#!/usr/bin/env bash
# gstack-relink — re-create skill symlinks based on skill_prefix config
#
# Usage:
#   gstack-relink
#
# Env overrides (for testing):
#   GSTACK_STATE_DIR   — override ~/.gstack state directory
#   GSTACK_INSTALL_DIR — override gstack install directory
#   GSTACK_SKILLS_DIR  — override target skills directory
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
GSTACK_CONFIG="${SCRIPT_DIR}/gstack-config"

# Detect install dir
INSTALL_DIR="${GSTACK_INSTALL_DIR:-}"
if [ -z "$INSTALL_DIR" ]; then
  if [ -d "$HOME/.claude/skills/gstack" ]; then
    INSTALL_DIR="$HOME/.claude/skills/gstack"
  elif [ -d "${SCRIPT_DIR}/.." ] && [ -f "${SCRIPT_DIR}/../setup" ]; then
    INSTALL_DIR="$(cd "${SCRIPT_DIR}/.." && pwd)"
  fi
fi

if [ -z "$INSTALL_DIR" ] || [ ! -d "$INSTALL_DIR" ]; then
  echo "Error: gstack install directory not found." >&2
  echo "Run: cd ~/.claude/skills/gstack && ./setup" >&2
  exit 1
fi

# Detect target skills dir
SKILLS_DIR="${GSTACK_SKILLS_DIR:-$(dirname "$INSTALL_DIR")}"
[ -d "$SKILLS_DIR" ] || mkdir -p "$SKILLS_DIR"

# Read prefix setting
PREFIX=$("$GSTACK_CONFIG" get skill_prefix 2>/dev/null || echo "false")

# #2569: rendered :user variants (brain-aware blocks) live in an UNTRACKED
# out-dir instead of the tracked install checkout. When a render exists for a
# skill, relink serves it — otherwise a config change would silently flip
# every skill back to the canonical (blockless) source.
RENDER_DIR="${GSTACK_USER_RENDER_DIR:-${GSTACK_HOME:-$HOME/.gstack}/render/claude}"

# Helper: remove old skill entry (symlink or real directory with symlinked SKILL.md)
_cleanup_skill_entry() {
  local entry="$1"
  if [ -L "$entry" ]; then
    rm -f "$entry"
  elif [ -d "$entry" ] && [ -L "$entry/SKILL.md" ]; then
    rm -rf "$entry"
  fi
}

_link_root_skill_alias() {
  local target="$SKILLS_DIR/_gstack-command"

  [ -f "$INSTALL_DIR/SKILL.md" ] || return 0
  [ -L "$target" ] && rm -f "$target"
  mkdir -p "$target"
  # Copy-then-rewrite, never a symlink (#2511): a symlinked alias re-serves
  # the canonical `name: gstack`, Claude Code sees a duplicate skill name,
  # and drops the ENTIRE personal-skills set. sed reads the source and writes
  # a fresh copy — remove any prior symlink first so the redirect can never
  # write through it into the generated source.
  rm -f "$target/SKILL.md"
  sed "1,/^---\$/ s/^name:[[:space:]].*/name: _gstack-command/" "$INSTALL_DIR/SKILL.md" > "$target/SKILL.md"
}

_link_root_skill_alias

# Discover skills (directories with SKILL.md, excluding meta dirs)
SKILL_COUNT=0
for skill_dir in "$INSTALL_DIR"/*/; do
  [ -d "$skill_dir" ] || continue
  # Skip symlinked skill dirs (connect-chrome → open-gstack-browser): linking
  # one under the symlink's basename would duplicate the canonical frontmatter
  # name and collide in Claude Code's skill registry (#2201). setup owns the
  # rewritten-copy alias for those.
  [ -L "${skill_dir%/}" ] && continue
  skill=$(basename "$skill_dir")
  # Skip non-skill directories
  case "$skill" in bin|browse|design|docs|extension|lib|node_modules|scripts|test|.git|.github) continue ;; esac
  [ -f "$skill_dir/SKILL.md" ] || continue

  if [ "$PREFIX" = "true" ]; then
    # Don't double-prefix directories already named gstack-*
    case "$skill" in
      gstack-*) link_name="$skill" ;;
      *)        link_name="gstack-$skill" ;;
    esac
    # Remove old flat entry if it exists (and isn't the same as the new link)
    [ "$link_name" != "$skill" ] && _cleanup_skill_entry "$SKILLS_DIR/$skill"
  else
    link_name="$skill"
    # Don't remove gstack-* dirs that are their real name (e.g., gstack-upgrade)
    case "$skill" in
      gstack-*) ;; # Already the real name, no old prefixed link to clean
      *)        _cleanup_skill_entry "$SKILLS_DIR/gstack-$skill" ;;
    esac
  fi
  target="$SKILLS_DIR/$link_name"
  # Upgrade old directory symlinks to real directories
  [ -L "$target" ] && rm -f "$target"
  # Create real directory with symlinked SKILL.md (absolute path)
  mkdir -p "$target"
  skill_md_src="$INSTALL_DIR/$skill/SKILL.md"
  [ -f "$RENDER_DIR/$skill/SKILL.md" ] && skill_md_src="$RENDER_DIR/$skill/SKILL.md"
  ln -snf "$skill_md_src" "$target/SKILL.md"
  SKILL_COUNT=$((SKILL_COUNT + 1))
done

# Patch SKILL.md name: fields to match prefix setting
"$INSTALL_DIR/bin/gstack-patch-names" "$INSTALL_DIR" "$PREFIX"

if [ "$PREFIX" = "true" ]; then
  echo "Relinked $SKILL_COUNT skills as gstack-*"
else
  echo "Relinked $SKILL_COUNT skills as flat names"
fi