user registration

README.md

@@ -0,0 +1,3 @@
+# API
+
+The backend API responsible for making things work!

pom.xml

@@ -48,6 +48,19 @@
         </plugins>
     </build>
 
+    <!-- Dependency Management -->
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>com.konghq</groupId>
+                <artifactId>unirest-java-bom</artifactId>
+                <version>4.4.4</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
     <!-- Dependencies -->
     <dependencies>
         <!-- Spring -->
@@ -63,14 +76,52 @@
             <version>1.18.34</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.relops</groupId>
+            <artifactId>snowflake</artifactId>
+            <version>1.1</version>
+            <scope>compile</scope>
+        </dependency>
+
+        <!-- Unirest -->
+        <dependency>
+            <groupId>com.konghq</groupId>
+            <artifactId>unirest-java-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.konghq</groupId>
+            <artifactId>unirest-modules-gson</artifactId>
+        </dependency>
+
+        <!-- MongoDB -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-mongodb</artifactId>
+        </dependency>
+
+        <!-- Redis -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-redis</artifactId>
+            <exclusions>
+                <exclusion>
+                    <groupId>io.lettuce</groupId>
+                    <artifactId>lettuce-core</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>redis.clients</groupId>
+            <artifactId>jedis</artifactId>
+        </dependency>
 
         <!-- Error Reporting & Metrics -->
-        <!--        <dependency>-->
-        <!--            <groupId>io.sentry</groupId>-->
-        <!--            <artifactId>sentry-spring-boot-starter-jakarta</artifactId>-->
-        <!--            <version>8.0.0-alpha.4</version>-->
-        <!--            <scope>compile</scope>-->
-        <!--        </dependency>-->
+        <dependency>
+            <groupId>io.sentry</groupId>
+            <artifactId>sentry-spring-boot-starter-jakarta</artifactId>
+            <version>8.0.0-alpha.4</version>
+            <scope>compile</scope>
+        </dependency>
         <dependency>
             <groupId>org.questdb</groupId>
             <artifactId>questdb</artifactId>

src/main/java/cc/pulseapp/api/common/HashUtils.java

@@ -0,0 +1,56 @@
+package cc.pulseapp.api.common;
+
+import lombok.NonNull;
+import lombok.SneakyThrows;
+import lombok.experimental.UtilityClass;
+
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.security.spec.KeySpec;
+import java.util.Base64;
+
+/**
+ * @author Braydon
+ */
+@UtilityClass
+public final class HashUtils {
+    private static final SecretKeyFactory PBKDF2;
+    private static final int ITERATION_COUNT = 512000;
+    private static final int KEY_LENGTH = 256;
+    private static final SecureRandom RANDOM = new SecureRandom();
+
+    static {
+        try {
+            PBKDF2 = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
+        } catch (NoSuchAlgorithmException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    /**
+     * Hash the given input.
+     *
+     * @param salt  the salt to hash with
+     * @param input the input to hash
+     * @return the hashed input
+     */
+    @SneakyThrows
+    public static String hash(byte[] salt, @NonNull String input) {
+        KeySpec spec = new PBEKeySpec(input.toCharArray(), salt, ITERATION_COUNT, KEY_LENGTH);
+        byte[] hash = PBKDF2.generateSecret(spec).getEncoded();
+        return Base64.getEncoder().encodeToString(hash);
+    }
+
+    /**
+     * Generate a salt.
+     *
+     * @return the generated salt
+     */
+    public static byte[] generateSalt() {
+        byte[] salt = new byte[32];
+        RANDOM.nextBytes(salt);
+        return salt;
+    }
+}

