# backend/app/modules/trial_balance/service.py
from decimal import Decimal
from typing import Dict, Any, List
from app.core.database import get_connection

def D(x) -> Decimal:
    return Decimal(str(x or 0))

# 科目グループ定義（表示順序を制御）- PDFフォーマットに準拠
ACCOUNT_GROUPS = [
    # 資産の部
    ("現金・預金合計", ["101", "102", "103", "104"]),
    ("流動資産合計", ["101", "102", "103", "104", "201", "202", "203", "204", "205"]),
    ("有価証券合計", ["301"]),
    ("有形固定資産合計", ["401", "402", "403", "404", "405", "406", "407"]),
    ("無形固定資産合計", ["408"]),
    ("投資その他の資産合計", ["301", "410"]),
    ("固定資産合計", ["301", "401", "402", "403", "404", "405", "406", "407", "408", "410"]),
    ("資産合計", ["101", "102", "103", "104", "201", "202", "203", "204", "205", "301", "401", "402", "403", "404", "405", "406", "407", "408", "410"]),
    # 負債の部
    ("仕入債務合計", ["501"]),
    ("流動負債合計", ["501", "502", "503", "504", "505", "506", "507", "508"]),
    ("固定負債合計", ["509"]),
    ("負債合計", ["501", "502", "503", "504", "505", "506", "507", "508", "509"]),
    # 資本の部
    ("資本金合計", ["601"]),
    ("利益剰余金合計", ["602"]),
    ("純資産合計", ["601", "602"])
]

def fetch_trial_balance(date_from: str, date_to: str):

    with get_connection() as conn, conn.cursor() as cur:

        # 勘定科目一覧
        cur.execute("""
            SELECT account_id, account_code, account_name, account_type
              FROM accounts
             WHERE is_active = true
             ORDER BY account_code
        """)
        accounts = cur.fetchall()

        # 科目データを格納
        account_data: Dict[str, Dict[str, Any]] = {}

        for acc in accounts:
            aid = acc["account_id"]
            code = acc["account_code"]

            # 期首残高: opening_balances テーブルの残高 + date_from より前の仕訳
            # まず opening_balances テーブルから取得
            cur.execute("""
                SELECT COALESCE(opening_debit, 0) - COALESCE(opening_credit, 0) AS ob
                  FROM opening_balances
                 WHERE account_id = %s
                   AND fiscal_year = EXTRACT(YEAR FROM %s::date)
            """, (aid, date_from))
            ob_row = cur.fetchone()
            opening_balance_from_table = D(ob_row["ob"]) if ob_row else D(0)

            # date_from より前の仕訳による増減
            cur.execute("""
                SELECT COALESCE(SUM(l.debit - l.credit), 0) AS opening
                  FROM journal_lines l
                  JOIN journal_entries j
                    ON j.journal_entry_id = l.journal_entry_id
                 WHERE l.account_id = %s
                   AND j.entry_date < %s
                   AND j.is_deleted = false
            """, (aid, date_from))
            opening_from_journals = D(cur.fetchone()["opening"])
            
            # 合計
            opening = opening_balance_from_table + opening_from_journals

            # 当期増減（date_from ～ date_to）
            cur.execute("""
                SELECT
                    COALESCE(SUM(l.debit), 0)  AS debit,
                    COALESCE(SUM(l.credit), 0) AS credit
                  FROM journal_lines l
                  JOIN journal_entries j
                    ON j.journal_entry_id = l.journal_entry_id
                 WHERE l.account_id = %s
                   AND j.entry_date BETWEEN %s AND %s
                   AND j.is_deleted = false
            """, (aid, date_from, date_to))
            row = cur.fetchone()
            debit = D(row["debit"])
            credit = D(row["credit"])

            closing = opening + debit - credit
            
            # 負債・資本は絶対値で表示（見やすくするため）
            if acc["account_type"] in ("liability", "equity"):
                opening = abs(opening)
                closing = abs(closing)

            account_data[code] = {
                "account_id": aid,
                "account_code": code,
                "account_name": acc["account_name"],
                "account_type": acc["account_type"],
                "opening_balance": opening,
                "debit": debit,
                "credit": credit,
                "closing_balance": closing,
            }

        # 結果リスト（グループ化）
        result_accounts: List[Dict[str, Any]] = []
        
        # 既に挿入された合計行を追跡
        inserted_totals = set()
        
        # 大区分の合計を保存（資産・負債・純資産の総合計）
        grand_total_closing = D(0)

        # 個別科目を追加
        for code in sorted(account_data.keys()):
            data = account_data[code]
            result_accounts.append({
                "account_code": data["account_code"],
                "account_name": data["account_name"],
                "account_type": data["account_type"],
                "opening_balance": str(data["opening_balance"]),
                "debit": str(data["debit"]),
                "credit": str(data["credit"]),
                "closing_balance": str(data["closing_balance"]),
                "ratio": None,  # 後で計算
                "is_total": False
            })
            
            # 大区分合計用に総計を積算
            grand_total_closing += data["closing_balance"]

            # 合計行を挿入（グループ定義の順序で）
            for group_name, group_codes in ACCOUNT_GROUPS:
                # このグループにまだ合計行を挿入していない
                if group_name in inserted_totals:
                    continue
                    
                # 現在の科目がこのグループに含まれる
                if code not in group_codes:
                    continue
                
                # このグループの全科目を取得
                group_codes_in_data = [gc for gc in group_codes if gc in account_data]
                if not group_codes_in_data:
                    continue
                
                # グループの最後の科目コードを取得
                last_code_in_group = max(group_codes_in_data)
                
                # 現在の科目がグループの最後の科目の場合
                if code == last_code_in_group:
                    # グループ合計を計算
                    group_opening = sum(account_data[gc]["opening_balance"] for gc in group_codes_in_data)
                    group_debit = sum(account_data[gc]["debit"] for gc in group_codes_in_data)
                    group_credit = sum(account_data[gc]["credit"] for gc in group_codes_in_data)
                    group_closing = sum(account_data[gc]["closing_balance"] for gc in group_codes_in_data)
                    
                    result_accounts.append({
                        "account_code": "",
                        "account_name": group_name,
                        "account_type": "",
                        "opening_balance": str(group_opening),
                        "debit": str(group_debit),
                        "credit": str(group_credit),
                        "closing_balance": str(group_closing),
                        "ratio": None,  # 後で計算
                        "is_total": True
                    })
                    
                    inserted_totals.add(group_name)
        
        # 構成比を計算（総資産に対する割合）
        for acc in result_accounts:
            closing = D(acc["closing_balance"])
            if grand_total_closing != 0:
                ratio = (closing / grand_total_closing) * 100
                acc["ratio"] = f"{ratio:.2f}"
            else:
                acc["ratio"] = "0.00"

        # 総合計を計算
        total_opening = sum(data["opening_balance"] for data in account_data.values())
        total_debit = sum(data["debit"] for data in account_data.values())
        total_credit = sum(data["credit"] for data in account_data.values())
        total_closing = sum(data["closing_balance"] for data in account_data.values())

    return {
        "totals": {
            "opening_balance": str(total_opening),
            "debit": str(total_debit),
            "credit": str(total_credit),
            "closing_balance": str(total_closing),
            "ratio": "100.00"
        },
        "accounts": result_accounts,
        "grand_total_closing": str(grand_total_closing)
    }