#!/usr/bin/env bash
# scripts/lib/env.sh
# Resolves which python to use, in priority order:
#   1. $PYTHON env var, if set
#   2. $CONDA_PREFIX/bin/python, if a conda env is active
#   3. ~/anaconda3/envs/causalgrok/bin/python, if it exists
#   4. system python, with a warning
#
# Source this; call `resolve_python` to set the global $PYTHON.

resolve_python() {
    if [[ -n "${PYTHON:-}" ]] && [[ -x "${PYTHON}" ]]; then
        return
    fi
    if [[ -n "${CONDA_PREFIX:-}" ]] && [[ -x "${CONDA_PREFIX}/bin/python" ]]; then
        PYTHON="${CONDA_PREFIX}/bin/python"
        return
    fi
    local cand="${HOME}/anaconda3/envs/causalgrok/bin/python"
    if [[ -x "${cand}" ]]; then
        PYTHON="${cand}"
        return
    fi
    if command -v python >/dev/null 2>&1; then
        PYTHON="$(command -v python)"
        echo "  warning: causalgrok env not found; using ${PYTHON}" >&2
        return
    fi
    echo "  error: no python interpreter found" >&2
    return 1
}