From aa941fd195c548aa6ef6e0c322ebd47f55871ea5 Mon Sep 17 00:00:00 2001
From: Moritz Ruth <dev@moritzruth.de>
Date: Fri, 24 Feb 2023 01:30:51 +0100
Subject: [PATCH] And again

---
 .idea/runConfigurations/Run__dry_.xml |   2 +-
 Cargo.lock                            | 359 ++++++++++++++++++++++++++
 Cargo.toml                            |   8 +
 rustfmt.toml                          |   1 +
 src/config.rs                         | 116 +++++++++
 src/main.rs                           |  70 ++---
 src/modules/mod.rs                    |   9 +-
 src/mqtt.rs                           | 133 ++++++++++
 8 files changed, 638 insertions(+), 60 deletions(-)
 create mode 100644 rustfmt.toml
 create mode 100644 src/config.rs
 create mode 100644 src/mqtt.rs

diff --git a/.idea/runConfigurations/Run__dry_.xml b/.idea/runConfigurations/Run__dry_.xml
index 4b2f4b8..4fd01b9 100644
--- a/.idea/runConfigurations/Run__dry_.xml
+++ b/.idea/runConfigurations/Run__dry_.xml
@@ -10,7 +10,7 @@
     <option name="buildTarget" value="REMOTE" />
     <option name="backtrace" value="SHORT" />
     <envs>
-      <env name="RUST_LOG" value="hassliebe" />
+      <env name="RUST_LOG" value="hassliebe=debug" />
     </envs>
     <option name="isRedirectInput" value="false" />
     <option name="redirectInputPath" value="" />
diff --git a/Cargo.lock b/Cargo.lock
index abaf2a5..60b55bf 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -75,6 +75,26 @@ version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5827cebf4670468b8772dd191856768aedcb1b0278a04f989f7766351917b9dc"
 
+[[package]]
+name = "directories"
+version = "4.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f51c5d4ddabd36886dd3e1438cb358cdcb0d7c499cb99cb4ac2e38e18b5cb210"
+dependencies = [
+ "dirs-sys",
+]
+
+[[package]]
+name = "dirs-sys"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b1d1d91c932ef41c0f2663aa8b0ca0342d444d842c06914aa0a7e352d0bada6"
+dependencies = [
+ "libc",
+ "redox_users",
+ "winapi",
+]
+
 [[package]]
 name = "env_logger"
 version = "0.10.0"
@@ -109,6 +129,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "exitcode"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de853764b47027c2e862a995c34978ffa63c1501f2e15f987ba11bd4f9bba193"
+
 [[package]]
 name = "flume"
 version = "0.10.14"
@@ -122,6 +148,15 @@ dependencies = [
  "spin 0.9.5",
 ]
 
+[[package]]
+name = "form_urlencoded"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9c384f161156f5260c24a097c56119f9be8c798586aecc13afbcbe7b7e26bf8"
+dependencies = [
+ "percent-encoding",
+]
+
 [[package]]
 name = "futures"
 version = "0.3.26"
@@ -224,17 +259,31 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
+
 [[package]]
 name = "hassliebe"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "directories",
  "env_logger",
+ "exitcode",
  "json",
+ "lazy_static",
  "log",
  "mac_address",
+ "rand",
+ "regex",
  "rumqttc",
+ "serde",
  "tokio",
+ "toml",
+ "validator",
 ]
 
 [[package]]
@@ -258,6 +307,43 @@ version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
 
+[[package]]
+name = "idna"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "418a0a6fab821475f634efe3ccc45c013f742efe03d853e8d3355d5cb850ecf8"
+dependencies = [
+ "matches",
+ "unicode-bidi",
+ "unicode-normalization",
+]
+
+[[package]]
+name = "idna"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e14ddfc70884202db2244c223200c204c2bda1bc6e0998d11b5e024d657209e6"
+dependencies = [
+ "unicode-bidi",
+ "unicode-normalization",
+]
+
+[[package]]
+name = "if_chain"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb56e1aa765b4b4f3aadfab769793b7087bb03a4ea4920644a6d238e2df5b9ed"
+
+[[package]]
+name = "indexmap"
+version = "1.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1885e79c1fc4b10f0e172c475f458b7f7b93061064d98c3293e98c5ba0c8b399"
+dependencies = [
+ "autocfg",
+ "hashbrown",
+]
+
 [[package]]
 name = "io-lifetimes"
 version = "1.0.5"
@@ -280,6 +366,12 @@ dependencies = [
  "windows-sys 0.45.0",
 ]
 
