"""PPT 场景、计算策略与模板的不可变发布版本。"""
import json

from sqlalchemy import BigInteger, Column, ForeignKey, Index, Integer, String, Text, TIMESTAMP, UniqueConstraint, event, func, inspect

from insurance.db.compat import db


VERSION_ID_TYPE = BigInteger().with_variant(Integer, "sqlite")
LIFECYCLES = {"draft", "validated", "published", "retired"}


def _load_json(value, fallback):
    if not value:
        return fallback
    try:
        return json.loads(value)
    except (TypeError, ValueError):
        return fallback


class PptScenarioVersion(db.Model):
    __tablename__ = "insurance_ppt_scenario_versions"
    __table_args__ = (
        UniqueConstraint("scenario_code", "version", name="uq_ppt_scenario_version"),
        Index("idx_ppt_scenario_versions_lifecycle", "scenario_code", "lifecycle"),
        Index("idx_ppt_scenario_versions_hash", "definition_hash"),
    )

    id = Column(VERSION_ID_TYPE, primary_key=True, autoincrement=True)
    scenario_code = Column(String(50), ForeignKey("insurance_ppt_scenarios.code"), nullable=False)
    version = Column(Integer, nullable=False)
    lifecycle = Column(String(20), nullable=False, default="draft")
    selector_json = Column(Text, nullable=False, default="{}")
    page_specs_json = Column(Text, nullable=False, default="[]")
    metric_specs_json = Column(Text, nullable=False, default="[]")
    comparison_years_json = Column(Text, nullable=False, default="[]")
    compatibility_rules_json = Column(Text, nullable=False, default="{}")
    fallback_scenario = Column(String(50), nullable=True)
    definition_hash = Column(String(64), nullable=False)
    validation_report_json = Column(Text, nullable=True)
    created_by = Column(String(64), nullable=False)
    published_by = Column(String(64), nullable=True)
    published_at = Column(TIMESTAMP, nullable=True)
    created_at = Column(TIMESTAMP, server_default=func.now())

    def definition(self):
        return {
            "selector": _load_json(self.selector_json, {}),
            "pageSpecs": _load_json(self.page_specs_json, []),
            "metricSpecs": _load_json(self.metric_specs_json, []),
            "comparisonYears": _load_json(self.comparison_years_json, []),
            "compatibilityRules": _load_json(self.compatibility_rules_json, {}),
            "fallbackScenario": self.fallback_scenario,
        }

    def to_public_dict(self):
        return {
            "id": self.id, "scenarioCode": self.scenario_code, "version": self.version,
            "lifecycle": self.lifecycle, **self.definition(), "definitionHash": self.definition_hash,
            "validationReport": _load_json(self.validation_report_json, None),
            "createdBy": self.created_by, "publishedBy": self.published_by,
            "publishedAt": self.published_at.isoformat() if self.published_at else None,
            "createdAt": self.created_at.isoformat() if self.created_at else None,
        }


class GenerationPolicyVersion(db.Model):
    __tablename__ = "insurance_generation_policy_versions"
    __table_args__ = (
        UniqueConstraint("code", "version", name="uq_generation_policy_version"),
        Index("idx_generation_policy_versions_lifecycle", "code", "lifecycle"),
    )

    id = Column(VERSION_ID_TYPE, primary_key=True, autoincrement=True)
    code = Column(String(50), nullable=False)
    version = Column(Integer, nullable=False)
    lifecycle = Column(String(20), nullable=False, default="draft")
    calculation_policy_json = Column(Text, nullable=False, default="{}")
    missing_value_policy_json = Column(Text, nullable=False, default="{}")
    conclusion_policy_json = Column(Text, nullable=False, default="{}")
    policy_hash = Column(String(64), nullable=False)
    validation_report_json = Column(Text, nullable=True)
    created_by = Column(String(64), nullable=False)
    published_by = Column(String(64), nullable=True)
    published_at = Column(TIMESTAMP, nullable=True)
    created_at = Column(TIMESTAMP, server_default=func.now())

