#!/usr/bin/env bash
# reconcile-hyde.sh — reconcile a HyDE update with your dots-tracked configs.
#
# HyDE's updater (`Scripts/install.sh -r`) overwrites every config listed in
# Scripts/restore_cfg.psv — including ~/.config/hypr/*. It backs the old ones up to
# ~/.config/cfg_backups and REPLACES your stow symlinks with real files (HyDE's new
# defaults). This tool, run ON THE GUI MACHINE right after that update, shows per file:
#   your dots version   vs   HyDE's new one
# lets you keep / take / merge each, then removes the severed real files and re-runs
# install.sh so everything is symlinked back to the repo.
#
#   ./bin/reconcile-hyde.sh [host]        report only — safe, changes nothing (default)
#   ./bin/reconcile-hyde.sh -i [host]     interactive: decide each conflicting file
#   ./bin/reconcile-hyde.sh --relink [host]   skip decisions: back up severed files,
#                                             then re-stow (repo versions win)
#
# host defaults to `hostname -s`. Commit your repo first so choices are reviewable/revertable.
set -uo pipefail

# Config subtrees where HyDE and your dots overlap. Add/remove as your setup needs.
SUBTREES=(.config/hypr .config/waybar)

# --- args ---
MODE=report
HOST=""
for a in "$@"; do
  case "$a" in
    -i|--interactive) MODE=interactive ;;
    --relink)         MODE=relink ;;
    -h|--help)        awk 'NR > 1 && !/^#/ { exit } NR > 1' "$0"; exit 0 ;;
    -*)               echo "unknown option: $a" >&2; exit 2 ;;
    *)                HOST="$a" ;;
  esac
done
[ -z "$HOST" ] && HOST="$(hostname -s)"
skip_relink=()   # files the user chose to skip during interactive reconcile

DOTS="$(cd "$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")/.." && pwd)"   # repo root (script in bin/)
[ -x "$DOTS/install.sh" ] || { echo "error: $DOTS/install.sh not found — run from inside the dots repo" >&2; exit 1; }

# repo package search order: host overlay wins, then gui, then common
PKGS=("$HOST" gui common)
repo_src() { # repo_src <rel-path> -> print the repo file stow would link, or nothing
  local rel="$1" p
  for p in "${PKGS[@]}"; do
    [ -f "$DOTS/$p/$rel" ] && { printf '%s\n' "$DOTS/$p/$rel"; return 0; }
  done
  return 1
}

echo "host=$HOST  dots=$DOTS  mode=$MODE"
if [ -n "$(git -C "$DOTS" status --porcelain 2>/dev/null)" ]; then
  echo "note: $DOTS has uncommitted changes — commit first so reconcile choices are reviewable." >&2
fi
[ -d "$HOME/.config/cfg_backups" ] && echo "HyDE's pre-update backups are in ~/.config/cfg_backups"
echo

# --- classify every live file under the managed subtrees ---
linked=0; foreign=0
same=(); conflicts=(); new_files=()
for st in "${SUBTREES[@]}"; do
  [ -d "$HOME/$st" ] || continue
  while IFS= read -r -d '' live; do
    rel="${live#"$HOME"/}"
    if [ -L "$live" ]; then                                   # still a symlink
      tgt="$(readlink -f "$live" 2>/dev/null || true)"
      case "$tgt" in
        "$DOTS"/*) linked=$((linked+1)) ;;                    # intact -> HyDE didn't sever it
        *)         foreign=$((foreign+1)); echo "  ?  $rel -> symlink outside repo: $tgt" ;;
      esac
      continue
    fi
    # real file: HyDE overwrote (severed) it, or it is brand new
    src="$(repo_src "$rel" || true)"
    if [ -z "$src" ]; then
      new_files+=("$rel")
    elif diff -q "$src" "$live" >/dev/null 2>&1; then
      same+=("$rel")                                          # content == repo; just relink
    else
      conflicts+=("$rel")                                     # HyDE's new content differs from yours
    fi
  done < <(find "$HOME/$st" \( -type f -o -type l \) -print0)
done

