"""
修正版本追踪管理器
記錄日記條目的修正歷史，追踪原始交易和修正版本
"""

from decimal import Decimal
from datetime import date
from typing import Optional, Dict, Any

def mark_old_version_as_outdated(conn, original_entry_id: int) -> None:
    """
    將舊版本標記為非最新版本 (is_latest = false)
    """
    with conn.cursor() as cur:
        cur.execute("""
            UPDATE journal_entries 
            SET is_latest = false 
            WHERE original_entry_id = %s OR journal_entry_id = %s
            ORDER BY created_at DESC
            OFFSET 1
        """, (original_entry_id, original_entry_id))


def create_new_revision(
    conn,
    entry_date: date,
    description: str,
    fiscal_year: int,
    lines: list,
    created_by: str = "system",
    original_entry_id: Optional[int] = None
) -> int:
    """
    創建新的修正版本
    
    返回: 新創建的 journal_entry_id
    """
    
    with conn.cursor() as cur:
        # ① 如果是修正交易，獲取最新版本的 revision_count
        revision_count = 1
        if original_entry_id:
            # 获取原始交易 ID（可能已有多個版本）
            cur.execute("""
                SELECT revision_count FROM journal_entries
                WHERE (journal_entry_id = %s OR original_entry_id = %s)
                AND is_latest = true
                ORDER BY created_at DESC
                LIMIT 1
            """, (original_entry_id, original_entry_id))
            
            row = cur.fetchone()
            if row:
                revision_count = row["revision_count"] + 1
            else:
                # 如果找不到最新版本，說明 original_entry_id 是第一個版本
                revision_count = 2
        
        # ② 如果是修正，標記舊版本
        if original_entry_id:
            cur.execute("""
                UPDATE journal_entries 
                SET is_latest = false 
                WHERE (journal_entry_id = %s OR original_entry_id = %s)
                AND is_latest = true
            """, (original_entry_id, original_entry_id))
        
        # ③ 創建新版本
        normalized_original_id = original_entry_id if original_entry_id else None
        
        cur.execute("""
            INSERT INTO journal_entries (
                entry_date,
                description,
                fiscal_year,
                is_latest,
                revision_count,
                original_entry_id,
                is_deleted,
                created_by
            )
            VALUES (%s, %s, %s, true, %s, %s, false, %s)
            RETURNING journal_entry_id
        """, (
            entry_date,
            description,
            fiscal_year,
            revision_count,
            normalized_original_id,
            created_by
        ))
        
        entry_id = cur.fetchone()["journal_entry_id"]
        
        # ④ 插入交易明細
        for line in lines:
            # 轉換 tax_direction
            tax_dir_db = None
            if line.get("tax_direction"):
                if line["tax_direction"] == 'paid':
                    tax_dir_db = 'INPUT'
                elif line["tax_direction"] == 'received':
                    tax_dir_db = 'OUTPUT'
                else:
                    tax_dir_db = line["tax_direction"].upper()
            
            cur.execute("""
                INSERT INTO journal_lines (
                    journal_entry_id,
                    account_id,
                    debit,
                    credit,
                    tax_rate,
                    tax_direction
                )
                VALUES (%s, %s, %s, %s, %s, %s)
            """, (
                entry_id,
                line.get("account_id"),
                line.get("debit", Decimal("0")),
                line.get("credit", Decimal("0")),
                line.get("tax_rate"),
                tax_dir_db
            ))
        
        return entry_id


def get_current_version(conn, journal_entry_id: int) -> Optional[Dict[str, Any]]:
    """
    取得指定交易的最新版本資訊
    """
    with conn.cursor() as cur:
        cur.execute("""
            SELECT 
                journal_entry_id,
                entry_date,
                description,
                revision_count,
                original_entry_id,
                is_latest,
                created_at,
                created_by
            FROM journal_entries
            WHERE journal_entry_id = %s
        """, (journal_entry_id,))
        
        row = cur.fetchone()
        if row:
            return dict(row)
        return None


def get_revision_history(conn, original_entry_id: int) -> list:
    """
    取得某個交易的所有修正版本歷史
    """
    with conn.cursor() as cur:
        cur.execute("""
            SELECT 
                journal_entry_id,
                entry_date,
                description,
                revision_count,
                is_latest,
                created_at,
                created_by
            FROM journal_entries
            WHERE original_entry_id = %s OR journal_entry_id = %s
            ORDER BY created_at ASC
        """, (original_entry_id, original_entry_id))
        
        rows = cur.fetchall()
        return [dict(row) for row in rows]