    def definition(self):
        return {
            "calculationPolicy": _load_json(self.calculation_policy_json, {}),
            "missingValuePolicy": _load_json(self.missing_value_policy_json, {}),
            "conclusionPolicy": _load_json(self.conclusion_policy_json, {}),
        }

    def to_public_dict(self):
        return {
            "id": self.id, "code": self.code, "version": self.version,
            "lifecycle": self.lifecycle, **self.definition(), "policyHash": self.policy_hash,
            "validationReport": _load_json(self.validation_report_json, None),
            "createdBy": self.created_by, "publishedBy": self.published_by,
            "publishedAt": self.published_at.isoformat() if self.published_at else None,
            "createdAt": self.created_at.isoformat() if self.created_at else None,
        }


class PptTemplateVersion(db.Model):
    __tablename__ = "insurance_ppt_template_versions"
    __table_args__ = (
        UniqueConstraint("template_id", "version", name="uq_ppt_template_version"),
        Index("idx_ppt_template_versions_lifecycle", "template_id", "lifecycle"),
    )

    id = Column(VERSION_ID_TYPE, primary_key=True, autoincrement=True)
    template_id = Column(String(50), ForeignKey("insurance_ppt_templates.id"), nullable=False)
    version = Column(Integer, nullable=False)
    lifecycle = Column(String(20), nullable=False, default="draft")
    asset_id = Column(String(255), nullable=False)
    asset_sha256 = Column(String(64), nullable=False)
    page_slots_json = Column(Text, nullable=False, default="[]")
    theme_json = Column(Text, nullable=False, default="{}")
    capacity_rules_json = Column(Text, nullable=False, default="{}")
    supported_scenario_versions_json = Column(Text, nullable=False, default="[]")
    validation_report_json = Column(Text, nullable=True)
    definition_hash = Column(String(64), nullable=False)
    created_by = Column(String(64), nullable=False)
    published_by = Column(String(64), nullable=True)
    published_at = Column(TIMESTAMP, nullable=True)
    created_at = Column(TIMESTAMP, server_default=func.now())

    def definition(self):
        return {
            "assetId": self.asset_id, "assetSha256": self.asset_sha256,
            "pageSlots": _load_json(self.page_slots_json, []),
            "theme": _load_json(self.theme_json, {}),
            "capacityRules": _load_json(self.capacity_rules_json, {}),
            "supportedScenarioVersionIds": _load_json(self.supported_scenario_versions_json, []),
        }

    def to_public_dict(self):
        return {
            "id": self.id, "templateId": self.template_id, "version": self.version,
            "lifecycle": self.lifecycle, **self.definition(), "definitionHash": self.definition_hash,
            "validationReport": _load_json(self.validation_report_json, None),
            "createdBy": self.created_by, "publishedBy": self.published_by,
            "publishedAt": self.published_at.isoformat() if self.published_at else None,
            "createdAt": self.created_at.isoformat() if self.created_at else None,
        }


def _protect_immutable_definition(mapper, connection, target):
    """阻止绕过服务直接篡改已发布/已退役定义。"""
    state = inspect(target)
    lifecycle_history = state.attrs.lifecycle.history
    previous = lifecycle_history.deleted[0] if lifecycle_history.deleted else target.lifecycle
    if previous not in {"published", "retired"}:
        return
    mutable_metadata = {"lifecycle", "published_by", "published_at", "validation_report_json"}
    changed = {
        attribute.key for attribute in state.mapper.column_attrs
        if attribute.key not in mutable_metadata and state.attrs[attribute.key].history.has_changes()
    }
    if changed:
        raise ValueError("published version definition is immutable")


for _model in (PptScenarioVersion, GenerationPolicyVersion, PptTemplateVersion):
    event.listen(_model, "before_update", _protect_immutable_definition)