import csv
import io
from datetime import datetime, timedelta, timezone

from fastapi import APIRouter, Depends, Query, HTTPException
from fastapi.responses import StreamingResponse
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, func, and_, text, Integer
from sqlalchemy.orm import joinedload
from pydantic import BaseModel
from app.core.database import get_db
from app.core.config import get_settings
from app.core.deps import get_current_user
from app.models.energy import EnergyData, EnergyDailySummary, EnergyCategory
from app.models.device import Device
from app.models.user import User
from app.core.deps import require_roles

router = APIRouter(prefix="/energy", tags=["能耗数据"])


@router.get("/history")
async def query_history(
    device_id: int | None = None,
    data_type: str = "power",
    start_time: str | None = None,
    end_time: str | None = None,
    granularity: str = Query("hour", pattern="^(raw|5min|hour|day)$"),
    page: int = Query(1, ge=1),
    page_size: int = Query(100, ge=1, le=1000),
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """历史数据查询"""
    query = select(EnergyData).where(EnergyData.data_type == data_type)
    if device_id:
        query = query.where(EnergyData.device_id == device_id)
    if start_time:
        query = query.where(EnergyData.timestamp >= start_time)
    if end_time:
        query = query.where(EnergyData.timestamp <= end_time)

    if granularity == "raw":
        query = query.order_by(EnergyData.timestamp.desc()).offset((page - 1) * page_size).limit(page_size)
        result = await db.execute(query)
        return [{"timestamp": str(d.timestamp), "value": d.value, "unit": d.unit, "device_id": d.device_id}
                for d in result.scalars().all()]
    else:
        settings = get_settings()
        if granularity == "5min":
            if settings.is_sqlite:
                time_bucket = func.strftime('%Y-%m-%d %H:', EnergyData.timestamp).op('||')(
                    func.printf('%02d:00', (func.cast(func.strftime('%M', EnergyData.timestamp), Integer) / 5) * 5)
                ).label('time_bucket')
            else:
                time_bucket = func.to_timestamp(
                    func.floor(func.extract('epoch', EnergyData.timestamp) / 300) * 300
                ).label('time_bucket')
        elif granularity == "hour":
            if settings.is_sqlite:
                time_bucket = func.strftime('%Y-%m-%d %H:00:00', EnergyData.timestamp).label('time_bucket')
            else:
                time_bucket = func.date_trunc('hour', EnergyData.timestamp).label('time_bucket')
        else:  # day
            if settings.is_sqlite:
                time_bucket = func.strftime('%Y-%m-%d', EnergyData.timestamp).label('time_bucket')
            else:
                time_bucket = func.date_trunc('day', EnergyData.timestamp).label('time_bucket')
        agg_query = select(
            time_bucket,
            func.avg(EnergyData.value).label('avg_value'),
            func.max(EnergyData.value).label('max_value'),
            func.min(EnergyData.value).label('min_value'),
        ).where(EnergyData.data_type == data_type)
        if device_id:
            agg_query = agg_query.where(EnergyData.device_id == device_id)
        if start_time:
            agg_query = agg_query.where(EnergyData.timestamp >= start_time)
        if end_time:
            agg_query = agg_query.where(EnergyData.timestamp <= end_time)
        agg_query = agg_query.group_by(text('time_bucket')).order_by(text('time_bucket'))
        result = await db.execute(agg_query)
        return [{"time": str(r[0]), "avg": round(r[1], 2), "max": round(r[2], 2), "min": round(r[3], 2)}
                for r in result.all()]


@router.get("/params")
async def query_electrical_params(
    device_id: int = Query(..., description="设备ID"),
    params: str = Query("power", description="参数列表(逗号分隔): power,voltage,current,power_factor,temperature,frequency,cop"),
    start_time: str | None = None,
    end_time: str | None = None,
    granularity: str = Query("raw", pattern="^(raw|5min|hour|day)$"),
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """电参量查询 - Query multiple electrical parameters for a device"""
    param_list = [p.strip() for p in params.split(",") if p.strip()]
    result_data = {}
    settings = get_settings()

    for param in param_list:
        base_filter = and_(
            EnergyData.device_id == device_id,
            EnergyData.data_type == param,
        )
        conditions = [base_filter]
        if start_time:
            conditions.append(EnergyData.timestamp >= start_time)
        if end_time:
            conditions.append(EnergyData.timestamp <= end_time)
        combined = and_(*conditions)

