#!/bin/bash
# claude-pull [--account NAME] [DIR]: written by Wren Linux extras/claude-vm.sh
# Brings Claude's work from the claude-vm VM into your copy of a repository
# (default: the one you're in), after showing you what it changes. Nothing
# comes in unless you say yes, and only on top of what you have.
# Claude commits to the branch "claude" in the VM's ~/projects/FOLDER, where
# FOLDER is the name of this copy's folder. That branch comes over the VM's own
# ssh login as a git bundle (claude-vm bundle): no git host in between, and the
# VM has no way to write anywhere of yours. git checks the bundle and every
# object in it; what it holds stays in refs/claude-vm/claude until you say yes.
# --account NAME: that account's VM.
# DIR: the copy to bring it into (default: the one you're in).
# -h, --help: this text.
set -euo pipefail

MAX_MB=${WREN_PULL_MAX_MB:-500}   # a whole repository's bundle; more is not one (the test sets less)
[[ $MAX_MB =~ ^[0-9]+$ ]] || { echo "claude-pull: WREN_PULL_MAX_MB is a number of MB." >&2; exit 1; }
die() { printf 'claude-pull: %s\n' "$*" >&2; exit 1; }
# Text from the VM, without control characters (an escape sequence could steer
# your terminal), the 8-bit ones in their UTF-8 form too
printable() { LC_ALL=C sed 's/\xc2[\x80-\x9f]//g' | LC_ALL=C tr -d '\000-\010\013-\037\177'; }

case ${1:-} in
    -h | --help) sed -n '2,/^set -euo/{ /^set -euo/d; s/^# \{0,1\}//; p }' "$0"; exit 0 ;;
esac
account=
if [ "${1:-}" = --account ]; then
    [ $# -ge 2 ] || die "--account needs a name"
    account=$2
    shift 2
fi
# (an option isn't a folder: given to cd, --help was cd's own help)
case ${1:-} in -*) die "usage: claude-pull [--account NAME] [DIR]   (claude-pull --help says more)" ;; esac
[ $# -le 1 ] || die "one folder at a time: claude-pull [--account NAME] [DIR]"
cd -- "${1:-.}"
git rev-parse --is-inside-work-tree >/dev/null 2>&1 || die "$PWD is not a git repository."
# A hooks folder that came in with the pull would run as you
[ -z "$(git config core.hooksPath)" ] || die "core.hooksPath is set here; remove it first: git config --unset core.hooksPath"
name=$(basename -- "$(git rev-parse --show-toplevel)")
# Changes of yours not committed: git wouldn't bring anything in over them, so
# this says so first, before asking the VM or you anything
changed=$(git status --porcelain --untracked-files=no | printable)
if [ -n "$changed" ]; then
    printf 'claude-pull: these have changes that aren'"'"'t committed:\n%s\n' "$changed" >&2
    die "Look at them: git diff. Keep them: commit them. Not wanted: git checkout -- FILE. Nothing changed."
fi
command -v claude-vm >/dev/null || die "claude-vm isn't installed: wrenctl install claude-vm"

tmp=$(mktemp -d)
trap 'rm -rf "$tmp"' EXIT
echo "Asking the VM${account:+ $account} for its branch claude in ~/projects/$name..."
rc=0
claude-vm ${account:+--account "$account"} bundle "$name" 2> >(printable >&2) |
    head -c $((MAX_MB * 1024 * 1024 + 1)) >"$tmp/claude.bundle" || rc=$?
[ "$(stat -c %s "$tmp/claude.bundle")" -le $((MAX_MB * 1024 * 1024)) ] ||
    die "the VM sent more than $MAX_MB MB, which is no bundle of a repository. Nothing changed."
[ "$rc" -eq 0 ] ||
    die "the VM didn't send its branch claude (is there one in ~/projects/$name?). Nothing changed."
git bundle verify "$tmp/claude.bundle" >/dev/null 2>&1 ||
    die "what the VM sent isn't a git bundle git accepts. Nothing changed."
git -c fetch.fsckObjects=true -c transfer.fsckObjects=true fetch --quiet --no-tags \
    "$tmp/claude.bundle" "+refs/heads/claude:refs/claude-vm/claude" ||
    die "git didn't accept what the VM sent. Nothing changed."
from=refs/claude-vm/claude

if [ -z "$(git rev-list "HEAD..$from")" ]; then
    echo "Up to date: nothing new from the VM."
    exit 0
fi
# Only on top of what you have, as it is now: said before the long list, with
# the commit Claude starts again from (git fetch, then a rebase onto it)
git merge-base --is-ancestor HEAD "$from" ||
    die "Not brought in: Claude's branch isn't on top of what you have. Tell Claude to start again from your $(git rev-parse --short=9 HEAD). Nothing changed."
git --no-pager log --stat --format='%n%h %s%n%b' "HEAD..$from" | printable
echo
echo "From the VM's branch claude. Every changed line: git diff HEAD...$from"
read -rp "Bring these in? [y/N] " answer
case $answer in
    [yY]*) git merge --ff-only "$from" ||
        die "Not brought in: it isn't on top of what you have. Ask Claude to start again from your branch as it is now." ;;
    *) echo "Nothing changed." ;;
esac