#!/usr/bin/env python
"""
parse_ml_data.py — Inject ML EPC brakets into EPW for HPRO/DeepH-E3 comparison.

For a given ML source (fd, hpro, e3):
  1. If source != 'fd': run julia run_hpro_brakets_epw.jl <source>
     (generates displacements/epw/braket_list_rotated_* from ao_brackets npz)
  2. Restore original DFPT EPB: diamond_dft.save/diamond.epb1 → tmp/diamond.epb1
  3. Inject ML brakets from displacements/epw/ into tmp/diamond.epb1
  4. Patch NSCF eigenvalues in diamond.save/ from Julia's scf_0 save

Usage:
  python parse_ml_data.py [--source {fd,hpro,e3}]
  python parse_ml_data.py --source hpro
  python parse_ml_data.py --source e3

Then run EPW2:
  mpirun -n 1 epw.x -npool 1 -in epw2.in > epw2_<source>.out
And compare:
  python $ELEPHANY_PATH/epw/compare_epw.py ./
"""
import argparse
import os
import re
import shutil
import subprocess
import xml.etree.ElementTree as ET

import numpy as np
from scipy.io import FortranFile
from ase.io import read as ase_read

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


def _determine_q_point_cart(nscf_out, iq):
    """Extract Cartesian k-point iq (1-based) from nscf.out."""
    count = 0
    with open(nscf_out) as f:
        for line in f:
            if "        k(" in line:
                count += 1
                if count == iq:
                    parts = line.split()
                    coords = [p.rstrip(',)') for p in parts[4:7]]
                    return [float(c) for c in coords]
    return [0.0, 0.0, 0.0]


def inject_brakets(path_to_epw, path_to_frozen, nbnd, nbndep, nks, nqs, nat, epb_name):
    """Inject FD/HPRO/E3 brakets from displacements/epw/ into the EPB binary."""
    nmodes = 3 * nat

    dtypes = [
        '<i',                                               # nqc
        np.dtype(('<d', (nqs, 3))),                        # xqc
        np.dtype(('<d', (nks, nbnd))),                     # et_loc
        np.dtype(('<c16', (nqs, nmodes, nmodes))),          # dynq
        np.dtype(('<c16', (nqs, nmodes, nks, nbnd, nbnd))), # epmatq
        np.dtype(('<d', (3, 3, nat))),                      # zstar
        np.dtype(('<d', (3, 3))),                           # epsi
    ]

    epb_path = os.path.join(path_to_epw, epb_name)
    with FortranFile(epb_path, 'r') as f:
        epb_data = list(f.read_record(*dtypes))
    xqc = epb_data[1]

    # Determine q-point ordering: match EPB xqc vs nscf.out
    nscf_out = os.path.join(path_to_epw, "nscf.out")
    atoms = ase_read(os.path.join(path_to_epw, "scf.out"))
    recip_T = atoms.cell.reciprocal().T
    a_factor = 2 * abs(recip_T[0, 0]) * atoms.get_cell_lengths_and_angles()[0]
    real_mat = np.linalg.inv(recip_T) / a_factor

    q_nscf = [_determine_q_point_cart(nscf_out, iq + 1) for iq in range(nqs)]
    iq_ph_list = []
    for q_ph in xqc:
        for i_nscf, q_ns in enumerate(q_nscf):
            dq = np.abs(real_mat @ q_ns - real_mat @ q_ph)
            if all(np.isclose(d, 0, atol=1e-5) or np.isclose(d, 1, atol=1e-5) for d in dq):
                iq_ph_list.append(i_nscf)
                break

    # Read braket files and fill g_frozen
    epw_dir = os.path.join(path_to_frozen, "epw")
    g_frozen = np.zeros((nbnd, nbnd, nks, nmodes, nqs), dtype=complex)
    for ik in range(1, nks + 1):
        for iq_ph, iq_nscf in enumerate(iq_ph_list):
            bfile = os.path.join(epw_dir, f"braket_list_rotated_{ik}_{iq_nscf + 1}")
            data = np.loadtxt(bfile)
            for line in data:
                iat    = int(line[0])
                i_cart = int(line[1])
                im     = 3 * (iat - 1) + i_cart
                i      = int(line[3])
                j      = int(line[2])
                if 1 <= i <= nbndep and 1 <= j <= nbndep:
                    g_frozen[i - 1, j - 1, ik - 1, im - 1, iq_ph] = line[4] - 1j * line[5]

    epb_data[4] = g_frozen.T
    with FortranFile(epb_path, 'w') as f:
        f.write_record(*epb_data)
    print(f"  Brakets injected into {epb_path}")


def patch_eigenvalues(path_to_kcw, path_to_save, path_to_out, nks):
    """Replace eigenvalues in NSCF save XML with Julia SCF eigenvalues; copy wfc files."""
    path_kp  = os.path.join(path_to_kcw,  "data-file-schema.xml")
    path_qe  = os.path.join(path_to_save, "data-file-schema.xml")
    path_out = os.path.join(path_to_out,  "data-file-schema.xml")

