"""PostgreSQL records owned by the Fiscal Hub."""

from datetime import datetime
from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, JSON, String, Text, UniqueConstraint, func
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column


class Base(DeclarativeBase):
    pass


class Dataset(Base):
    __tablename__ = "datasets"
    __table_args__ = (UniqueConstraint("provider", "sha256", name="uq_dataset_provider_hash"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    kind: Mapped[str] = mapped_column(String(32), index=True)
    provider: Mapped[str] = mapped_column(String(128))
    sha256: Mapped[str] = mapped_column(String(64))
    raw_sha256: Mapped[str | None] = mapped_column(String(64), nullable=True)
    version_label: Mapped[str] = mapped_column(String(256))
    act: Mapped[str] = mapped_column(Text)
    source_url: Mapped[str] = mapped_column(Text)
    downloaded_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    status: Mapped[str] = mapped_column(String(32), index=True)
    record_count: Mapped[int] = mapped_column(Integer, default=0)


class NcmEntry(Base):
    __tablename__ = "ncm_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "code", "valid_from", "valid_to", name="uq_ncm_versioned_entry"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    code: Mapped[str] = mapped_column(String(16), index=True)
    description: Mapped[str] = mapped_column(Text)
    valid_from: Mapped[str] = mapped_column(String(32))
    valid_to: Mapped[str] = mapped_column(String(32))


class LegacyNcmEntry(Base):
    __tablename__ = "legacy_ncm_entries"
    code: Mapped[str] = mapped_column(String(16), primary_key=True)
    source: Mapped[str] = mapped_column(Text)
    source_date: Mapped[str] = mapped_column(String(32))
    reason: Mapped[str] = mapped_column(Text)
    successor_code: Mapped[str | None] = mapped_column(String(16), nullable=True)


class CestEntry(Base):
    __tablename__ = "cest_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "code", name="uq_cest_versioned_entry"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    code: Mapped[str] = mapped_column(String(16), index=True)
    description: Mapped[str] = mapped_column(Text)
    annex: Mapped[str] = mapped_column(String(8))


class CestNcmEntry(Base):
    __tablename__ = "cest_ncm_entries"
    __table_args__ = (UniqueConstraint("cest_entry_id", "ncm_code", name="uq_cest_ncm_link"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    cest_entry_id: Mapped[int] = mapped_column(ForeignKey("cest_entries.id"), index=True)
    ncm_code: Mapped[str] = mapped_column(String(16), index=True)


class TipiEntry(Base):
    __tablename__ = "tipi_entries"
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    ncm: Mapped[str] = mapped_column(String(8), index=True)
    ex: Mapped[str | None] = mapped_column(String(32), nullable=True)
    description: Mapped[str] = mapped_column(Text)
    ipi_rate: Mapped[float | None] = mapped_column(nullable=True)
    ipi_rate_text: Mapped[str | None] = mapped_column(String(32), nullable=True)
    source_row: Mapped[int] = mapped_column(Integer)
    metadata_json: Mapped[dict] = mapped_column(JSON, default=dict)


class BaStMvaEntry(Base):
    __tablename__ = "ba_st_mva_entries"
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    item: Mapped[str] = mapped_column(String(32))
    segment: Mapped[str | None] = mapped_column(Text, nullable=True)
    cest: Mapped[str | None] = mapped_column(String(16), index=True, nullable=True)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    mva_original: Mapped[str | None] = mapped_column(String(32), nullable=True)
    mva_adjusted: Mapped[str | None] = mapped_column(String(32), nullable=True)
    agreement_info: Mapped[str | None] = mapped_column(Text, nullable=True)
    source_page: Mapped[int] = mapped_column(Integer)
    metadata_json: Mapped[dict] = mapped_column(JSON, default=dict)

class BaStMvaNcmSh(Base):
    __tablename__ = "ba_st_mva_ncm_sh"
    __table_args__ = (UniqueConstraint("entry_id", "ncm_sh", name="uq_ba_st_mva_entry_ncm_sh"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    entry_id: Mapped[int] = mapped_column(ForeignKey("ba_st_mva_entries.id"), index=True)
    ncm_sh: Mapped[str] = mapped_column(String(32), index=True)
    metadata_json: Mapped[dict] = mapped_column(JSON, default=dict)


