#!/usr/bin/env python3
#
# traj_isob.py --- forward and backward trajectory with final position chaining
#                  See HYSPLIT Tutorial Sec. 5.3
#
# Change history:
# 06 Aug 2025 (BB) - standard-aligned, cross-platform version
# 08 Aug 2025 (SZ) - display all three plots sequentially with a pause between
#                    each, or generate three image files without displaying
#                    the plots if DSP is set to "NO".
# 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_isob.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
syr, smo, sda, shr = 83, 9, 1, 0
lat, lon, lvl = 45.0, -125.0, 750.0
run, top = 72, 10000.0
met = TTR / "captex"
dat = "RP198309.gbl"

# Clean up
for f in ["ASCDATA.CFG", "SETUP.CFG", "CONTROL", "LABELS.CFG",
          "fdump", "bdump", "trajplot.html"]:
    file = OUT / f
    if file.exists():
        file.unlink()

# Create 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")

# SETUP.CFG (terrain map mode)
(OUT / "SETUP.CFG").write_text("&SETUP\ntm_terr=1,\n/\n", encoding="ascii")


def write_control(year, month, day, hour, lat, lon, lvl, run_hours, output):
    ctl = OUT / "CONTROL"
    with ctl.open("w", encoding="ascii") as f:
        f.write(f"{year} {month} {day} {hour}\n")
        f.write("1\n")
        f.write(f"{lat} {lon} {lvl}\n")
        f.write(f"{run_hours}\n")
        f.write("1\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"{output}\n")
    print(f"\nCONTROL file preview ({output}):")
    print(ctl.read_text(encoding="ascii"))


def read_final_position(tdump_file):
    try:
        with open(tdump_file, "r", encoding="ascii") as f:
            lines = f.readlines()
            for line in reversed(lines):
                tokens = line.strip().split()
                if len(tokens) >= 12:
                    return float(tokens[9]), float(tokens[10]), float(tokens[11])
    except Exception as e:
        print(f"ERROR reading {tdump_file}: {e}")
        sys.exit(1)
    print("ERROR: Could not extract final position")
    sys.exit(1)


# === FORWARD TRAJECTORY ===
write_control(syr, smo, sda, shr, lat, lon, lvl, run, "fdump")
run_cmd([str(PGM / "exec" / f"hyts_std{exe_suffix}")], "Running forward trajectory")

(OUT / "LABELS.CFG").write_text("'TITLE&','### traj_isob.py: forward ### &'\n",
                                encoding="ascii")
run_cmd([
    str(PGM / "exec" / f"trajplot{exe_suffix}"),
    "+g1", "-ifdump", "-v1", "-z80",
    f"-j{PGM / 'graphics' / 'arlmap'}"
], "Plotting forward trajectory")

html_file = OUT / "trajplot.html"
if html_file.exists():
    if DSP == "YES":
        webbrowser.open(str(html_file.resolve()))
    else:
        convert_html_to_img(str(html_file), [("tisob004.png",1)])
else:
    print("Warning: trajplot.html not generated")

if DSP == "YES":
    input("Press Enter to continue...")

# === BACKWARD TRAJECTORY ===
final_lat, final_lon, final_lvl = read_final_position("fdump")
sda, shr = 4, 0
write_control(syr, smo, sda, shr, final_lat, final_lon, final_lvl, -run, "bdump")
run_cmd([str(PGM / "exec" / f"hyts_std{exe_suffix}")], "Running backward trajectory")

(OUT / "LABELS.CFG").write_text("'TITLE&','### traj_isob.py: backward ### &'\n",
                                encoding="ascii")
run_cmd([
    str(PGM / "exec" / f"trajplot{exe_suffix}"),
    "+g1", "-ibdump", "-v1", "-z80",
    f"-j{PGM / 'graphics' / 'arlmap'}"
], "Plotting backward trajectory")

html_file = OUT / "trajplot.html"
if html_file.exists():
    if DSP == "YES":
        webbrowser.open(str(html_file.resolve()))
    else:
        convert_html_to_img(str(html_file), [("tisob007.png",1)])
else:
    print("Warning: trajplot.html not generated")

if DSP == "YES":
    input("Press Enter to continue...")

# === COMBINED PLOT ===
(OUT / "LABELS.CFG").write_text("'TITLE&','### traj_isob.py: combined ### &'\n",
                                encoding="ascii")
run_cmd([
    str(PGM / "exec" / f"trajplot{exe_suffix}"),
    "+g1", "-ifdump+bdump", "-v1", "-z80",
    f"-j{PGM / 'graphics' / 'arlmap'}"
], "Plotting combined trajectory")

html_file = OUT / "trajplot.html"
if html_file.exists():
    if DSP == "YES":
        webbrowser.open(str(html_file.resolve()))
    else:
        convert_html_to_img(str(html_file), [("tisob008.png",1)])
else:
    print("Warning: trajplot.html not generated")

print("\nScript completed successfully!")