# Copyright (c) 2022 Espresso Systems (espressosys.com)
# This file is part of the Tide Disco library.
#
# This program is free software: you can redistribute it and/or modify it under the terms of the GNU
# General Public License as published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
# even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
# You should have received a copy of the GNU General Public License along with this program. If not,
# see <https://www.gnu.org/licenses/>.

{
  description = "Development shell for Tide Disco";

  nixConfig = {
    extra-substituters = [
      "https://espresso-systems-private.cachix.org"
      "https://nixpkgs-cross-overlay.cachix.org"
    ];
    extra-trusted-public-keys = [
      "espresso-systems-private.cachix.org-1:LHYk03zKQCeZ4dvg3NctyCq88e44oBZVug5LpYKjPRI="
      "nixpkgs-cross-overlay.cachix.org-1:TjKExGN4ys960TlsGqNOI/NBdoz2Jdr2ow1VybWV5JM="
    ];
  };

  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

  inputs.flake-utils.url = "github:numtide/flake-utils";

  inputs.flake-compat.url = "github:edolstra/flake-compat";
  inputs.flake-compat.flake = false;

  inputs.rust-overlay.url = "github:oxalica/rust-overlay";

  inputs.fenix.url = "github:nix-community/fenix";
  inputs.fenix.inputs.nixpkgs.follows = "nixpkgs";

  outputs = { self, nixpkgs, flake-utils, rust-overlay, fenix, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        info = builtins.split "\([a-zA-Z0-9_]+\)" system;
        arch = (builtins.elemAt (builtins.elemAt info 1) 0);
        os = (builtins.elemAt (builtins.elemAt info 3) 0);
        overlays = [ (import rust-overlay) ];
        pkgs = import nixpkgs { inherit system overlays; };
        rustToolchain = pkgs.rust-bin.stable.latest.minimal.override {
          extensions = [ "rustfmt" "clippy" "llvm-tools-preview" "rust-src" ];
        };
        rustDeps = with pkgs;
          [
            pkg-config
            openssl

            curl

            cargo-edit
            cargo-udeps
            cargo-sort
          ] ++ lib.optionals stdenv.isDarwin [
            darwin.apple_sdk.frameworks.Security
            darwin.apple_sdk.frameworks.CoreFoundation
            darwin.apple_sdk.frameworks.SystemConfiguration

            # https://github.com/NixOS/nixpkgs/issues/126182
            libiconv
          ] ++ lib.optionals (!stdenv.isDarwin) [
            cargo-watch # broken: https://github.com/NixOS/nixpkgs/issues/146349
          ];
        # nixWithFlakes allows pre v2.4 nix installations to use
        # flake commands (like `nix flake update`)
        nixWithFlakes = pkgs.writeShellScriptBin "nix" ''
          exec ${pkgs.nixFlakes}/bin/nix --experimental-features "nix-command flakes" "$@"
        '';
      in {
        devShell = pkgs.mkShell {
          shellHook = ''
          # Prevent cargo aliases from using programs in `~/.cargo` to avoid conflicts with rustup
          # installations.
          export CARGO_HOME=$HOME/.cargo-nix
          '';

          buildInputs = with pkgs;
            [
              fenix.packages.${system}.rust-analyzer
              nixWithFlakes
              nixpkgs-fmt
              rustToolchain
            ] ++ rustDeps;

          # Use a distinct target dir for builds from within nix shells.
          CARGO_TARGET_DIR = "target/nix";
          RUST_SRC_PATH = "${rustToolchain}/lib/rustlib/src/rust/library";
          RUST_BACKTRACE = 1;
          RUST_LOG = "info";
          RUSTFLAGS = "--cfg async_executor_impl=\"async-std\" --cfg async_channel_impl=\"async-std\"";
        };
      });
}