#!/usr/bin/env python3

"""A program to retrieve Presto solar storm alerts
<http://www.sidc.be/products/presto/> and transform them to gemtext
<https://gemini.circumlunar.space/>.

Run it from cron from time to time.

"""

# Standard library
import getopt
import time
import sys
import re
import os
import shutil

# Other libraries
# http://python-requests.org/
import requests

PRESTO_URL = "https://www.sidc.be/spaceweatherservices/managed/services/applications/managed/services/archive/product/presto"
SOURCE_URL = "https://forge.chapril.org/bortzmeyer/presto2gemini"

# Defaults
date = time.strftime("%Y-%m-%d", time.gmtime(time.time()))
dest_dir = "/var/gemini/presto"
raw_file_dir = dest_dir + "/raw-files"
maintainer = "Stéphane Bortzmeyer stephane+gemini@bortzmeyer.org"
verbose = False
index = True
force_index = False
input = None

def usage(msg=None):
    print("Usage: %s [--date YYYY-MM-DD] [--destination STRING] [--raw-directory] [--verbose]" % sys.argv[0], file=sys.stderr)
    if msg is not None:
        print(msg, file=sys.stderr)

def create_index(gem_dir, raw_dir):
    f = open("%s%s" % (gem_dir, "index.gmi"), "w")
    print("""# List of Presto solar storms alerts

From the alerts sent by SIDC (Solar Influences Data analysis Center).

=> http://www.sidc.be/products/presto/ SIDC Presto reference site
=> https://en.wikipedia.org/wiki/Solar_storm Wikipedia on solar storms

""", file=f)
    files = []
    for file in os.listdir(raw_dir):
        files.append(file)
    sorted_files = sorted(files, reverse=True)
    if len(sorted_files) != 0:
        fs = open("%s%s.txt" % (gem_dir, sorted_files[0]), "r")
        print("""
Last alert:

%s
""" % fs.read(), file=f)
        fs.close()
        for file in sorted(files, reverse=True):
            print("=> %s.gmi Alert of %s" % (file, file), file=f)
    print("""
## Legal and contact

### This Gemini mirror

Maintained by %s from the SIDC data.

=> %s Source code for the conversion program

### SIDC - Solar Influences Data analysis Center - RWC Belgium           

Royal Observatory of Belgium                                      
                  
=> http://www.sidc.be/ Website

E-mail          sidc-support@oma.be                               
 
=> http://www.astro.oma.be/common/internet/en/data-policy-en.pdf Intellectual Property Rights
=> http://www.astro.oma.be/common/internet/en/disclaimer-en.pdf Liability Disclaimer
=> http://www.astro.oma.be/common/internet/en/privacy-policy-en.pdf Use and processing of your personal information
""" % (maintainer, SOURCE_URL), file=f)
    f.close()

try:
    optlist, args = getopt.getopt (sys.argv[1:], "d:vi",
                                   ["date=", "help", "verbose",
                                    "force-index", "no-index",
                                    "destination=", "source=", "input="])
    for option, value in optlist:
        if option == "--help" or option == "-h":
            usage()
            sys.exit(0)
        elif option == "--date" or option == "-d":
            date = value # TODO check the syntax?
        elif option == "--destination":
            dest_dir = value
        elif option == "--destination":
            raw_dir = value
        elif option == "--source":
            raw_file_dir = value
        elif option == "--verbose" or option == "-v":
            verbose = True
        elif option == "--force-index" or option == "-i":
            force_index = True
        elif option == "--no-index":
            index = False
        elif option == "--input":
            input = value
        else:
            # Should never occur, it is trapped by getopt
            usage("Unknown option %s" % option)
except getopt.error as reason:
    usage(reason)
    sys.exit(1)
if len(args) != 0:
    usage()
    sys.exit(1)

urlpath = date.replace("-", "/")
url = "%s/%s" % (PRESTO_URL, urlpath)
if not raw_file_dir.endswith("/"):
    raw_file_dir += "/"
if not dest_dir.endswith("/"):
    dest_dir += "/"
input_ok = False
if input is None:
    r = requests.get(url, allow_redirects = False)
    if r.status_code != 200:
        print("Wrong status code %s from %s" % (r.status_code, PRESTO_URL), file=sys.stderr)
        sys.exit(1)
    if r.status_code == 200 and r.text != "" and r.text != "\r\n" and r.text != "\n": # Yes,
        # when there is no alert, they reply with 200 and an empty file :-(
        raw = open("%s%s" % (raw_file_dir, date), "w")
        print(r.text, file=raw)
        raw.close()
        input_ok = True
else:
    shutil.copyfile(input, "%s%s" % (raw_file_dir, date))
    input_ok = True
if input_ok:
    gemfile = open ("%s%s.gmi" % (dest_dir, date), "w")
    txtfile = open ("%s%s.txt" % (dest_dir, date), "w")
    raw = open("%s%s" % (raw_file_dir, date), "r")
    print("""
# Solar alert

""", file=gemfile)
    for line in raw.readlines():
        line=line[:-1] # Chop end-of-line
        if re.search("^\s*#", line):
            continue # Ignore comments
        else:
            match = re.search("^\s*:([a-zA-Z]+):\s*(.*)", line)
            if match:
                if match.group(1) == "Issued":
                    issued = match.group(2)
                    print("""
Issued on %s

""" % issued, file=gemfile)
                    print("""
Issued on %s

""" % issued, file=txtfile)
                continue # Ignore other metadata 
            else:
                print(line, file=gemfile, end=" ")
                print(line, file=txtfile, end=" ")
                if line == "":
                    print("", file=gemfile)
                    print("", file=txtfile)
    print("""

=> %s Reference for this alert
=> /presto/ All Presto solar alerts
""" % url, file=gemfile)
    raw.close()
    gemfile.close()
    txtfile.close()
    if index:
        create_index(dest_dir, raw_file_dir)
elif force_index and index:
    create_index(dest_dir, raw_file_dir)