"""审计台账（PRD §4.6）：本人操作记录筛选 + CSV 导出。"""
from __future__ import annotations

import csv
import io
from datetime import datetime

from sqlalchemy.ext.asyncio import AsyncSession

from model.sys_user import SysUser
from repositories.audit_log import AuditLogRepo


def _audit_item(a) -> dict:
    return {
        "id": a.id,
        "module": a.module,
        "action": a.action,
        "target": a.target,
        "detail": a.detail,
        "trace_id": a.trace_id,
        "status": a.status,
        "create_time": a.create_time.isoformat() if a.create_time else None,
    }


async def list_ledger(
    db: AsyncSession,
    user: SysUser,
    *,
    action: str | None = None,
    customer_id: int | None = None,
    keyword: str | None = None,
    start: datetime | None = None,
    end: datetime | None = None,
    page: int = 1,
    page_size: int = 20,
) -> dict:
    repo = AuditLogRepo(db)
    items = await repo.list_by_advisor(
        user_id=user.id, action=action, customer_id=customer_id, keyword=keyword, start=start, end=end,
        limit=page_size, offset=(page - 1) * page_size,
    )
    total = await repo.count_by_advisor(
        user_id=user.id, action=action, keyword=keyword, start=start, end=end
    )
    return {"total": total, "page": page, "page_size": page_size, "items": [_audit_item(a) for a in items]}


def _to_csv(rows: list[dict]) -> str:
    """行列表 → CSV 文本（空列表返回空串）。"""
    if not rows:
        return ""
    buf = io.StringIO()
    writer = csv.DictWriter(buf, fieldnames=list(rows[0].keys()))
    writer.writeheader()
    writer.writerows(rows)
    return buf.getvalue()


async def export_ledger(
    db: AsyncSession,
    user: SysUser,
    *,
    action: str | None = None,
    customer_id: int | None = None,
    keyword: str | None = None,
    start: datetime | None = None,
    end: datetime | None = None,
) -> str:
    """导出本人审计台账为 CSV 文本（全量，不限分页大小，上限 10000 条）。"""
    repo = AuditLogRepo(db)
    items = await repo.list_by_advisor(
        user_id=user.id, action=action, customer_id=customer_id, keyword=keyword, start=start, end=end,
        limit=10000, offset=0,
    )
    return _to_csv([_audit_item(a) for a in items])