"""report 流水线编排的纯逻辑单测（不连库）。

覆盖任务文档 §4 的两条：assemble_stages 缺失即 CONFIG_ERROR 且列出缺失项；
run_pipeline 顺序执行、产物按键写入、第二阶段抛错 → failed 且已完成阶段
产物仍在。
"""

from __future__ import annotations

import json

import pytest

from packages.report.pipeline import (
    ReportContext,
    StageFailureError,
    assemble_stages,
    run_pipeline,
)
from packages.shared.config import Settings
from packages.shared.errors import AppError, ErrorCode
from packages.shared.models import RpInput, RpReport


class FakeSession:
    """只满足 flush/commit/rollback 的最小会话——单测不连库。"""

    def __init__(self) -> None:
        self.flush_count = 0
        self.commit_count = 0

    async def flush(self) -> None:
        self.flush_count += 1

    async def commit(self) -> None:
        self.commit_count += 1

    async def rollback(self) -> None: ...


def _stage_settings(*paths: str) -> Settings:
    """按别名构造阶段配置——字段名带 alias 且未开 populate_by_name，
    用字段名构造会被静默忽略、落回默认值（踩过坑，写下来防再踩）。"""
    return Settings(REPORT_PIPELINE_STAGES_JSON=json.dumps(list(paths)))


def _make_ctx() -> tuple[ReportContext, FakeSession]:
    # 瞬态 ORM 对象：default=dict 只在 INSERT 时生效，这里必须显式给 JSONB 列初值。
    report = RpReport(
        report_id=101,
        user_id=1,
        status="running",
        result={},
        model_info={},
    )
    report_input = RpInput(
        input_id=11,
        report_id=101,
        questionnaire={},
        photo_meta={},
        derived_features={},
    )
    session = FakeSession()
    ctx = ReportContext(
        report=report,
        report_input=report_input,
        session=session,  # type: ignore[arg-type]
        settings=Settings(),
    )
    return ctx, session


class AlphaStage:
    name = "alpha"

    async def run(self, ctx: ReportContext) -> None:
        ctx.report.result["alpha"] = {"value": 1}
        ctx.report_input.derived_features["pose"] = {"kps": 3}


class BetaStage:
    name = "beta"

    async def run(self, ctx: ReportContext) -> None:
        # 顺序契约：后一阶段能读到前一阶段的产物。
        assert ctx.report.result.get("alpha") == {"value": 1}
        ctx.report.result["beta"] = {"value": ctx.report.result["alpha"]["value"] + 1}


class BoomStage:
    name = "boom"

    async def run(self, ctx: ReportContext) -> None:
        raise RuntimeError("爆了：模拟阶段失败")


async def test_run_pipeline_executes_stages_in_order_and_flushes_each() -> None:
    ctx, session = _make_ctx()

    await run_pipeline(ctx, [AlphaStage(), BetaStage()])

    assert ctx.report.result == {"alpha": {"value": 1}, "beta": {"value": 2}}
    assert ctx.report_input.derived_features == {"pose": {"kps": 3}}
    # 每个阶段一次 flush：中间态逐段落库（T-P3-09）的结构保证。
    assert session.flush_count == 2


async def test_run_pipeline_failure_keeps_completed_stage_and_marks_failed() -> None:
    ctx, session = _make_ctx()

    with pytest.raises(StageFailureError) as excinfo:
        await run_pipeline(ctx, [AlphaStage(), BoomStage()])

    assert excinfo.value.stage_name == "boom"
    assert ctx.report.status == "failed"
    # 已完成阶段的产物与视觉中间态都还在——重试/重生成不重跑的结构基础。
    assert ctx.report.result["alpha"] == {"value": 1}
    assert ctx.report_input.derived_features == {"pose": {"kps": 3}}
    # 错误摘要写进 result，且失败结案在事务里先行提交（退款事务纪律）。
    assert ctx.report.result["error"]["stage"] == "boom"
    assert ctx.report.result["error"]["type"] == "RuntimeError"
    assert session.commit_count == 1


def test_assemble_stages_lists_all_missing_paths() -> None:
    settings = _stage_settings(
        "packages.report.no_such_module:Nope",
        "packages.report.pipeline:NotAClass",
    )

    with pytest.raises(AppError) as excinfo:
        assemble_stages(settings)

    assert excinfo.value.code == ErrorCode.CONFIG_ERROR
    assert excinfo.value.data == {
        "missing": [
            "packages.report.no_such_module:Nope",
            "packages.report.pipeline:NotAClass",
        ]
    }


def test_assemble_stages_rejects_empty_config() -> None:
    settings = _stage_settings()

    with pytest.raises(AppError) as excinfo:
        assemble_stages(settings)

    assert excinfo.value.code == ErrorCode.CONFIG_ERROR


class _NotAStage:
    """存在但不满足 Stage 协议（没有 run）——必须被当成配置错误拦下。"""

    name = "broken"


def test_assemble_stages_rejects_protocol_violations() -> None:
    settings = _stage_settings(
        "tests.unit.test_report_pipeline:AlphaStage",
        "tests.unit.test_report_pipeline:_NotAStage",
    )

    with pytest.raises(AppError) as excinfo:
        assemble_stages(settings)

    assert excinfo.value.code == ErrorCode.CONFIG_ERROR
    assert excinfo.value.data == {"missing": ["tests.unit.test_report_pipeline:_NotAStage"]}


def test_assemble_stages_imports_from_any_module_path() -> None:
    """dotted path 装配对本模块的 Fake 阶段同样生效（importlib 动态导入路径）。"""
    settings = _stage_settings("tests.unit.test_report_pipeline:AlphaStage")
    stages = assemble_stages(settings)
    assert [s.name for s in stages] == ["alpha"]