"""库存管理业务逻辑"""
import uuid
from datetime import date, datetime
from typing import Optional, List
from sqlalchemy.orm import Session
from sqlalchemy import func, text
from fastapi import HTTPException

from app.models.inventory import (
    MaterialCategory, Material, InventoryBatch,
    SerialDevice, InventoryTransaction, InventoryCheck
)


def _gen_no(prefix: str) -> str:
    return f"{prefix}{datetime.now().strftime('%Y%m%d%H%M%S')}{uuid.uuid4().hex[:4].upper()}"


# ── 物料分类 ──────────────────────────────────────────────────────────────────

def get_categories(db: Session) -> List[MaterialCategory]:
    return db.query(MaterialCategory).order_by(MaterialCategory.id).all()


def create_category(db: Session, name: str, code: str, description: Optional[str]) -> MaterialCategory:
    if db.query(MaterialCategory).filter(MaterialCategory.code == code).first():
        raise HTTPException(status_code=400, detail="分类代码已存在")
    cat = MaterialCategory(name=name, code=code, description=description)
    db.add(cat)
    db.commit()
    db.refresh(cat)
    return cat


# ── 物料 ──────────────────────────────────────────────────────────────────────

def get_materials(db: Session, skip: int, limit: int, category_id: Optional[int], keyword: Optional[str]):
    q = db.query(Material)
    if category_id:
        q = q.filter(Material.category_id == category_id)
    if keyword:
        q = q.filter(Material.name.contains(keyword) | Material.model.contains(keyword))
    total = q.count()
    items = q.order_by(Material.id).offset(skip).limit(limit).all()

    result = []
    for m in items:
        total_qty = db.query(func.sum(InventoryBatch.quantity)).filter(
            InventoryBatch.material_id == m.id
        ).scalar() or 0
        avail_qty = db.query(func.sum(InventoryBatch.available_quantity)).filter(
            InventoryBatch.material_id == m.id
        ).scalar() or 0
        item = {
            "id": m.id,
            "category_id": m.category_id,
            "category_name": m.category.name if m.category else None,
            "name": m.name,
            "model": m.model,
            "specification": m.specification,
            "brand": m.brand,
            "unit": m.unit,
            "safe_quantity": m.safe_quantity,
            "notes": m.notes,
            "total_quantity": total_qty,
            "available_quantity": avail_qty,
            "created_at": m.created_at,
        }
        result.append(item)
    return {"total": total, "items": result}


def create_material(db: Session, data: dict) -> Material:
    m = Material(**data)
    db.add(m)
    db.commit()
    db.refresh(m)
    return m


def update_material(db: Session, material_id: int, data: dict) -> Material:
    m = db.query(Material).filter(Material.id == material_id).first()
    if not m:
        raise HTTPException(status_code=404, detail="物料不存在")
    for k, v in data.items():
        if v is not None:
            setattr(m, k, v)
    db.commit()
    db.refresh(m)
    return m


def delete_material(db: Session, material_id: int):
    m = db.query(Material).filter(Material.id == material_id).first()
    if not m:
        raise HTTPException(status_code=404, detail="物料不存在")
    has_stock = db.query(InventoryBatch).filter(
        InventoryBatch.material_id == material_id,
        InventoryBatch.available_quantity > 0,
    ).first()
    if has_stock:
        raise HTTPException(status_code=400, detail="该物料仍有库存，请先出库后再删除")
    db.delete(m)
    db.commit()


# ── 采购入库 ──────────────────────────────────────────────────────────────────

def purchase_in(db: Session, data: dict, operator_id: int) -> dict:
    material_id = data["material_id"]
    m = db.query(Material).filter(Material.id == material_id).first()
    if not m:
        raise HTTPException(status_code=404, detail="物料不存在")

    serial_nos = data.pop("serial_nos", None) or []
    quantity = data["quantity"]

    batch = InventoryBatch(
        material_id=material_id,
        batch_no=data["batch_no"],
        quantity=quantity,
        available_quantity=quantity,
        supplier=data.get("supplier"),
        purchase_date=data.get("purchase_date"),
        purchase_price=data.get("purchase_price"),
        location=data.get("location"),
        status="in_stock",
    )
    db.add(batch)
    db.flush()

    # 高价值设备：逐个创建序列号记录
    for sn in serial_nos:
        sd = SerialDevice(
            material_id=material_id,
            batch_id=batch.id,
            serial_no=sn,
            status="in_stock",
        )
        db.add(sd)

    txn = InventoryTransaction(
        transaction_no=_gen_no("PI"),
        transaction_type="purchase_in",
        material_id=material_id,
        batch_id=batch.id,
        quantity=quantity,
        from_status=None,
        to_status="in_stock",
        operator_id=operator_id,
        notes=data.get("notes"),
    )
    db.add(txn)
    db.commit()
    return {"message": "入库成功", "batch_id": batch.id, "transaction_no": txn.transaction_no}


