# 用例导出服务：将用例集转换为 YAML / CSV 格式

import csv
import io
import logging

import yaml

from server.services.testcase_engine.generator import tc_generator

logger = logging.getLogger(__name__)


class TestCaseExporter:
    """Export test case sets to YAML, CSV, or structured data."""

    async def export(self, tc_set_id: str, fmt: str) -> tuple[bytes | str, str]:
        """Export testcases in specified format. Returns (content, mime_type, filename)."""
        tc_set = await tc_generator.get_tc_set(tc_set_id)
        if not tc_set:
            raise ValueError(f"Test case set not found: {tc_set_id}")

        cases = tc_set.get("cases", [])

        if fmt == "yaml":
            return self._to_yaml(cases), "application/x-yaml", f"testcases_{tc_set_id}.yaml"
        elif fmt == "csv":
            return self._to_csv(cases), "text/csv", f"testcases_{tc_set_id}.csv"
        elif fmt == "json":
            import json
            return json.dumps(tc_set, ensure_ascii=False, indent=2), "application/json", f"testcases_{tc_set_id}.json"
        else:
            raise ValueError(f"Unsupported export format: {fmt}")

    def _to_yaml(self, cases: list[dict]) -> str:
        """Convert cases to YAML string."""
        output = {
            "testcases": cases,
            "metadata": {
                "total": len(cases),
                "exported_format": "yaml",
            },
        }
        return yaml.dump(output, allow_unicode=True, sort_keys=False, default_flow_style=False)

    def _to_csv(self, cases: list[dict]) -> str:
        """Convert cases to CSV string."""
        if not cases:
            return ""

        # Flatten tags for CSV
        flattened = []
        for c in cases:
            row = {k: v for k, v in c.items() if k != "tags"}
            row["tags"] = ";".join(c.get("tags", []))
            flattened.append(row)

        output = io.StringIO()
        fieldnames = ["id", "module", "feature", "case_title", "preconditions", "steps", "expected_result", "priority", "tags"]
        writer = csv.DictWriter(output, fieldnames=fieldnames, extrasaction="ignore")
        writer.writeheader()
        writer.writerows(flattened)
        return output.getvalue()


tc_exporter = TestCaseExporter()