Ok(repo) => repo,
        Err(_) => {
            return None;
        }
    };
    let mut head = repo.head().ok()?;
    let commit = head.peel_to_commit_in_place().ok()?;
    let mut commit_id = commit.id().to_string();
    // Now we actually want to trim this to only 10 chars?
    commit_id.truncate(10);
    Some(commit_id)
}

fn main() {
    /*
     * https://doc.rust-lang.org/cargo/reference/build-scripts.html#change-detection
     * If the build script inherently does not need to re-run under any circumstance, then emitting
     * cargo:rerun-if-changed=build.rs is a simple way to prevent it from being re-run (otherwise,
     * the default if no rerun-if instructions are emitted is to scan the entire package directory
     * for changes).
     */
    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-env-changed=KANIDM_BUILD_PROFILE");

    let profile = env::var("KANIDM_BUILD_PROFILE").unwrap_or_else(|_| "developer".to_string());

    let profile_path: PathBuf = ["./", format!("{}.toml", profile).as_str()]
        .iter()
        .collect();

    let data =
        fs::read(&profile_path).unwrap_or_else(|_| panic!("Failed to read {:?}", profile_path));

    let contents = general_purpose::STANDARD.encode(data);

    if let Some(commit_rev) = determine_git_rev() {
        println!("cargo:rustc-env=KANIDM_PKG_COMMIT_REV={}", commit_rev);
    }

    println!("cargo:rerun-if-changed={}", profile_path.to_str().unwrap());

    println!("cargo:rustc-env=KANIDM_BUILD_PROFILE={}", profile);
    println!("cargo:rustc-env=KANIDM_BUILD_PROFILE_TOML={}", contents);
}