        if granularity == "raw":
            query = (
                select(EnergyData.timestamp, EnergyData.value, EnergyData.unit)
                .where(combined)
                .order_by(EnergyData.timestamp)
                .limit(5000)
            )
            rows = await db.execute(query)
            result_data[param] = [
                {"timestamp": str(r[0]), "value": r[1], "unit": r[2]}
                for r in rows.all()
            ]
        else:
            if granularity == "5min":
                if settings.is_sqlite:
                    time_bucket = func.strftime('%Y-%m-%d %H:', EnergyData.timestamp).op('||')(
                        func.printf('%02d:00', (func.cast(func.strftime('%M', EnergyData.timestamp), Integer) / 5) * 5)
                    ).label('time_bucket')
                else:
                    time_bucket = func.to_timestamp(
                        func.floor(func.extract('epoch', EnergyData.timestamp) / 300) * 300
                    ).label('time_bucket')
            elif granularity == "hour":
                if settings.is_sqlite:
                    time_bucket = func.strftime('%Y-%m-%d %H:00:00', EnergyData.timestamp).label('time_bucket')
                else:
                    time_bucket = func.date_trunc('hour', EnergyData.timestamp).label('time_bucket')
            else:  # day
                if settings.is_sqlite:
                    time_bucket = func.strftime('%Y-%m-%d', EnergyData.timestamp).label('time_bucket')
                else:
                    time_bucket = func.date_trunc('day', EnergyData.timestamp).label('time_bucket')

            agg_query = (
                select(time_bucket, func.avg(EnergyData.value).label('avg_value'))
                .where(combined)
                .group_by(text('time_bucket'))
                .order_by(text('time_bucket'))
            )
            rows = await db.execute(agg_query)
            result_data[param] = [
                {"timestamp": str(r[0]), "value": round(r[1], 2)}
                for r in rows.all()
            ]

    return result_data


@router.get("/daily-summary")
async def daily_summary(
    start_date: str | None = None,
    end_date: str | None = None,
    energy_type: str | None = None,
    device_id: int | None = None,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """每日能耗汇总"""
    query = select(EnergyDailySummary)
    if start_date:
        query = query.where(EnergyDailySummary.date >= start_date)
    if end_date:
        query = query.where(EnergyDailySummary.date <= end_date)
    if energy_type:
        query = query.where(EnergyDailySummary.energy_type == energy_type)
    if device_id:
        query = query.where(EnergyDailySummary.device_id == device_id)
    query = query.order_by(EnergyDailySummary.date.desc()).limit(365)
    result = await db.execute(query)
    return [{
        "date": str(s.date), "device_id": s.device_id, "energy_type": s.energy_type,
        "consumption": s.total_consumption, "generation": s.total_generation,
        "peak_power": s.peak_power, "avg_power": s.avg_power,
        "operating_hours": s.operating_hours, "cost": s.cost, "carbon_emission": s.carbon_emission,
    } for s in result.scalars().all()]


@router.get("/comparison")
async def energy_comparison(
    device_id: int | None = None,
    energy_type: str = "electricity",
    period: str = Query("month", pattern="^(day|week|month|year)$"),
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """能耗同比环比分析"""
    now = datetime.now(timezone.utc)
    if period == "day":
        current_start = now.replace(hour=0, minute=0, second=0, microsecond=0)
        prev_start = current_start - timedelta(days=1)
        yoy_start = current_start.replace(year=current_start.year - 1)
    elif period == "week":
        current_start = now - timedelta(days=now.weekday())
        current_start = current_start.replace(hour=0, minute=0, second=0, microsecond=0)
        prev_start = current_start - timedelta(weeks=1)
        yoy_start = current_start.replace(year=current_start.year - 1)
    elif period == "month":
        current_start = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
        prev_start = (current_start - timedelta(days=1)).replace(day=1)
        yoy_start = current_start.replace(year=current_start.year - 1)
    else:
        current_start = now.replace(month=1, day=1, hour=0, minute=0, second=0, microsecond=0)
        prev_start = current_start.replace(year=current_start.year - 1)
        yoy_start = prev_start

    async def sum_consumption(start, end):
        q = select(func.sum(EnergyDailySummary.total_consumption)).where(
            and_(EnergyDailySummary.date >= start, EnergyDailySummary.date < end,
                 EnergyDailySummary.energy_type == energy_type)
        )
        if device_id:
            q = q.where(EnergyDailySummary.device_id == device_id)
        r = await db.execute(q)
        return r.scalar() or 0

    current = await sum_consumption(current_start, now)
    previous = await sum_consumption(prev_start, current_start)
    yoy = await sum_consumption(yoy_start, yoy_start.replace(year=yoy_start.year + 1))

    return {
        "current": round(current, 2),
        "previous": round(previous, 2),
        "yoy": round(yoy, 2),
        "mom_change": round((current - previous) / previous * 100, 1) if previous else 0,
        "yoy_change": round((current - yoy) / yoy * 100, 1) if yoy else 0,
    }


