"""Immutable public data contracts for news relevance decisions."""

from __future__ import annotations

import html
from collections.abc import Mapping
from dataclasses import dataclass, field
from datetime import datetime
from enum import Enum
from types import MappingProxyType
from zoneinfo import ZoneInfo

_ARTICLE_TIMEZONE = ZoneInfo("America/New_York")


def parse_article_time(value: datetime | str) -> datetime:
    """Parse an article time, interpreting naive values as America/New_York."""

    if isinstance(value, datetime):
        timestamp = value
    elif isinstance(value, str) and value.strip():
        timestamp = datetime.fromisoformat(value.strip())
    else:
        raise TypeError("timestamp must be a datetime or non-empty ISO-8601 string")
    if timestamp.tzinfo is None:
        timestamp = timestamp.replace(tzinfo=_ARTICLE_TIMEZONE)
    return timestamp


class ArticleAdmissibilityStatus(str, Enum):
    ACCEPTED = "accepted"
    PLAUSIBLE_UNRESOLVED = "plausible_unresolved"
    REJECTED = "rejected"


class ExposureRelevanceStatus(str, Enum):
    SUPPORTED = "supported"
    PLAUSIBLE_UNRESOLVED = "plausible_unresolved"
    NOT_SUPPORTED = "not_supported"


class ExposureFamily(str, Enum):
    SP500 = "EXPOSURE:SP500"
    NASDAQ100 = "EXPOSURE:NASDAQ100"
    RUSSELL2000 = "EXPOSURE:RUSSELL2000"
    MARKET_WIDE = "MARKET_WIDE"

    @property
    def label(self) -> str:
        """Return the concise name used in user-facing summaries."""

        return {
            ExposureFamily.SP500: "S&P 500",
            ExposureFamily.NASDAQ100: "Nasdaq-100",
            ExposureFamily.RUSSELL2000: "Russell 2000",
            ExposureFamily.MARKET_WIDE: "Broad market",
        }[self]


class IdentityStatus(str, Enum):
    ACCEPTED = "accepted"
    AMBIGUOUS = "ambiguous"
    REJECTED = "rejected"
    UNRESOLVED = "unresolved"


class EvidenceStatus(str, Enum):
    ACCEPTED = "accepted"
    UNRESOLVED = "unresolved"
    REJECTED = "rejected"


@dataclass(frozen=True, slots=True)
class Article:
    article_id: str
    timestamp: datetime | str
    text: str
    source: str = "unknown"
    content_id: str | None = None
    decision_bucket: str | None = None

    def __post_init__(self) -> None:
        if not self.article_id.strip():
            raise ValueError("article_id must be non-empty")
        if not isinstance(self.text, str) or not self.text.strip():
            raise ValueError("text must be a non-empty string")
        object.__setattr__(self, "timestamp", parse_article_time(self.timestamp))
        object.__setattr__(self, "content_id", self.content_id or self.article_id)


@dataclass(frozen=True, slots=True)
class Observation:
    observation_id: str
    article_id: str
    matched_surface: str
    span_start: int
    span_end: int
    entity_concept: str
    detection_method: str
    confidence: float | None = None
    candidate_canonical_id: str | None = None
    catalog_entry_id: str | None = None
    catalog_version: str | None = None
    rule_id: str | None = None
    tag_type: str | None = None
    event_family: str | None = None
    market_wide_authorized: bool = False
    context_status: str = "not_required"
    source_id: str | None = None

    def __post_init__(self) -> None:
        if self.span_start < 0 or self.span_end <= self.span_start:
            raise ValueError("observation offsets must describe a non-empty span")
        if not self.observation_id or not self.article_id or not self.matched_surface:
            raise ValueError("observation identity and surface must be non-empty")
        if self.confidence is not None and not 0 <= self.confidence <= 1:
            raise ValueError("confidence must be in [0, 1]")


@dataclass(frozen=True, slots=True)
class ObservationBundle:
    article: Article
    observations: tuple[Observation, ...] = ()


@dataclass(frozen=True, slots=True)
class IdentityResolution:
    resolution_id: str
    observation_id: str
    article_id: str
    status: IdentityStatus
    canonical_id: str | None
    reason_code: str
    resolution_method: str
    catalog_version: str | None = None

    def __post_init__(self) -> None:
        if self.status is IdentityStatus.ACCEPTED and not self.canonical_id:
            raise ValueError("accepted identities require a canonical_id")
        if self.status is not IdentityStatus.ACCEPTED and self.canonical_id is not None:
            raise ValueError("only accepted identities may assign canonical_id")


