#!/usr/bin/env bash

# Author        : Allan Christensen
# First Created : 14-02-2026 (DD-MM-YYYY)
# Description   : Updates DokuWiki installations safely (does not modify the data directory)
# License       : MIT License

#
# Are we root
#
if [[ $(id -u) -ne 0 ]]; then echo "" && echo "Must be root or use sudo" && echo "" ; exit ; fi

#
# Validate input
#
if [[ $# -ne 1 ]]; then
    echo ""
    echo "Usage:"
    echo "  dokuwikiupdate /path/to/wiki"
    echo ""
    exit 1
fi

wikidir="$1"

if [[ ! -d "$wikidir" ]]; then
    echo ""
    echo "Directory not found: $wikidir"
    echo ""
    exit 1
fi

if [[ ! -f "$wikidir/VERSION" ]]; then
    echo ""
    echo "VERSION file not found in $wikidir — not a valid DokuWiki installation."
    echo ""
    exit 1
fi

#
# Variables
#
logdir="/var/log/dokuwiki"
tmpdir=$(mktemp -d /tmp/dokuwiki-update.XXXXXX)

wikiid=$(echo "$wikidir" | sed 's#^/##; s#/#_#g')

logfile="$logdir/${wikiid}.log"
backupfile="$logdir/${wikiid}-core-backup.tar.gz"

tarball="$tmpdir/dokuwiki-stable.tgz"
extractdir="$tmpdir/extracted"

#
# Prepare logging
#
mkdir -p "$logdir"
touch "$logfile"
chmod 640 "$logfile"

#
# Detect interactive mode
#
if [[ -t 1 ]]; then
    interactive=true
else
    interactive=false
fi

#
# Redirect output to logfile
#
exec >>"$logfile" 2>&1

echo "============================================================"
echo "DokuWiki update run : $(date)"
echo "Wiki path           : $wikidir"
echo "============================================================"

#
# Logging helper
#
log() {
    echo "$1"
    if [[ "$interactive" == true ]]; then
        echo "$1" > /dev/tty
    fi
}

#
# Cleanup tmpdir automatically
#
trap 'rm -rf "$tmpdir" 2>/dev/null' EXIT

#
# Read installed version
#
installed_version=$(tr -d '\r\n' < "$wikidir/VERSION")

if [[ -z "$installed_version" ]]; then
    log ""
    log "Could not determine installed version — aborting."
    log ""
    exit 1
fi

#
# Download latest DokuWiki
#
log ""
log "Downloading latest DokuWiki..."

curl -fL https://download.dokuwiki.org/src/dokuwiki/dokuwiki-stable.tgz -o "$tarball" \
    || { log "Download failed — aborting."; exit 1; }

#
# Extract archive
#
log "Extracting archive..."

mkdir -p "$extractdir"

tar -xzf "$tarball" -C "$extractdir" --strip-components=1 \
    || { log "Extraction failed — aborting."; exit 1; }

#
# Read latest version
#
if [[ ! -f "$extractdir/VERSION" ]]; then
    log "VERSION file missing in downloaded archive — aborting."
    exit 1
fi

latest_version=$(tr -d '\r\n' < "$extractdir/VERSION")

log ""
log "Installed version : $installed_version"
log "Latest version    : $latest_version"

#
# Compare versions
#
if [[ "$installed_version" == "$latest_version" ]]; then
    log ""
    log "Already up to date. Nothing to do."
    log ""
    exit 0
fi

log ""
log "Updating DokuWiki to version: $latest_version"

#
# Clear cache before backup
#
log ""
log "Clearing DokuWiki cache..."

rm -rf "$wikidir/data/cache/"* 2>/dev/null
rm -rf "$wikidir/data/tmp/"* 2>/dev/null

#
# Estimate backup size
#
log ""
log "Checking available disk space..."

estimated_size=$(du -sb \
    --exclude=data \
    --exclude=lib/plugins \
    "$wikidir" | awk '{print $1}')

available_space=$(df --output=avail -B1 "$logdir" | tail -1)

log "Estimated backup size : $estimated_size bytes"
log "Available space       : $available_space bytes"

if (( available_space < estimated_size )); then
    log ""
    log "Not enough free space in $logdir to create backup."
    log "Aborting update."
    log ""
    exit 1
fi

#
# Backup current installation (core only)
#
log ""
log "Creating backup..."

rm -f "$backupfile"

tar \
  --exclude='data' \
  --exclude='lib/plugins' \
  -czf "$backupfile" \
  -C "$wikidir" . \
  || { log "Backup failed — aborting."; exit 1; }

log "Backup saved to: $backupfile"

#
# Inform user what will happen
#
log ""
log "Core files will be overwritten with the latest DokuWiki release."
log "User data and plugins will NOT be modified."

#
# Prepare extracted files
#
log ""
log "Preparing files (setting ownership to www-data)..."
chown -R www-data:www-data "$extractdir"

#
# Copy files over existing installation
#
log "Updating core files..."

cp -a "$extractdir/." "$wikidir/" \
    || { log "Copy failed — aborting."; exit 1; }

#
# Completed
#
log ""
log "DokuWiki successfully updated to: $latest_version"
log ""

#
# All done
#
printf "\nAll Done...\n"

#
# End of script
#