"""Build the fund-flow graph from deduplicated transactions."""
from uuid import UUID
from collections import defaultdict

from sqlalchemy.ext.asyncio import AsyncSession

from app.repositories.transaction_repo import TransactionRepository
from app.schemas.transaction import FlowGraphOut, FlowNodeOut, FlowEdgeOut


async def build_flow_graph(case_id: UUID, db: AsyncSession) -> FlowGraphOut:
    repo = TransactionRepository(db)
    transactions = await repo.get_all_by_case(case_id)

    valid = [tx for tx in transactions if not tx.is_duplicate]

    nodes_map: dict[str, str] = {}  # label -> type
    edge_agg: dict[tuple[str, str], dict] = defaultdict(
        lambda: {"amount": 0.0, "count": 0, "trade_time": ""}
    )

    for tx in valid:
        self_label = _self_label(tx)
        counter_label = tx.counterparty_name or "未知对手方"

        if self_label not in nodes_map:
            nodes_map[self_label] = "self"

        if counter_label not in nodes_map:
            nodes_map[counter_label] = "suspect" if not tx.is_transit else "transit"

        if tx.direction.value == "out":
            key = (self_label, counter_label)
        else:
            key = (counter_label, self_label)

        edge_agg[key]["amount"] += float(tx.amount)
        edge_agg[key]["count"] += 1
        time_str = tx.trade_time.strftime("%Y-%m-%d %H:%M") if tx.trade_time else ""
        if not edge_agg[key]["trade_time"]:
            edge_agg[key]["trade_time"] = time_str

    nodes = [
        FlowNodeOut(id=f"n-{i}", label=label, type=ntype)
        for i, (label, ntype) in enumerate(nodes_map.items())
    ]

    label_to_id = {n.label: n.id for n in nodes}

    edges = [
        FlowEdgeOut(
            source=label_to_id[src],
            target=label_to_id[tgt],
            amount=info["amount"],
            count=info["count"],
            trade_time=info["trade_time"],
        )
        for (src, tgt), info in edge_agg.items()
    ]

    return FlowGraphOut(nodes=nodes, edges=edges)


def _self_label(tx) -> str:
    app_names = {
        "wechat": "微信支付",
        "alipay": "支付宝",
        "bank": f"银行卡({tx.self_account_tail_no})" if tx.self_account_tail_no else "银行卡",
        "digital_wallet": "数字钱包",
        "other": "其他账户",
    }
    return app_names.get(tx.source_app.value, "未知账户")