{ pkgs ? import <nixpkgs> { } }:

# FHS development shell for somafm-tui.
#
# Why FHS?  uv installs manylinux wheels from PyPI (notably NumPy) that expect
# libstdc++.so.6 and friends in the usual FHS locations (/usr/lib, /lib).
# NixOS doesn't populate those paths, so a normal mkShell fails at runtime with
#   libstdc++.so.6: cannot open shared object file
# buildFHSEnv gives us a tiny FHS root with the Nix store mounted, and
# stdenv.cc.cc.lib supplies the missing C++ runtime.
#
#   nix-shell            # enter the FHS shell
#   rm -rf .venv         # once, if the venv was created by an older setup
#   uv sync              # install Python deps with uv
#   uv run somafm-tui    # start the radio
#
# Note: `nix-shell --run "..."` is not supported by FHS shell.nix files; enter
# the shell interactively and run commands there.

(pkgs.buildFHSEnv {
  name = "somafm-tui";

  targetPkgs = pkgs: with pkgs; [
    # --- Python toolchain; uv owns all Python dependencies ---------------
    # Nix's default python3 (not a patch/minor pin).  Outside this shell,
    # uv accepts any CPython >= 3.10, or downloads one if needed.
    python3
    uv

    # --- the actual fix for NumPy/manylinux wheels ------------------------
    stdenv.cc.cc.lib   # libstdc++.so.6
    zlib

    # --- radio ------------------------------------------------------------
    mpv
    ffmpeg
    dbus
    playerctl
    tmux                 # detect the outer terminal inside tmux for TGP

    # --- audio backends that mpv / ffplay load at runtime -----------------
    alsa-lib
    libpulseaudio
    pipewire
    pulseaudio          # parec/pactl: synced spectrum capture (works with PipeWire)

    # --- shell / terminal helpers -----------------------------------------
    bashInteractive
    ncurses
    coreutils
    findutils
    gnused
    gnugrep
    which
    curl
    cacert
    git

    # --- mpv/ffmpeg optional display libs (harmless with --no-video) ------
    libGL
    libxkbcommon
    wayland
    libx11
    libxext
  ];

  profile = ''
    # Use the shell's interpreter here; this is not a project-wide pin.
    export UV_PYTHON="${pkgs.python3}/bin/python3"
    export UV_PYTHON_DOWNLOADS=never
    export UV_PROJECT_ENVIRONMENT="${toString ./.}/.venv"
    export UV_LINK_MODE=copy
    export SSL_CERT_FILE="${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"

    # Audio/MPRIS sockets live under XDG_RUNTIME_DIR.
    if [ -z "$XDG_RUNTIME_DIR" ] && [ -d "/run/user/$(id -u)" ]; then
      export XDG_RUNTIME_DIR="/run/user/$(id -u)"
    fi

    # A session bus is what lets desktop media widgets see MPRIS.
    if [ -z "$DBUS_SESSION_BUS_ADDRESS" ] && [ -n "$XDG_RUNTIME_DIR" ] \
       && [ -S "$XDG_RUNTIME_DIR/bus" ]; then
      export DBUS_SESSION_BUS_ADDRESS="unix:path=$XDG_RUNTIME_DIR/bus"
    fi

    export PS1='\[\e[1;35m\][somafm-tui]\[\e[0m\] \w \$ '

    echo ""
    echo "  somafm-tui — FHS dev shell"
    echo "  --------------------------"
    echo "  uv sync            install / update python deps"
    echo "  uv run somafm-tui  start the radio"
    echo ""
    echo "  python : $(python3 --version 2>&1)"
    echo "  uv     : $(uv --version 2>&1)"
    echo "  mpv    : $(mpv --version 2>&1 | head -n1)"
    echo "  ffmpeg : $(ffmpeg -version 2>&1 | head -n1)"
    echo ""
    echo "  If NumPy still fails to load, recreate the venv once:"
    echo "    rm -rf .venv && uv sync"
    echo ""
  '';

  runScript = "bash";
}).env