# ── 领用出库 ──────────────────────────────────────────────────────────────────

def allocate_out(db: Session, data: dict, operator_id: int) -> dict:
    serial_device_id = data.get("serial_device_id")
    batch_id = data.get("batch_id")
    quantity = data.get("quantity", 1)

    if serial_device_id:
        sd = db.query(SerialDevice).filter(SerialDevice.id == serial_device_id).first()
        if not sd:
            raise HTTPException(status_code=404, detail="设备不存在")
        if sd.status != "in_stock":
            raise HTTPException(status_code=400, detail=f"设备当前状态为 {sd.status}，无法领用")

        batch = db.query(InventoryBatch).filter(InventoryBatch.id == sd.batch_id).first()
        if batch:
            batch.available_quantity = max(0, batch.available_quantity - 1)

        sd.status = "allocated"
        sd.installed_info = data.get("installation_info")

        txn = InventoryTransaction(
            transaction_no=_gen_no("AO"),
            transaction_type="allocate_out",
            material_id=sd.material_id,
            batch_id=sd.batch_id,
            serial_device_id=sd.id,
            quantity=1,
            from_status="in_stock",
            to_status="allocated",
            operator_id=operator_id,
            project_name=data.get("project_name"),
            installation_info=data.get("installation_info"),
            notes=data.get("notes"),
        )
        db.add(txn)
        db.commit()
        return {"message": "领用成功", "transaction_no": txn.transaction_no}

    elif batch_id:
        batch = db.query(InventoryBatch).filter(InventoryBatch.id == batch_id).first()
        if not batch:
            raise HTTPException(status_code=404, detail="批次不存在")
        if batch.available_quantity < quantity:
            raise HTTPException(status_code=400, detail="库存不足")

        batch.available_quantity -= quantity

        # 方案三：领用时补录设备标识，存入 installation_info
        device_info = data.get("installation_info") or {}
        if isinstance(device_info, str):
            device_info = {}
        mac = data.get("mac_address", "").strip() if data.get("mac_address") else ""
        sn = data.get("serial_no", "").strip() if data.get("serial_no") else ""
        asset = data.get("asset_no", "").strip() if data.get("asset_no") else ""
        if mac or sn or asset:
            device_info = {k: v for k, v in {"mac_address": mac, "serial_no": sn, "asset_no": asset}.items() if v}

        txn = InventoryTransaction(
            transaction_no=_gen_no("AO"),
            transaction_type="allocate_out",
            material_id=batch.material_id,
            batch_id=batch_id,
            quantity=quantity,
            from_status="in_stock",
            to_status="allocated",
            operator_id=operator_id,
            project_name=data.get("project_name"),
            installation_info=device_info if device_info else None,
            notes=data.get("notes"),
        )
        db.add(txn)
        db.commit()
        return {"message": "领用成功", "transaction_no": txn.transaction_no}

    raise HTTPException(status_code=400, detail="需要指定序列号设备或批次")


# ── 退库 ──────────────────────────────────────────────────────────────────────

def return_in(db: Session, serial_device_id: int, return_type: str, notes: Optional[str], operator_id: int) -> dict:
    sd = db.query(SerialDevice).filter(SerialDevice.id == serial_device_id).first()
    if not sd:
        raise HTTPException(status_code=404, detail="设备不存在")

    from_status = sd.status
    if return_type == "scrap":
        to_status = "scrapped"
    elif return_type == "repair":
        to_status = "repairing"
    else:
        to_status = "in_stock"
        # 归还时恢复批次可用数量
        if sd.batch_id:
            batch = db.query(InventoryBatch).filter(InventoryBatch.id == sd.batch_id).first()
            if batch:
                batch.available_quantity += 1

    sd.status = to_status

    txn = InventoryTransaction(
        transaction_no=_gen_no("RI"),
        transaction_type="return_in" if return_type != "scrap" else "scrap_out",
        material_id=sd.material_id,
        batch_id=sd.batch_id,
        serial_device_id=sd.id,
        quantity=1,
        from_status=from_status,
        to_status=to_status,
        operator_id=operator_id,
        notes=notes,
    )
    db.add(txn)
    db.commit()
    return {"message": "退库成功", "transaction_no": txn.transaction_no}