class FiscalCodeEntry(Base):
    """Small national fiscal code domains sourced from the official NF-e MOC
    manual: ORIGEM_MERCADORIA, CST_ICMS, CSOSN, CST_PIS, CST_COFINS."""
    __tablename__ = "fiscal_code_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "domain", "code", name="uq_fiscal_code_entry"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    domain: Mapped[str] = mapped_column(String(32), index=True)
    code: Mapped[str] = mapped_column(String(8), index=True)
    description: Mapped[str] = mapped_column(Text)
    source_section: Mapped[str] = mapped_column(String(96))
    metadata_json: Mapped[dict] = mapped_column(JSON, default=dict)


class CfopEntry(Base):
    """CFOP (Código Fiscal de Operações e Prestações) — Portal Nacional NF-e."""
    __tablename__ = "cfop_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "code", name="uq_cfop_entry"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    code: Mapped[str] = mapped_column(String(8), index=True)
    title: Mapped[str] = mapped_column(Text)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    effective_from: Mapped[str | None] = mapped_column(String(32), nullable=True)
    effective_to: Mapped[str | None] = mapped_column(String(32), nullable=True)
    ind_nfe: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_comunica: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_transp: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_devol: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_retor: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_anula: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_remes: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_comb: Mapped[str | None] = mapped_column(String(4), nullable=True)
    ind_exc_ibscbs: Mapped[str | None] = mapped_column(String(4), nullable=True)


class FcpRate(Base):
    """FCP (Fundo de Combate à Pobreza) alíquotas por UF — Portal Nacional NF-e."""
    __tablename__ = "fcp_rates"
    __table_args__ = (UniqueConstraint("dataset_id", "uf", name="uq_fcp_rate_uf"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    uf_code: Mapped[str] = mapped_column(String(4))
    uf: Mapped[str] = mapped_column(String(4), index=True)
    uf_name: Mapped[str] = mapped_column(String(64))
    aliq_1: Mapped[str | None] = mapped_column(String(32), nullable=True)
    aliq_2: Mapped[str | None] = mapped_column(String(32), nullable=True)
    aliq_3: Mapped[str | None] = mapped_column(String(32), nullable=True)
    observacao: Mapped[str | None] = mapped_column(Text, nullable=True)


class AnpProductCode(Base):
    """cProdANP — official code list used by NF-e, published on the Portal Nacional NF-e."""
    __tablename__ = "anp_product_codes"
    __table_args__ = (UniqueConstraint("dataset_id", "cprod_anp", name="uq_anp_product_code"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    cprod_anp: Mapped[str] = mapped_column(String(16), index=True)


class NcmUtribEntry(Base):
    """NCM x uTrib (unidade tributável de comércio exterior) — Portal Nacional NF-e."""
    __tablename__ = "ncm_utrib_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "ncm", name="uq_ncm_utrib_entry"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    ncm: Mapped[str] = mapped_column(String(16), index=True)
    effective_from: Mapped[str | None] = mapped_column(String(32), nullable=True)
    effective_to: Mapped[str | None] = mapped_column(String(32), nullable=True)
    utrib_abbreviation: Mapped[str | None] = mapped_column(String(16), nullable=True)
    utrib_description: Mapped[str | None] = mapped_column(Text, nullable=True)


class RtcBiofuelIndexEntry(Base):
    """RTC pBioObrigatorio (índice de biocombustível) by cProdANP — Portal Nacional NF-e."""
    __tablename__ = "rtc_biofuel_index_entries"
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    cprod_anp: Mapped[str | None] = mapped_column(String(16), index=True, nullable=True)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    p_bio_percent: Mapped[float | None] = mapped_column(nullable=True)
    effective_from: Mapped[str | None] = mapped_column(String(32), nullable=True)
    effective_to: Mapped[str | None] = mapped_column(String(32), nullable=True)
    is_historical: Mapped[bool] = mapped_column(Boolean, default=False)


