"""
Databricks — Lineage Push (push-only)
=======================================
Reads a JSON manifest file produced by collect_lineage.py and pushes the lineage
events to Monte Carlo via the push ingestion API, with configurable batching to
keep compressed payloads under 1 MB.

Substitution points (search for "← SUBSTITUTE"):
  - MCD_INGEST_ID / MCD_INGEST_TOKEN : Monte Carlo API credentials
  - MCD_RESOURCE_UUID      : UUID of the Databricks connection in Monte Carlo
  - PUSH_BATCH_SIZE       : number of events per API call (default 500)

Prerequisites:
  pip install pycarlo
"""

from __future__ import annotations

import argparse
import json
import logging
import os
from concurrent.futures import ThreadPoolExecutor, as_completed
from datetime import datetime, timezone
from typing import Any

from pycarlo.core import Client, Session
from pycarlo.features.ingestion import IngestionService
from pycarlo.features.ingestion.models import (
    ColumnLineageField,
    ColumnLineageSourceField,
    LineageAssetRef,
    LineageEvent,
)

logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(message)s")
log = logging.getLogger(__name__)

RESOURCE_TYPE = "databricks"
DEFAULT_BATCH_SIZE = 500  # ← SUBSTITUTE: conservative default to stay under 1 MB compressed


def _ref_from_dict(d: dict[str, Any]) -> LineageAssetRef:
    database = d.get("database", "")
    schema = d.get("schema", "")
    name = d["asset_name"]
    return LineageAssetRef(
        type="TABLE",
        name=name,
        database=database,
        schema=schema,
        asset_id=f"{database}__{schema}__{name}",
    )


def _event_from_dict(d: dict[str, Any]) -> LineageEvent:
    """Reconstruct a LineageEvent from a manifest dict."""
    sources = [_ref_from_dict(s) for s in d.get("sources", [])]
    destination = _ref_from_dict(d["destination"])

    fields: list[ColumnLineageField] | None = None
    if d.get("column_lineage"):
        fields = []
        for cl in d["column_lineage"]:
            src_fields = []
            for s in cl.get("sources", []):
                asset_id = f"{s.get('database', '')}__{s.get('schema', '')}__{s['asset_name']}"
                src_fields.append(
                    ColumnLineageSourceField(
                        asset_id=asset_id,
                        field_name=s["field"],
                    )
                )
            fields.append(
                ColumnLineageField(
                    name=cl["destination_field"],
                    source_fields=src_fields,
                )
            )

    return LineageEvent(
        sources=sources,
        destination=destination,
        fields=fields,
    )


def push(
    manifest_path: str,
    resource_uuid: str,
    key_id: str,
    key_token: str,
    batch_size: int = DEFAULT_BATCH_SIZE,
) -> dict[str, Any]:
    """Read a collect manifest and push lineage events to Monte Carlo in batches.

    Returns a summary dict with invocation IDs and counts.
    """
    with open(manifest_path) as fh:
        manifest = json.load(fh)

    event_dicts: list[dict[str, Any]] = manifest["events"]
    events = [_event_from_dict(d) for d in event_dicts]
    log.info("Loaded %d lineage events from %s", len(events), manifest_path)

    # Split into batches
    batches = []
    for i in range(0, len(events), batch_size):
        batches.append(events[i : i + batch_size])
    total_batches = len(batches)

    def _push_batch(batch: list, batch_num: int) -> str | None:
        """Push a single batch using a dedicated Session (thread-safe)."""
        log.info("Pushing batch %d/%d (%d events) ...", batch_num, total_batches, len(batch))
        client = Client(session=Session(mcd_id=key_id, mcd_token=key_token, scope="Ingestion"))
        service = IngestionService(mc_client=client)
        result = service.send_lineage(
            resource_uuid=resource_uuid,
            resource_type=RESOURCE_TYPE,
            events=batch,
        )
        invocation_id = service.extract_invocation_id(result)
        if invocation_id:
            log.info("Batch %d: invocation_id=%s", batch_num, invocation_id)
        return invocation_id

    # Push batches in parallel (each thread gets its own pycarlo Session)
    max_workers = min(4, total_batches)
    invocation_ids: list[str | None] = [None] * total_batches

    with ThreadPoolExecutor(max_workers=max_workers) as pool:
        futures = {
            pool.submit(_push_batch, batch, i + 1): i
            for i, batch in enumerate(batches)
        }
        for future in as_completed(futures):
            idx = futures[future]
            try:
                invocation_ids[idx] = future.result()
            except Exception as exc:
                log.error("ERROR pushing batch %d: %s", idx + 1, exc)
                raise

    log.info("All %d batches pushed (%d workers)", total_batches, max_workers)

    pushed_at = datetime.now(timezone.utc).isoformat()
    summary = {
        "resource_uuid": resource_uuid,
        "resource_type": RESOURCE_TYPE,
        "invocation_ids": invocation_ids,
        "pushed_at": pushed_at,
        "event_count": len(events),
        "batch_count": total_batches,
        "batch_size": batch_size,
        "lookback_days": manifest.get("lookback_days"),
        "table_lineage_events": manifest.get("table_lineage_events"),
        "column_lineage_events": manifest.get("column_lineage_events"),
    }

    push_manifest_path = manifest_path.replace(".json", "_push_result.json")
    with open(push_manifest_path, "w") as fh:
        json.dump(summary, fh, indent=2)
    log.info("Push result written to %s", push_manifest_path)

    return summary


def main() -> None:
    parser = argparse.ArgumentParser(description="Push Databricks lineage to Monte Carlo from manifest")
    parser.add_argument("--manifest", default="manifest_lineage.json")
    parser.add_argument("--resource-uuid", default=os.getenv("MCD_RESOURCE_UUID"))
    parser.add_argument("--key-id", default=os.getenv("MCD_INGEST_ID"))
    parser.add_argument("--key-token", default=os.getenv("MCD_INGEST_TOKEN"))
    parser.add_argument("--batch-size", type=int, default=DEFAULT_BATCH_SIZE)
    args = parser.parse_args()

    required = ["resource_uuid", "key_id", "key_token"]
    missing = [k for k in required if getattr(args, k) is None]
    if missing:
        parser.error(f"Missing required arguments/env vars: {missing}")

    push(
        manifest_path=args.manifest,
        resource_uuid=args.resource_uuid,
        key_id=args.key_id,
        key_token=args.key_token,
        batch_size=args.batch_size,
    )


if __name__ == "__main__":
    main()