"""Phase 7: 分割系测试 — 基于 parametrized.generate_division_data。

测试覆盖:
  - 50% / 25% / 100% 分割
  - 余数处理（奇偶 / 不可整除）
  - 边界条件（单条记录 / 大量记录）
"""

from __future__ import annotations

import pytest

from parametrized import generate_division_data


class TestDivisionFifty:
    """50% 对半分割 → 2 个文件"""

    def test_50_even_split(self):
        result = generate_division_data(50, 100)
        assert len(result) == 2
        assert len(result[0]) == 50
        assert len(result[1]) == 50
        assert sum(len(f) for f in result) == 100

    def test_50_odd_remainder(self):
        """奇数条记录: 最后一条应归属第 2 个文件"""
        result = generate_division_data(50, 5)
        assert len(result) == 2
        assert len(result[0]) + len(result[1]) == 5

    def test_50_single_record(self):
        result = generate_division_data(50, 1)
        assert len(result) == 2
        assert len(result[0]) == 0
        assert len(result[1]) == 1

    def test_50_content_check(self):
        result = generate_division_data(50, 10)
        for file_no, records in enumerate(result, 1):
            for rec in records:
                assert rec["FILE_NO"] == file_no
                assert rec["KEY"].startswith("DIV")
                assert "SEQ" in rec
                assert "DATA" in rec


class TestDivisionTwentyFive:
    """25% 四等分分割 → 4 个文件"""

    def test_25_even_split(self):
        result = generate_division_data(25, 100)
        assert len(result) == 4
        # 100/4 = 25 各
        for records in result:
            assert len(records) == 25

    def test_25_remainder(self):
        """不可被 4 整除时，最后文件拿到剩余条数"""
        result = generate_division_data(25, 10)
        assert len(result) == 4
        total = sum(len(f) for f in result)
        assert total == 10
        # 前 3 个文件各 2 条（floor(10*0.25)=2）→ 第 4 个文件得 4 条
        assert len(result[0]) == 2
        assert len(result[1]) == 2
        assert len(result[2]) == 2
        assert len(result[3]) == 4

    def test_25_single_record(self):
        result = generate_division_data(25, 1)
        assert len(result) == 4
        assert len(result[0]) == 0
        assert len(result[1]) == 0
        assert len(result[2]) == 0
        assert len(result[3]) == 1

    def test_25_content_check(self):
        result = generate_division_data(25, 40)
        for file_no, records in enumerate(result, 1):
            for rec in records:
                assert rec["FILE_NO"] == file_no


class TestDivisionOneHundred:
    """100% 全量（不分）→ 1 个文件"""

    def test_100_all_in_one(self):
        result = generate_division_data(100, 50)
        assert len(result) == 1
        assert len(result[0]) == 50

    def test_100_single_record(self):
        result = generate_division_data(100, 1)
        assert len(result) == 1
        assert len(result[0]) == 1
        assert result[0][0]["FILE_NO"] == 1

    def test_100_large_count(self):
        result = generate_division_data(100, 10000)
        assert len(result) == 1
        assert len(result[0]) == 10000
        assert result[0][0]["SEQ"] == 1
        assert result[0][-1]["SEQ"] == 10000


class TestDivisionEdgeCases:
    """边界与异常"""

    def test_invalid_division_type(self):
        with pytest.raises(ValueError, match="division_type"):
            generate_division_data(99, 50)

    def test_invalid_record_count(self):
        with pytest.raises(ValueError, match="record_count"):
            generate_division_data(50, 0)

    def test_sequence_global(self):
        """验证 SEQ 全局递增，不重复"""
        result = generate_division_data(25, 30)
        all_seq = []
        for records in result:
            for rec in records:
                all_seq.append(rec["SEQ"])
        assert all_seq == sorted(all_seq)
        assert len(set(all_seq)) == len(all_seq)