import git
import os
from datetime import datetime, timezone
from neo4j import GraphDatabase
import scriptBase.base

# --- Neo4j 連線資訊 ---
# 請替換為你自己的 Neo4j 伺服器地址、用戶名和密碼
NEO4J_URI = "bolt://99.12.23.49:7687"
NEO4J_USER = "neo4j"
NEO4J_PASSWORD = "1234.cc-"

# --- 新增功能：清除 Neo4j 資料庫 ---
def clear_neo4j_database():
    """
    使用 Cypher 查詢清除 Neo4j 資料庫中的所有節點和關係。
    警告：此操作不可逆！
    """
    try:
        driver = GraphDatabase.driver(NEO4J_URI, auth=(NEO4J_USER, NEO4J_PASSWORD))
        with driver.session() as session:
            # Cypher 查詢：DETACH DELETE 會在刪除節點的同時，先刪除與之相關的所有關係
            print("正在清空 Neo4j 資料庫，此操作無法撤銷...")
            session.run("MATCH (n) DETACH DELETE n")
            print("資料庫已成功清空。")
        driver.close()
    except Exception as e:
        print(f"清空 Neo4j 失敗: {e}")

# --- 核心函數： Git 歷史提取與 Neo4j 匯入 ---
def import_git_to_neo4j(repo_path, since=None):
    """
    提取 Git 倉庫的提交歷史，並直接匯入到 Neo4j 圖資料庫中。

    Args:
        repo_path (str): Git 倉庫的本地路徑。
        since (datetime, optional): 獲取提交的起始時間。如果為 None，則全量獲取。
    """
    # 驗證 Git 倉庫路徑
    if not os.path.exists(repo_path) or not git.repo.base.is_git_dir(os.path.join(repo_path, '.git')):
        print(f"錯誤: '{repo_path}' 不是一個有效的 Git 倉庫路徑。")
        return

    try:
        repo = git.Repo(repo_path)
    except git.InvalidGitRepositoryError:
        print(f"錯誤: '{repo_path}' 不是一個有效的 Git 倉庫。請檢查路徑。")
        return
        
    # 連接 Neo4j 資料庫
    try:
        driver = GraphDatabase.driver(NEO4J_URI, auth=(NEO4J_USER, NEO4J_PASSWORD))
        print("成功連接到 Neo4j 資料庫。")
    except Exception as e:
        print(f"連接 Neo4j 失敗: {e}")
        return

    # 提交事務函數
    def import_transaction(tx, commit_data):
        # 創建或匹配作者節點
        tx.run("""
            MERGE (a:Author {email: $author_email})
            ON CREATE SET a.name = $author_name
            """, author_email=commit_data['author_email'], author_name=commit_data['author_name'])
        
        # 創建提交節點
        tx.run("""
            MERGE (c:Commit {id: $commit_id})
            ON CREATE SET c.message = $message, c.timestamp = $timestamp
            """, commit_id=commit_data['commit_id'], message=commit_data['commit_message'], timestamp=commit_data['committed_datetime'])
        
        # 創建作者與提交之間的關係
        tx.run("""
            MATCH (a:Author {email: $author_email})
            MATCH (c:Commit {id: $commit_id})
            MERGE (a)-[:AUTHORED]->(c)
            """, author_email=commit_data['author_email'], commit_id=commit_data['commit_id'])

        # 創建父提交關係
        if commit_data['parent_id']:
            tx.run("""
                MATCH (parent:Commit {id: $parent_id})
                MATCH (child:Commit {id: $child_id})
                MERGE (child)-[:PARENT]->(parent)
                """, parent_id=commit_data['parent_id'], child_id=commit_data['commit_id'])

        # 創建文件變更關係
        for file_change in commit_data['file_changes']:
            # 創建或匹配文件節點
            tx.run("""
                MERGE (f:File {path: $file_path})
                """, file_path=file_change['new_path'])
            
