#!/bin/bash

# omarchy:summary=Restore channel and regional pacman defaults in an installed target
# omarchy:args=<stable|rc|edge> [target-root] | --render <stable|rc|edge> <output-dir> [target-root]
# omarchy:requires-sudo=true
# omarchy:hidden=true

set -euo pipefail

usage() {
  echo "Usage: omarchy-apply-pacman <stable|rc|edge> [target-root]" >&2
  echo "       omarchy-apply-pacman --render <stable|rc|edge> <output-dir> [target-root]" >&2
  exit 1
}

# --render only builds the two files, so an unprivileged caller can hand root
# nothing but plain copies of the finished result.
render_dir=""
if [[ ${1:-} == "--render" ]]; then
  (( $# == 3 || $# == 4 )) || usage
  channel="$2"
  render_dir="$3"
  [[ -d $render_dir ]] || { echo "Render directory not found: $render_dir" >&2; exit 1; }
  etc="${4:-/}/etc"
else
  (( $# >= 1 && $# <= 2 )) || usage
  channel="$1"
  etc="${2:-/}/etc"
fi

case "$channel" in
  stable|rc|edge) ;;
  *) echo "Invalid pacman channel: $channel" >&2; exit 1 ;;
esac

# The ISO writes this plain-text marker before target finalization. Missing
# markers keep existing installations global; never source it as shell code.
region=global
if [[ -e $etc/omarchy/region ]]; then
  region=$(<"$etc/omarchy/region")
fi
case "$region" in
  global|cn) ;;
  *) echo "Unsupported region: $region (expected global or cn)" >&2; exit 1 ;;
esac

# Build both files before replacing either. Explicit refreshes retain backups;
# ordinary updates do not call this command or enforce regional defaults.
if [[ -n $render_dir ]]; then
  staging="$render_dir"
else
  staging=$(mktemp -d)
  trap 'rm -rf "$staging"' EXIT
fi
cp "$OMARCHY_PATH/default/pacman/pacman-$channel.conf" "$staging/pacman.conf"
if [[ $region == "global" ]]; then
  cp "$OMARCHY_PATH/default/pacman/mirrorlist-$channel" "$staging/mirrorlist"
else
  profile="$OMARCHY_PATH/default/regions/$region/pacman"
  printf '\n' >> "$staging/pacman.conf"
  cat "$profile/pacman.conf.append" >> "$staging/pacman.conf"
  # pacman tries servers in order, so the regional mirror leads and the
  # channel's own mirror stays as the fallback.
  cat "$profile/mirrorlist-$channel.prepend" "$OMARCHY_PATH/default/pacman/mirrorlist-$channel" > "$staging/mirrorlist"
fi

if [[ -z $render_dir ]]; then
  mkdir -p "$etc/pacman.d"
  for file in pacman.conf pacman.d/mirrorlist; do
    if [[ -e $etc/$file ]]; then
      cp -f "$etc/$file" "$etc/$file.bak"
    fi
  done
  # Copying over an existing file keeps its owner and mode, as refresh always has.
  cp -f "$staging/pacman.conf" "$etc/pacman.conf"
  cp -f "$staging/mirrorlist" "$etc/pacman.d/mirrorlist"
fi