@router.get("/export")
async def export_energy_data(
    start_time: str = Query(..., description="开始时间, e.g. 2026-03-01"),
    end_time: str = Query(..., description="结束时间, e.g. 2026-03-31"),
    device_id: int | None = Query(None, description="设备ID (可选)"),
    data_type: str | None = Query(None, description="数据类型 (可选, e.g. power, energy)"),
    format: str = Query("csv", pattern="^(csv|xlsx)$", description="导出格式: csv 或 xlsx"),
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """导出能耗数据为CSV或Excel文件"""
    # Parse date strings to datetime for proper PostgreSQL comparison
    try:
        start_dt = datetime.fromisoformat(start_time)
    except ValueError:
        start_dt = datetime.strptime(start_time, "%Y-%m-%d")
    try:
        end_dt = datetime.fromisoformat(end_time)
    except ValueError:
        end_dt = datetime.strptime(end_time, "%Y-%m-%d").replace(hour=23, minute=59, second=59)

    # If end_time was just a date (no time component), set to end of day
    if end_dt.hour == 0 and end_dt.minute == 0 and end_dt.second == 0 and "T" not in end_time:
        end_dt = end_dt.replace(hour=23, minute=59, second=59)

    # Query energy data with device names
    query = (
        select(EnergyData, Device.name.label("device_name"))
        .join(Device, EnergyData.device_id == Device.id, isouter=True)
        .where(
            and_(
                EnergyData.timestamp >= start_dt,
                EnergyData.timestamp <= end_dt,
            )
        )
    )
    if device_id:
        query = query.where(EnergyData.device_id == device_id)
    if data_type:
        query = query.where(EnergyData.data_type == data_type)
    query = query.order_by(EnergyData.timestamp)

    result = await db.execute(query)
    rows = result.all()

    headers = ["timestamp", "device_name", "data_type", "value", "unit"]
    data_rows = []
    for row in rows:
        energy = row[0]  # EnergyData object
        device_name = row[1] or f"Device#{energy.device_id}"
        data_rows.append([
            str(energy.timestamp) if energy.timestamp else "",
            device_name,
            energy.data_type or "",
            energy.value,
            energy.unit or "",
        ])

    date_suffix = f"{start_time}_{end_time}".replace("-", "")
    if format == "xlsx":
        return _export_xlsx(headers, data_rows, f"energy_export_{date_suffix}.xlsx")
    else:
        return _export_csv(headers, data_rows, f"energy_export_{date_suffix}.csv")


def _export_csv(headers: list[str], rows: list[list], filename: str) -> StreamingResponse:
    """Generate CSV streaming response."""
    output = io.StringIO()
    # Add BOM for Excel compatibility with Chinese characters
    output.write('\ufeff')
    writer = csv.writer(output)
    writer.writerow(headers)
    writer.writerows(rows)
    output.seek(0)
    return StreamingResponse(
        iter([output.getvalue()]),
        media_type="text/csv; charset=utf-8",
        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
    )


def _export_xlsx(headers: list[str], rows: list[list], filename: str) -> StreamingResponse:
    """Generate XLSX streaming response."""
    from openpyxl import Workbook
    from openpyxl.styles import Font, PatternFill, Alignment, Border, Side

    wb = Workbook()
    ws = wb.active
    ws.title = "能耗数据"

    header_font = Font(bold=True, color="FFFFFF", size=11)
    header_fill = PatternFill(start_color="336699", end_color="336699", fill_type="solid")
    header_align = Alignment(horizontal="center", vertical="center")
    thin_border = Border(
        left=Side(style="thin", color="CCCCCC"),
        right=Side(style="thin", color="CCCCCC"),
        top=Side(style="thin", color="CCCCCC"),
        bottom=Side(style="thin", color="CCCCCC"),
    )

    # Write headers
    for col_idx, h in enumerate(headers, 1):
        cell = ws.cell(row=1, column=col_idx, value=h)
        cell.font = header_font
        cell.fill = header_fill
        cell.alignment = header_align
        cell.border = thin_border

