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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let manifest_dir = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR")?);
    let out_dir = PathBuf::from(std::env::var("OUT_DIR")?);
    fs::create_dir_all(&out_dir)?;
    let email_dir = manifest_dir.join("proto/email");
    let email_protos = proto_files(&email_dir)?;
    for proto in &email_protos {
        println!("cargo:rerun-if-changed={}", proto.display());
    }
    tonic_prost_build::configure()
        .build_client(true)
        .build_server(false)
        .out_dir(&out_dir)
        .compile_protos(&email_protos, &[email_dir])?;

    let git_dir = manifest_dir.join("proto/git");
    let git_protos = proto_files(&git_dir)?;
    for proto in &git_protos {
        println!("cargo:rerun-if-changed={}", proto.display());
    }
    tonic_prost_build::configure()
        .build_client(true)
        .build_server(false)
        .type_attribute(
            ".",
            "#[derive(serde::Serialize, serde::Deserialize, utoipa::ToSchema)]",
        )
        .extern_path(".google.protobuf.Timestamp", "crate::pb::Timestamp")
        .out_dir(&out_dir)
        .compile_protos(&git_protos, &[git_dir])?;

    let this_dir = manifest_dir.join("proto/this");
    let this_protos = proto_files(&this_dir)?;
    for proto in &this_protos {
        println!("cargo:rerun-if-changed={}", proto.display());
    }
    tonic_prost_build::configure()
        .build_client(false)
        .build_server(true)
        .out_dir(&out_dir)
        .compile_protos(&this_protos, &[this_dir])?;

    let im_dir = manifest_dir.join("proto/this/im");
    let im_protos = proto_files(&im_dir)?;
    for proto in &im_protos {
        println!("cargo:rerun-if-changed={}", proto.display());
    }
    tonic_prost_build::configure()
        .build_client(false)
        .build_server(true)
        .out_dir(&out_dir)
        .compile_protos(&im_protos, &[im_dir])?;

    Ok(())
}

fn proto_files(proto_dir: &Path) -> Result<Vec<PathBuf>, Box<dyn std::error::Error>> {
    let mut files = fs::read_dir(proto_dir)?
        .map(|entry| entry.map(|entry| entry.path()))
        .collect::<Result<Vec<_>, _>>()?;

    files.retain(|path| path.extension().is_some_and(|ext| ext == "proto"));
    files.sort();

    if files.is_empty() {
        return Err(format!("no .proto files found in {}", proto_dir.display()).into());
    }

    Ok(files)
}