#!/usr/bin/env python3
"""Shared utilities for Settled Reach DB tooling scripts.

Provides the standard DB path resolution, config loading, and connection
helpers used across ticket, sprint, sqlite_connector, and decisions_sync.
"""

import json
import os
import sqlite3
import sys
from pathlib import Path

# ---------------------------------------------------------------------------
# Paths
# ---------------------------------------------------------------------------

SCRIPT_DIR = Path(__file__).resolve().parent
CONFIG_PATH = SCRIPT_DIR / "config.json"
WORKTREE_ROOT = (SCRIPT_DIR / ".." / "..").resolve()


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------


def resolve_db_path() -> Path:
    """Return the ticket database path.

    Prefers the SR_DB_PATH environment variable (absolute path).
    Falls back to <worktree-parent>/settledreach.db — the shared DB location
    used when working directly in the main repo checkout.
    """
    if os.environ.get("SR_DB_PATH"):
        return Path(os.environ["SR_DB_PATH"]).resolve()
    return (WORKTREE_ROOT / ".." / "settledreach.db").resolve()


def load_config() -> dict:
    """Load tooling/db/config.json and inject the resolved DB path."""
    with open(CONFIG_PATH) as f:
        cfg = json.load(f)
    cfg["sqlite_db_resolved"] = str(resolve_db_path())
    return cfg


def get_connection(cfg: dict) -> sqlite3.Connection:
    """Return a WAL-mode SQLite connection with foreign keys enabled."""
    conn = sqlite3.connect(cfg["sqlite_db_resolved"])
    conn.execute("PRAGMA journal_mode=WAL;")
    conn.execute("PRAGMA foreign_keys=ON;")
    conn.row_factory = sqlite3.Row
    return conn


def ensure_venv() -> None:
    """Re-exec into the project .venv Python if not already running there.

    Call this at the top of any script that uses third-party packages,
    before those imports. Pure-stdlib scripts (ticket, sprint,
    sqlite_connector, decisions_sync) do not need it.

    Usage::

        from common import ensure_venv
        ensure_venv()
        import numpy as np  # third-party import follows
    """
    venv_python = WORKTREE_ROOT / ".venv" / "bin" / "python"

    # Already running inside the venv — nothing to do.
    if Path(sys.executable).resolve() == venv_python.resolve():
        return

    # .venv not set up yet — fail with a helpful message.
    if not venv_python.exists():
        print(
            "error: .venv not found — run `make setup-venv` first.",
            file=sys.stderr,
        )
        sys.exit(1)

    # Re-exec into the venv Python, preserving all arguments.
    os.execv(str(venv_python), [str(venv_python)] + sys.argv)