"""Replay reports and promotion gate evaluation.

Produces field-level, calibration, resource, and difficulty-bucket
reports. Enforces safety-critical gates for promotion decisions.
"""

from __future__ import annotations

import enum
from dataclasses import dataclass, field
from typing import Any
from uuid import UUID


class GateStatus(str, enum.Enum):
    """Promotion gate evaluation status."""

    PASSED = "passed"
    FAILED = "failed"
    WARNING = "warning"
    NOT_EVALUATED = "not_evaluated"


@dataclass(frozen=True)
class PromotionGate:
    """A single promotion gate with a threshold and evaluation logic."""

    name: str
    metric_name: str
    threshold: float
    direction: str  # "above" (value must be >= threshold) or "below" (value must be <= threshold)
    safety_critical: bool = False
    description: str = ""

    def evaluate(self, value: float) -> GateStatus:
        """Evaluate the gate against a metric value."""
        if self.direction == "above":
            return GateStatus.PASSED if value >= self.threshold else GateStatus.FAILED
        elif self.direction == "below":
            return GateStatus.PASSED if value <= self.threshold else GateStatus.FAILED
        return GateStatus.NOT_EVALUATED


# Default promotion gates per Requirement 16.5
DEFAULT_PROMOTION_GATES: list[PromotionGate] = [
    PromotionGate(
        name="entity_f1",
        metric_name="entity_f1",
        threshold=0.0,  # No regression allowed (relative)
        direction="above",
        safety_critical=True,
        description="Entity/ticker F1 must not regress",
    ),
    PromotionGate(
        name="evidence_support_rate",
        metric_name="evidence_support_rate",
        threshold=0.85,
        direction="above",
        safety_critical=True,
        description="Evidence support rate must exceed 85%",
    ),
    PromotionGate(
        name="schema_validity",
        metric_name="schema_validity_rate",
        threshold=0.99,
        direction="above",
        safety_critical=True,
        description="Schema validity must exceed 99%",
    ),
    PromotionGate(
        name="calibration_ece",
        metric_name="calibration_ece",
        threshold=0.08,
        direction="below",
        safety_critical=False,
        description="Calibration ECE should be below 8%",
    ),
    PromotionGate(
        name="fast_path_coverage",
        metric_name="fast_path_rate",
        threshold=0.60,
        direction="above",
        safety_critical=False,
        description="Fast-path coverage should reach 60%",
    ),
    PromotionGate(
        name="gpu_reduction",
        metric_name="gpu_seconds_ratio",
        threshold=0.50,
        direction="below",
        safety_critical=False,
        description="GPU-seconds per doc should be ≤50% of baseline (2x improvement)",
    ),
]


@dataclass
class FieldReport:
    """Field-level metrics for a specific field across all documents."""

    field_name: str
    precision: float = 0.0
    recall: float = 0.0
    f1: float = 0.0
    exact_match: float = 0.0
    support_count: int = 0
    error_count: int = 0

    @property
    def accuracy(self) -> float:
        if self.support_count == 0:
            return 0.0
        return (self.support_count - self.error_count) / self.support_count


@dataclass
class ReplayReport:
    """Complete replay comparison report.

    Compares configurations, evaluates promotion gates, and produces
    field-level, resource, and difficulty-bucket breakdowns.
    """

    report_id: UUID
    config_id: UUID
    baseline_config_id: UUID | None
    total_documents: int = 0
    success_rate: float = 0.0
    avg_latency_ms: float = 0.0
    total_gpu_seconds: float = 0.0
    schema_validity_rate: float = 0.0
    fast_path_rate: float = 0.0
    field_reports: list[FieldReport] = field(default_factory=list)
    gate_results: dict[str, GateStatus] = field(default_factory=dict)
    difficulty_buckets: dict[str, dict[str, float]] = field(default_factory=dict)
    document_type_breakdown: dict[str, dict[str, float]] = field(
        default_factory=dict
    )

    def evaluate_gates(
        self,
        metrics: dict[str, float],
        gates: list[PromotionGate] | None = None,
    ) -> dict[str, GateStatus]:
        """Evaluate all promotion gates against collected metrics."""
        gates = gates or DEFAULT_PROMOTION_GATES
        results: dict[str, GateStatus] = {}
        for gate in gates:
            value = metrics.get(gate.metric_name)
            if value is None:
                results[gate.name] = GateStatus.NOT_EVALUATED
            else:
                results[gate.name] = gate.evaluate(value)
        self.gate_results = results
        return results

    @property
    def all_safety_gates_passed(self) -> bool:
        """Whether all safety-critical gates passed."""
        for gate in DEFAULT_PROMOTION_GATES:
            if gate.safety_critical:
                status = self.gate_results.get(gate.name, GateStatus.NOT_EVALUATED)
                if status != GateStatus.PASSED:
                    return False
        return True

    @property
    def all_gates_passed(self) -> bool:
        """Whether all gates passed."""
        return all(
            status == GateStatus.PASSED
            for status in self.gate_results.values()
        )

    def to_dict(self) -> dict[str, Any]:
        """Serialize for storage/API response."""
        return {
            "report_id": str(self.report_id),
            "config_id": str(self.config_id),
            "total_documents": self.total_documents,
            "success_rate": self.success_rate,
            "avg_latency_ms": self.avg_latency_ms,
            "total_gpu_seconds": self.total_gpu_seconds,
            "schema_validity_rate": self.schema_validity_rate,
            "fast_path_rate": self.fast_path_rate,
            "gate_results": {k: v.value for k, v in self.gate_results.items()},
            "all_safety_gates_passed": self.all_safety_gates_passed,
            "all_gates_passed": self.all_gates_passed,
        }