#!/usr/bin/env python3
#
# traj_ensem.py --- Meteorological Grid Ensemble
#                   See HYSPLIT Tutorial Sec. 5.6
#
# Change history:
# 07 Aug 2025 (BB) - standard-aligned, cross-platform version
# 21 Aug 2025 (SZ) - add a pause between plots when DSP is set to "YES."
#                  - change image filenames.
#                  - use backward slash as directory separator for Windows PC.
# 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
import webbrowser

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 "traj_ensem.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 functions
# ------------------------------------------------------------------

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)


def convert_html_to_img(html_file, img_name_frame_nums):
    # Split SVG into Linux-consistent naming: F00-sec71_001.svg, etc.
    temp_img_name = "temp"
    run_cmd([str(PGM / "exec" / f"splitsvg{exe_suffix}"),
             f"-i{html_file}", f"-o{temp_img_name}.svg"])

    # Locate ImageMagick for cross-platform conversion
    if system == "windows":
        convert_exe = None
        imgk_dir = next(
            (k for k in os.environ.get('PATH', '').split(os.pathsep)
             if "ImageMagick" in k),
            None
        )
        if imgk_dir:
            # Use magick.exe for ImageMagick 7.x and later. Use convert.exe for earlier versions.
            for cmd in ('magick', 'convert'):
                candidate = os.path.join(imgk_dir, f'{cmd}{exe_suffix}')
                if os.path.exists(candidate):
                    convert_exe = candidate
                    break
    else:
        convert_exe = "convert"

    if convert_exe:
        # Match Linux naming for DSP=NO mode exactly
        for img_name, frame_num in img_name_frame_nums:
            svg = Path(f"F{frame_num:02d}-{temp_img_name}.svg")
            run_cmd([convert_exe, str(svg), img_name])
            print(f"Converted {svg} -> {img_name}")
            svg.unlink()
    else:
        print("ImageMagick not found — skipping .svg conversion")


# Parameters
syr, smo = 83, 9
sda_f, shr_f = 25, 17
sda_b, shr_b = 28, 13
lat_f, lon_f, lvl_f = 39.90, -84.22, 600.0
lat_b, lon_b, lvl_b = 38.665, -71.369, 216.4
run_f, run_b = 68, -68
top = 10000.0
met = TTR / "captex"
dat = "captex2_wrf27uw.bin"

# Cleanup
for f in ["ASCDATA.CFG", "SETUP.CFG", "CONTROL", "LABELS.CFG",
          "tdump_fwrd", "tdump_back", "trajplot.html"]:
    path = OUT / f
    if path.exists():
        path.unlink()

# Write ASCDATA.CFG
ascdata = OUT / "ASCDATA.CFG"
with ascdata.open("w", encoding="ascii") as f:
    f.write("-90.0   -180.0  lat/lon of lower left corner\n")
    f.write("1.0     1.0     lat/lon spacing in degrees\n")
    f.write("180     360     lat/lon number of data points\n")
    f.write("2               default land use category\n")
    f.write("0.2             default roughness length (m)\n")
    f.write(f"'{PGM / 'bdyfiles'}{os.sep}'  directory of files\n")


def write_control(syr, smo, sda, shr, lat, lon, lvl, run, out_name):
    ctl = OUT / "CONTROL"
    with ctl.open("w", encoding="ascii") as f:
        f.write(f"{syr} {smo} {sda} {shr}\n")
        f.write("1\n")
        f.write(f"{lat} {lon} {lvl}\n")
        f.write(f"{run}\n")
        f.write("0\n")
        f.write(f"{top}\n")
        f.write("1\n")
        f.write(f"{met}{os.sep}\n")
        f.write(f"{dat}\n")
        f.write(f".{os.sep}\n")
        f.write(f"{out_name}\n")


def write_setup():
    setup = OUT / "SETUP.CFG"
    with setup.open("w", encoding="ascii") as f:
        f.write("&SETUP\n")
        f.write("dxf = 1.00,\n")
        f.write("dyf = 1.00,\n")
        f.write("dzf = 0.01,\n")
        f.write("/\n")


def plot_traj(tdump_file, label_desc, img_name):
    (OUT / "LABELS.CFG").write_text(f"'TITLE&','### traj_ensem.py: {label_desc} ### &'\n",
                                    encoding="ascii")
    run_cmd([str(PGM / "exec" / f"trajplot{exe_suffix}"),
             "+g1", f"-i{tdump_file}", "-v0", "-z80", f"-j{PGM / 'graphics' / 'arlmap'}"],
            f"Plotting {label_desc} trajectory")

    html_file = OUT / "trajplot.html"
    if html_file.exists():
        if DSP == "YES":  # Show plot in the browser
            webbrowser.open(html_file.resolve().as_uri())
        else:  # If DSP is "NO", convert to PNG
            convert_html_to_img(str(html_file), [(img_name, 1)])
    else:
        print("Warning: trajplot.html not generated")


# === Forward trajectory ensemble ===
write_control(syr, smo, sda_f, shr_f, lat_f, lon_f, lvl_f, run_f, "tdump_fwrd")
write_setup()
run_cmd([str(PGM / "exec" / f"hyts_ens{exe_suffix}")], "Running ensemble forward trajectory")
plot_traj("tdump_fwrd", "fwrd", "tensem003.png")
if DSP == "YES":
    input("Enter to continue ...")

# === Backward trajectory ensemble ===
write_control(syr, smo, sda_b, shr_b, lat_b, lon_b, lvl_b, run_b, "tdump_back")
write_setup()
run_cmd([str(PGM / "exec" / f"hyts_ens{exe_suffix}")], "Running ensemble backward trajectory")
plot_traj("tdump_back", "back", "tensem004.png")

print("\nScript completed successfully!")