mod bundled;
mod from_source;

#[cfg(any(feature = "bundled", feature = "from-source"))]
mod download;

extern crate bindgen;

use glob::glob;
use std::env;
use std::error::Error;
use std::path::PathBuf;

use bundled::*;
use crate::from_source::{download_scip_source, is_from_source_feature_enabled, compile_scip};

#[cfg(not(feature = "bundled"))]
pub fn is_bundled_feature_enabled() -> bool {
    false
}

fn _build_from_scip_dir(path: &str) -> bindgen::Builder {
    let lib_dir = PathBuf::from(&path).join("lib");
    let lib_dir_path = lib_dir.to_str().unwrap();

    if lib_dir.exists() {
        println!("cargo:warning=Using SCIP from {}", lib_dir_path);
        println!("cargo:rustc-link-search={}", lib_dir_path);
        println!("cargo:libdir={}", lib_dir_path);

        #[cfg(windows)]
            let lib_dir_path = PathBuf::from(&path).join("bin");
        #[cfg(windows)]
        println!("cargo:rustc-link-search={}", lib_dir_path.to_str().unwrap());
    } else {
        panic!(
            "{}",
            format!(
                "{}/lib does not exist, please check your SCIP installation",
                path
            )
        );
    }

    println!("cargo:rustc-link-arg=-Wl,-rpath,{}", lib_dir_path);

    let include_dir = PathBuf::from(&path).join("include");
    let include_dir_path = include_dir.to_str().unwrap();
    let scip_header_file = PathBuf::from(&path)
        .join("include")
        .join("scip")
        .join("scip.h")
        .to_str()
        .unwrap()
        .to_owned();
    let scipdefplugins_header_file = PathBuf::from(&path)
        .join("include")
        .join("scip")
        .join("scipdefplugins.h")
        .to_str()
        .unwrap()
        .to_owned();

    bindgen::Builder::default()
        .header(scip_header_file)
        .header(scipdefplugins_header_file)
        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
        .clang_arg(format!("-I{}", include_dir_path))
}

fn lib_scip_in_dir(path: &str) -> bool {
    glob(&format!("{}/lib/libscip*", path)).unwrap().count() > 0
}

fn look_in_scipoptdir_and_conda_env() -> Option<bindgen::Builder> {
    let env_vars = vec!["SCIPOPTDIR", "CONDA_PREFIX"];

    for env_var_name in env_vars {
        println!("cargo:rerun-if-env-changed={}", env_var_name);
        let env_var = env::var(env_var_name);
        if let Ok(scip_dir) = env_var {
            println!("cargo:warning=Looking for SCIP in {}", scip_dir);
            if lib_scip_in_dir(&scip_dir) {
                return Some(_build_from_scip_dir(&scip_dir));
            } else {
                println!("cargo:warning=SCIP was not found in {}", scip_dir);
            }
        } else {
            println!("cargo:warning={} is not set", env_var_name);
        }
    }

    return None;
}

fn main() -> Result<(), Box<dyn Error>> {
    let builder =
        if is_bundled_feature_enabled() {
            download_scip();
            let path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("scip_install");
            _build_from_scip_dir(path.to_str().unwrap())
        } else if is_from_source_feature_enabled() {
            let source_path = download_scip_source();
            let build_path = compile_scip(source_path);
            _build_from_scip_dir(build_path.to_str().unwrap())
        } else {
            let builder = look_in_scipoptdir_and_conda_env();
            if builder.is_some() {
                builder.unwrap()
            } else {
                println!("cargo:warning=SCIP was not found in SCIPOPTDIR or in Conda environemnt");
                println!("cargo:warning=Looking for SCIP in system libraries");

                let headers_dir_path = "headers/";
                let headers_dir = PathBuf::from(headers_dir_path);
                let scip_header_file = PathBuf::from(&headers_dir)
                    .join("scip")
                    .join("scip.h")
                    .to_str()
                    .unwrap()
                    .to_owned();
                let scipdefplugins_header_file = PathBuf::from(&headers_dir)
                    .join("scip")
                    .join("scipdefplugins.h")
                    .to_str()
                    .unwrap()
                    .to_owned();

                bindgen::Builder::default()
                    .header(scip_header_file)
                    .header(scipdefplugins_header_file)
                    .parse_callbacks(Box::new(bindgen::CargoCallbacks))
                    .clang_arg(format!("-I{}", headers_dir_path))
            }
        };


    #[cfg(windows)] {
        println!("cargo:rustc-link-lib=libscip");
    }
    #[cfg(not(windows))] {
        println!("cargo:rustc-link-lib=scip");
    }

    #[cfg(feature = "from-source")] {
        let target = env::var("TARGET").unwrap();
        let apple = target.contains("apple");
        let linux = target.contains("linux");
        let mingw = target.contains("pc-windows-gnu");
        if apple {
            println!("cargo:rustc-link-lib=dylib=c++");
        } else if linux || mingw {
            println!("cargo:rustc-link-lib=dylib=stdc++");
        }

        #[cfg(windows)] {
            println!("cargo:rustc-link-lib=libsoplex");
        }
        #[cfg(not(windows))] {
            println!("cargo:rustc-link-lib=soplex");
        }
    }

    let builder = builder
        .blocklist_item("FP_NAN")
        .blocklist_item("FP_INFINITE")
        .blocklist_item("FP_ZERO")
        .blocklist_item("FP_SUBNORMAL")
        .blocklist_item("FP_NORMAL")
        .parse_callbacks(Box::new(bindgen::CargoCallbacks));

    let bindings = builder.generate()?;
    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
    bindings.write_to_file(out_path.join("bindings.rs"))?;

    Ok(())
}