+[[package]]
+name = "itoa"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fad582f4b9e86b6caa621cabeb0963332d92eea04729ab12892c2533951e6440"
+
 [[package]]
 name = "js-sys"
 version = "0.3.61"
@@ -295,6 +387,12 @@ version = "0.12.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "078e285eafdfb6c4b434e0d31e8cfcb5115b651496faca5749b88fafd4f23bfd"
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
 [[package]]
 name = "libc"
 version = "0.2.139"
@@ -336,6 +434,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "matches"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2532096657941c2fea9c289d370a250971c689d4f143798ff67113ec042024a5"
+
 [[package]]
 name = "memchr"
 version = "2.5.0"
@@ -385,6 +489,15 @@ dependencies = [
  "memoffset",
 ]
 
+[[package]]
+name = "nom8"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae01545c9c7fc4486ab7debaf2aad7003ac19431791868fb2e8066df97fad2f8"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "num_cpus"
 version = "1.15.0"
@@ -430,6 +543,12 @@ dependencies = [
  "windows-sys 0.45.0",
 ]
 
+[[package]]
+name = "percent-encoding"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "478c572c3d73181ff3c2539045f6eb99e5491218eae919370993b890cdbdd98e"
+
 [[package]]
 name = "pin-project"
 version = "1.0.12"
@@ -468,6 +587,36 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5da3b0203fd7ee5720aa0b5e790b591aa5d3f41c3ed2c34a3a393382198af2f7"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
+
+[[package]]
+name = "proc-macro-error"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
+dependencies = [
+ "proc-macro-error-attr",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro-error-attr"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "version_check",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.51"
@@ -486,6 +635,36 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.2.16"
@@ -495,6 +674,17 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "redox_users"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b033d837a7cf162d7993aded9304e30a83213c648b6e389db233191f891e5c2b"
+dependencies = [
+ "getrandom",
+ "redox_syscall",
+ "thiserror",
+]
+
 [[package]]
 name = "regex"
 version = "1.7.1"
@@ -592,6 +782,12 @@ dependencies = [
  "base64",
 ]
 
+[[package]]
+name = "ryu"
+version = "1.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b4b9743ed687d4b4bcedf9ff5eaa7398495ae14e61cba0a295704edbc7decde"
+
 [[package]]
 name = "schannel"
 version = "0.1.21"
@@ -640,6 +836,46 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "serde"
+version = "1.0.152"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb7d1f0d3021d347a83e556fc4683dea2ea09d87bccdf88ff5c12545d89d5efb"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.152"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af487d118eecd09402d70a5d72551860e788df87b464af30e5ea6a38c75c541e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.93"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cad406b69c91885b5107daf2c29572f6c8cdb3c66826821e286c533490c0bc76"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "serde_spanned"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0efd8caf556a6cebd3b285caf480045fcc1ac04f6bd786b09a6f11af30c4fcf4"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "signal-hook-registry"
 version = "1.4.1"
@@ -729,6 +965,21 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tinyvec"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87cc5ceb3875bb20c2890005a4e226a4651264a5c75edb2421b52861a0a0cb50"
+dependencies = [
+ "tinyvec_macros",
+]
+
+[[package]]
+name = "tinyvec_macros"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
+
 [[package]]
 name = "tokio"
 version = "1.25.0"
@@ -771,18 +1022,126 @@ dependencies = [
  "webpki",
 ]
 
