"""Immutable lifecycle and result documents for the reference perception graph."""

from __future__ import annotations

import hashlib
import json
import re
from dataclasses import dataclass
from enum import StrEnum
from typing import Final

from .contracts import LocalObstacleMap, ThreatAssessment

GRAPH_RESULT_SCHEMA: Final = "missioncore.reference-perception-graph-result/v1"
TERMINAL_OUTCOME_SCHEMA: Final = "missioncore.perception-terminal-outcome/v1"
REFERENCE_GRAPH_ID: Final = "reference-perception-graph/v1"
_SAFE_IDENTIFIER: Final = re.compile(r"^[A-Za-z0-9][A-Za-z0-9._:/-]{0,159}$")


class GraphExecutionError(RuntimeError):
    """The graph cannot preserve its bounded lifecycle or product accounting."""


class GraphState(StrEnum):
    CREATED = "created"
    STARTING = "starting"
    RUNNING = "running"
    STOPPING = "stopping"
    STOPPED = "stopped"
    CANCELLED = "cancelled"
    FAILED = "failed"


class TerminalOutcomeType(StrEnum):
    DELIVERED = "delivered"
    SUPERSEDED = "superseded"
    STALE = "stale"
    REJECTED = "rejected"
    FAILED = "failed"
    UNAVAILABLE = "unavailable"


@dataclass(frozen=True, slots=True)
class TerminalOutcome:
    source_id: str
    session_id: str
    frame_id: str
    sequence: int
    outcome: TerminalOutcomeType
    stage_id: str
    reason: str

    def __post_init__(self) -> None:
        for value in (self.source_id, self.session_id, self.frame_id, self.stage_id, self.reason):
            if _SAFE_IDENTIFIER.fullmatch(value) is None:
                raise GraphExecutionError("terminal outcome contains an unsafe identifier")
        if self.sequence < 0:
            raise GraphExecutionError("terminal sequence must be nonnegative")

    def to_dict(self) -> dict[str, object]:
        return {
            "schema_version": TERMINAL_OUTCOME_SCHEMA,
            "source_id": self.source_id,
            "session_id": self.session_id,
            "frame_id": self.frame_id,
            "sequence": self.sequence,
            "outcome": self.outcome.value,
            "stage_id": self.stage_id,
            "reason": self.reason,
        }


@dataclass(frozen=True, slots=True)
class DeliveredFrame:
    sequence: int
    obstacle_map: LocalObstacleMap
    threats: tuple[ThreatAssessment, ...]

    def canonical_dict(self) -> dict[str, object]:
        obstacle_map = self.obstacle_map.to_dict()
        obstacle_map.pop("generated_monotonic_ns")
        obstacle_map.pop("output_age_ns")
        return {
            "sequence": self.sequence,
            "obstacle_map": obstacle_map,
            "threats": [item.to_dict() for item in self.threats],
        }


@dataclass(frozen=True, slots=True)
class GraphRunResult:
    graph_id: str
    source_profile_id: str
    state: GraphState
    admitted_count: int
    terminal_outcomes: tuple[TerminalOutcome, ...]
    deliveries: tuple[DeliveredFrame, ...]
    canonical_payload_sha256: str

    def to_dict(self) -> dict[str, object]:
        return {
            "schema_version": GRAPH_RESULT_SCHEMA,
            "graph_id": self.graph_id,
            "source_profile_id": self.source_profile_id,
            "state": self.state.value,
            "admitted_count": self.admitted_count,
            "terminal_outcomes": [item.to_dict() for item in self.terminal_outcomes],
            "deliveries": [item.canonical_dict() for item in self.deliveries],
            "canonical_payload_sha256": self.canonical_payload_sha256,
        }


def build_graph_run_result(
    *,
    graph_id: str,
    source_profile_id: str,
    state: GraphState,
    admitted_count: int,
    outcomes: tuple[TerminalOutcome, ...],
    deliveries: tuple[DeliveredFrame, ...],
) -> GraphRunResult:
    canonical = {
        "graph_id": graph_id,
        "source_profile_id": source_profile_id,
        "terminal_outcomes": [item.to_dict() for item in outcomes],
        "deliveries": [item.canonical_dict() for item in deliveries],
    }
    payload = json.dumps(canonical, sort_keys=True, separators=(",", ":")).encode()
    return GraphRunResult(
        graph_id=graph_id,
        source_profile_id=source_profile_id,
        state=state,
        admitted_count=admitted_count,
        terminal_outcomes=outcomes,
        deliveries=deliveries,
        canonical_payload_sha256=hashlib.sha256(payload).hexdigest(),
    )


__all__ = [
    "GRAPH_RESULT_SCHEMA",
    "REFERENCE_GRAPH_ID",
    "TERMINAL_OUTCOME_SCHEMA",
    "DeliveredFrame",
    "GraphExecutionError",
    "GraphRunResult",
    "GraphState",
    "TerminalOutcome",
    "TerminalOutcomeType",
    "build_graph_run_result",
]