# ── 批次查询 ──────────────────────────────────────────────────────────────────

def get_batches_by_material(db: Session, material_id: int) -> list:
    batches = db.query(InventoryBatch).filter(
        InventoryBatch.material_id == material_id,
        InventoryBatch.available_quantity > 0,
    ).order_by(InventoryBatch.id.desc()).all()
    return [
        {
            "id": b.id,
            "batch_no": b.batch_no,
            "quantity": b.quantity,
            "available_quantity": b.available_quantity,
            "supplier": b.supplier,
            "location": b.location,
        }
        for b in batches
    ]


# ── 序列号设备查询 ────────────────────────────────────────────────────────────

def get_serial_devices(db: Session, skip: int, limit: int, material_id: Optional[int], status: Optional[str], keyword: Optional[str]):
    q = db.query(SerialDevice)
    if material_id:
        q = q.filter(SerialDevice.material_id == material_id)
    if status:
        q = q.filter(SerialDevice.status == status)
    if keyword:
        q = q.filter(
            SerialDevice.serial_no.contains(keyword) |
            SerialDevice.mac_address.contains(keyword) |
            SerialDevice.asset_no.contains(keyword)
        )
    total = q.count()
    items = q.order_by(SerialDevice.id.desc()).offset(skip).limit(limit).all()

    result = []
    for sd in items:
        result.append({
            "id": sd.id,
            "material_id": sd.material_id,
            "material_name": sd.material.name if sd.material else None,
            "batch_id": sd.batch_id,
            "serial_no": sd.serial_no,
            "mac_address": sd.mac_address,
            "asset_no": sd.asset_no,
            "status": sd.status,
            "current_location": sd.current_location,
            "installed_info": sd.installed_info,
            "notes": sd.notes,
            "created_at": sd.created_at,
            "updated_at": sd.updated_at,
        })
    return {"total": total, "items": result}


def get_transaction_detail(db: Session, transaction_id: int) -> dict:
    t = db.query(InventoryTransaction).filter(InventoryTransaction.id == transaction_id).first()
    if not t:
        raise HTTPException(status_code=404, detail="记录不存在")

    m = db.query(Material).filter(Material.id == t.material_id).first()
    batch = db.query(InventoryBatch).filter(InventoryBatch.id == t.batch_id).first() if t.batch_id else None
    sd = db.query(SerialDevice).filter(SerialDevice.id == t.serial_device_id).first() if t.serial_device_id else None

    return {
        "id": t.id,
        "transaction_no": t.transaction_no,
        "transaction_type": t.transaction_type,
        "material_id": t.material_id,
        "material_name": m.name if m else None,
        "material_model": m.model if m else None,
        "material_brand": m.brand if m else None,
        "quantity": t.quantity,
        "from_status": t.from_status,
        "to_status": t.to_status,
        "operator_id": t.operator_id,
        "project_name": t.project_name,
        "installation_info": t.installation_info,
        "notes": t.notes,
        "created_at": t.created_at,
        "batch": {
            "id": batch.id,
            "batch_no": batch.batch_no,
            "supplier": batch.supplier,
            "purchase_date": str(batch.purchase_date) if batch.purchase_date else None,
            "purchase_price": str(batch.purchase_price) if batch.purchase_price else None,
            "location": batch.location,
        } if batch else None,
        "serial_device": {
            "id": sd.id,
            "serial_no": sd.serial_no,
            "mac_address": sd.mac_address,
            "asset_no": sd.asset_no,
        } if sd else None,
    }




def get_transactions(db: Session, skip: int, limit: int, transaction_type: Optional[str], material_id: Optional[int]):
    q = db.query(InventoryTransaction)
    if transaction_type:
        q = q.filter(InventoryTransaction.transaction_type == transaction_type)
    if material_id:
        q = q.filter(InventoryTransaction.material_id == material_id)
    total = q.count()
    items = q.order_by(InventoryTransaction.id.desc()).offset(skip).limit(limit).all()

    result = []
    for t in items:
        m = db.query(Material).filter(Material.id == t.material_id).first()
        result.append({
            "id": t.id,
            "transaction_no": t.transaction_no,
            "transaction_type": t.transaction_type,
            "material_id": t.material_id,
            "material_name": m.name if m else None,
            "quantity": t.quantity,
            "from_status": t.from_status,
            "to_status": t.to_status,
            "operator_id": t.operator_id,
            "project_name": t.project_name,
            "installation_info": t.installation_info,
            "notes": t.notes,
            "created_at": t.created_at,
        })
    return {"total": total, "items": result}


# ── 库存总览 ──────────────────────────────────────────────────────────────────

def get_summary(db: Session) -> dict:
    total_materials = db.query(Material).count()
    total_qty = db.query(func.sum(InventoryBatch.quantity)).scalar() or 0
    avail_qty = db.query(func.sum(InventoryBatch.available_quantity)).scalar() or 0
    allocated_qty = total_qty - avail_qty

