from sqlalchemy import Column, Integer, String, Float, DateTime, Text, Boolean, Date, JSON, ForeignKey
from sqlalchemy.sql import func
from app.core.database import Base


class EmissionFactor(Base):
    """碳排放因子"""
    __tablename__ = "emission_factors"

    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(100), nullable=False)
    energy_type = Column(String(50), nullable=False)  # electricity, natural_gas, diesel, etc.
    factor = Column(Float, nullable=False)  # kgCO2/单位
    unit = Column(String(20), nullable=False)  # kWh, m³, L, etc.
    region = Column(String(50), default="north_china")  # 区域电网
    scope = Column(Integer, nullable=False)  # 1, 2, 3
    source = Column(String(200))  # 数据来源
    year = Column(Integer)
    created_at = Column(DateTime(timezone=True), server_default=func.now())


class CarbonTarget(Base):
    """碳减排目标"""
    __tablename__ = "carbon_targets"

    id = Column(Integer, primary_key=True, autoincrement=True)
    year = Column(Integer, nullable=False)
    month = Column(Integer, nullable=True)  # NULL for annual target
    target_emission_tons = Column(Float, nullable=False)
    actual_emission_tons = Column(Float, default=0)
    status = Column(String(20), default="on_track")  # on_track / warning / exceeded
    created_at = Column(DateTime(timezone=True), server_default=func.now())


class CarbonReduction(Base):
    """碳减排活动"""
    __tablename__ = "carbon_reductions"

    id = Column(Integer, primary_key=True, autoincrement=True)
    source_type = Column(String(50), nullable=False)  # pv_generation / heat_pump_cop / energy_saving
    date = Column(Date, nullable=False, index=True)
    reduction_tons = Column(Float, nullable=False)
    equivalent_trees = Column(Float, default=0)
    methodology = Column(String(200))
    verified = Column(Boolean, default=False)
    verification_date = Column(DateTime(timezone=True), nullable=True)
    device_id = Column(Integer, ForeignKey("devices.id"), nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())


class GreenCertificate(Base):
    """绿证管理"""
    __tablename__ = "green_certificates"

    id = Column(Integer, primary_key=True, autoincrement=True)
    certificate_type = Column(String(20), nullable=False)  # GEC / IREC / CCER
    certificate_number = Column(String(100), unique=True, nullable=False)
    issue_date = Column(Date, nullable=False)
    expiry_date = Column(Date, nullable=True)
    energy_mwh = Column(Float, nullable=False)
    price_yuan = Column(Float, default=0)
    status = Column(String(20), default="active")  # active / used / expired / traded
    source_device_id = Column(Integer, ForeignKey("devices.id"), nullable=True)
    notes = Column(Text)
    created_at = Column(DateTime(timezone=True), server_default=func.now())


class CarbonReport(Base):
    """碳排放报告"""
    __tablename__ = "carbon_reports"

    id = Column(Integer, primary_key=True, autoincrement=True)
    report_type = Column(String(20), nullable=False)  # monthly / quarterly / annual
    period_start = Column(Date, nullable=False)
    period_end = Column(Date, nullable=False)
    generated_at = Column(DateTime(timezone=True), server_default=func.now())
    scope1_tons = Column(Float, default=0)
    scope2_tons = Column(Float, default=0)
    scope3_tons = Column(Float, nullable=True)
    total_tons = Column(Float, default=0)
    reduction_tons = Column(Float, default=0)
    net_tons = Column(Float, default=0)
    report_data = Column(JSON, nullable=True)
    file_path = Column(String(500), nullable=True)


class CarbonBenchmark(Base):
    """行业碳排放基准"""
    __tablename__ = "carbon_benchmarks"

    id = Column(Integer, primary_key=True, autoincrement=True)
    industry = Column(String(100), nullable=False)
    metric_name = Column(String(100), nullable=False)
    benchmark_value = Column(Float, nullable=False)
    unit = Column(String(50), nullable=False)
    year = Column(Integer)
    source = Column(String(200))
    notes = Column(Text)


class CarbonEmission(Base):
    """碳排放记录"""
    __tablename__ = "carbon_emissions"

    id = Column(Integer, primary_key=True, autoincrement=True)
    date = Column(DateTime(timezone=True), nullable=False, index=True)
    scope = Column(Integer, nullable=False)  # 1, 2, 3
    category = Column(String(50), nullable=False)  # electricity, gas, heat, etc.
    emission = Column(Float, nullable=False)  # kgCO2e
    reduction = Column(Float, default=0)  # 减排量 kgCO2e (光伏、热泵节能等)
    energy_consumption = Column(Float)  # 对应能耗量
    energy_unit = Column(String(20))
    emission_factor_id = Column(Integer)
    note = Column(Text)
    created_at = Column(DateTime(timezone=True), server_default=func.now())