#!/usr/bin/env bash
# sync-upstream.sh — 从 upstream (origin/main) 同步更新，保留自定义改动
# 用法: ./tools/scripts/sync-upstream.sh
set -euo pipefail

REPO_ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
UPSTREAM="origin/main"

cd "$REPO_ROOT"

echo "========================================"
echo " Antigravity Fork — Upstream Sync Tool"
echo "========================================"
echo ""

# Step 1: 检查工作区
if ! git diff --quiet || ! git diff --staged --quiet; then
    echo "❌ 工作区有未提交的改动，请先 git stash 或 git commit"
    git status --short
    exit 1
fi

# Step 2: Fetch
echo "[1/4] Fetching upstream..."
git fetch origin

# Step 3: 检查是否有新 commits
NEW=$(git log --oneline HEAD.."$UPSTREAM" 2>/dev/null | wc -l | tr -d ' ')
if [ "$NEW" -eq 0 ]; then
    echo "✅ 已是最新，无需同步。"
    exit 0
fi

echo ""
echo "上游有 $NEW 个新 commits:"
git log --oneline HEAD.."$UPSTREAM"
echo ""

# Step 4: 备份当前 patches
PATCH_DIR="/tmp/antigravity-patches-$(date +%Y%m%d-%H%M%S)"
echo "[2/4] 备份自定义 patches 到 $PATCH_DIR ..."
mkdir -p "$PATCH_DIR"
git format-patch "$UPSTREAM"..HEAD -o "$PATCH_DIR/" --no-stat
BACKED=$(ls "$PATCH_DIR"/*.patch 2>/dev/null | wc -l | tr -d ' ')
echo "  已备份 $BACKED 个 patch"

# Step 5: Rebase
echo ""
echo "[3/4] 执行 rebase (git rebase $UPSTREAM)..."
echo "  如果出现冲突，请参考 .agents/workflows/sync-upstream.md 中的冲突解决指南"
echo ""
if ! git rebase "$UPSTREAM"; then
    echo ""
    echo "❌ Rebase 出现冲突！"
    echo ""
    echo "请按以下步骤处理："
    echo "  1. 查看冲突文件: git diff --name-only --diff-filter=U"
    echo "  2. 解决冲突（参考 .agents/workflows/sync-upstream.md）"
    echo "  3. git add <解决的文件>"
    echo "  4. git rebase --continue"
    echo ""
    echo "备份的 patches 在: $PATCH_DIR"
    exit 1
fi

# Step 6: 编译验证
echo "[4/4] 编译验证..."
if ! (cd "$REPO_ROOT/backend" && go build ./... 2>&1); then
    echo ""
    echo "❌ 编译失败！rebase 后有破坏性改动需要修复。"
    echo "备份的 patches 在: $PATCH_DIR"
    exit 1
fi

echo ""
echo "✅ 同步完成！"
echo ""
echo "自定义改动（我方 commits）已成功移植到最新 upstream 上。"
echo "请运行以下命令推送："
echo "  git push origin main --force-with-lease"
echo ""
echo "备份路径（可删除）: $PATCH_DIR"