    # Write data
    for row_idx, row_data in enumerate(rows, 2):
        for col_idx, val in enumerate(row_data, 1):
            cell = ws.cell(row=row_idx, column=col_idx, value=val)
            cell.border = thin_border
            if isinstance(val, float):
                cell.number_format = "#,##0.00"

    # Auto-width
    for col_idx in range(1, len(headers) + 1):
        max_len = len(str(headers[col_idx - 1]))
        for row_idx in range(2, min(len(rows) + 2, 102)):
            val = ws.cell(row=row_idx, column=col_idx).value
            if val:
                max_len = max(max_len, len(str(val)))
        ws.column_dimensions[ws.cell(row=1, column=col_idx).column_letter].width = min(max_len + 4, 40)

    ws.freeze_panes = "A2"
    if rows:
        ws.auto_filter.ref = f"A1:{ws.cell(row=1, column=len(headers)).column_letter}{len(rows) + 1}"

    output = io.BytesIO()
    wb.save(output)
    output.seek(0)

    return StreamingResponse(
        output,
        media_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
    )


# ── Energy Category (分项能耗) ──────────────────────────────────────

class CategoryCreate(BaseModel):
    name: str
    code: str
    parent_id: int | None = None
    sort_order: int = 0
    icon: str | None = None
    color: str | None = None


def _category_to_dict(c: EnergyCategory) -> dict:
    return {
        "id": c.id, "name": c.name, "code": c.code,
        "parent_id": c.parent_id, "sort_order": c.sort_order,
        "icon": c.icon, "color": c.color,
        "created_at": str(c.created_at) if c.created_at else None,
    }


def _build_category_tree(items: list[dict], parent_id: int | None = None) -> list[dict]:
    tree = []
    for item in items:
        if item["parent_id"] == parent_id:
            children = _build_category_tree(items, item["id"])
            if children:
                item["children"] = children
            tree.append(item)
    return tree


@router.get("/categories")
async def list_categories(
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """获取能耗分项类别(树结构)"""
    result = await db.execute(
        select(EnergyCategory).order_by(EnergyCategory.sort_order, EnergyCategory.id)
    )
    items = [_category_to_dict(c) for c in result.scalars().all()]
    return _build_category_tree(items)


@router.post("/categories")
async def create_category(
    data: CategoryCreate,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(require_roles("admin", "energy_manager")),
):
    """创建能耗分项类别"""
    cat = EnergyCategory(**data.model_dump())
    db.add(cat)
    await db.flush()
    return _category_to_dict(cat)


@router.put("/categories/{cat_id}")
async def update_category(
    cat_id: int,
    data: CategoryCreate,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(require_roles("admin", "energy_manager")),
):
    """更新能耗分项类别"""
    result = await db.execute(select(EnergyCategory).where(EnergyCategory.id == cat_id))
    cat = result.scalar_one_or_none()
    if not cat:
        raise HTTPException(status_code=404, detail="分项类别不存在")
    for k, v in data.model_dump(exclude_unset=True).items():
        setattr(cat, k, v)
    return _category_to_dict(cat)


@router.get("/by-category")
async def energy_by_category(
    start_date: str | None = None,
    end_date: str | None = None,
    energy_type: str = "electricity",
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """按分项类别统计能耗"""
    query = (
        select(
            EnergyCategory.id,
            EnergyCategory.name,
            EnergyCategory.code,
            EnergyCategory.color,
            func.coalesce(func.sum(EnergyDailySummary.total_consumption), 0).label("consumption"),
        )
        .select_from(EnergyCategory)
        .outerjoin(Device, Device.category_id == EnergyCategory.id)
        .outerjoin(
            EnergyDailySummary,
            and_(
                EnergyDailySummary.device_id == Device.id,
                EnergyDailySummary.energy_type == energy_type,
            ),
        )
    )
    if start_date:
        query = query.where(EnergyDailySummary.date >= start_date)
    if end_date:
        query = query.where(EnergyDailySummary.date <= end_date)
    query = query.group_by(EnergyCategory.id, EnergyCategory.name, EnergyCategory.code, EnergyCategory.color)
    result = await db.execute(query)
    rows = result.all()
    total = sum(r.consumption for r in rows) or 1
    return [
        {
            "id": r.id, "name": r.name, "code": r.code, "color": r.color,
            "consumption": round(r.consumption, 2),
            "percentage": round(r.consumption / total * 100, 1),
        }
        for r in rows
    ]