@dataclass(frozen=True, slots=True)
class EvidencePath:
    evidence_id: str
    article_id: str
    tag_type: str
    tag_detail: str
    matched_surface: str
    detection_method: str
    status: EvidenceStatus
    link_status: str
    target_id: str | None
    exposure_family: ExposureFamily | None
    reason_code: str
    tier: int
    observation_ids: tuple[str, ...] = ()
    identity_resolution_ids: tuple[str, ...] = ()
    relationship_ids: tuple[str, ...] = ()
    catalog_version: str | None = None
    event_family: str | None = None
    explicit_market_wide_rule: bool = False

    def __post_init__(self) -> None:
        if self.tier < 0:
            raise ValueError("evidence tier must be non-negative")
        if self.status is EvidenceStatus.ACCEPTED and self.exposure_family is None:
            raise ValueError("accepted exposure evidence requires an exposure family")
        if self.link_status == "resolved_exposure" and not self.relationship_ids:
            raise ValueError("resolved exposure evidence requires relationship lineage")
        if self.exposure_family is ExposureFamily.MARKET_WIDE and (
            self.link_status != "market_wide" or not self.explicit_market_wide_rule
        ):
            raise ValueError("MARKET_WIDE requires an explicitly authorized rule")


@dataclass(frozen=True, slots=True)
class ArticleAdmissibilityDecision:
    article_id: str
    status: ArticleAdmissibilityStatus
    accepted_evidence: tuple[EvidencePath, ...] = ()
    unresolved_evidence: tuple[EvidencePath, ...] = ()
    rejected_evidence: tuple[EvidencePath, ...] = ()
    reason_codes: tuple[str, ...] = ()


@dataclass(frozen=True, slots=True)
class ExposureRelevanceDecision:
    article_id: str
    exposure_family: ExposureFamily
    status: ExposureRelevanceStatus
    evidence_paths: tuple[EvidencePath, ...] = ()
    unresolved_paths: tuple[EvidencePath, ...] = ()
    reason_codes: tuple[str, ...] = ()

    def __post_init__(self) -> None:
        if self.status is ExposureRelevanceStatus.SUPPORTED and not self.evidence_paths:
            raise ValueError("supported exposure decisions require evidence lineage")
        if (
            self.status is ExposureRelevanceStatus.PLAUSIBLE_UNRESOLVED
            and not self.unresolved_paths
        ):
            raise ValueError(
                "plausible unresolved exposure decisions require unresolved evidence"
            )
        if any(
            path.exposure_family is not self.exposure_family
            for path in self.evidence_paths
        ):
            raise ValueError("evidence paths must support the decision exposure family")


@dataclass(frozen=True, slots=True, repr=False)
class RelevanceDecision:
    article: Article
    article_decision: ArticleAdmissibilityDecision
    exposure_decisions: Mapping[ExposureFamily, ExposureRelevanceDecision]
    observations: tuple[Observation, ...] = ()
    resolutions: tuple[IdentityResolution, ...] = ()

    def __post_init__(self) -> None:
        if self.article.article_id != self.article_decision.article_id:
            raise ValueError("article decision provenance mismatch")
        decisions = dict(self.exposure_decisions)
        if any(key is not value.exposure_family for key, value in decisions.items()):
            raise ValueError("exposure decision mapping keys must match their values")

        observation_ids = {row.observation_id for row in self.observations}
        if len(observation_ids) != len(self.observations):
            raise ValueError("observation IDs must be unique")
        if any(row.article_id != self.article.article_id for row in self.observations):
            raise ValueError("observation provenance mismatch")

        resolution_ids = {row.resolution_id for row in self.resolutions}
        if len(resolution_ids) != len(self.resolutions):
            raise ValueError("identity resolution IDs must be unique")
        for resolution in self.resolutions:
            if resolution.article_id != self.article.article_id:
                raise ValueError("identity resolution provenance mismatch")
            if resolution.observation_id not in observation_ids:
                raise ValueError(
                    "identity resolution references an unknown observation"
                )

        article_paths = (
            *self.article_decision.accepted_evidence,
            *self.article_decision.unresolved_evidence,
            *self.article_decision.rejected_evidence,
        )
        exposure_paths = tuple(
            path
            for decision in decisions.values()
            for path in (*decision.evidence_paths, *decision.unresolved_paths)
        )
        for path in (*article_paths, *exposure_paths):
            if path.article_id != self.article.article_id:
                raise ValueError("evidence path provenance mismatch")
            if not set(path.observation_ids).issubset(observation_ids):
                raise ValueError("evidence path references an unknown observation")
            if not set(path.identity_resolution_ids).issubset(resolution_ids):
                raise ValueError(
                    "evidence path references an unknown identity resolution"
                )
        object.__setattr__(self, "exposure_decisions", MappingProxyType(decisions))

    @property
    def status(self) -> str:
        """Return the plain-language overall result."""

