#!/usr/bin/env python
"""
Run QE calculations for all displaced configs and band structure folders.

Runs:
  - SCF + pw2bgw for each data/disp-XX/
  - SCF + pw2bgw + bands + bands.x for data/bands/uc/ and data/bands/sc/

If params.json has cluster.run_sh set, wraps each job for cluster submission.
Otherwise runs locally with mpirun.

Usage: python run.py [params.json]
"""
import glob
import json
import os
import subprocess
import sys

SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))


def load_params(path=None):
    if path is None:
        path = os.path.join(SCRIPT_DIR, 'params.json')
    with open(path) as f:
        return json.load(f)


def run_qe(cmd_args, cwd, qe_setup, np, log_file, env=None):
    """Run a QE command with mpirun, sourcing qe_setup first."""
    mpi = ['mpirun', '-np', str(np)]
    bash_cmd = f"source {qe_setup} 2>/dev/null; " + \
               ' '.join(mpi + cmd_args + [f'> {log_file} 2>&1'])
    subprocess.run(['bash', '-c', bash_cmd], cwd=cwd, check=True)


def run_scf(scf_dir, qe_setup, np):
    xml = os.path.join(scf_dir, 'diamond.xml')
    if os.path.exists(xml):
        print(f"    SCF already done: {scf_dir}")
        return
    print(f"    Running SCF in {scf_dir}")
    run_qe(['pw.x', '<', 'pw.in'], scf_dir, qe_setup, np, 'pw.out')


def run_pw2bgw(scf_dir, qe_setup, np):
    vsc = os.path.join(scf_dir, 'VSC')
    if os.path.exists(vsc):
        print(f"    pw2bgw already done: {scf_dir}")
        return
    print(f"    Running pw2bgw in {scf_dir}")
    run_qe(['pw2bgw.x', '<', 'pw2bgw.in'], scf_dir, qe_setup, np, 'pw2bgw.out')


def run_bands(scf_dir, qe_setup, np):
    gnu = os.path.join(scf_dir, 'bands.dat.gnu')
    if os.path.exists(gnu):
        print(f"    Bands already done: {scf_dir}")
        return
    print(f"    Running bands in {scf_dir}")
    run_qe(['pw.x', '<', 'bands.in'], scf_dir, qe_setup, np, 'bands.out')
    # bands post-processing
    bash_cmd = f"source {qe_setup} 2>/dev/null; bands.x < bands_pp.in > bands_pp.out 2>&1"
    subprocess.run(['bash', '-c', bash_cmd], cwd=scf_dir, check=True)


def submit_cluster(script_path, cwd):
    """Submit to cluster using the provided run_sh script."""
    subprocess.run(['bash', script_path], cwd=cwd, check=True)


def main():
    params_path = sys.argv[1] if len(sys.argv) > 1 else \
        os.path.join(SCRIPT_DIR, 'params.json')
    params = load_params(params_path)

    data_dir = os.path.join(SCRIPT_DIR, 'data')
    qe_setup = params['paths']['qe_setup']
    np_qe = params['execution']['mpi_np']
    run_sh = params['execution'].get('run_sh')

    if not os.path.isdir(data_dir):
        print("data/ not found – run prepare.py first")
        sys.exit(1)

    # -------------------------------------------------------
    # Displaced configurations: SCF + pw2bgw
    # -------------------------------------------------------
    disp_dirs = sorted(glob.glob(os.path.join(data_dir, 'disp-*')))
    print(f"Processing {len(disp_dirs)} displaced configurations...")

    for disp_dir in disp_dirs:
        label = os.path.basename(disp_dir)
        scf_dir = os.path.join(disp_dir, 'scf')
        recon_done = os.path.join(disp_dir, 'reconstruction',
                                   'aohamiltonian', 'hamiltonians.h5')
        if os.path.exists(recon_done):
            print(f"  [{label}] Already fully done, skipping")
            continue

        print(f"  [{label}]")
        if run_sh:
            submit_cluster(run_sh, disp_dir)
        else:
            run_scf(scf_dir, qe_setup, np_qe)
            run_pw2bgw(scf_dir, qe_setup, np_qe)

    # -------------------------------------------------------
    # Band structure folders: SCF + pw2bgw + bands
    # -------------------------------------------------------
    for cell_label in ('uc', 'sc'):
        bands_dir = os.path.join(data_dir, 'bands', cell_label)
        if not os.path.isdir(bands_dir):
            continue
        scf_dir = os.path.join(bands_dir, 'scf')
        print(f"\nProcessing bands/{cell_label}...")

        if run_sh:
            submit_cluster(run_sh, bands_dir)
        else:
            run_scf(scf_dir, qe_setup, np_qe)
            run_pw2bgw(scf_dir, qe_setup, np_qe)
            if os.path.exists(os.path.join(scf_dir, 'bands.in')):
                run_bands(scf_dir, qe_setup, np_qe)

    print("\nrun.py done. Run reconstruct.py next.")


if __name__ == '__main__':
    main()