class RtcCredPresEntry(Base):
    """RTC cCredPres (crédito presumido IBS/CBS), LC 214/2025 — Portal Nacional NF-e.
    Keeps every official field distinctly so future automatic determination
    doesn't require re-parsing the source."""
    __tablename__ = "rtc_cred_pres_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "code", name="uq_rtc_cred_pres_code"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    code: Mapped[str] = mapped_column(String(8), index=True)
    description: Mapped[str] = mapped_column(Text)
    legal_basis: Mapped[str | None] = mapped_column(Text, nullable=True)
    apropria_via_nf: Mapped[bool | None] = mapped_column(Boolean, nullable=True)
    apropria_via_evento: Mapped[bool | None] = mapped_column(Boolean, nullable=True)
    ind_deduz_cred_pres: Mapped[str | None] = mapped_column(String(8), nullable=True)
    ind_g_cbs_cred_pres: Mapped[str | None] = mapped_column(String(8), nullable=True)
    ind_g_ibs_cred_pres: Mapped[str | None] = mapped_column(String(8), nullable=True)
    aliquota_cbs_text: Mapped[str | None] = mapped_column(Text, nullable=True)
    aliquota_ibs_text: Mapped[str | None] = mapped_column(Text, nullable=True)
    p_aliq_cred_pres_cbs: Mapped[str | None] = mapped_column(Text, nullable=True)
    p_aliq_cred_pres_ibs: Mapped[str | None] = mapped_column(Text, nullable=True)
    p_red_transicao_ibs: Mapped[str | None] = mapped_column(Text, nullable=True)
    # Free text in some rows (e.g. "cClass de alíquota zero"), not always the numeric code.
    cclass_nota_referenciada: Mapped[str | None] = mapped_column(Text, nullable=True)
    d_ini_vig_cbs: Mapped[str | None] = mapped_column(String(32), nullable=True)
    d_fim_vig_cbs: Mapped[str | None] = mapped_column(String(32), nullable=True)
    d_ini_vig_ibs: Mapped[str | None] = mapped_column(String(32), nullable=True)
    d_fim_vig_ibs: Mapped[str | None] = mapped_column(String(32), nullable=True)


class Tenant(Base):
    __tablename__ = "tenants"
    id: Mapped[int] = mapped_column(primary_key=True)
    name: Mapped[str] = mapped_column(String(128), unique=True)


class Agent(Base):
    __tablename__ = "agents"
    id: Mapped[int] = mapped_column(primary_key=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id"), index=True)  # company_id
    name: Mapped[str] = mapped_column(String(128))
    token_hash: Mapped[str] = mapped_column(String(64), unique=True)
    enabled: Mapped[bool] = mapped_column(Boolean, default=True, server_default="true")
    last_seen_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    last_status: Mapped[str | None] = mapped_column(String(32), nullable=True)
    schema_fingerprint: Mapped[str | None] = mapped_column(String(64), nullable=True)
    agent_version: Mapped[str | None] = mapped_column(String(32), nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())


class Job(Base):
    __tablename__ = "jobs"
    id: Mapped[int] = mapped_column(primary_key=True)
    agent_id: Mapped[int] = mapped_column(ForeignKey("agents.id"), index=True)
    kind: Mapped[str] = mapped_column(String(32), index=True)  # REPROCESS_ALL | REPROCESS_PRODUCTS
    status: Mapped[str] = mapped_column(String(16), index=True, default="PENDING", server_default="PENDING")
    payload: Mapped[dict] = mapped_column(JSON, default=dict)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    started_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    finished_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    attempts: Mapped[int] = mapped_column(Integer, default=0, server_default="0")
    result_summary: Mapped[dict | None] = mapped_column(JSON, nullable=True)
    error: Mapped[str | None] = mapped_column(Text, nullable=True)