    with open(path_qe) as f:
        lines_qe = f.readlines()
    header = lines_qe[:3]
    footer = lines_qe[-1]

    tree_kp = ET.parse(path_kp)
    tree_qe = ET.parse(path_qe)

    kp_energies = []
    for ks in tree_kp.iter('ks_energies'):
        vals = re.findall(r"[-+]?[0-9]*\.?[0-9]+(?:[eE][-+]?[0-9]+)?", ks[2].text)
        kp_energies.append(vals)

    for idx, ks in enumerate(tree_qe.iter('ks_energies')):
        raw = ks[2].text
        qe_vals = re.findall(r"[-+]?[0-9]*\.?[0-9]+(?:[eE][-+]?[0-9]+)?", raw)
        for i, (old, new) in enumerate(zip(qe_vals, kp_energies[idx])):
            raw = raw.replace(old, new, 1)
        ks[2].text = raw

    tree_qe.write(path_out, encoding='UTF-8', xml_declaration=True, short_empty_elements=False)

    with open(path_out) as f:
        out_lines = f.readlines()
    out_lines[:3] = header
    out_lines[-1]  = footer
    with open(path_out, 'w') as f:
        f.writelines(out_lines)

    # Copy wfc files and charge density
    for i in range(nks):
        src  = os.path.join(path_to_kcw, f"wfc{i + 1}.dat")
        dest = os.path.join(path_to_out,  f"wfc{i + 1}.dat")
        shutil.copy2(src, dest)
    shutil.copy2(os.path.join(path_to_kcw, "charge-density.dat"), path_to_out)
    print(f"  Eigenvalues patched and {nks} wfc files copied to {path_to_out}")


def main():
    parser = argparse.ArgumentParser(
        description="Inject ML EPC brakets into EPW binary for HPRO/E3 comparison."
    )
    parser.add_argument("--source", choices=["fd", "hpro", "e3"], default="fd",
                        help="Braket source: fd (FD from diamond.jl), hpro, or e3")
    parser.add_argument("--path_to_epw", default=SCRIPT_DIR + "/",
                        help="Path to 4_epw directory (default: script dir)")
    parser.add_argument("--path_to_frozen", default=None,
                        help="Path to displacements/ dir (default: <path_to_epw>/displacements/)")
    parser.add_argument("--nbnd",    default=4,   type=int, help="Number of Wannier bands")
    parser.add_argument("--nbndep",  default=4,   type=int, help="Number of EP bands")
    parser.add_argument("--mesh",    default=216, type=int, help="Number of k-points")
    parser.add_argument("--mesh_q",  default=1,   type=int, help="Number of q-points")
    parser.add_argument("--nat",     default=2,   type=int, help="Number of atoms")
    parser.add_argument("--epb",     default="tmp/diamond.epb1", help="EPB file (relative to path_to_epw)")
    args = parser.parse_args()

    path_to_epw    = args.path_to_epw
    path_to_frozen = args.path_to_frozen or os.path.join(path_to_epw, "displacements") + "/"

    # Step 1: Generate HPRO/E3 braket files via Julia
    if args.source != "fd":
        print(f"Step 1: Generating {args.source.upper()} braket files via Julia...")
        jl_script = os.path.join(SCRIPT_DIR, "run_hpro_brakets_epw.jl")
        subprocess.run(["julia", jl_script, args.source], cwd=SCRIPT_DIR, check=True)
        print("Step 1 done.")
    else:
        print("Step 1: Using FD braket files (displacements/epw/ from diamond.jl calc_ep)")

    # Step 2: Restore original DFPT EPB
    print("Step 2: Restoring DFPT EPB backup...")
    epb_backup = os.path.join(path_to_epw, "diamond_dft.save", "diamond.epb1")
    epb_target = os.path.join(path_to_epw, args.epb)
    os.makedirs(os.path.dirname(epb_target), exist_ok=True)
    shutil.copy2(epb_backup, epb_target)
    print(f"  {epb_backup} → {epb_target}")

    # Step 3: Inject brakets into EPB
    print("Step 3: Injecting brakets into EPB binary...")
    inject_brakets(
        path_to_epw, path_to_frozen,
        args.nbnd, args.nbndep, args.mesh, args.mesh_q, args.nat, args.epb,
    )
    print("Step 3 done.")

    # Step 4: Patch NSCF eigenvalues from Julia SCF
    print("Step 4: Patching NSCF eigenvalues...")
    path_to_kcw  = os.path.join(path_to_frozen, "scf_0", "tmp", "scf.save") + "/"
    path_to_save = os.path.join(path_to_epw, "diamond_dft.save") + "/"
    path_to_out  = os.path.join(path_to_epw, "tmp", "diamond.save") + "/"
    patch_eigenvalues(path_to_kcw, path_to_save, path_to_out, nks=args.mesh)
    print("Step 4 done.")

    print(f"\nAll done. Now run:")
    print(f"  mpirun -n 1 epw.x -npool 1 -in epw2.in > epw2_{args.source}.out")
    print(f"  python $ELEPHANY_PATH/epw/compare_epw.py ./")


if __name__ == "__main__":
    main()