+[[package]]
+name = "toml"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7afcae9e3f0fe2c370fd4657108972cbb2fa9db1b9f84849cefd80741b01cb6"
+dependencies = [
+ "serde",
+ "serde_spanned",
+ "toml_datetime",
+ "toml_edit",
+]
+
+[[package]]
+name = "toml_datetime"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ab8ed2edee10b50132aed5f331333428b011c99402b5a534154ed15746f9622"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "toml_edit"
+version = "0.19.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e6a7712b49e1775fb9a7b998de6635b299237f48b404dde71704f2e0e7f37e5"
+dependencies = [
+ "indexmap",
+ "nom8",
+ "serde",
+ "serde_spanned",
+ "toml_datetime",
+]
+
+[[package]]
+name = "unicode-bidi"
+version = "0.3.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d54675592c1dbefd78cbd98db9bacd89886e1ca50692a0692baefffdeb92dd58"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "84a22b9f218b40614adcb3f4ff08b703773ad44fa9423e4e0d346d5db86e4ebc"
 
+[[package]]
+name = "unicode-normalization"
+version = "0.1.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c5713f0fc4b5db668a2ac63cdb7bb4469d8c9fed047b1d0292cc7b0ce2ba921"
+dependencies = [
+ "tinyvec",
+]
+
 [[package]]
 name = "untrusted"
 version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
 
+[[package]]
+name = "url"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0d68c799ae75762b8c3fe375feb6600ef5602c883c5d21eb51c09f22b83c4643"
+dependencies = [
+ "form_urlencoded",
+ "idna 0.3.0",
+ "percent-encoding",
+]
+
+[[package]]
+name = "validator"
+version = "0.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32ad5bf234c7d3ad1042e5252b7eddb2c4669ee23f32c7dd0e9b7705f07ef591"
+dependencies = [
+ "idna 0.2.3",
+ "lazy_static",
+ "regex",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "url",
+ "validator_derive",
+]
+
+[[package]]
+name = "validator_derive"
+version = "0.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc44ca3088bb3ba384d9aecf40c6a23a676ce23e09bdaca2073d99c207f864af"
+dependencies = [
+ "if_chain",
+ "lazy_static",
+ "proc-macro-error",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "syn",
+ "validator_types",
+]
+
+[[package]]
+name = "validator_types"
+version = "0.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "111abfe30072511849c5910134e8baf8dc05de4c0e5903d681cbd5c9c4d611e3"
+dependencies = [
+ "proc-macro2",
+ "syn",
+]
+
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
diff --git a/Cargo.toml b/Cargo.toml
index 7b78a78..a29ea5d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,9 +10,17 @@ dry_run = [] # will prevent some actions like shutting down
 