@router.get("/category-ranking")
async def category_ranking(
    start_date: str | None = None,
    end_date: str | None = None,
    energy_type: str = "electricity",
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """分项能耗排名"""
    query = (
        select(
            EnergyCategory.name,
            EnergyCategory.color,
            func.coalesce(func.sum(EnergyDailySummary.total_consumption), 0).label("consumption"),
        )
        .select_from(EnergyCategory)
        .outerjoin(Device, Device.category_id == EnergyCategory.id)
        .outerjoin(
            EnergyDailySummary,
            and_(
                EnergyDailySummary.device_id == Device.id,
                EnergyDailySummary.energy_type == energy_type,
            ),
        )
    )
    if start_date:
        query = query.where(EnergyDailySummary.date >= start_date)
    if end_date:
        query = query.where(EnergyDailySummary.date <= end_date)
    query = query.group_by(EnergyCategory.name, EnergyCategory.color).order_by(text("consumption DESC"))
    result = await db.execute(query)
    return [{"name": r.name, "color": r.color, "consumption": round(r.consumption, 2)} for r in result.all()]


@router.get("/category-trend")
async def category_trend(
    start_date: str | None = None,
    end_date: str | None = None,
    energy_type: str = "electricity",
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """分项能耗每日趋势"""
    query = (
        select(
            EnergyDailySummary.date,
            EnergyCategory.name,
            EnergyCategory.color,
            func.coalesce(func.sum(EnergyDailySummary.total_consumption), 0).label("consumption"),
        )
        .select_from(EnergyDailySummary)
        .join(Device, EnergyDailySummary.device_id == Device.id)
        .join(EnergyCategory, Device.category_id == EnergyCategory.id)
        .where(EnergyDailySummary.energy_type == energy_type)
    )
    if start_date:
        query = query.where(EnergyDailySummary.date >= start_date)
    if end_date:
        query = query.where(EnergyDailySummary.date <= end_date)
    query = query.group_by(EnergyDailySummary.date, EnergyCategory.name, EnergyCategory.color)
    query = query.order_by(EnergyDailySummary.date)
    result = await db.execute(query)
    return [
        {"date": str(r.date), "category": r.name, "color": r.color, "consumption": round(r.consumption, 2)}
        for r in result.all()
    ]


# ── Loss / YoY / MoM Analysis ─────────────────────────────────────

from app.models.device import DeviceGroup


@router.get("/loss")
async def get_energy_loss(
    start_date: str,
    end_date: str,
    energy_type: str = "electricity",
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """能耗损耗分析 - Compare parent meter vs sum of sub-meters"""
    # Get all groups that have children
    groups_result = await db.execute(select(DeviceGroup))
    all_groups = groups_result.scalars().all()
    group_map = {g.id: g for g in all_groups}
    parent_ids = {g.parent_id for g in all_groups if g.parent_id is not None}

    results = []
    for gid in parent_ids:
        group = group_map.get(gid)
        if not group:
            continue
        child_group_ids = [g.id for g in all_groups if g.parent_id == gid]

        # Parent consumption: devices directly in this group
        parent_q = select(func.coalesce(func.sum(EnergyDailySummary.total_consumption), 0)).select_from(
            EnergyDailySummary
        ).join(Device, EnergyDailySummary.device_id == Device.id).where(
            and_(
                Device.group_id == gid,
                EnergyDailySummary.energy_type == energy_type,
                EnergyDailySummary.date >= start_date,
                EnergyDailySummary.date <= end_date,
            )
        )
        parent_consumption = (await db.execute(parent_q)).scalar() or 0

        # Children consumption: devices in child groups
        if child_group_ids:
            children_q = select(func.coalesce(func.sum(EnergyDailySummary.total_consumption), 0)).select_from(
                EnergyDailySummary
            ).join(Device, EnergyDailySummary.device_id == Device.id).where(
                and_(
                    Device.group_id.in_(child_group_ids),
                    EnergyDailySummary.energy_type == energy_type,
                    EnergyDailySummary.date >= start_date,
                    EnergyDailySummary.date <= end_date,
                )
            )
            children_consumption = (await db.execute(children_q)).scalar() or 0
        else:
            children_consumption = 0

        loss = parent_consumption - children_consumption
        loss_rate = (loss / parent_consumption * 100) if parent_consumption > 0 else 0

        results.append({
            "group_name": group.name,
            "parent_consumption": round(parent_consumption, 2),
            "children_consumption": round(children_consumption, 2),
            "loss": round(loss, 2),
            "loss_rate_pct": round(loss_rate, 1),
        })