src/main/java/cc/pulseapp/api/common/StringUtils.java

@@ -0,0 +1,119 @@
+package cc.pulseapp.api.common;
+
+import cc.pulseapp.api.model.IGenericResponse;
+import lombok.NonNull;
+import lombok.experimental.UtilityClass;
+
+import java.security.SecureRandom;
+import java.util.regex.Pattern;
+
+/**
+ * @author Braydon
+ */
+@UtilityClass
+public final class StringUtils {
+    private static final String ALPHABET_STRING = "abcdefghijklmnopqrstuvwxyzABCDEFGJKLMNPRSTUVWXYZ";
+    private static final String NUMERIC_STRING = "0123456789";
+    private static final String SPECIAL_STRING = "!@#$%^&*()_+-=[]{}|;:,.<>?";
+    private static final SecureRandom RANDOM = new SecureRandom();
+
+    private static final Pattern EMAIL_PATTERN = Pattern.compile("^[A-Za-z0-9+_.-]+@(.+)$");
+    private static final Pattern USERNAME_PATTERN = Pattern.compile("^[a-zA-Z0-9_.]*$");
+
+    /**
+     * Check if the given email is valid.
+     *
+     * @param email the email to check
+     * @return whether the email is valid
+     */
+    public static boolean isValidEmail(@NonNull String email) {
+        return !email.isBlank() && EMAIL_PATTERN.matcher(email).matches();
+    }
+
+    /**
+     * Check if the given username is valid.
+     *
+     * @param username the username to check
+     * @return whether the username is valid
+     */
+    public static boolean isValidUsername(@NonNull String username) {
+        return USERNAME_PATTERN.matcher(username).matches();
+    }
+
+    /**
+     * Check if the given password meets the requirements.
+     *
+     * @param password the password to check
+     * @return the error if password requirements are not met, otherwise null
+     */
+    public static PasswordError checkPasswordRequirements(@NonNull String password) {
+        return checkPasswordRequirements(password, 8, 76, true, true, true);
+    }
+
+    /**
+     * Check if the given password meets the requirements.
+     *
+     * @param password  the password to check
+     * @param minLength the minimum length of the password
+     * @param maxLength the maximum length of the password
+     * @param alphabet  whether the password must contain alphabet characters
+     * @param numeric   whether the password must contain numeric characters
+     * @param special   whether the password must contain special characters
+     * @return the error if password requirements are not met, otherwise null
+     */
+    private static PasswordError checkPasswordRequirements(@NonNull String password, int minLength, int maxLength, boolean alphabet, boolean numeric, boolean special) {
+        boolean tooShort = password.length() < minLength;
+        if (password.length() < minLength || password.length() > maxLength) {
+            return tooShort ? PasswordError.PASSWORD_TOO_SHORT : PasswordError.PASSWORD_TOO_LONG;
+        }
+        if (alphabet && !password.matches(".*[a-zA-Z].*")) {
+            return PasswordError.PASSWORD_MISSING_ALPHABET;
+        }
+        if (numeric && !password.matches(".*\\d.*")) {
+            return PasswordError.PASSWORD_MISSING_NUMERIC;
+        }
+        if (special && !password.matches(".*[^a-zA-Z0-9].*")) {
+            return PasswordError.PASSWORD_MISSING_SPECIAL;
+        }
+        return null; // Password meets the requirements
+    }
+
+    /**
+     * Generate a random string with the given length.
+     *
+     * @param length   the length of the string
+     * @param alphabet whether the string should contain alphabet characters
+     * @param numeric  whether the string should contain numeric characters
+     * @param special  whether the string should contain special characters
+     * @return the generated random string
+     */
+    @NonNull
+    public static String generateRandom(int length, boolean alphabet, boolean numeric, boolean special) {
+        if (length < 1) {
+            throw new IllegalArgumentException("Length must be at least 1");
+        }
+        if (!alphabet && !numeric && !special) { // Validate
+            throw new IllegalArgumentException("At least one of alphabet, numeric, or special must be true");
+        }
+        // Build the symbols string
+        StringBuilder symbols = new StringBuilder();
+        if (alphabet) symbols.append(ALPHABET_STRING);
+        if (numeric) symbols.append(NUMERIC_STRING);
+        if (special) symbols.append(SPECIAL_STRING);
+
+        // Generate the random string
+        char[] buffer = new char[length];
+        for (int idx = 0; idx < buffer.length; ++idx) {
+            buffer[idx] = symbols.charAt(RANDOM.nextInt(symbols.length()));
+        }
+        return new String(buffer);
+    }
+
+    public enum PasswordError implements IGenericResponse {
+        PASSWORD_TOO_SHORT,
+        PASSWORD_TOO_LONG,
+        PASSWORD_MISSING_ALPHABET,
+        PASSWORD_MISSING_NUMERIC,
+        PASSWORD_MISSING_SPECIAL
+    }
+}