echo "== summary =="
echo "  intact symlinks (untouched):        $linked"
echo "  severed but identical (relink):     ${#same[@]}"
echo "  severed & CHANGED (need decision):  ${#conflicts[@]}"
echo "  new HyDE files not tracked by dots: ${#new_files[@]}"
[ "$foreign" -gt 0 ] && echo "  foreign symlinks flagged above:     $foreign"
echo
if [ "$linked" -gt 0 ]; then
  echo "For intact symlinks, check whether HyDE wrote THROUGH them into the repo:"
  echo "    git -C $DOTS diff -- '*/.config/hypr/*' '*/.config/waybar/*'"
  echo
fi
if [ "${#new_files[@]}" -gt 0 ]; then
  echo "New HyDE files (left as-is; add to a package + re-stow if you want them tracked):"
  printf '    %s\n' "${new_files[@]}"
  echo
fi
if [ "${#conflicts[@]}" -gt 0 ]; then
  echo "Changed files (your dots version vs HyDE's new default):"
  for rel in "${conflicts[@]}"; do
    src="$(repo_src "$rel")"
    printf '    %-45s %s changed lines\n' "$rel" "$(diff "$src" "$HOME/$rel" | grep -cE '^[<>]')"
  done
  echo
fi

# report-only ends here
if [ "$MODE" = report ]; then
  if [ "${#conflicts[@]}" -gt 0 ]; then
    echo "Re-run with -i to decide each changed file, or --relink to keep your repo versions wholesale."
  elif [ "${#same[@]}" -gt 0 ]; then
    echo "No content conflicts. Re-run with --relink to drop the severed files and re-symlink."
  else
    echo "Nothing to reconcile."
  fi
  exit 0
fi

# --- interactive: decide each changed file, writing the choice into the repo copy ---
if [ "$MODE" = interactive ] && [ "${#conflicts[@]}" -gt 0 ]; then
  for rel in "${conflicts[@]}"; do
    src="$(repo_src "$rel")"; live="$HOME/$rel"
    echo "──────── $rel ────────"
    echo "  repo (yours): ${src#"$DOTS"/}"
    diff "$src" "$live" | sed 's/^/    /' | head -60
    echo "  [k]eep yours (default)   [t]ake HyDE's   [m]erge in \$EDITOR -d   [s]kip"
    read -r -p "  choice> " ans </dev/tty || ans=k
    case "$ans" in
      t|take) cp "$live" "$src"; echo "    -> took HyDE's version into $src" ;;
      m|merge) "${EDITOR:-nvim}" -d "$src" "$live" </dev/tty >/dev/tty 2>&1; echo "    -> merged (saved $src)" ;;
      s|skip) echo "    -> skipped (left severed; not relinked)"; skip_relink+=("$rel") ;;
      *) echo "    -> kept your repo version" ;;
    esac
  done
  echo
fi

# --- relink: back up severed files that the repo owns, remove them, re-stow ---
BK="$HOME/.config/hyde-reconcile-backup-$(date +%Y%m%d-%H%M%S)"
to_relink=()
for st in "${SUBTREES[@]}"; do
  [ -d "$HOME/$st" ] || continue
  while IFS= read -r -d '' live; do
    [ -L "$live" ] && continue                                # only real (severed) files
    rel="${live#"$HOME"/}"
    repo_src "$rel" >/dev/null || continue                    # only files the repo can provide
    for s in "${skip_relink[@]}"; do [ "$s" = "$rel" ] && continue 2; done
    to_relink+=("$rel")
  done < <(find "$HOME/$st" -type f -print0)
done

if [ "${#to_relink[@]}" -eq 0 ]; then
  echo "nothing to relink."; exit 0
fi
echo "will back up + remove ${#to_relink[@]} severed file(s), then re-stow so they link to the repo:"
printf '    %s\n' "${to_relink[@]}"
read -r -p "proceed? [y/N] " go </dev/tty || go=n
case "$go" in y|Y|yes) ;; *) echo "aborted — nothing changed."; exit 0 ;; esac

for rel in "${to_relink[@]}"; do
  mkdir -p "$BK/$(dirname "$rel")"
  cp -a "$HOME/$rel" "$BK/$rel"
  rm -f "$HOME/$rel"
done
echo "backed up to $BK; removed severed files. re-stowing…"
"$DOTS/install.sh" "$HOST"

echo
echo "done. verify a couple of links resolve into the repo, e.g.:"
echo "    readlink ~/.config/hypr/keybindings.conf"