#!/usr/bin/env python3
#
# src_coef.py --- Solving the Coefficient Matrix
#                 See HYSPLIT Tutorial Sec. 13.6
#
# Change history:
# 18 Oct 2025 (BB) - standard-aligned, cross-platform version
# 12 Feb 2026 (SZ) - minor edits for style consistency
# 18 Jun 2026 (SZ) - standardize code for run_cmd(), convert_html_to_img(),
#                    etc. across Python scripts
#                  - ensure encoding is specified when opening files

import os
import sys
import platform
from pathlib import Path
import subprocess

if sys.version_info < (3, 8):
    print("Please use Python 3.8 or higher.")
    sys.exit(1)

system = platform.system().lower()
if system == "windows":
    PGM = Path(sys.argv[1]) if len(sys.argv) > 1 else Path("C:\\hysplit")
    OUT = Path(sys.argv[2]) if len(sys.argv) > 2 else PGM / "working"
    DSP = sys.argv[3] if len(sys.argv) > 3 else "YES"
    TTR = Path(os.environ.get("TTR", "C:\\Tutorial"))
    exe_suffix = ".exe"
else:
    PGM = Path(sys.argv[1]) if len(sys.argv) > 1 else Path.home() / "hysplit"
    OUT = Path(sys.argv[2]) if len(sys.argv) > 2 else PGM / "working"
    DSP = sys.argv[3] if len(sys.argv) > 3 else "YES"
    TTR = Path(os.environ.get("TTR", Path.home() / "tutorial"))
    exe_suffix = ""

if not PGM.exists():
    script = Path(__file__).name if "__file__" in globals() else "src_coef.py"
    print(f"ERROR: HYSPLIT not found at {PGM}")
    print(f"""
Please specify the path to your HYSPLIT installation using a command-line argument:

python {script} YOUR_HYSPLIT_DIRECTORY [OUT] [DSP (YES|NO)]

Example:
    python {script} C:\\hysplit C:\\hysplit\\working YES
""")
    sys.exit(1)

if not TTR.exists():
    print(f"ERROR: HYSPLIT tutorial not found at {TTR}")
    print("""
Please set the TTR environment variable to point to your HYSPLIT tutorial directory.

For Windows users (Command Prompt):
   SET TTR=YOUR_HYSPLIT_TUTORIAL_DIRECTORY

For Linux users (bash shell):
   export TTR='YOUR_HYSPLIT_TUTORIAL_DIRECTORY'

For Linux users (csh or tcsh shell):
   setenv TTR 'YOUR_HYSPLIT_TUTORIAL_DIRECTORY'""")
    sys.exit(1)

os.chdir(OUT)

# ------------------------------------------------------------------
# Helper function
# ------------------------------------------------------------------

def run_cmd(cmd, desc="", allow_fail=False, stdout_file=None, append=False):
    if desc:
        print(f"{desc}...")

    exitcode = 0
    with subprocess.Popen(cmd,
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT,
                         text=True) as p:
        if stdout_file:
            mode="a" if append else "w"
            with open(stdout_file, mode, encoding="utf-8") as f_out:
                for ln in p.stdout:
                    print(ln, end="")
                    f_out.write(ln)
        else:
            with p.stdout as f:
                for ln in iter(f.readline, b'\n'):
                    if len(ln) == 0:
                        break
                    print(ln.rstrip())

        done = False
        while not done:
            try:
                exitcode = p.wait(timeout=1)
                done = True
            except subprocess.TimeoutExpired:
                print("WARN: subprocess timed out.")

    if exitcode != 0:
        if allow_fail:
            print(f"WARN: command failed with exit code {exitcode} -> {' '.join(cmd)}")
        else:
            print(f"ERROR: command failed with exit code {exitcode} -> {' '.join(cmd)}")
            sys.exit(1)


# -------------------------------------------------------------------
# constants
# -------------------------------------------------------------------
wrk = TTR
met_dir = wrk / "captex"
met_file = "RP198309.gbl"

lat = 43.0
lon = -75.0
lvl = 10.0
top = 10000.0

# -------------------------------------------------------------------
# ASCDATA.CFG
# -------------------------------------------------------------------
with open("ASCDATA.CFG", "w", encoding="ascii") as f:
    f.write(
        "-90.0   -180.0\n"
        "1.0     1.0\n"
        "180     360\n"
        "2\n"
        "0.2\n"
        f"'{PGM / 'bdyfiles'}{os.sep}'  directory of files\n"
    )

# -------------------------------------------------------------------
# SETUP.CFG
# -------------------------------------------------------------------
with open("SETUP.CFG", "w", encoding="ascii") as f:
    f.write("&SETUP\n")
    f.write(" numpar = 10000,\n")
    f.write(" maxpar = 20000,\n")
    f.write("/\n")

# -------------------------------------------------------------------
# remove old INFILE
# -------------------------------------------------------------------
Path("INFILE").unlink(missing_ok=True)

# -------------------------------------------------------------------
# build coefficient matrix runs
# -------------------------------------------------------------------
run_hours = 72

for day in ("01", "02", "03"):
    for hour in ("00", "12"):

        run_hours -= 12

        tag = f"tcm09{day}{hour}"

        with open("CONTROL", "w", encoding="ascii") as f:
            f.write(f"83 09 {day} {hour}\n")
            f.write("1\n")
            f.write(f"{lat} {lon} {lvl}\n")
            f.write(f"{run_hours}\n")
            f.write("0\n")
            f.write(f"{top}\n")
            f.write("1\n")
            f.write(f"{met_dir}{os.sep}\n")
            f.write(f"{met_file}\n")
            f.write("1\n")
            f.write("PMCH\n")
            f.write("1.0\n")
            f.write("12.0\n")
            f.write("00 00 00 00 00\n")
            f.write("1\n")
            f.write("41.0 -73.0\n")
            f.write("0.10 0.10\n")
            f.write("15.0 25.0\n")
            f.write(f".{os.sep}\n")
            f.write(f"{tag}\n")
            f.write("1\n")
            f.write("100\n")
            f.write("83 09 01 00 00\n")
            f.write("83 09 03 12 00\n")
            f.write("00 03 00\n")
            f.write("1\n")
            f.write("0.0 0.0 0.0\n")
            f.write("0.0 0.0 0.0 0.0 0.0\n")
            f.write("0.0 0.0 0.0\n")
            f.write("0.0\n")
            f.write("0.0\n")

        Path(tag).unlink(missing_ok=True)

        if run_hours >= 12:
            run_cmd([str(PGM / "exec" / f"hycs_std{exe_suffix}")])
            with open("INFILE", "a", encoding="ascii") as f:
                f.write(f"{tag}\n")

# -------------------------------------------------------------------
# coefficient array
# -------------------------------------------------------------------
Path("c2array.txt").unlink(missing_ok=True)

run_cmd([
    str(PGM / "exec" / f"c2array{exe_suffix}"),
    "-c1.0E+12",
    "-iINFILE",
    f"-m{met_dir}{os.sep}hypo_meas.txt",
    "-oc2array.csv"
])

with open("c2array.csv", "r", encoding="ascii", errors="ignore") as f:
    print(f.read())
if DSP.upper() == "YES":
    input("Press Enter to continue...")

# -------------------------------------------------------------------
# solve coefficient matrix
# -------------------------------------------------------------------
run_cmd([
    str(PGM / "exec" / f"tcsolve{exe_suffix}"),
    "-ic2array.csv",
    "-otcsolve.dat",
    "-z0.0"
])

with open("tcsolve.dat", "r", encoding="ascii", errors="ignore") as f:
    print(f.read())