 [dependencies]
 anyhow = "1.0.69"
+directories = "4.0.1"
 env_logger = "0.10.0"
+exitcode = "1.1.2"
 json = "0.12.4"
+lazy_static = "1.4.0"
 log = "0.4.17"
 mac_address = "1.1.4"
+rand = "0.8.5"
+regex = "1.7.1"
 rumqttc = "0.20.0"
+serde = { version = "1.0.152", features = ["derive"] }
 tokio = { version = "1.25.0", features = ["full"] }
+toml = "0.7.2"
+validator = { version = "0.16.0", features = ["derive"] }
diff --git a/rustfmt.toml b/rustfmt.toml
new file mode 100644
index 0000000..1cbd329
--- /dev/null
+++ b/rustfmt.toml
@@ -0,0 +1 @@
+max_width = 160
\ No newline at end of file
diff --git a/src/config.rs b/src/config.rs
new file mode 100644
index 0000000..f831bde
--- /dev/null
+++ b/src/config.rs
@@ -0,0 +1,116 @@
+use std::borrow::ToOwned;
+use std::fs;
+use std::fs::File;
+use std::io::{ErrorKind, Read, Write};
+
+use anyhow::{anyhow, bail, Context, Result};
+use rand::distributions::Alphanumeric;
+use rand::Rng;
+use regex::Regex;
+use serde::{Deserialize, Serialize};
+use validator::{Validate, ValidationError};
+
+#[derive(Serialize, Deserialize, Validate)]
+pub struct Mqtt {
+    #[validate(length(min = 1))]
+    pub host: String,
+    pub port: u16,
+
+    #[serde(default)]
+    #[validate]
+    pub credentials: Option<MqttCredentials>,
+}
+
+#[derive(Serialize, Deserialize, Validate)]
+pub struct MqttCredentials {
+    pub user: String,
+    pub password: String,
+}
+
+#[derive(Serialize, Deserialize, Validate)]
+pub struct Internal {
+    #[validate(length(min = 2))]
+    pub stable_id: String,
+}
+
+#[derive(Serialize, Deserialize, Validate)]
+pub struct Config {
+    #[validate(custom = "validate_unique_id")]
+    pub unique_id: String,
+    #[validate(length(min = 1))]
+    pub display_name: String,
+    pub announce_mac_address: bool,
+    #[validate]
+    pub mqtt: Mqtt,
+    #[serde(rename = "DO_NOT_CHANGE")]
+    #[validate]
+    pub internal: Internal,
+}
+
+fn validate_unique_id(value: &str) -> Result<(), ValidationError> {
+    if Regex::new(r"^[a-zA-Z0-9]+(_[a-zA-Z0-9])*$").unwrap().is_match(value) {
+        Ok(())
+    } else {
+        Err(ValidationError::new("invalid_unique_id"))
+    }
+}
+
+fn generate_unique_id() -> String {
+    rand::thread_rng().sample_iter(&Alphanumeric).take(12).map(char::from).collect()
+}
+
+fn create_example_config() -> Config {
+    Config {
+        unique_id: "my_pc".to_owned(),
+        display_name: "My PC".to_owned(),
+        announce_mac_address: true,
+        mqtt: Mqtt {
+            host: "".to_owned(),
+            port: 1883,
+            credentials: None,
+        },
+        internal: Internal {
+            stable_id: generate_unique_id(),
+        },
+    }
+}
+
+pub fn load() -> Result<Option<Config>> {
+    let dirs = directories::ProjectDirs::from("", "", "Hassliebe")
+        .ok_or_else(|| anyhow!("Could not determine a valid home directory path. Please specify a custom config file path via HASS_CONFIG"))?;
+
+    let mut path = dirs.config_dir().to_owned();
+    path.push("config.toml");
+
+    match File::open(&path) {
+        Ok(mut file) => {
+            log::info!("Reading config file: {}", path.to_string_lossy());
+
+            let mut string_content = String::new();
+            file.read_to_string(&mut string_content).context("while reading the config file")?;
+
+            let parsed = toml::from_str::<Config>(string_content.as_str()).context("while parsing the config file")?;
+
+            Ok(Some(parsed))
+        }
+
+        Err(error) if error.kind() == ErrorKind::NotFound => {
+            if let Some(parent) = path.parent() {
+                fs::create_dir_all(parent)?;
+            }
+
+            let mut file = File::create(&path).context("while creating the default config file")?;
+
+            let default = toml::to_string::<Config>(&create_example_config()).expect("create_example_config() should be valid");
+
+            file.write_all(default.as_bytes())?;
+
+            log::warn!("Created an example config file at {}", path.to_string_lossy());
+            log::warn!("Make sure to edit the file before running again.");
+
+            Ok(None)
+        }
+
+        Err(error) => bail!("Config file could not be opened: {}", error),
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 22d8962..8dd67af 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,47 +1,28 @@
-use crate::modules::ModuleContext;
-use anyhow::Result;
-use rumqttc::Event::Incoming;
-use rumqttc::QoS;
-use rumqttc::{AsyncClient as MqttClient, LastWill, MqttOptions, Packet, SubscribeFilter};
 use std::collections::HashMap;
-use std::time::Duration;
+use std::process::exit;
+
+use anyhow::Result;
+
+use crate::modules::ModuleContext;
 
 mod modules;
-
-const DEVICE_ID: &str = "linux-agent-m6";
+mod config;
+mod mqtt;
 
 #[tokio::main]
 async fn main() -> Result<()> {
     env_logger::init();
-    start_mqtt_communication().await
-}
 
-async fn start_mqtt_communication() -> Result<()> {
-    let availability_topic = DEVICE_ID.to_owned() + "/availability";
-
-    let mac_address = mac_address::get_mac_address().unwrap_or(None);
-    let discovery_device_object = json::object! {
-        "connections": mac_address.map(|a| json::array![["mac", a.to_string()]]).unwrap_or(json::array![]),
-        "name": "m6"
+    let Some(config) = config::load()? else {
+        exit(exitcode::CONFIG);
     };
 
