#!/usr/bin/env python3
#
# traj_flow.py --- run HYSPLIT meteorological flow field contours
#                  See HYSPLIT Tutorial Sec. 5.2
#
# Change history:
# 06 Aug 2025 (BB) - standard, cross-platform version
# 08 Aug 2025 (SZ) - add arlmap background to the plot.
#                  - change image filename to vert010.png.
# 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

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

# Detect OS and set paths
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 = ""

# Validate paths
if not PGM.exists():
    script = Path(__file__).name if "__file__" in globals() else "traj_flow.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_TOTURIAL_DIRECTORY'

For Linux users (csh or tcsh shell):
   setenv TTR 'YOUR_HYSPLIT_TOTURIAL_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
met = TTR / "captex"
dat = "captex2_gblr.bin"
offset = 48
lat, lon = 40.0, -80.0

# Verify met file exists
met_file = met / dat
if not met_file.exists():
    print(f"ERROR: Meteorological file not found: {met_file}")
    print("Please adjust the HYSPLIT Tutorial path for your system")
    sys.exit(1)

# Clean up previous outputs
for f in ["contour.html"]:
    f_path = OUT / f
    if f_path.exists():
        f_path.unlink()

# Run contour executable
arlmap = PGM / "graphics" / "arlmap"
run_cmd([
    str(PGM / "exec" / f"contour{exe_suffix}"),
    "+g1",
    f"-g{arlmap}",
    f"-d{met}{os.sep}",
    f"-f{dat}",
    f"-y{lat}",
    f"-x{lon}",
    f"-o{offset}",
    "-l4",
    "-r25.0",
    "-c1",
    "-vHGTS"
], "Running contour plot for meteorological flow fields")

# Handle output
html_file = OUT / "contour.html"
if html_file.exists():
    print("contour.html generated successfully")

    if DSP == "YES":
        webbrowser.open(str(html_file))
    else:
        convert_html_to_img(str(html_file), [("vert010.png", 1)])
else:
    print("Warning: contour.html not generated")

print("\nScript completed successfully!")