from fastapi import APIRouter, HTTPException, Query
from typing import Optional
from decimal import Decimal
from datetime import date

from app.core.database import get_connection
from app.models.journal_entry import JournalEntryRequest

router = APIRouter(prefix="/journal-entries", tags=["仕訳"])


# -------------------------------------------------
# 仕訳登録
# -------------------------------------------------
@router.post("", summary="仕訳登録")
def create_journal_entry(req: JournalEntryRequest):

    if len(req.lines) < 2:
        raise HTTPException(status_code=400, detail="仕訳行は2行以上必要です")

    if req.entry_date < date(2025, 6, 1):
        raise HTTPException(status_code=400, detail="仕訳日は2025-06-01以降である必要があります")

    debit_total = Decimal("0")
    credit_total = Decimal("0")

    for line in req.lines:
        if line.debit < 0 or line.credit < 0:
            raise HTTPException(status_code=400, detail="金額は正数で入力してください")

        if line.debit > 0 and line.credit > 0:
            raise HTTPException(status_code=400, detail="同一行で借方・貸方の同時入力は不可です")

        debit_total += line.debit
        credit_total += line.credit

    if debit_total != credit_total:
        raise HTTPException(
            status_code=400,
            detail=f"借方合計({debit_total})と貸方合計({credit_total})が一致しません"
        )

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

        # 期首ロック確認
        cur.execute("""
            SELECT is_locked
            FROM opening_balance_locks
            WHERE fiscal_year = 2025
        """)
        row = cur.fetchone()
        if not row or not row[0]:
            raise HTTPException(status_code=400, detail="期首残高が確定（lock）されていません")

        # ヘッダ登録
        cur.execute("""
            INSERT INTO journal_entries (entry_date, description)
            VALUES (%s, %s)
            RETURNING journal_entry_id
        """, (req.entry_date, req.description))
        journal_entry_id = cur.fetchone()[0]

        # 明細登録
        for line in req.lines:
            cur.execute("""
                INSERT INTO journal_lines
                (journal_entry_id, account_id, debit, credit)
                VALUES (%s, %s, %s, %s)
            """, (
                journal_entry_id,
                line.account_id,
                line.debit,
                line.credit
            ))

    return {
        "message": "仕訳を登録しました",
        "journal_entry_id": journal_entry_id
    }


# -------------------------------------------------
# 仕訳一覧取得
# -------------------------------------------------
@router.get("", summary="仕訳一覧取得")
def list_journal_entries(
    from_date: Optional[str] = Query(None),
    to_date: Optional[str] = Query(None),
    keyword: Optional[str] = Query(None)
):
    sql = """
      SELECT
        je.journal_entry_id,
        je.entry_date,
        je.description,
        SUM(jl.debit)  AS debit_total,
        SUM(jl.credit) AS credit_total
      FROM journal_entries je
      JOIN journal_lines jl
        ON jl.journal_entry_id = je.journal_entry_id
      WHERE 1=1
    """
    params = []

    if from_date:
        sql += " AND je.entry_date >= %s"
        params.append(from_date)
    if to_date:
        sql += " AND je.entry_date <= %s"
        params.append(to_date)
    if keyword:
        sql += " AND je.description ILIKE %s"
        params.append(f"%{keyword}%")

    sql += """
      GROUP BY je.journal_entry_id, je.entry_date, je.description
      ORDER BY je.entry_date DESC, je.journal_entry_id DESC
    """

    with get_connection() as conn, conn.cursor() as cur:
        cur.execute(sql, params)
        rows = cur.fetchall()

    return [
        {
            "journal_entry_id": r[0],
            "entry_date": r[1],
            "description": r[2],
            "debit_total": r[3],
            "credit_total": r[4],
        }
        for r in rows
    ]


# -------------------------------------------------
# 仕訳明細取得
# -------------------------------------------------
@router.get("/{journal_entry_id}", summary="仕訳明細取得")
def get_journal_entry(journal_entry_id: int):
    with get_connection() as conn, conn.cursor() as cur:

        cur.execute("""
          SELECT entry_date, description
          FROM journal_entries
          WHERE journal_entry_id = %s
        """, (journal_entry_id,))
        header = cur.fetchone()
        if not header:
            raise HTTPException(status_code=404, detail="仕訳が存在しません")

        cur.execute("""
          SELECT
            jl.account_id,
            a.account_code,
            a.account_name,
            jl.debit,
            jl.credit
          FROM journal_lines jl
          JOIN accounts a ON a.account_id = jl.account_id
          WHERE jl.journal_entry_id = %s
        """, (journal_entry_id,))
        lines = cur.fetchall()

    return {
        "entry_date": header[0],
        "description": header[1],
        "lines": [
            {
                "account_id": l[0],
                "account_code": l[1],
                "account_name": l[2],
                "debit": l[3],
                "credit": l[4]
            } for l in lines
        ]
    }


# -------------------------------------------------
# 逆仕訳生成（修正仕訳）
# -------------------------------------------------
@router.post("/{journal_entry_id}/reverse", summary="逆仕訳生成")
def reverse_journal_entry(journal_entry_id: int):
    with get_connection() as conn, conn.cursor() as cur:

        # 元仕訳取得
        cur.execute("""
            SELECT entry_date, description
            FROM journal_entries
            WHERE journal_entry_id = %s
        """, (journal_entry_id,))
        header = cur.fetchone()
        if not header:
            raise HTTPException(status_code=404, detail="仕訳が存在しません")

        entry_date, description = header

        cur.execute("""
            SELECT account_id, debit, credit
            FROM journal_lines
            WHERE journal_entry_id = %s
        """, (journal_entry_id,))
        lines = cur.fetchall()
        if not lines:
            raise HTTPException(status_code=400, detail="仕訳明細が存在しません")

        # 逆仕訳ヘッダ
        cur.execute("""
            INSERT INTO journal_entries (entry_date, description)
            VALUES (%s, %s)
            RETURNING journal_entry_id
        """, (entry_date, f"【修正】{description}"))
        new_entry_id = cur.fetchone()[0]

        # 逆仕訳明細（借贷反転）
        for account_id, debit, credit in lines:
            cur.execute("""
                INSERT INTO journal_lines
                (journal_entry_id, account_id, debit, credit)
                VALUES (%s, %s, %s, %s)
            """, (
                new_entry_id,
                account_id,
                credit,
                debit
            ))

    return {
        "message": "逆仕訳を作成しました",
        "reversed_journal_entry_id": new_entry_id
    }