-    let mut mqtt_options = MqttOptions::new(DEVICE_ID, "192.168.188.48", 1883);
-    mqtt_options.set_clean_session(true);
-    mqtt_options.set_keep_alive(Duration::from_secs(5));
-    mqtt_options.set_last_will(LastWill::new(
-        &availability_topic,
-        "offline",
-        QoS::AtLeastOnce,
-        true,
-    ));
-
-    let (mqtt_client, mut event_loop) = MqttClient::new(mqtt_options, 10);
-    mqtt_client
-        .publish(&availability_topic, QoS::AtLeastOnce, true, "online")
-        .await?;
+    let availability_topic = config.unique_id.to_owned() + "/availability";
+    let (mqtt_client, event_loop) = mqtt::create_client(&config, &availability_topic).await?;
+    let discovery_device_object = mqtt::create_discovery_device_object(&config);
 
     let mut module_context = ModuleContext {
-        device_id: DEVICE_ID,
+        config: &config,
         mqtt_client: &mqtt_client,
         mqtt_availability_topic: availability_topic.as_str(),
         mqtt_discovery_device_object: &discovery_device_object,
@@ -50,27 +31,6 @@ async fn start_mqtt_communication() -> Result<()> {
 
     modules::init_all(&mut module_context).await?;
 
-    mqtt_client
-        .subscribe_many(
-            module_context
-                .mqtt_message_handler_by_topic
-                .keys()
-                .map(|k| SubscribeFilter::new(k.to_owned(), QoS::AtLeastOnce)),
-        )
-        .await?;
-
-    loop {
-        let notification = event_loop.poll().await?;
-
-        if let Incoming(Packet::Publish(message)) = notification {
-            let text = std::str::from_utf8(&message.payload)?;
-
-            if let Some(handler) = module_context
-                .mqtt_message_handler_by_topic
-                .get(message.topic.as_str())
-            {
-                handler(text)?;
-            }
-        }
-    }
+    mqtt::start_communication(&module_context, event_loop).await
 }
+
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index 1154b1c..0cf24ef 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -1,14 +1,15 @@
-pub mod power;
+use std::collections::HashMap;
 
 use anyhow::Result;
 use json::JsonValue;
 use rumqttc::AsyncClient as MqttClient;
-use std::collections::HashMap;
+
+pub mod power;
 
 type MqttMessageHandler<'a> = dyn Fn(&str) -> Result<()> + 'a;
 
 pub struct ModuleContext<'a> {
-    pub device_id: &'a str,
+    pub config: &'a super::config::Config,
     pub mqtt_discovery_device_object: &'a JsonValue,
     pub mqtt_availability_topic: &'a str,
     pub mqtt_client: &'a MqttClient,
@@ -21,7 +22,7 @@ impl<'a> ModuleContext<'a> {
     }
 
     fn get_entity_id(&self, module_id: &str, sub_id: &str) -> String {
-        format!("{}__{}__{}", self.device_id, module_id, sub_id)
+        format!("{}_{}_{}", self.config.unique_id, module_id, sub_id)
     }
 
