hledger/bin/hledger-pijul

#!/usr/bin/env bash
set -e

# * About
usage() { line80; cat <<EOF # keep synced with Commands below
hledger-pijul - easy version control for your hledger journal.

An experimental prototype, currently works for the default journal only.
This uses pijul, the VCS most likely to support a simple just-works UI.
A pijul repo in the main file's directory, and a pijul commit-signing key,
will be autocreated if needed.

Subcommands: 

hledger pijul record [MSG] - record the journal's files (as listed by 'files')
hledger pijul status       - show unrecorded changes (after first record)
hledger pijul log          - list the journal's change history (after record)
hledger pijul              - show this help

Extra arguments are passed to pijul (pijul flags should be preceded by --).
You can install these as more convenient top-level commands by creating 
hledger-record, hledger-status, hledger-log scripts like:

    #!/bin/sh
    hledger-pijul record "\$@"

EOF
}

# * Utils

line80() { cat <<EOF
--------------------------------------------------------------------------------
EOF
}

no_repo_msg() {
    echo "Try this again after 'record'."
}

MAINFILE=$LEDGER_FILE
FILES=$(hledger -f "$MAINFILE" files)
DIR=$(dirname "$MAINFILE")
# pijul executable name, just one word
PIJUL=pijul

ensure_pijul() {
    if ! hash $PIJUL 2>/dev/null; then
        cat >&2 <<EOF
This command requires '$PIJUL', but it's not installed in \$PATH.
Please install it (see https://pijul.org/downloads) and try again.
EOF
        exit 1
    fi
}

# TODO: also look in parent directories
ensure_pijul_repo() {
    if [[ ! -d "$DIR/.pijul" ]]; then
        $PIJUL init "$DIR"
        echo "Created pijul repo in $DIR"
    fi
}

ensure_pijul_key() {
    PIJULDIR=$(pijul_config_dir)
    if [[ ! -e $PIJULDIR/publickey.json ]]; then
        echo "Creating a pijul commit signing key in $PIJULDIR"
        echo "If you set a password below, you'll have to enter it every time you record."
        #     --------------------------------------------------------------------------------
        $PIJUL key generate "$USER"
    fi
}

pijul_config_dir() {
    if [[ $(uname) == Darwin ]]; then
        echo "$HOME/Library/Application Support/pijul"
    else
        echo "$HOME/.config/pijul"  # guess
    fi
}

# * Commands
# keep synced with usage() above

record() {
    ensure_pijul
    ensure_pijul_repo
    ensure_pijul_key
    cd "$DIR"
    for F in $FILES; do $PIJUL add -f "$F"; done
    MSG=${1:-$(date +'%Y-%m-%d %H:%M:%S %Z')}; shift || true
    $PIJUL record -m "$MSG" "$@"
}

status() {
    ensure_pijul
    $PIJUL diff --repository "$DIR" "$@" #| sed -n '/^# Hunks/,$ p'
}

log() {
    ensure_pijul
    # ensure_pijul_repo
    $PIJUL log --repository "$DIR" "$@"
}

# * Main

# NOTE intended to run Commands but will run any function above
if declare -f "$1" > /dev/null; then "$@"; else usage; fi