"""Shared post-build processing pipeline.

After the core Tree-sitter parse (full_build or incremental_update), four
post-processing steps must run to populate derived tables:

1. Compute node signatures
2. Rebuild FTS5 search index
3. Trace execution flows
4. Detect code communities

This module extracts that pipeline so every entry point — MCP tool, CLI
commands, and watch mode — produces identical results.
"""

from __future__ import annotations

import logging
import sqlite3
from typing import Any

from .graph import GraphStore

logger = logging.getLogger(__name__)


def run_post_processing(store: GraphStore) -> dict[str, Any]:
    """Run all post-build steps on a populated graph.

    Each step is non-fatal: failures are logged and collected as warnings
    so the primary build result is never lost.

    Args:
        store: An open GraphStore with nodes and edges already populated.

    Returns:
        Dict with keys for each step's result count and a ``warnings``
        list (only present when at least one step failed).
    """
    result: dict[str, Any] = {}
    warnings: list[str] = []

    _compute_signatures(store, result, warnings)
    _rebuild_fts_index(store, result, warnings)
    _trace_flows(store, result, warnings)
    _detect_communities(store, result, warnings)

    if warnings:
        result["warnings"] = warnings
    return result


# -- Individual steps (private) ------------------------------------------


def _compute_signatures(
    store: GraphStore,
    result: dict[str, Any],
    warnings: list[str],
) -> None:
    """Compute human-readable signatures for nodes that lack one."""
    try:
        rows = store.get_nodes_without_signature()
        for row in rows:
            node_id, name, kind, params, ret = (
                row[0],
                row[1],
                row[2],
                row[3],
                row[4],
            )
            if kind in ("Function", "Test"):
                sig = f"def {name}({params or ''})"
                if ret:
                    sig += f" -> {ret}"
            elif kind == "Class":
                sig = f"class {name}"
            else:
                sig = name
            store.update_node_signature(node_id, sig[:512])
        store.commit()
        result["signatures_computed"] = len(rows)
    except (sqlite3.OperationalError, TypeError, KeyError) as e:
        logger.warning("Signature computation failed: %s", e)
        warnings.append(f"Signature computation failed: {type(e).__name__}: {e}")


def _rebuild_fts_index(
    store: GraphStore,
    result: dict[str, Any],
    warnings: list[str],
) -> None:
    """Rebuild the FTS5 full-text search index."""
    try:
        from .search import rebuild_fts_index

        fts_count = rebuild_fts_index(store)
        result["fts_indexed"] = fts_count
    except (sqlite3.OperationalError, ImportError) as e:
        logger.warning("FTS index rebuild failed: %s", e)
        warnings.append(f"FTS index rebuild failed: {type(e).__name__}: {e}")


def _trace_flows(
    store: GraphStore,
    result: dict[str, Any],
    warnings: list[str],
) -> None:
    """Trace execution flows from entry points."""
    try:
        from .flows import store_flows, trace_flows

        flows = trace_flows(store)
        count = store_flows(store, flows)
        result["flows_detected"] = count
    except (sqlite3.OperationalError, ImportError) as e:
        logger.warning("Flow detection failed: %s", e)
        warnings.append(f"Flow detection failed: {type(e).__name__}: {e}")


def _detect_communities(
    store: GraphStore,
    result: dict[str, Any],
    warnings: list[str],
) -> None:
    """Detect code communities via Leiden algorithm or file grouping."""
    try:
        from .communities import detect_communities, store_communities

        comms = detect_communities(store)
        count = store_communities(store, comms)
        result["communities_detected"] = count
    except (sqlite3.OperationalError, ImportError) as e:
        logger.warning("Community detection failed: %s", e)
        warnings.append(f"Community detection failed: {type(e).__name__}: {e}")