nginx.nix

{ pkgs, ... }: let
    lib = pkgs.lib;
in {
    Host = host: service: {
        inherit host service;
        extraHosts = [];
        secure = true;
        type = "hosts";
    };
    Hosts = hosts: service: {
        inherit service;
        host = elemAt hosts 0;
        extraHosts = tail hosts;
        secure = true;
        type = "hosts";
    };
    InsecureHost = host: service: {
        inherit host service;
        extraHosts = [];
        secure = false;
        type = "hosts";
    };
    InsecureHosts = hosts: service: {
        inherit service;
        host = elemAt hosts 0;
        extraHosts = tail hosts;
        secure = false;
        type = "hosts";
    };
    ReverseProxy = to: {
        inherit to;
        type = "reverseproxy";
    };
    PHP = root: socket: {
        inherit root socket;
        type = "php";
    };
    Redirect = to: permanent: {
        inherit to permanent;
        type = "redirect";
    };
    Directory = root: {
        inherit root;
        private = false;
        type = "directory";
    };
    PrivateDirectory = root: {
        inherit root;
        private = true;
        type = "directory";
    };
    File = path: {
        inherit path;
        type = "file";
    };
    Compose = services: {
        inherit services;
        type = "compose";
    };
    Path = path: service: {
        inherit path service;
        type = "path";
    };

    Merge = let
    # builtins.length and count up
        _iterateCompose = services: currentConfig: currentPath: secure: priority: i:
            if i > length services
                then currentConfig
                else _iterateCompose services (_merge (elemAt services i) currentConfig currentPath secure priority+i) currentPath secure priority (i+1);

        _iterateMerge = i: current: services:
            if i > length services
                then current
                else _iterateMerge (i+1) (current++[_merge (elemAt services i) {} "/" true 1000]) services;

        _merge = service: currentConfig: currentPath: secure: priority:
            if service.type == "hosts"
                then _merge service.service (lib.mkMerge currentConfig {
                    name = service.host;
                    value = {
                        serverAliases = service.extraHosts;

                        enableACME = service.secure;
                        forceSSL = service.secure;
                        listen = [
                            {
                                addr = "0.0.0.0";
                                port = if service.secure then 443 else 80;
                                ssl = service.secure;
                            }
                        ];
                    };
                }) currentPath service.secure priority
            else if service.type == "reverseproxy"
                then (lib.mkMerge currentConfig {
                    value.locations.${currentPath} = {
                        proxyPass = service.to;
                        proxyWebsockets = true;
                        recommendedProxySettings = true;
                    };
                })
            else if service.type == "php"
                then (lib.mkMerge currentConfig {
                    value.locations.${currentPath} = {
                        root = service.root;
                        index = "index.php index.html index.htm";
                        tryFiles = "$uri $uri/ ${currentPath}index.php?$query_string =404";
                    };
                    value.locations."~ ^${currentPath}.*\.php$" = {
                        tryFiles = "$uri $uri/ ${currentPath}index.php?$query_string =404";
                        extraConfig = ''
                            include ${pkgs.nginx}/conf/fastcgi_params;
                            fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                            fastcgi_param REDIRECT_STATUS 200;
                            fastcgi_pass unix:${service.socket};
                            fastcgi_intercept_errors on;
                            ${lib.optionalString secure "fastcgi_param HTTPS on;"}
                        '';
                    };
                })
            else if service.type == "redirect"
                then (lib.mkMerge currentConfig {
                    value.locations.${currentPath}.return =
                        if service.permanent
                            then "308 ${service.to}"
                            else "307 ${service.to}";
                })
            else if service.type == "directory"
                then (lib.mkMerge currentConfig {
                    value.locations.${currentPath} = {
                        root = service.root;
                        index = "index.html index.htm";
                        tryFiles = "$uri $uri/ =404";
                        extraConfig = lib.optionalString !service.private "autoindex on;";
                    };
                })
            else if service.type == "file"
                then (lib.mkMerge currentConfig {
                    value.locations.${currentPath} = {
                        tryFiles = "${service.path} =404";
                    };
                })
            else if service.type == "path"
                then _merge service.service currentConfig service.path service.secure
            else if service.type == "compose"
                then (_iterateCompose service.services currentConfig currentPath secure priority 0)
            else throw "Unknown service type: ${service.type}";
    in (services: lib.pipe services [
        (_iterateMerge 0 [])
        builtins.listToAttrs
    ]);

    # https://www.nginx.com/resources/wiki/start/topics/examples/full/

    /**
    Internal needs to be a string that is both a host and a port, e.g. generic:1000
    External should only be a port
    Protocol should be TCP or UDP
    */
    Stream = external: internal: protocol: ''
        server {
            listen ${builtins.toString external} ${protocol};
            proxy_pass ${internal};
        }
    '';

    Alias = host: alias: {
        inherit host;
        aliases = [ alias ];
        type = "aliases";
    };

    Aliases = host: aliases: {
        inherit host aliases;
        type = "aliases";
    };
}