    # 低库存物料数
    low_stock = db.execute(text("""
        SELECT COUNT(*) FROM (
            SELECT m.id, m.safe_quantity, COALESCE(SUM(b.available_quantity), 0) AS avail
            FROM materials m
            LEFT JOIN inventory_batches b ON b.material_id = m.id
            GROUP BY m.id, m.safe_quantity
            HAVING COALESCE(SUM(b.available_quantity), 0) <= m.safe_quantity AND m.safe_quantity > 0
        ) t
    """)).scalar() or 0

    # 按分类统计
    rows = db.execute(text("""
        SELECT c.name, COUNT(m.id) AS material_count,
               COALESCE(SUM(b.available_quantity), 0) AS available
        FROM material_categories c
        LEFT JOIN materials m ON m.category_id = c.id
        LEFT JOIN inventory_batches b ON b.material_id = m.id
        GROUP BY c.id, c.name
        ORDER BY c.id
    """)).fetchall()

    category_stats = [{"name": r[0], "material_count": r[1], "available": r[2]} for r in rows]

    return {
        "total_materials": total_materials,
        "total_quantity": total_qty,
        "available_quantity": avail_qty,
        "allocated_quantity": allocated_qty,
        "low_stock_count": low_stock,
        "category_stats": category_stats,
    }


# ── 盘点 ──────────────────────────────────────────────────────────────────────

def create_check(db: Session, data: dict, checker_id: int) -> InventoryCheck:
    material_id = data["material_id"]
    batch_id = data.get("batch_id")

    if batch_id:
        batch = db.query(InventoryBatch).filter(InventoryBatch.id == batch_id).first()
        book_qty = batch.available_quantity if batch else 0
    else:
        book_qty = db.query(func.sum(InventoryBatch.available_quantity)).filter(
            InventoryBatch.material_id == material_id
        ).scalar() or 0

    actual_qty = data["actual_quantity"]
    diff = actual_qty - book_qty

    check = InventoryCheck(
        check_no=_gen_no("CK"),
        check_date=data["check_date"],
        checker_id=checker_id,
        material_id=material_id,
        batch_id=batch_id,
        book_quantity=book_qty,
        actual_quantity=actual_qty,
        difference=diff,
        reason=data.get("reason"),
        adjusted=False,
    )
    db.add(check)
    db.commit()
    db.refresh(check)
    return check


def adjust_check(db: Session, check_id: int, operator_id: int) -> dict:
    check = db.query(InventoryCheck).filter(InventoryCheck.id == check_id).first()
    if not check:
        raise HTTPException(status_code=404, detail="盘点记录不存在")
    if check.adjusted:
        raise HTTPException(status_code=400, detail="已调整过")

    if check.batch_id:
        batch = db.query(InventoryBatch).filter(InventoryBatch.id == check.batch_id).first()
        if batch:
            batch.available_quantity = check.actual_quantity
    else:
        # 调整第一个批次（简化处理）
        batch = db.query(InventoryBatch).filter(
            InventoryBatch.material_id == check.material_id
        ).first()
        if batch:
            batch.available_quantity = check.actual_quantity

    txn = InventoryTransaction(
        transaction_no=_gen_no("ADJ"),
        transaction_type="adjust",
        material_id=check.material_id,
        batch_id=check.batch_id,
        quantity=abs(check.difference or 0),
        from_status="in_stock",
        to_status="in_stock",
        operator_id=operator_id,
        notes=f"盘点调整：{check.check_no}，差异 {check.difference}",
    )
    db.add(txn)
    check.adjusted = True
    db.commit()
    return {"message": "调整成功"}


def get_checks(db: Session, skip: int, limit: int, material_id: Optional[int]):
    q = db.query(InventoryCheck)
    if material_id:
        q = q.filter(InventoryCheck.material_id == material_id)
    total = q.count()
    items = q.order_by(InventoryCheck.id.desc()).offset(skip).limit(limit).all()

    result = []
    for c in items:
        m = db.query(Material).filter(Material.id == c.material_id).first()
        result.append({
            "id": c.id,
            "check_no": c.check_no,
            "check_date": c.check_date,
            "material_id": c.material_id,
            "material_name": m.name if m else None,
            "batch_id": c.batch_id,
            "book_quantity": c.book_quantity,
            "actual_quantity": c.actual_quantity,
            "difference": c.difference,
            "reason": c.reason,
            "adjusted": c.adjusted,
            "created_at": c.created_at,
        })
    return {"total": total, "items": result}