class ClassificationRequest(Base):
    __tablename__ = "classification_requests"
    id: Mapped[int] = mapped_column(primary_key=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id"), index=True)
    agent_id: Mapped[int] = mapped_column(ForeignKey("agents.id"), index=True)
    fingerprint: Mapped[str] = mapped_column(String(64), unique=True)
    payload: Mapped[dict] = mapped_column(JSON)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())


class ClassificationResult(Base):
    __tablename__ = "classification_results"
    id: Mapped[int] = mapped_column(primary_key=True)
    request_id: Mapped[int] = mapped_column(ForeignKey("classification_requests.id"), unique=True)
    result: Mapped[dict] = mapped_column(JSON)


class ClassificationCache(Base):
    __tablename__ = "classification_cache"
    fingerprint: Mapped[str] = mapped_column(String(64), primary_key=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id"), index=True)
    result: Mapped[dict] = mapped_column(JSON)


class RtcCstIbsCbsEntry(Base):
    """RTC CST-IBS/CBS (sheet 'CST ...' of the official cClassTrib workbook)."""
    __tablename__ = "rtc_cst_ibscbs_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "cst", name="uq_rtc_cst_ibscbs"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    cst: Mapped[str] = mapped_column(String(8), index=True)
    description: Mapped[str] = mapped_column(Text)
    indicators: Mapped[dict] = mapped_column(JSON)


class RtcCClassTribEntry(Base):
    """RTC cClassTrib (sheet 'cClass ...'). Every official column is kept:
    key fields typed, all ind_* flags in `indicators` keyed by official header."""
    __tablename__ = "rtc_cclasstrib_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "cclasstrib", name="uq_rtc_cclasstrib"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    cst: Mapped[str] = mapped_column(String(8), index=True)
    cst_description: Mapped[str | None] = mapped_column(Text, nullable=True)
    cclasstrib: Mapped[str] = mapped_column(String(8), index=True)
    name: Mapped[str | None] = mapped_column(Text, nullable=True)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    lc_redacao: Mapped[str | None] = mapped_column(Text, nullable=True)
    lc_214: Mapped[str | None] = mapped_column(Text, nullable=True)
    regulamento_cbs: Mapped[str | None] = mapped_column(Text, nullable=True)
    regulamento_ibs: Mapped[str | None] = mapped_column(Text, nullable=True)
    tipo_aliquota: Mapped[str | None] = mapped_column(String(64), nullable=True)
    p_red_ibs: Mapped[str | None] = mapped_column(String(32), nullable=True)
    p_red_cbs: Mapped[str | None] = mapped_column(String(32), nullable=True)
    d_ini_vig: Mapped[str | None] = mapped_column(String(32), nullable=True)
    d_fim_vig: Mapped[str | None] = mapped_column(String(32), nullable=True)
    data_atualizacao: Mapped[str | None] = mapped_column(String(32), nullable=True)
    anexo: Mapped[str | None] = mapped_column(Text, nullable=True)
    link: Mapped[str | None] = mapped_column(Text, nullable=True)
    indicators: Mapped[dict] = mapped_column(JSON)


class RtcCbsRateEntry(Base):
    """RTC CBS rate per year (IT 2026.002). rate is NULL when the official
    text has no number yet (e.g. 'aguarda legislação')."""
    __tablename__ = "rtc_cbs_rate_entries"
    __table_args__ = (UniqueConstraint("dataset_id", "year", name="uq_rtc_cbs_rate_year"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    dataset_id: Mapped[int] = mapped_column(ForeignKey("datasets.id"), index=True)
    year: Mapped[int] = mapped_column(Integer, index=True)
    rate_text: Mapped[str] = mapped_column(Text)
    rate: Mapped[float | None] = mapped_column(nullable=True)


class FiscalContextEntry(Base):
    """Operator-supplied fiscal fact (product role, origin, ST retention, treatment, ...). Hierarchy: PRODUCT > GROUP > COMPANY."""
    __tablename__ = "fiscal_context_entries"
    __table_args__ = (UniqueConstraint("tenant_id", "company_key", "scope", "scope_key", "key", name="uq_fiscal_context_entry"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id"), index=True)
    company_key: Mapped[str] = mapped_column(String(64), index=True)
    scope: Mapped[str] = mapped_column(String(8))
    scope_key: Mapped[str] = mapped_column(String(64), default="", server_default="")
    key: Mapped[str] = mapped_column(String(48))
    value: Mapped[str] = mapped_column(Text)
    source: Mapped[str] = mapped_column(String(16), default="OPERATOR", server_default="OPERATOR")
    reason: Mapped[str | None] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())


