"""Tests for structured JSON logging."""

import json
import logging

from derp.log import JsonFormatter


class TestJsonFormatter:
    """Test JsonFormatter output."""

    @staticmethod
    def _make_record(msg: str, level: int = logging.INFO,
                     name: str = "derp.test") -> logging.LogRecord:
        """Create a LogRecord for testing."""
        return logging.LogRecord(
            name=name, level=level, pathname="", lineno=0,
            msg=msg, args=(), exc_info=None,
        )

    def test_basic_fields(self):
        fmt = JsonFormatter()
        record = self._make_record("hello world")
        output = fmt.format(record)
        entry = json.loads(output)
        assert entry["msg"] == "hello world"
        assert entry["level"] == "info"
        assert entry["logger"] == "derp.test"
        assert "ts" in entry

    def test_level_name(self):
        fmt = JsonFormatter()
        record = self._make_record("warn", level=logging.WARNING)
        entry = json.loads(fmt.format(record))
        assert entry["level"] == "warning"

    def test_no_exc_key_without_exception(self):
        fmt = JsonFormatter()
        record = self._make_record("clean")
        entry = json.loads(fmt.format(record))
        assert "exc" not in entry

    def test_exception_included(self):
        fmt = JsonFormatter()
        import sys
        try:
            raise ValueError("boom")
        except ValueError:
            exc_info = sys.exc_info()
            record = logging.LogRecord(
                name="derp.test", level=logging.ERROR, pathname="", lineno=0,
                msg="failed", args=(), exc_info=exc_info,
            )
        entry = json.loads(fmt.format(record))
        assert "exc" in entry
        assert "ValueError" in entry["exc"]
        assert "boom" in entry["exc"]

    def test_output_is_single_line(self):
        fmt = JsonFormatter()
        record = self._make_record("one liner")
        output = fmt.format(record)
        assert "\n" not in output

    def test_unicode_preserved(self):
        fmt = JsonFormatter()
        record = self._make_record("cafe\u0301")
        entry = json.loads(fmt.format(record))
        assert entry["msg"] == "cafe\u0301"

    def test_timestamp_format(self):
        fmt = JsonFormatter()
        record = self._make_record("ts check")
        entry = json.loads(fmt.format(record))
        # ISO-ish: YYYY-MM-DDTHH:MM:SS
        assert "T" in entry["ts"]
        assert len(entry["ts"]) == 19