from __future__ import annotations

import json
from typing import Any

from config.client import ODataClient, flatten_guid_like_fields, utc_now_iso
from config.settings import LOGS_DIR, load_settings


def _load_probe_targets() -> list[str]:
    report_file = LOGS_DIR / "probe_report.json"
    if not report_file.exists():
        return []

    payload = json.loads(report_file.read_text(encoding="utf-8"))
    targets: list[str] = []
    for entity in payload.get("entities", []):
        if entity.get("status") == "ok" and entity.get("entity_set"):
            targets.append(str(entity["entity_set"]))
    return targets[:10]


def _extract_link_map(records: list[dict[str, Any]]) -> dict[str, list[str]]:
    field_map: dict[str, set[str]] = {}
    for row in records:
        for field in flatten_guid_like_fields(row):
            value = row.get(field)
            if value is None:
                continue
            field_map.setdefault(field, set()).add(str(value))

    normalized: dict[str, list[str]] = {}
    for field, values in field_map.items():
        normalized[field] = sorted(values)[:5]
    return normalized


def main() -> int:
    settings = load_settings()
    client = ODataClient(settings)
    targets = _load_probe_targets()

    if not targets:
        print(
            "[error] probe_report.json not found or empty. "
            "Run `python -m odata_probe.probe_entities` first."
        )
        return 1

    links_payload: dict[str, Any] = {
        "generated_at": utc_now_iso(),
        "service_root": settings.service_root,
        "entities": [],
    }

    for entity_set in targets:
        try:
            records = client.read_entity_set_records(entity_set, top=min(settings.probe_top, 5))
            links_payload["entities"].append(
                {
                    "entity_set": entity_set,
                    "records_fetched": len(records),
                    "link_field_samples": _extract_link_map(records),
                }
            )
            print(f"[ok] {entity_set}: link map generated")
        except Exception as exc:
            links_payload["entities"].append(
                {
                    "entity_set": entity_set,
                    "error": str(exc),
                }
            )
            print(f"[warn] {entity_set}: {exc}")

    output_file = LOGS_DIR / "sample_links.json"
    output_file.write_text(
        json.dumps(links_payload, ensure_ascii=False, indent=2),
        encoding="utf-8",
    )
    print(f"[ok] saved link map: {output_file}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())