"""Task-record / thread model + LangGraph graph-state schema (design §3.3).

A task is a long-lived, resumable record (a LangGraph thread). This module is
the pure model layer — no I/O — defining:

* :class:`TaskStatus` / :class:`Phase` — task lifecycle enums.
* :class:`TaskRecord` — the durable task record (§3.3 "the task record holds:
  status, current phase, the full Q&A history, the plan, review verdicts, the
  candidate diff, and CI results").
* :class:`PipelineState` — a ``TypedDict`` used as the LangGraph graph state
  schema; its keys mirror :class:`TaskRecord` fields.
* :func:`new_thread_id` — uuid thread-id minting.
* JSON serialization helpers (:func:`task_to_dict` / :func:`task_from_dict` /
  :func:`task_to_json` / :func:`task_from_json`).

The signatures here are CONTRACTS leaf builders import verbatim.
"""

from __future__ import annotations

import json
import uuid
from dataclasses import asdict, dataclass, field
from enum import Enum
from typing import Any, TypedDict

__all__ = [
    "Phase",
    "PipelineState",
    "TaskRecord",
    "TaskStatus",
    "new_thread_id",
    "task_from_dict",
    "task_from_json",
    "task_to_dict",
    "task_to_json",
]


class TaskStatus(Enum):
    """Top-level task lifecycle status.

    ``ACTIVE`` — progressing through stages. ``WAITING_HUMAN`` — suspended on a
    LangGraph ``interrupt()`` awaiting Adam's answer. ``PARKED`` — stalled
    (no answer in window, N failed build loops, or budget contention) and
    ALARM-ed rather than spinning (§3.3, §6.6). ``DONE`` — draft PR + report
    produced. ``FAILED`` — terminal failure.
    """

    ACTIVE = "active"
    WAITING_HUMAN = "waiting_human"
    PARKED = "parked"
    DONE = "done"
    FAILED = "failed"


class Phase(Enum):
    """Pipeline phase the task is currently in (§3.3)."""

    INTAKE = "intake"
    CLARIFY = "clarify"
    PLAN = "plan"
    REVIEW = "review"
    BUILD = "build"
    VERIFY = "verify"
    PARKED = "parked"
    DONE = "done"


def new_thread_id() -> str:
    """Mint a fresh unique ``thread_id`` (uuid4 hex)."""
    return uuid.uuid4().hex


@dataclass
class TaskRecord:
    """The durable per-task record (§3.3, §3.3.1).

    Mirrors the LangGraph thread state; the SQLite checkpointer persists the
    graph state while this record is the logical view the coordinator reasons
    over. ``qa_history`` is the full clarifier Q&A; ``review_verdicts`` the
    adversarial review outcomes; ``candidate_diff`` + ``diff_hash`` the builder
    output and its ledger-recorded hash (§3.3.2); ``ci_results`` the
    authenticated CI conclusion the verifier reads.
    """

    thread_id: str
    status: TaskStatus
    current_phase: Phase
    # Intake task description (mirrors PipelineState.task).
    task: str = ""
    # Slack root-message ts for one-thread-per-task (mirrors
    # PipelineState.slack_thread_ts). Empty for non-/new-task origins.
    slack_thread_ts: str = ""
    qa_history: list[Any] = field(default_factory=list)
    plan: dict[str, Any] | None = None
    review_verdicts: list[Any] = field(default_factory=list)
    candidate_diff: str | None = None
    diff_hash: str | None = None
    ci_results: dict[str, Any] | None = None
    transport: str = ""
    created_at: str | None = None
    updated_at: str | None = None


class PipelineState(TypedDict, total=False):
    """LangGraph graph-state schema; keys mirror :class:`TaskRecord` (§3.3).

    Used as the graph's state type. ``total=False`` so a node may write a
    subset of keys per checkpoint transition.
    """

    thread_id: str
    status: str
    current_phase: str
    # The intake task description (Slack /new-task text, GitHub issue body, etc.).
    # Seeded by graph.start_task and read by the clarifier/planner; a first-class
    # channel so the seeded value persists across node transitions.
    task: str
    # The Slack root-message ``ts`` for a /new-task task (the "📥 Task received"
    # ack post). All of the task's clarifier questions and lifecycle milestone
    # notifications thread under this ``ts`` so one task maps to one Slack thread.
    # Empty/absent for a task that did not originate from /new-task (no root post),
    # in which case posts are top-level exactly as before.
    slack_thread_ts: str
    qa_history: list[Any]
    plan: dict[str, Any] | None
    review_verdicts: list[Any]
    candidate_diff: str | None
    diff_hash: str | None
    ci_results: dict[str, Any] | None
    transport: str
    created_at: str | None
    updated_at: str | None


def task_to_dict(record: TaskRecord) -> dict[str, Any]:
    """Serialize a :class:`TaskRecord` to a JSON-safe dict (enums -> values)."""
    data = asdict(record)
    data["status"] = record.status.value
    data["current_phase"] = record.current_phase.value
    return data


def task_from_dict(data: dict[str, Any]) -> TaskRecord:
    """Rebuild a :class:`TaskRecord` from a :func:`task_to_dict` dict."""
    return TaskRecord(
        thread_id=data["thread_id"],
        status=TaskStatus(data["status"]),
        current_phase=Phase(data["current_phase"]),
        task=data.get("task", ""),
        slack_thread_ts=data.get("slack_thread_ts", ""),
        qa_history=list(data.get("qa_history", [])),
        plan=data.get("plan"),
        review_verdicts=list(data.get("review_verdicts", [])),
        candidate_diff=data.get("candidate_diff"),
        diff_hash=data.get("diff_hash"),
        ci_results=data.get("ci_results"),
        transport=data.get("transport", ""),
        created_at=data.get("created_at"),
        updated_at=data.get("updated_at"),
    )


def task_to_json(record: TaskRecord) -> str:
    """Serialize a :class:`TaskRecord` to a JSON string."""
    return json.dumps(task_to_dict(record), sort_keys=True)


def task_from_json(payload: str | bytes) -> TaskRecord:
    """Deserialize a :class:`TaskRecord` from a JSON string/bytes."""
    return task_from_dict(json.loads(payload))