            # 創建提交與文件之間的修改關係
            tx.run("""
                MATCH (c:Commit {id: $commit_id})
                MATCH (f:File {path: $file_path})
                MERGE (c)-[:CHANGED {
                    change_type: $change_type,
                    lines_added: $lines_added,
                    lines_deleted: $lines_deleted
                }]->(f)
                """,
                commit_id=commit_data['commit_id'],
                file_path=file_change['new_path'],
                change_type=file_change['change_type'],
                lines_added=file_change['lines_added'],
                lines_deleted=file_change['lines_deleted'])

    # 根據 'since' 參數選擇提交迭代器
    if since:
        print(f"正在進行增量匯入，從 {since.isoformat()} 開始...")
        since_utc = since.astimezone(timezone.utc)
        commits = repo.iter_commits('--all', after=since_utc)
    else:
        print("正在進行全量匯入...")
        commits = repo.iter_commits('--all')
    
    with driver.session() as session:
        for commit in commits:
            # 排除合併提交
            if len(commit.parents) > 1:
                continue

            file_changes = []
            try:
                diff_index = commit.diff(commit.parents[0] if commit.parents else git.NULL_TREE, create_patch=True)
                for diff in diff_index:
                    diff_text = diff.diff.decode('utf-8', errors='ignore')
                    lines_added = diff_text.count('\n+') - diff_text.count('\n+++')
                    lines_deleted = diff_text.count('\n-') - diff_text.count('\n---')
                    change_type = diff.change_type if diff.change_type is not None else ""
                    old_path = diff.a_path if diff.a_path is not None else ""
                    new_path = diff.b_path if diff.b_path is not None else ""
                    
                    appendStr = {
                        "change_type": change_type,
                        "old_path": old_path,
                        "new_path": new_path,
                        "lines_added": lines_added,
                        "lines_deleted": lines_deleted,
                    }

                    file_changes.append(appendStr)
            except Exception as e:
                print(f"警告: 處理提交 {commit.hexsha} 的文件變更時發生錯誤: {e}")
                continue

            parent_id = commit.parents[0].hexsha if commit.parents else None
            commit_data = {
                    "commit_id": commit.hexsha,
                    "parent_id": parent_id,
                    "author_name": commit.author.name,
                    "author_email": commit.author.email,
                    "committed_datetime": commit.committed_datetime.isoformat(),
                    "commit_message": commit.message.strip(),
                    "file_changes": file_changes
                }
            
            try:
                session.execute_write(import_transaction, commit_data)
                print(f"已匯入提交: {commit.hexsha[:7]}, commit_data: {commit_data}")
            except Exception as e:
                print(f"警告: 匯入提交 {commit.hexsha[:7]} 時發生錯誤: {e}, commit_data: {commit_data}")

    driver.close()
    print("匯入完成，Neo4j 連接已關閉。")

# --- 執行腳本 ---
if __name__ == "__main__":
    # 替換為你的 Git 倉庫路徑
    repo_path = 'D:/mayun/LR04.02_RVCTerminalPlus'

    # 步驟1: 清空資料庫
    # 執行全量匯入前，通常會先清空資料庫以避免資料重複
    print("----- 開始清空資料庫 -----")
    clear_neo4j_database()
    print("----- 資料庫清空完成 -----")
    
    # 步驟2：執行全量匯入
    print("\n" + "="*50 + "\n")
    print("----- 執行全量匯入 -----")
    import_git_to_neo4j(repo_path)
    print("----- 全量匯入完成 -----")
    
    # 示例2：執行增量匯入
    # 設置增量獲取的起始時間，例如從 2024年7月1日 開始
    # start_time = datetime(2024, 7, 1, 0, 0, 0, tzinfo=timezone.utc)
    # print("\n" + "="*50 + "\n")
    # print("----- 執行增量匯入 -----")
    # import_git_to_neo4j(repo_path, since=start_time)