#!/usr/bin/env sh
set -eu

# Sync standards snapshot to project root.
# - Copies <snapshot>/.agents -> <project-root>/.agents/tsl
# - Copies <snapshot>/.gitattributes -> <project-root>/.gitattributes
# Existing targets are backed up before overwrite.

SCRIPT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd -P)"
SRC="$(CDPATH= cd -- "$SCRIPT_DIR/.." && pwd -P)"
ROOT="$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null || pwd)"
ROOT="$(CDPATH= cd -- "$ROOT" && pwd -P)"
AGENTS_SRC="$SRC/.agents"
GITATTR_SRC="$SRC/.gitattributes"

if [ ! -d "$AGENTS_SRC" ]; then
  echo "ERROR: Standards snapshot not found at $AGENTS_SRC" >&2
  echo "Run: git subtree add --prefix <your-prefix> <standards-url> <branch> --squash" >&2
  exit 1
fi

timestamp="$(date +%Y%m%d%H%M%S 2>/dev/null || echo bak)"

if [ "$SRC" = "$ROOT" ]; then
  echo "Skip: snapshot root equals project root."
  echo "Done."
  exit 0
fi

: "${AGENTS_NS:=tsl}"
case "$AGENTS_NS" in
  ""|*/*|*\\*|*..*)
    echo "ERROR: invalid AGENTS_NS=$AGENTS_NS" >&2
    exit 1
    ;;
esac

AGENTS_ROOT="$ROOT/.agents"
AGENTS_DST="$AGENTS_ROOT/$AGENTS_NS"
mkdir -p "$AGENTS_ROOT"

if [ -e "$AGENTS_DST" ]; then
  mv "$AGENTS_DST" "$AGENTS_ROOT/$AGENTS_NS.bak.$timestamp"
  echo "Backed up existing $AGENTS_NS agents -> $AGENTS_NS.bak.$timestamp"
fi

cp -R "$AGENTS_SRC" "$AGENTS_DST"
echo "Synced .agents/$AGENTS_NS from standards."

AGENTS_INDEX="$AGENTS_ROOT/index.md"
if [ ! -f "$AGENTS_INDEX" ]; then
  cat >"$AGENTS_INDEX" <<'EOF'
# .agents（多语言）

本目录用于存放仓库级/语言级的代理规则集。

建议约定：

- `.agents/tsl/`：TSL 相关标准（由 `sync_standards.*` 同步）
- `.agents/cpp/`、`.agents/python/` 等：其他语言的规则集（按需增加）

规则发生冲突时，建议以“更靠近代码的目录规则更具体”为准。
EOF
  echo "Created .agents/index.md"
fi

echo "Synced agents ruleset to $AGENTS_DST."

GITATTR_DST="$ROOT/.gitattributes"
if [ -f "$GITATTR_SRC" ]; then
  if [ "$(CDPATH= cd -- "$(dirname -- "$GITATTR_SRC")" && pwd -P)/$(basename -- "$GITATTR_SRC")" = "$GITATTR_DST" ]; then
    echo "Skip: .gitattributes source equals destination."
  else
    if [ -e "$GITATTR_DST" ]; then
      mv "$GITATTR_DST" "$ROOT/.gitattributes.bak.$timestamp"
      echo "Backed up existing .gitattributes -> .gitattributes.bak.$timestamp"
    fi
    cp "$GITATTR_SRC" "$GITATTR_DST"
    echo "Synced .gitattributes from standards."
  fi
fi

echo "Done."