#!/usr/bin/env python3
# encoding: utf-8

##
# This script checks all media files in the repository for whether they've been modified or added without updating the file tracking image, sound, and music copyright
##

import argparse
import contextlib
import csv
import hashlib
from operator import itemgetter
import os
from pathlib import Path
from subprocess import check_output
import sys

##
# csv file layout:
# [0] = current git commit date
# [1] = file path, relative to the repository root
# [2] = license name(s)
# [3] = authorship information
# [4] = notes
# [5] = new git commit date, if different from the value in [0]
# [6] = current md5 hash
##

##
# Add new licenses to this list:
# Avoid things like "GNU GPL v2+;CC BY-SA 4.0", unless you mean to dual license
# under either GNU GPL v2+ or CC BY-SA 4.0.  GNU GPL v2+ and CC BY-SA 4.0 (e.g.
# a GNU GPL v2+ file with CC BY-SA 4.0 modifications) isn't legally possible.
##
known_licenses = (
        "CC BY-SA 4.0",
        "CC0",
        "GNU GPL v2+",
        )

def do_git(file):
    return str(check_output(["git", "log", "-1", "--format=%ad", "--date=format:%Y/%m/%d", file]), 'UTF-8').rstrip('\n')

def do_hash(file):
    md5 = hashlib.md5()
    with open(file, 'rb') as f:
        while True:
            data = f.read(65536)
            if not data:
                break
            md5.update(data)
    return str(md5.hexdigest())

##
# program logic start
##

args = argparse.ArgumentParser()
args.add_argument("--repo", default=".", help="The directory of the Wesnoth repository to run this script against.")
args.add_argument("--output", default="copyrights.csv", help="The file to write the results of this script to.")
args.add_argument("--input", default="copyrights.csv", help="The file to read the existing copyright data from.")
options = args.parse_args()
os.chdir(options.repo)

csv_data = {}
# Too few fields
missing_fields = []
# Too many fields, possibly due to an unquoted comma
extra_fields = []
# New images
added = []
# Changed images
changed = []
# Already mentioned in the CSV file, but lacking something in either the license or author fields
incomplete = []
# Already mentioned in the CSV file, but have something in the needs update field
update = []
unchanged = []
removed = []
# Sanity-check that the input is in the same order as the output would be
csvfile_needs_sorting = False
# Sanity-check for known licenses
unknown_licenses = []

with open(options.input, encoding="utf-8") as csvfile:
    reader = csv.reader(csvfile)
    previous_file = ""
    for row in reader:
        if row[0] == "Date":
            continue

        file = row[1]
        if file < previous_file:
            csvfile_needs_sorting = True
        previous_file = file

        if not os.path.exists(file):
            removed.append(file)
            continue

        csv_data[file] = row

with contextlib.suppress(FileNotFoundError):
    os.remove(options.output)

for root, _, files in os.walk(options.repo):
    for filename in files:
        filetype = Path(filename).suffix
        if filetype == ".png" or filetype == ".jpg" or filetype == ".webp" or filetype == ".wav" or filetype == ".ogg":
            file = os.path.normpath(os.path.join(root, filename))
            hash = do_hash(file)

            if not file in csv_data:
                added.append(["", file, "", "", "", do_git(file), hash])
            elif len(csv_data[file]) < 7:
                missing_fields.append(csv_data[file])
            elif len(csv_data[file]) > 7:
                extra_fields.append(csv_data[file])
            elif csv_data[file][5] != "":
                update.append(csv_data[file])
            elif csv_data[file][6] != hash:
                csv_data[file][5] = do_git(file)
                csv_data[file][6] = hash
                changed.append(csv_data[file])
            elif csv_data[file][2].strip() == "" or csv_data[file][3].strip() == "":
                incomplete.append(csv_data[file])
            elif not csv_data[file][2] in known_licenses:
                unknown_licenses.append(csv_data[file][2])
                incomplete.append(csv_data[file])
            else:
                unchanged.append(csv_data[file])

missing_fields.sort(key=itemgetter(1))
extra_fields.sort(key=itemgetter(1))
added.sort(key=itemgetter(1))
changed.sort(key=itemgetter(1))
incomplete.sort(key=itemgetter(1))
update.sort(key=itemgetter(1))
unchanged.sort(key=itemgetter(1))

final_output = missing_fields + extra_fields + added + changed + incomplete + update + unchanged

if options.output != "":
    with open(options.output, 'w') as f:
        writer = csv.writer(f, lineterminator="\n")
        writer.writerow(["Date", "File", "License", "Author - Real Name(other name);Real Name(other name);etc", "Notes", "Needs Update", "MD5"])
        writer.writerows(final_output)
else:
    writer = csv.writer(sys.stdout, lineterminator="\n")
    writer.writerows(final_output)

any_check_failed = False
if len(removed) > 0:
    any_check_failed = True
    print("There are "+str(len(removed))+" removed images")

if len(missing_fields) > 0 or len(extra_fields) > 0 or len(added) > 0 or len(changed) > 0 or len(incomplete) > 0 or len(update) > 0:
    any_check_failed = True
    print("There are "+str(len(missing_fields))+" rows with too few fields")
    print("There are "+str(len(extra_fields))+" rows with too many fields, possibly due to an unquoted comma")
    print("There are "+str(len(added))+" new images")
    print("There are "+str(len(changed))+" changed images")
    print("There are "+str(len(incomplete))+" images that lack license or author information")
    print("There are "+str(len(update))+" images that need updated information")
    if options.output != "":
        print("These are at the top of the output for easy editing, run the tool again after editing to sort the file")

if csvfile_needs_sorting:
    print("The input file isn’t sorted by filename")

    if options.output != "" and final_output == unchanged:
        print("The new output file is correctly sorted")

if len(unknown_licenses) > 0:
    any_check_failed = True
    print("Unknown licenses:")
    print("    " + "\n    ".join(unknown_licenses))

if any_check_failed:
    sys.exit(1)