# ================= AI semantic layer V1 =================
# The AI layer is NOT a fiscal authority: it only selects among official candidates and
# never writes to Firebird. Knowledge is versioned, provenance-tracked and never deleted.


class KbProduct(Base):
    """GLOBAL product knowledge: only facts inherent to the product (never tenant context)."""
    __tablename__ = "kb_products"
    id: Mapped[int] = mapped_column(primary_key=True)
    fingerprint: Mapped[str] = mapped_column(String(64), unique=True, index=True)
    gtin: Mapped[str | None] = mapped_column(String(16), unique=True, nullable=True, index=True)
    identity_kind: Mapped[str] = mapped_column(String(16), default="FINGERPRINT")  # GTIN | FINGERPRINT | SEMANTIC | UNKNOWN
    normalized_description: Mapped[str] = mapped_column(Text, default="")
    brand: Mapped[str | None] = mapped_column(Text, nullable=True)
    unit: Mapped[str | None] = mapped_column(String(32), nullable=True)
    package_quantity: Mapped[str | None] = mapped_column(String(32), nullable=True)
    category: Mapped[str | None] = mapped_column(Text, nullable=True)
    semantic_attributes: Mapped[dict] = mapped_column(JSON, default=dict)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())


class KbKnowledge(Base):
    """Versioned knowledge rows. Unique per (product, key, value): conflicting values for the
    same key are kept side by side and surfaced as KNOWLEDGE_CONFLICT, never majority-picked."""
    __tablename__ = "kb_knowledge"
    __table_args__ = (UniqueConstraint("kb_product_id", "knowledge_key", "value", name="uq_kb_knowledge_value"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    kb_product_id: Mapped[int] = mapped_column(ForeignKey("kb_products.id"), index=True)
    knowledge_key: Mapped[str] = mapped_column(String(48), index=True)  # candidate_ncm | validated_ncm | candidate_cest | candidate_ex_tipi | ...
    value: Mapped[str] = mapped_column(Text)
    source: Mapped[str] = mapped_column(String(32))  # OFFICIAL_DATASET | ERP_OBSERVATION | OPERATOR | AI | AI_PLUS_OFFICIAL_VALIDATION
    confidence: Mapped[float] = mapped_column(default=0.0)
    evidence: Mapped[dict] = mapped_column(JSON, default=dict)
    model: Mapped[str | None] = mapped_column(String(64), nullable=True)
    prompt_version: Mapped[str | None] = mapped_column(String(32), nullable=True)
    dataset_versions: Mapped[dict] = mapped_column(JSON, default=dict)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    validated_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)


class KbObservation(Base):
    """Raw per-tenant ERP observation of a KB product (evidence aggregation only)."""
    __tablename__ = "kb_observations"
    id: Mapped[int] = mapped_column(primary_key=True)
    kb_product_id: Mapped[int] = mapped_column(ForeignKey("kb_products.id"), index=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id"), index=True)
    company_key: Mapped[str] = mapped_column(String(64), index=True)
    erp_code: Mapped[str] = mapped_column(String(32))
    database_label: Mapped[str] = mapped_column(String(64))
    observed_fields: Mapped[dict] = mapped_column(JSON, default=dict)
    source: Mapped[str] = mapped_column(String(32), default="ERP_OBSERVATION")
    observed_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())