src/main/java/cc/pulseapp/api/config/RedisConfig.java

@@ -0,0 +1,73 @@
+package cc.pulseapp.api.config;
+
+import lombok.NonNull;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
+import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
+import org.springframework.data.redis.core.RedisTemplate;
+
+/**
+ * @author Braydon
+ */
+@Configuration
+@Log4j2(topic = "Redis")
+public class RedisConfig {
+    /**
+     * The Redis server host.
+     */
+    @Value("${spring.data.redis.host}")
+    private String host;
+
+    /**
+     * The Redis server port.
+     */
+    @Value("${spring.data.redis.port}")
+    private int port;
+
+    /**
+     * The Redis database index.
+     */
+    @Value("${spring.data.redis.database}")
+    private int database;
+
+    /**
+     * The optional Redis password.
+     */
+    @Value("${spring.data.redis.auth}")
+    private String auth;
+
+    /**
+     * Build the config to use for Redis.
+     *
+     * @return the config
+     * @see RedisTemplate for config
+     */
+    @Bean @NonNull
+    public RedisTemplate<String, Object> redisTemplate() {
+        RedisTemplate<String, Object> template = new RedisTemplate<>();
+        template.setConnectionFactory(jedisConnectionFactory());
+        return template;
+    }
+
+    /**
+     * Build the connection factory to use
+     * when making connections to Redis.
+     *
+     * @return the built factory
+     * @see JedisConnectionFactory for factory
+     */
+    @Bean @NonNull
+    public JedisConnectionFactory jedisConnectionFactory() {
+        log.info("Connecting to Redis at {}:{}/{}", host, port, database);
+        RedisStandaloneConfiguration config = new RedisStandaloneConfiguration(host, port);
+        config.setDatabase(database);
+        if (!auth.trim().isEmpty()) { // Auth with our provided password
+            log.info("Using auth...");
+            config.setPassword(auth);
+        }
+        return new JedisConnectionFactory(config);
+    }
+}

src/main/java/cc/pulseapp/api/controller/AppController.java

@@ -0,0 +1,46 @@
+package cc.pulseapp.api.controller;
+
+import cc.pulseapp.api.common.EnvironmentUtils;
+import cc.pulseapp.api.model.AppInformation;
+import lombok.NonNull;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.info.BuildProperties;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.lang.Nullable;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * The root controller for this app.
+ *
+ * @author Braydon
+ */
+@RestController
+@RequestMapping(value = "/", produces = MediaType.APPLICATION_JSON_VALUE)
+public final class AppController {
+    /**
+     * The build properties for this app, null if not available.
+     */
+    private final BuildProperties buildProperties;
+
+    @Autowired
+    public AppController(@Nullable BuildProperties buildProperties) {
+        this.buildProperties = buildProperties;
+    }
+
+    /**
+     * A GET endpoint to get info about this app.
+     *
+     * @return the info response
+     */
+    @GetMapping @ResponseBody @NonNull
+    public ResponseEntity<AppInformation> getAppInfo() {
+        return ResponseEntity.ok(new AppInformation(
+                buildProperties == null ? "unknown" : buildProperties.getVersion(),
+                EnvironmentUtils.isProduction() ? "production" : "staging"
+        ));
+    }
+}

