#!/usr/bin/env nix-shell
#! nix-shell -p python3 -i python

# based off of https://git.sr.ht/~sircmpwn/dotfiles/tree/master/item/bin/semver

import os
import subprocess
import sys
import tempfile

if subprocess.run(["git", "branch", "--show-current"], stdout=subprocess.PIPE
        ).stdout.decode().strip() != "main":
    print("WARNING! Not on the main branch.")

subprocess.run(["git", "pull", "--rebase"])
p = subprocess.run(["git", "describe", "--abbrev=0"], stdout=subprocess.PIPE)
describe = p.stdout.decode().strip()
old_version = describe.split("-")[0].split(".")
if len(old_version) == 2:
    [major, minor] = old_version
    [major, minor] = map(int, [major, minor])
    patch = 0
else:
    [major, minor, patch] = old_version
    [major, minor, patch] = map(int, [major, minor, patch])

p = subprocess.run(["git", "shortlog", "--no-merges", f"{describe}..HEAD"],
        stdout=subprocess.PIPE)
shortlog = p.stdout.decode()

new_version = None

if sys.argv[1] == "patch":
    patch += 1
elif sys.argv[1] == "minor":
    minor += 1
    patch = 0
elif sys.argv[1] == "major":
    major += 1
    minor = patch = 0
else:
    new_version = sys.argv[1]

if new_version is None:
    if len(old_version) == 2 and patch == 0:
        new_version = f"{major}.{minor}"
    else:
        new_version = f"{major}.{minor}.{patch}"

p = None
if os.path.exists("contrib/_incr_version"):
    p = subprocess.run(["contrib/_incr_version", describe, new_version])
else:
    print("Warning: no _incr_version script. " +
        "Does this project have any specific release requirements?")

if p and p.returncode != 0:
    print("Error: _incr_version returned nonzero exit code")
    sys.exit(1)

with tempfile.NamedTemporaryFile() as f:
    basename = os.path.basename(os.getcwd())
    f.write(f"{basename} {new_version}\n\n".encode())
    f.write(shortlog.encode())
    f.flush()
    subprocess.run(["git", "tag", "-e", "-F", f.name, "-a", new_version])
    print(new_version)