"""素材片段使用记录追踪服务测试（asset_segment_tracker）.

覆盖：
- get_used_segments 聚合 metadata 中持久化的区间
- record_used_segments 追加记录（不 commit，保留原有 metadata 字段）
- remove_used_segment 匹配删除（tolerance + plan_id）
- reset_used_segments 清空轮回（其他字段不动）
- make_reset_callback 同时清持久化和内存
- _calc_random_start_time 的 on_exhausted 轮回回调
"""

from __future__ import annotations

import json
import os
import sys
from pathlib import Path

os.environ.setdefault("JWT_SECRET_KEY", "unit-test-secret-key-for-testing")
os.environ.setdefault("DATABASE_URL", "sqlite:///test.db")

sys.path.insert(0, str(Path(__file__).resolve().parents[2] / "apps" / "api"))

import pytest
from app.services import asset_segment_tracker as ast
from app.services.asset_segment_tracker import (
    get_used_segments,
    make_reset_callback,
    record_used_segments,
    remove_used_segment,
    reset_used_segments,
)

from packages.domain.plan_generator_utils import _calc_random_start_time


class FakeModel:
    """模拟 AssetModel：id + classification_result（JSON Text）+ updated_at。"""

    def __init__(self, asset_id: str, meta: dict | None = None):
        self.id = asset_id
        self.classification_result = json.dumps(meta, ensure_ascii=False) if meta else None
        self.updated_at = None

    def meta(self) -> dict:
        return json.loads(self.classification_result) if self.classification_result else {}


class _InExpr:
    def __init__(self, ids, models):
        self._ids = ids
        self._models = models

    def all(self):
        return [self._models[i] for i in self._ids if i in self._models]


class _EqExpr:
    def __init__(self, target_id, models):
        self._target_id = target_id
        self._models = models

    def first(self):
        return self._models.get(self._target_id)


class FakeSession:
    """模拟 db：db.query(Model).filter(Model.id.in_(ids)).all() / .filter(Model.id == id).first()。

    tracker 模块里的 AssetModel 被 monkeypatch 为 FakeModel 类，
    这里用挂在类上的伪 column 对象接住 in_ / __eq__。
    """

    class _Col:
        def __init__(self, models):
            self._models = models

        def in_(self, ids):
            return _InExpr(list(ids), self._models)

        def __eq__(self, other):
            return _EqExpr(other, self._models)

    def __init__(self, models: dict[str, FakeModel]):
        self._models = models
        self.commits = 0

    def query(self, _model):
        col = self._Col(self._models)

        class _Q:
            def filter(self_inner, expr):
                return expr

        q = _Q()
        # 让 tracker 里 AssetModel.id 能取到伪 column
        _model.id = col
        return q

    def commit(self):
        self.commits += 1


@pytest.fixture
def patched_model(monkeypatch):
    """把 tracker 模块内的 AssetModel 替换为 FakeModel（供 FakeSession 挂伪 column）。"""
    monkeypatch.setattr(ast, "AssetModel", FakeModel)


@pytest.fixture
def models():
    return {}


def _db(models):
    return FakeSession(models)


# ── get_used_segments ─────────────────────────────────────────────────────────


def test_get_used_segments_aggregates_ranges(patched_model):
    models = {
        "a1": FakeModel(
            "a1",
            {
                "used_time_ranges": [
                    {"start": 1.0, "end": 5.0, "plan_id": "p1"},
                    {"start": 9.0, "end": 12.0, "plan_id": "p2"},
                ]
            },
        ),
        "a2": FakeModel("a2", {"other": 1}),  # 无区间记录
        "a3": FakeModel("a3"),  # metadata 为空
    }
    db = _db(models)

    result = get_used_segments(db, ["a1", "a2", "a3", "missing"])

    assert result == {"a1": [(1.0, 5.0), (9.0, 12.0)]}


def test_get_used_segments_empty_input(patched_model):
    assert get_used_segments(_db({}), []) == {}


# ── record_used_segments ──────────────────────────────────────────────────────


def test_record_appends_and_no_commit(patched_model):
    models = {"a1": FakeModel("a1", {"generation_use_count": 3})}
    db = _db(models)

    record_used_segments(db, "a1", 2.0, 6.5, "plan-x")

    meta = models["a1"].meta()
    assert meta["generation_use_count"] == 3  # 原有字段保留
    ranges = meta["used_time_ranges"]
    assert len(ranges) == 1
    assert ranges[0]["start"] == 2.0
    assert ranges[0]["end"] == 6.5
    assert ranges[0]["plan_id"] == "plan-x"
    assert "created_at" in ranges[0]
    assert db.commits == 0  # 不自行 commit（事务由调用方控制）


def test_record_multiple_appends_in_order(patched_model):
    models = {"a1": FakeModel("a1")}
    db = _db(models)

    record_used_segments(db, "a1", 0.0, 4.0, "p1")
    record_used_segments(db, "a1", 10.0, 14.0, "p1")

    ranges = models["a1"].meta()["used_time_ranges"]
    assert [r["start"] for r in ranges] == [0.0, 10.0]


def test_record_missing_asset_is_noop(patched_model):
    db = _db({})
    record_used_segments(db, "ghost", 0.0, 1.0, "p1")  # 不抛异常