    return results


@router.get("/yoy")
async def get_yoy_comparison(
    year: int | None = None,
    energy_type: str = "electricity",
    group_id: int | None = None,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """同比分析 - Current year vs previous year, month by month"""
    current_year = year or datetime.now(timezone.utc).year
    prev_year = current_year - 1
    settings = get_settings()

    results = []
    for month in range(1, 13):
        for yr, label in [(current_year, "current_year"), (prev_year, "previous_year")]:
            month_start = f"{yr}-{month:02d}-01"
            if month == 12:
                month_end = f"{yr + 1}-01-01"
            else:
                month_end = f"{yr}-{month + 1:02d}-01"

            q = select(func.coalesce(func.sum(EnergyDailySummary.total_consumption), 0)).where(
                and_(
                    EnergyDailySummary.energy_type == energy_type,
                    EnergyDailySummary.date >= month_start,
                    EnergyDailySummary.date < month_end,
                )
            )
            if group_id:
                q = q.select_from(EnergyDailySummary).join(
                    Device, EnergyDailySummary.device_id == Device.id
                ).where(Device.group_id == group_id)

            val = (await db.execute(q)).scalar() or 0
            # Find or create month entry
            existing = next((r for r in results if r["month"] == month), None)
            if not existing:
                existing = {"month": month, "current_year": 0, "previous_year": 0, "change_pct": 0}
                results.append(existing)
            existing[label] = round(val, 2)

    # Calculate change percentages
    for r in results:
        if r["previous_year"] > 0:
            r["change_pct"] = round((r["current_year"] - r["previous_year"]) / r["previous_year"] * 100, 1)

    return results


@router.get("/mom")
async def get_mom_comparison(
    period: str = "month",
    energy_type: str = "electricity",
    group_id: int | None = None,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """环比分析 - Current period vs previous period"""
    now = datetime.now(timezone.utc)

    if period == "month":
        current_start = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
        prev_start = (current_start - timedelta(days=1)).replace(day=1)
        # Generate daily labels
        days_in_month = (now - current_start).days + 1
        prev_end = current_start
        labels = [f"{i + 1}日" for i in range(31)]
    elif period == "week":
        current_start = (now - timedelta(days=now.weekday())).replace(hour=0, minute=0, second=0, microsecond=0)
        prev_start = current_start - timedelta(weeks=1)
        prev_end = current_start
        labels = ["周一", "周二", "周三", "周四", "周五", "周六", "周日"]
    else:  # day
        current_start = now.replace(hour=0, minute=0, second=0, microsecond=0)
        prev_start = current_start - timedelta(days=1)
        prev_end = current_start
        labels = [f"{i}:00" for i in range(24)]

    async def get_period_data(start, end):
        q = select(
            EnergyDailySummary.date,
            func.sum(EnergyDailySummary.total_consumption).label("consumption"),
        ).where(
            and_(
                EnergyDailySummary.energy_type == energy_type,
                EnergyDailySummary.date >= str(start)[:10],
                EnergyDailySummary.date < str(end)[:10],
            )
        )
        if group_id:
            q = q.select_from(EnergyDailySummary).join(
                Device, EnergyDailySummary.device_id == Device.id
            ).where(Device.group_id == group_id)
        q = q.group_by(EnergyDailySummary.date).order_by(EnergyDailySummary.date)
        result = await db.execute(q)
        return [{"date": str(r.date), "consumption": round(r.consumption, 2)} for r in result.all()]

    current_data = await get_period_data(current_start, now)
    previous_data = await get_period_data(prev_start, prev_end)

    # Build comparison items
    max_len = max(len(current_data), len(previous_data), 1)
    items = []
    for i in range(max_len):
        cur_val = current_data[i]["consumption"] if i < len(current_data) else 0
        prev_val = previous_data[i]["consumption"] if i < len(previous_data) else 0
        change_pct = round((cur_val - prev_val) / prev_val * 100, 1) if prev_val > 0 else 0
        items.append({
            "label": labels[i] if i < len(labels) else str(i + 1),
            "current_period": cur_val,
            "previous_period": prev_val,
            "change_pct": change_pct,
        })

    total_current = sum(d["consumption"] for d in current_data)
    total_previous = sum(d["consumption"] for d in previous_data)
    total_change = round((total_current - total_previous) / total_previous * 100, 1) if total_previous > 0 else 0

    return {
        "items": items,
        "total_current": round(total_current, 2),
        "total_previous": round(total_previous, 2),
        "total_change_pct": total_change,
    }