     fn subscribe_mqtt_topic<F: Fn(&str) -> Result<()> + 'a>(
diff --git a/src/mqtt.rs b/src/mqtt.rs
new file mode 100644
index 0000000..ba7259f
--- /dev/null
+++ b/src/mqtt.rs
@@ -0,0 +1,133 @@
+use std::time::Duration;
+
+use anyhow::Result;
+use json::JsonValue;
+use rumqttc::{AsyncClient as MqttClient, AsyncClient, EventLoop, LastWill, MqttOptions, Packet, SubscribeFilter};
+use rumqttc::Event::Incoming;
+use rumqttc::QoS;
+use tokio::time::{Instant, sleep};
+
+use crate::modules::ModuleContext;
+
+use super::config;
+
+pub async fn create_client(config: &config::Config, availability_topic: &str) -> Result<(AsyncClient, EventLoop)> {
+    let mut options = MqttOptions::new(&config.internal.stable_id, config.mqtt.host.to_owned(), config.mqtt.port);
+    options.set_clean_session(true);
+    options.set_keep_alive(Duration::from_secs(5));
+    options.set_last_will(LastWill::new(availability_topic, "offline", QoS::AtLeastOnce, true));
+
+    let (mqtt_client, event_loop) = MqttClient::new(options, 10);
+    mqtt_client.publish(availability_topic, QoS::AtLeastOnce, true, "online").await?;
+
+    Ok((mqtt_client, event_loop))
+}
+
+pub fn create_discovery_device_object(config: &config::Config) -> JsonValue {
+    json::object! {
+        "connections": if config.announce_mac_address {
+            mac_address::get_mac_address().unwrap_or(None).map(|a| json::array![["mac", a.to_string()]]).unwrap_or(json::array![])
+        } else {
+            json::array![]
+        },
+        "name": config.display_name.as_str()
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum ConnectionState {
+    NotConnected,
+    FastRetrying { since: Instant },
+    SlowRetrying,
+    Connected,
+}
+
+const FAST_RETRYING_INTERVAL_MS: u64 = 500;
+const FAST_RETRYING_LIMIT_SECONDS: u64 = 15;
+const SLOW_RETRYING_INTERVAL_SECONDS: u64 = 5;
+
+pub async fn start_communication(context: &ModuleContext<'_>, mut event_loop: EventLoop) -> Result<()> {
+    log::info!("Connecting to MQTT broker at {}:{}", context.config.mqtt.host, context.config.mqtt.port);
+
+    context
+        .mqtt_client
+        .subscribe_many(
+            context
+                .mqtt_message_handler_by_topic
+                .keys()
+                .map(|k| SubscribeFilter::new(k.to_owned(), QoS::AtLeastOnce)),
+        )
+        .await?;
+
+    let mut connection_state = ConnectionState::NotConnected;
+
+    loop {
+        match connection_state {
+            ConnectionState::FastRetrying { since } => {
+                sleep(Duration::from_millis(FAST_RETRYING_INTERVAL_MS)).await;
+
+                if since.elapsed().as_secs() >= FAST_RETRYING_LIMIT_SECONDS {
+                    log::warn!(
+                        "Could not fast-reconnect within {}s. Now retrying every {}s.",
+                        FAST_RETRYING_LIMIT_SECONDS,
+                        SLOW_RETRYING_INTERVAL_SECONDS
+                    );
+                    connection_state = ConnectionState::SlowRetrying;
+                }
+            }
+
+            ConnectionState::SlowRetrying => {
+                sleep(Duration::from_secs(SLOW_RETRYING_INTERVAL_SECONDS)).await;
+            }
+
+            _ => {}
+        }
+
+        let notification = event_loop.poll().await;
+
+        match notification {
+            Err(error) => {
+                log::debug!("Connection error: {}", error);
+
+                match connection_state {
+                    ConnectionState::Connected => {
+                        log::warn!("Connection lost. Trying to fast-reconnect…");
+                        connection_state = ConnectionState::FastRetrying { since: Instant::now() };
+                    }
+
+                    ConnectionState::NotConnected => {
+                        log::warn!("Connection failed. Retrying every {}s.", SLOW_RETRYING_INTERVAL_SECONDS);
+                        connection_state = ConnectionState::SlowRetrying;
+                    }
+
+                    _ => {}
+                }
+            }
+            Ok(event) => match event {
+                Incoming(Packet::ConnAck(_)) => {
+                    if connection_state == ConnectionState::NotConnected {
+                        log::info!("Connection established")
+                    } else {
+                        log::info!("Connection restored")
+                    }
+
+                    connection_state = ConnectionState::Connected;
+                }
+
+                Incoming(Packet::Publish(message)) => {
+                    let text = std::str::from_utf8(&message.payload)?;
+
+                    if let Some(handler) = context.mqtt_message_handler_by_topic.get(message.topic.as_str()) {
+                        handler(text)?;
+                    }
+                }
+
+                Incoming(packet) => {
+                    log::trace!("Unhandled packet received: {:?}", packet)
+                }
+
+                _ => {}
+            },
+        }
+    }
+}