"""tk_task state machine (架构文档 §6.2 task 域, FR-TASK-01)."""

from __future__ import annotations

from itertools import pairwise

import pytest

from packages.domain.errors import InvalidTaskTransitionError
from packages.domain.task.state import (
    ALLOWED_TRANSITIONS,
    TaskStatus,
    TaskType,
    assert_transition,
    can_transition,
    is_terminal,
    needs_refund,
    progress_for,
)


def test_happy_path() -> None:
    path = [TaskStatus.PENDING, TaskStatus.QUEUED, TaskStatus.RUNNING, TaskStatus.SUCCEEDED]
    for current, target in pairwise(path):
        assert can_transition(current, target)


def test_terminal_states_are_final_except_retry() -> None:
    assert ALLOWED_TRANSITIONS[TaskStatus.SUCCEEDED] == frozenset()
    assert ALLOWED_TRANSITIONS[TaskStatus.CANCELED] == frozenset()
    # FR-TASK-03: 失败项有原因与重试入口
    assert can_transition(TaskStatus.FAILED, TaskStatus.QUEUED)


def test_illegal_transition_names_both_states() -> None:
    with pytest.raises(InvalidTaskTransitionError) as excinfo:
        assert_transition(TaskStatus.SUCCEEDED, TaskStatus.RUNNING)
    assert excinfo.value.current == "succeeded"
    assert excinfo.value.target == "running"


def test_cannot_skip_straight_from_pending_to_succeeded() -> None:
    assert not can_transition(TaskStatus.PENDING, TaskStatus.SUCCEEDED)


def test_terminal_and_refund_classification() -> None:
    assert is_terminal(TaskStatus.SUCCEEDED)
    assert not is_terminal(TaskStatus.RUNNING)
    # FR-TRY-05 / FR-BILL-05: 无「扣了额度但没出图」case
    assert needs_refund(TaskStatus.FAILED)
    assert needs_refund(TaskStatus.CANCELED)
    assert not needs_refund(TaskStatus.SUCCEEDED)


def test_progress_is_defined_for_every_status() -> None:
    for status in TaskStatus:
        assert 0 <= progress_for(status) <= 100
    assert progress_for(TaskStatus.SUCCEEDED) == 100


def test_every_status_has_a_transition_entry() -> None:
    assert set(ALLOWED_TRANSITIONS) == set(TaskStatus)


def test_task_types_cover_the_long_running_work() -> None:
    assert {"report", "tryon", "hairstyle", "matting", "render"} <= {t.value for t in TaskType}