#!/bin/env python3

# This is a script to update checksums for sources in lure build scripts
# This is a crude analog for updpkgsums for PKGBUILD files
# The script assumed that matching sources* and checksums* lines are already there

import os
import re
import subprocess
import time

# Check if the build script exists
if not os.path.isfile('lure.sh'):
    print("Couldn't find a lure.sh file in the current directory.")
    exit(1)

with open('lure.sh', 'r') as script_file:
    script = script_file.readlines()

vars = {}
for line in script:
    if '=' not in line or '\t' in line:
        continue
    var, val = line.strip('\n').split('=')
    vars[var] = val.strip('""').strip("''")

for src_type in [k for k in vars.keys() if "sources" in k]:
    suffix = src_type.split('_')[1]
    if suffix != "":
        suffix = "_"+suffix

    # Read all the links
    links = [link.strip('""').strip("''")
             for link in vars[src_type].strip('()').split()]

    # Get the old sums
    old_sums = vars["checksums"+suffix].strip('()').split()
    old_sums = [sum.strip('""').strip("''") for sum in old_sums]

    checksums = []
    for i, link in enumerate(links):
        if old_sums[i] == 'SKIP':
            checksums.append('SKIP')
            continue
        # Try to do variable expansions (works up to one level, should be enough)
        to_replace = list(set(re.findall('(\${.+?})', link)))
        for str in to_replace:
            str_clean = str.strip('${}')
            link = link.replace(str, vars[str_clean])

        filename = subprocess.run(
            ['curl', '-sLO', '-w', '%{filename_effective}', link], stdout=subprocess.PIPE)
        filename = filename.stdout.decode('utf-8')

        checksum = subprocess.run(
            ['sha256sum', filename], stdout=subprocess.PIPE)
        checksum = checksum.stdout.decode('utf-8').split()[0]
        checksums.append(checksum)

    # Build the output line
    sum_out = "checksums"+suffix+"=('"+"' '".join(checksums)+"')\n"
    for i, line in enumerate(script):
        if "checksums"+suffix in line:
            script[i] = sum_out
            print("Updated checksums for "+suffix[1:]+" sources")

timestamp = "{}".format(int(time.time()))

with open(timestamp, 'w') as tempfile:
    tempfile.writelines(script)

os.rename('lure.sh', "lure-"+timestamp+".sh")
os.rename(timestamp, 'lure.sh')

print("Done!")