class TenantProductContext(Base):
    """TENANT-specific product context: role, ST-withheld, operation profile, operator decisions.
    Never promoted to global knowledge."""
    __tablename__ = "tenant_product_context"
    __table_args__ = (UniqueConstraint("tenant_id", "company_key", "erp_code", name="uq_tenant_product_context"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id"), index=True)
    company_key: Mapped[str] = mapped_column(String(64), index=True)
    erp_code: Mapped[str] = mapped_column(String(32))
    kb_product_id: Mapped[int | None] = mapped_column(ForeignKey("kb_products.id"), nullable=True)
    product_role: Mapped[str | None] = mapped_column(String(16), nullable=True)  # RESALE | OWN_PRODUCTION | INPUT | SERVICE | UNKNOWN
    st_withheld: Mapped[str | None] = mapped_column(String(4), nullable=True)    # Y | N — never AI-decided
    operation_profile: Mapped[dict] = mapped_column(JSON, default=dict)
    source: Mapped[str] = mapped_column(String(32), default="ERP_OBSERVATION")
    confidence: Mapped[float] = mapped_column(default=0.0)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())


class AiWorkItem(Base):
    """Deduplicated semantic work item (one knowledge need, many pending cells)."""
    __tablename__ = "ai_work_items"
    __table_args__ = (UniqueConstraint("dedup_key", name="uq_ai_work_item_dedup"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    task_type: Mapped[str] = mapped_column(String(24), index=True)  # INVALID_NCM | CEST | EX_TIPI | PRODUCT_ROLE
    dedup_key: Mapped[str] = mapped_column(String(160))
    question_refs: Mapped[list] = mapped_column(JSON, default=list)
    payload: Mapped[dict] = mapped_column(JSON, default=dict)
    status: Mapped[str] = mapped_column(String(32), default="PENDING", index=True)  # PENDING | KB_EXACT_HIT | KB_FINGERPRINT_HIT | HIGH_CONFIDENCE_RETRIEVAL | SINGLE_OFFICIAL_CANDIDATE | LLM_SELECTION_REQUIRED | UNRESOLVED | UNRESOLVED_NO_OFFICIAL_MAPPING | CONFLICT | DONE | SKIPPED
    kb_product_id: Mapped[int | None] = mapped_column(ForeignKey("kb_products.id"), nullable=True)
    cells_covered: Mapped[int] = mapped_column(Integer, default=0)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())


class AiRun(Base):
    """One provider execution over a batch of work items, with budget-guard evidence."""
    __tablename__ = "ai_runs"
    id: Mapped[int] = mapped_column(primary_key=True)
    provider: Mapped[str] = mapped_column(String(64))
    model: Mapped[str] = mapped_column(String(64))
    prompt_version: Mapped[str] = mapped_column(String(32))
    work_item_ids: Mapped[list] = mapped_column(JSON, default=list)
    input_tokens: Mapped[int] = mapped_column(Integer, default=0)
    output_tokens: Mapped[int] = mapped_column(Integer, default=0)
    cost_usd: Mapped[float] = mapped_column(default=0.0)
    status: Mapped[str] = mapped_column(String(16), default="RUN")
    results: Mapped[list] = mapped_column(JSON, default=list)
    budget_guard: Mapped[dict] = mapped_column(JSON, default=dict)
    started_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
    finished_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)


class AiEvalCache(Base):
    """Persistent LLM result cache: identical (input_fingerprint, candidate_set_hash,
    prompt_version, model, dataset_versions) re-execution makes ZERO new calls."""
    __tablename__ = "ai_eval_cache"
    __table_args__ = (UniqueConstraint("input_fingerprint", "candidate_set_hash", "prompt_version", "model", "dataset_version_ncm", name="uq_ai_eval_cache"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    input_fingerprint: Mapped[str] = mapped_column(String(64), index=True)
    candidate_set_hash: Mapped[str] = mapped_column(String(64))
    prompt_version: Mapped[str] = mapped_column(String(32))
    model: Mapped[str] = mapped_column(String(64))
    dataset_version_ncm: Mapped[str] = mapped_column(String(64))
    phase: Mapped[str] = mapped_column(String(16))
    answer: Mapped[dict] = mapped_column(JSON)
    gold_ncm: Mapped[str | None] = mapped_column(String(8), nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())