        return {
            ArticleAdmissibilityStatus.ACCEPTED: "relevant",
            ArticleAdmissibilityStatus.PLAUSIBLE_UNRESOLVED: "needs_review",
            ArticleAdmissibilityStatus.REJECTED: "not_relevant",
        }[self.article_decision.status]

    @property
    def accepted(self) -> bool:
        """Whether the article has accepted financial evidence."""

        return self.article_decision.status is ArticleAdmissibilityStatus.ACCEPTED

    @property
    def relevant_to(self) -> tuple[str, ...]:
        """Plain-language markets with a completed relevance path."""

        return tuple(
            family.label
            for family in ExposureFamily
            if (
                (result := self.exposure_decisions.get(family)) is not None
                and result.status is ExposureRelevanceStatus.SUPPORTED
            )
        )

    @staticmethod
    def _surface(path: EvidencePath) -> str:
        surface = " ".join(path.matched_surface.split())
        return surface if len(surface) <= 60 else surface[:57].rstrip() + "..."

    @classmethod
    def _why_for_path(cls, path: EvidencePath) -> str:
        surface = cls._surface(path)
        if path.link_status == "resolved_exposure" and path.exposure_family:
            return f"{surface} connects to {path.exposure_family.label}"
        if path.link_status == "direct_asset":
            return f"fund or ticker found: {surface}"
        if path.link_status == "direct_benchmark":
            return f"index or benchmark found: {surface}"
        if path.link_status == "market_wide":
            return f"broad-market news found: {surface}"
        return {
            "macroeconomic_indicator": f"economic indicator found: {surface}",
            "financial_regulator": f"financial regulator found: {surface}",
            "sector_or_industry": f"industry or sector found: {surface}",
            "company_event": f"company event found: {surface}",
        }.get(path.tag_type, f"financial information found: {surface}")

    @property
    def why(self) -> str:
        """Return a short explanation; detailed lineage remains available separately."""

        if self.article_decision.status is ArticleAdmissibilityStatus.REJECTED:
            return "No financial match found."

        paths = (
            self.article_decision.accepted_evidence
            if self.article_decision.status is ArticleAdmissibilityStatus.ACCEPTED
            else self.article_decision.unresolved_evidence
        )
        phrases: list[str] = []
        seen: set[str] = set()
        for path in sorted(
            paths,
            key=lambda item: (
                item.tier,
                item.matched_surface.casefold(),
                item.evidence_id,
            ),
        ):
            key = path.matched_surface.casefold().strip()
            if key in seen:
                continue
            seen.add(key)
            phrases.append(self._why_for_path(path))

        if not phrases:
            return (
                "Possible financial information was found, but it needs review."
                if self.status == "needs_review"
                else "Financial information found."
            )
        visible = phrases[:3]
        reason = "; ".join(visible)
        if len(phrases) > len(visible):
            reason += f"; and {len(phrases) - len(visible)} more match(es)"
        if self.status == "needs_review":
            reason += ", but it could not be connected to a configured market"
        return reason[0].upper() + reason[1:] + "."

    def summary(self) -> dict[str, object]:
        """Return the small, JSON-friendly result most callers need."""

        return {
            "article_id": self.article.article_id,
            "status": self.status,
            "accepted": self.accepted,
            "why": self.why,
            "relevant_to": list(self.relevant_to),
        }

    def __repr__(self) -> str:
        return (
            "RelevanceDecision("
            f"article_id={self.article.article_id!r}, "
            f"status={self.status!r}, "
            f"relevant_to={self.relevant_to!r}, "
            f"why={self.why!r})"
        )

    def _repr_markdown_(self) -> str:
        """Render a concise decision card in Jupyter without an IPython dependency."""

        def markdown(value: object) -> str:
            escaped = html.escape(str(value))
            for character in ("\\", "`", "*", "_", "[", "]"):
                escaped = escaped.replace(character, f"\\{character}")
            return escaped

        heading = {
            "relevant": "Keep",
            "needs_review": "Check",
            "not_relevant": "Ignore",
        }[self.status]
        lines = [f"### {heading}", "", f"**Why:** {markdown(self.why)}"]
        if self.relevant_to:
            lines.extend(("", f"**Markets:** {', '.join(self.relevant_to)}"))
        lines.extend(
            (
                "",
                (
                    f"*{markdown(self.article.source)} | "
                    f"{markdown(self.article.timestamp.isoformat())} | "
                    f"{markdown(self.article.article_id)}*"
                ),
            )
        )
        return "\n".join(lines)


@dataclass(frozen=True, slots=True)
class RankedCandidate:
    decision_bucket: str
    exposure_family: ExposureFamily
    rank: int
    article_id: str
    accepted_evidence_ids: tuple[str, ...]
    decision: RelevanceDecision = field(compare=False, repr=False)