"""
Regression tests for offline trace parsing (实验 7-9 成本分析).

Covers two crash classes found in --offline mode:
  - Tracer.from_records: trace JSON with explicit null token fields -> int(None) TypeError
  - demo.collect_offline: scenario dict missing the optional "spans" key -> KeyError
"""
import json

import pytest

import config
import demo
from tracer import Tracer


def _span(**overrides):
    span = {
        "step": "turn-1",
        "tool": "query_order",
        "kind": "llm",
        "prompt_tokens": 100,
        "cached_tokens": 10,
        "completion_tokens": 12,
        "tool_ctx_tokens": 50,
        "latency_s": 1.2,
    }
    span.update(overrides)
    return span


def test_from_records_tolerates_null_fields():
    """Explicit JSON nulls in numeric fields are coerced, not int(None) TypeError."""
    records = [_span(prompt_tokens=None, cached_tokens=None,
                     completion_tokens=None, tool_ctx_tokens=None, latency_s=None)]
    tr = Tracer.from_records(records, pricing=config.default_pricing())
    s = tr.spans[0]
    assert s.prompt_tokens == 0
    assert s.cached_tokens == 0
    assert s.completion_tokens == 0
    assert s.tool_ctx_tokens == -1   # null tool_ctx 视为「未知」
    assert s.latency_s == 0.0


def test_from_records_tolerates_missing_fields():
    """Minimal span dicts (only step/tool) still parse."""
    tr = Tracer.from_records([{"step": "turn-1", "tool": "query_order"}],
                             pricing=config.default_pricing())
    assert tr.spans[0].prompt_tokens == 0
    assert tr.spans[0].tool_ctx_tokens == -1


def test_from_records_keeps_real_values():
    """Normal values pass through unchanged (no coercion side effects)."""
    tr = Tracer.from_records([_span()], pricing=config.default_pricing())
    s = tr.spans[0]
    assert (s.prompt_tokens, s.cached_tokens, s.completion_tokens) == (100, 10, 12)
    assert s.tool_ctx_tokens == 50
    assert s.latency_s == 1.2


def test_from_records_keeps_zero_tool_ctx_tokens():
    """Explicit 0 means known-zero tool context, not unknown (-1)."""
    tr = Tracer.from_records([_span(tool_ctx_tokens=0)],
                             pricing=config.default_pricing())
    assert tr.spans[0].tool_ctx_tokens == 0
    assert tr.total_tool_ctx_tokens() == 0


def _write_trace(tmp_path, scenarios):
    path = tmp_path / "trace.json"
    path.write_text(json.dumps({"model": "gpt-5.6-luna", "scenarios": scenarios}),
                    encoding="utf-8")
    return str(path)


def test_collect_offline_skips_scenario_without_spans(tmp_path, capsys):
    """A scenario missing 'spans' is skipped with a warning, not a KeyError crash."""
    trace = _write_trace(tmp_path, [
        {"key": "naive", "name": "A naive"},                      # no spans -> skip
        {"key": "both", "name": "B both", "spans": [_span()]},    # valid
    ])
    tracers = demo.collect_offline(["naive", "both"], config.default_pricing(), trace)
    assert [k for k, _ in tracers] == ["both"]
    assert "缺少 spans" in capsys.readouterr().err


def test_collect_offline_exits_when_no_usable_scenario(tmp_path):
    """When every selected scenario lacks spans, exit cleanly like the empty-trace path."""
    trace = _write_trace(tmp_path, [{"key": "naive", "name": "A naive"}])
    with pytest.raises(SystemExit):
        demo.collect_offline(["naive"], config.default_pricing(), trace)


if __name__ == "__main__":
    pytest.main([__file__, "-v"])