# Inspiration from: https://technogothic.net/pages/JekyllOnNix/
{
  inputs = {
    nixpkgs.url = "github:cachix/devenv-nixpkgs/rolling";
    systems.url = "github:nix-systems/default";
    devenv.url = "github:cachix/devenv";
    devenv.inputs.nixpkgs.follows = "nixpkgs";

    nginx = {
      url = "github:nginx/nginx";
      flake = false;
    };
  };

  nixConfig = {
    extra-trusted-public-keys = "devenv.cachix.org-1:w1cLUi8dv3hnoSPGAuibQv+f9TZLr6cv/Hm9XgU50cw=";
    extra-substituters = "https://devenv.cachix.org";
  };

  outputs = { self, nixpkgs, devenv, systems, nginx, ... }@inputs:
    let
      forEachSystem = nixpkgs.lib.genAttrs (import systems);
    in
    rec {
      packages = forEachSystem (system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
        in
        {
          # Copied from: https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/docker/examples.nix
          nginx =
            let
              nginxPort = "80";
              nginxConf = pkgs.writeText "nginx.conf" ''
                user nobody nobody;
                daemon off;
                error_log /dev/stdout info;
                pid /dev/null;
                events {}
                http {
                  access_log /dev/stdout;
                  include ${nginx.outPath}/conf/mime.types;

                  server {
                    listen ${nginxPort};
                    index index.html;
                    location / {
                      root ${packages.${system}.website};
                    }
                  }
                }
              '';
            in
            pkgs.dockerTools.buildLayeredImage {
              name = "static";
              tag = "test";
              contents = [
                pkgs.fakeNss
                pkgs.nginx
              ];

              extraCommands = ''
                mkdir -p tmp/nginx_client_body

                # nginx still tries to read this directory even if error_log
                # directive is specifying another file :/
                mkdir -p var/log/nginx
              '';

              config = {
                Cmd = [ "nginx" "-c" nginxConf ];
                ExposedPorts = {
                  "${nginxPort}/tcp" = { };
                };
              };
            };

          website = pkgs.stdenv.mkDerivation
            (
              let
                # TODO: DRY
                gems = pkgs.bundlerEnv {
                  name = "static";
                  gemdir = ./src;
                };
              in
              {
                version = "0.0.1";
                name = "website";

                src = ./src;

                buildInputs = [
                  gems
                  gems.wrappedRuby
                ];

                sourceRoot = "src";

                buildPhase = ''
                  bundle exec jekyll build 
                '';

                installPhase = ''
                  mkdir -p $out
                  cp -r _site/* $out/
                '';
              }
            );
        }
      );

      devShells = forEachSystem
        (system:
          let
            pkgs = nixpkgs.legacyPackages.${system};
            gems = pkgs.bundlerEnv {
              name = "static";
              gemdir = ./src;
            };
          in
          {
            default = devenv.lib.mkShell {
              inherit inputs pkgs;
              modules = [
                {
                  packages = [ gems gems.wrappedRuby ];
                }
              ];
            };
          });
    };
}