#!/usr/bin/env python3
import os
import subprocess
import time
import argparse


# Helper class to change directory via context manager
class os_chdir:
    def __init__(self, new_dir):
        self.new_dir = new_dir
        self.saved_dir = os.getcwd()
    
    def __enter__(self):
        os.chdir(self.new_dir)
    
    def __exit__(self, exc_type, exc_val, exc_tb):
        os.chdir(self.saved_dir)


def build_toolchains(
    mpsd_spack_ver=None,
    toolchain_list=None,
    toolchain_base_dir="/opt_mpsd/",
    skip_build_cache=False,
    skip_dir_check=False,
):
    """
    Build toolchains using Spack.

    This function builds toolchains for toolchains at the appropriate directory for the current system architecture
    and MPSD software stack version.
    The toolchains are built using the bash script spack_setup.sh, and the results are logged.
    """
    mpsd_os = os.environ["MPSD_OS"]
    mpsd_microarch = os.environ["MPSD_MICROARCH"]
    current_branch = (
        subprocess.run(
            ["git", "rev-parse", "--abbrev-ref", "HEAD"], stdout=subprocess.PIPE
        )
        .stdout.decode()
        .strip()
    )
    current_commit_hash = (
        subprocess.run(
            ["git", "rev-parse", "--short", "HEAD"], stdout=subprocess.PIPE
        )
    )
    current_dir = os.getcwd()

    # Checks

    ## Check that some mpsd_spack_ver is passed.
    if mpsd_spack_ver is None:
        raise ValueError(
            "Error: MPSD_SPACK_VER not passed. Please pass the MPSD Software stack version."
        )
    ## Check if toolchains directory exists
    spack_env_path = os.path.join(toolchain_base_dir, mpsd_os, mpsd_spack_ver)
    toolchains_path = os.path.join(spack_env_path, mpsd_microarch)
    if not os.path.exists(toolchains_path):
        os.makedirs(toolchains_path)
    else:
        if not skip_dir_check:
            raise ValueError(
                f"Error: Toolchains directory {toolchains_path} already exists. \n\
                Please remove it and try again."
            )
    ### Clone spack-env repo at spack_env_path
    with os.chdir(spack_env_path + "/spack-environments"):
        subprocess.run("git clone git@gitlab.gwdg.de:mpsd-cs/spack-environments.git .", shell=True, check=True)
        subprocess.run(f"git checkout {mpsd_spack_ver}", shell=True, check=True)
    ## Check if TOOLCHAIN_LIST is valid
    available_toolchains = os.listdir("toolchains")

    if skip_build_cache:
        flags = "-b"
    else:
        flags = ""

    if toolchain_list is None:
        toolchains = available_toolchains
    else:
        toolchains = toolchain_list.split(",")
        # if not set(toolchains)<=set(available_toolchains):
        for toolchain in toolchains:
            if toolchain not in available_toolchains:
                raise ValueError(
                    f"Error: Toolchain '{toolchain}' not found in toolchains directory. \n\
                    Please check the toolchain argument and try again."
                )

    # Build toolchains

    log_file = f"build_toolchains_{mpsd_spack_ver}_{time.strftime('%Y%m%d-%H%M%S')}.log"
    print(f"Building at {toolchains_path}...")
    for toolchain in toolchains:
        with os_chdir(toolchains_path):
            print(f">>>> Building {toolchain}...")
            subprocess.run(
                f" bash {spack_env_path}/spack-environments/spack_setup.sh {flags} {toolchain}|tee -a {log_file} 2>&1", 
                shell=True, check=True
            )
            # copy the octopus configs to the toolchain directory
            # subprocess.run(f"cp -r {current_dir}/octopus