# ── remove_used_segment ───────────────────────────────────────────────────────


def test_remove_matching_segment(patched_model):
    models = {"a1": FakeModel("a1")}
    db = _db(models)
    record_used_segments(db, "a1", 0.0, 4.0, "p1")
    record_used_segments(db, "a1", 10.0, 14.0, "p1")

    removed = remove_used_segment(db, "a1", 0.0, 4.0, plan_id="p1")

    assert removed is True
    ranges = models["a1"].meta()["used_time_ranges"]
    assert len(ranges) == 1
    assert ranges[0]["start"] == 10.0


def test_remove_not_found_returns_false(patched_model):
    models = {"a1": FakeModel("a1")}
    db = _db(models)
    record_used_segments(db, "a1", 0.0, 4.0, "p1")

    assert remove_used_segment(db, "a1", 99.0, 100.0, plan_id="p1") is False


def test_remove_respects_tolerance(patched_model):
    models = {
        "a1": FakeModel("a1", {"used_time_ranges": [{"start": 5.0, "end": 9.0, "plan_id": "p1"}]}),
        "a2": FakeModel("a2", {"used_time_ranges": [{"start": 5.0, "end": 9.0, "plan_id": "p1"}]}),
    }
    db = _db(models)

    # 偏差 0.3 秒，在 tolerance=0.5 内 → 删除成功
    assert remove_used_segment(db, "a1", 5.3, 8.7, plan_id="p1") is True
    # 偏差 2 秒，超出 tolerance → 删除失败
    assert remove_used_segment(db, "a2", 7.0, 11.0, plan_id="p1") is False


def test_remove_plan_id_must_match(patched_model):
    models = {"a1": FakeModel("a1", {"used_time_ranges": [{"start": 5.0, "end": 9.0, "plan_id": "plan-A"}]})}
    db = _db(models)

    # 时间匹配但 plan_id 不同 → 不删除
    assert remove_used_segment(db, "a1", 5.0, 9.0, plan_id="plan-B") is False
    assert len(models["a1"].meta()["used_time_ranges"]) == 1


def test_remove_legacy_record_without_plan_id(patched_model):
    """旧数据记录没有 plan_id 字段时，MediaKit 移动片段仍能按时间匹配删除（防容量泄漏）。"""
    models = {
        "a1": FakeModel(
            "a1",
            {"used_time_ranges": [{"start": 5.0, "end": 9.0}]},  # 旧记录无 plan_id
        )
    }
    db = _db(models)

    # 传入 plan_id，但记录本身无 plan_id → 按时间匹配，允许删除
    assert remove_used_segment(db, "a1", 5.0, 9.0, plan_id="plan-new") is True
    assert models["a1"].meta()["used_time_ranges"] == []


# ── reset_used_segments ───────────────────────────────────────────────────────


def test_reset_clears_ranges_keeps_other_fields(patched_model):
    models = {
        "a1": FakeModel(
            "a1",
            {
                "generation_use_count": 9,
                "used_time_ranges": [{"start": 1, "end": 2}],
            },
        )
    }
    db = _db(models)

    reset_used_segments(db, "a1")

    meta = models["a1"].meta()
    assert meta["used_time_ranges"] == []
    assert meta["generation_use_count"] == 9
    assert db.commits == 0


# ── make_reset_callback ───────────────────────────────────────────────────────


def test_reset_callback_clears_persisted_and_memory(patched_model):
    models = {"a1": FakeModel("a1", {"used_time_ranges": [{"start": 0, "end": 30}]})}
    db = _db(models)

    used_segments = {"a1": [(0.0, 30.0)], "a2": [(1.0, 2.0)]}
    cb = make_reset_callback(db, used_segments)
    cb("a1")

    assert "a1" not in used_segments  # 内存清空
    assert "a2" in used_segments  # 其他素材不受影响
    assert models["a1"].meta()["used_time_ranges"] == []


# ── _calc_random_start_time 轮回回调 ──────────────────────────────────────────


def test_calc_random_start_invokes_reset_when_exhausted():
    """素材区间被占满（100 次随机必重叠）→ 触发 on_exhausted，重置后重试成功。"""
    durations = {"a1": 30.0}
    used = {"a1": [(0.0, 10.0), (10.0, 20.0), (20.0, 30.0)]}
    reset_called = []

    def _on_exhausted(asset_id):
        reset_called.append(asset_id)
        used.pop(asset_id, None)  # 模拟轮回清空

    result = _calc_random_start_time("a1", 10.0, durations, used, on_exhausted=_on_exhausted)

    assert reset_called == ["a1"]
    assert result is not None
    assert 0.0 <= result <= 20.0  # max_start = 30 - 10


def test_calc_random_start_no_callback_keeps_legacy_fallback():
    """不传 on_exhausted 时保持旧降级行为，不报错。"""
    durations = {"a1": 30.0}
    used = {"a1": [(0.0, 10.0), (10.0, 20.0), (20.0, 30.0)]}

    result = _calc_random_start_time("a1", 10.0, durations, used)

    assert result is not None


def test_calc_random_start_with_space_does_not_reset():
    """有充足空闲区间时不触发 reset。"""
    durations = {"a1": 100.0}
    used = {"a1": [(0.0, 50.0)]}
    reset_called = []

    result = _calc_random_start_time("a1", 5.0, durations, used, on_exhausted=lambda aid: reset_called.append(aid))

    assert reset_called == []
    assert result is not None