#!/bin/bash
# Hermes Sync Script - 真正的双向合并同步
# 策略：先 pull（合并远程），再 push（推送本地）。不做 force push。
# 冲突处理：MEMORY.md 使用 " ours" 策略（优先保留本地），其他文件手动合并
set -e

SYNC_DIR="${SYNC_DIR:-$HOME/.hermes-sync}"
HERMES_HOME="${HERMES_HOME:-$HOME/.hermes}"

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'
info()  { echo -e "${GREEN}[$(date '+%H:%M:%S')]${NC} $*"; }
warn()  { echo -e "${YELLOW}[$(date '+%H:%M:%S')] WARN:${NC} $*"; }
error() { echo -e "${RED}[$(date '+%H:%M:%S')] ERROR:${NC} $*"; }

cd "$SYNC_DIR"

# 确保在 main 分支
git checkout main 2>/dev/null || true

# ===== 步骤 1: 复制本地文件到同步目录 =====
info "Staging local changes..."
cp "$HERMES_HOME/memories/MEMORY.md" "$SYNC_DIR/memories/MEMORY.md" 2>/dev/null || true
# 复制所有技能（rsync 增量同步）
if [ -d "$HERMES_HOME/skills" ]; then
    mkdir -p "$SYNC_DIR/skills"
    rsync -a --delete "$HERMES_HOME/skills/" "$SYNC_DIR/skills/" 2>/dev/null || true
fi
git add -A

# 检查本地是否有变更
if git diff --cached --quiet && git diff --quiet; then
    LOCAL_CHANGES=false
else
    LOCAL_CHANGES=true
fi

# ===== 步骤 2: 拉取远程并合并 =====
info "Fetching remote changes..."
git fetch origin main

# 检查远程是否有新提交
if git rev-parse HEAD >/dev/null 2>&1 && \
   git rev-parse origin/main >/dev/null 2>&1 && \
   ! git merge-base --is-ancestor HEAD origin/main 2>/dev/null; then
    REMOTE_AHEAD=true
else
    REMOTE_AHEAD=false
fi

if [ "$REMOTE_AHEAD" = true ]; then
    info "Remote has new changes, merging..."
    
    if [ "$LOCAL_CHANGES" = true ]; then
        # 本地和远程都有改动 → 需要 merge
        # 先暂存本地改动
        git stash push -m "local before merge $(date)" 2>/dev/null || true
        
        # 合并远程
        if git merge origin/main --no-edit 2>/dev/null; then
            info "Merge successful"
        else
            warn "Merge conflict, attempting auto-resolve..."
            # 自动解决：skills 目录的文件取两方混合（保留ours）
            # MEMORY.md 取 ours
            git checkout --ours memories/MEMORY.md 2>/dev/null || true
            # 其他冲突文件：取ours（避免复杂冲突）
            git diff --name-only --diff-filter=U | grep -v "^memories/" | while read f; do
                git checkout --ours "$f" 2>/dev/null || true
            done
            git add -A
            git commit -m "Auto-resolve merge conflict $(date)" 2>/dev/null || true
        fi
        
        # 恢复本地改动并重新合并
        if git stash list | grep -q "local before merge"; then
            git stash pop || true
            # 再次合并（这次远程 ours，本地 theirs → 但 git 没有 --theirs 选项）
            # 改用 rebase 策略
            git rebase origin/main 2>/dev/null || {
                warn "Rebase conflict, using ours strategy..."
                git rebase --abort 2>/dev/null || true
                git merge origin/main --no-edit 2>/dev/null || true
            }
        fi
    else
        # 只有远程有新改动 → 直接 merge
        git merge origin/main --no-edit 2>/dev/null || {
            warn "Fast-forward only merge..."
            git merge --ff-only origin/main 2>/dev/null || {
                git reset --hard origin/main
            }
        }
    fi
else
    info "Remote up to date"
fi

# ===== 步骤 3: 提交本地变更并推送 =====
if [ "$LOCAL_CHANGES" = true ]; then
    info "Committing local changes..."
    git commit -m "Sync $(date '+%Y-%m-%d %H:%M')" 2>/dev/null || true
    
    info "Pushing to remote..."
    if git push origin main 2>&1; then
        info "Push successful"
    else
        warn "Push rejected (remote advanced), pulling and retrying..."
        git pull origin main --no-edit 2>/dev/null || true
        git push origin main 2>&1 || error "Push failed after retry"
    fi
else
    info "No local changes to push"
fi

# ===== 步骤 4: 合并结果应用到本地 hermes =====
info "Applying merged changes to local hermes..."
cp "$SYNC_DIR/memories/MEMORY.md" "$HERMES_HOME/memories/MEMORY.md" 2>/dev/null || true

# Skills: rsync 合并（不覆盖本地已有的，保留本地独有的）
if [ -d "$SYNC_DIR/skills" ]; then
    rsync -a --ignore-existing "$SYNC_DIR/skills/" "$HERMES_HOME/skills/" 2>/dev/null || \
        cp -rn "$SYNC_DIR/skills/"* "$HERMES_HOME/skills/" 2>/dev/null || true
fi

info "Sync complete"