src/main/java/cc/pulseapp/api/controller/v1/AuthController.java

@@ -0,0 +1,39 @@
+package cc.pulseapp.api.controller.v1;
+
+import cc.pulseapp.api.exception.impl.BadRequestException;
+import cc.pulseapp.api.model.user.AuthToken;
+import cc.pulseapp.api.model.user.input.UserRegistrationInput;
+import cc.pulseapp.api.service.AuthService;
+import lombok.NonNull;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * This controller is responsible for
+ * handling user authentication requests.
+ *
+ * @author Braydon
+ */
+@RestController
+@RequestMapping(value = "/v1/auth", produces = MediaType.APPLICATION_JSON_VALUE)
+public final class AuthController {
+    /**
+     * The user service to use.
+     */
+    @NonNull private final AuthService authService;
+
+    @Autowired
+    public AuthController(@NonNull AuthService authService) {
+        this.authService = authService;
+    }
+
+    @PostMapping("/register") @ResponseBody @NonNull
+    public ResponseEntity<AuthToken> register(UserRegistrationInput input) throws BadRequestException {
+        return ResponseEntity.ok(authService.registerUser(input));
+    }
+}

src/main/java/cc/pulseapp/api/exception/impl/BadRequestException.java

@@ -1,5 +1,6 @@
 package cc.pulseapp.api.exception.impl;
 
+import cc.pulseapp.api.model.IGenericResponse;
 import lombok.NonNull;
 import org.springframework.http.HttpStatus;
 import org.springframework.web.bind.annotation.ResponseStatus;
@@ -12,7 +13,7 @@ import org.springframework.web.bind.annotation.ResponseStatus;
  */
 @ResponseStatus(HttpStatus.BAD_REQUEST)
 public final class BadRequestException extends RuntimeException {
-    public BadRequestException(@NonNull String message) {
-        super(message);
+    public BadRequestException(@NonNull IGenericResponse error) {
+        super(error.name());
     }
 }

src/main/java/cc/pulseapp/api/log/RequestLogger.java

@@ -22,7 +22,7 @@ import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;
  * @author Braydon
  */
 @ControllerAdvice
-@Slf4j(topic = "Req/Res Transaction")
+@Slf4j(topic = "HTTP Request")
 public class RequestLogger implements ResponseBodyAdvice<Object> {
     @Override
     public boolean supports(@NonNull MethodParameter returnType, @NonNull Class<? extends HttpMessageConverter<?>> converterType) {

src/main/java/cc/pulseapp/api/model/AppInformation.java

@@ -0,0 +1,24 @@
+package cc.pulseapp.api.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NonNull;
+import lombok.ToString;
+
+/**
+ * Information about this app.
+ *
+ * @author Braydon
+ */
+@AllArgsConstructor @Getter @ToString
+public final class AppInformation {
+    /**
+     * The version of the app.
+     */
+    @NonNull private final String version;
+
+    /**
+     * The environment of the app.
+     */
+    @NonNull private final String environment;
+}

src/main/java/cc/pulseapp/api/model/IGenericResponse.java

@@ -0,0 +1,17 @@
+package cc.pulseapp.api.model;
+
+import lombok.NonNull;
+
+/**
+ * Represents a generic response.
+ *
+ * @author Braydon
+ */
+public interface IGenericResponse {
+    /**
+     * Get the name of this response.
+     *
+     * @return the response name
+     */
+    @NonNull String name();
+}

src/main/java/cc/pulseapp/api/model/User.java

@@ -1,36 +0,0 @@
-package cc.pulseapp.api.model;
-
-import lombok.*;
-
-import java.util.Date;
-
-/**
- * @author Braydon
- */
-@AllArgsConstructor @Getter @EqualsAndHashCode(onlyExplicitlyIncluded = true) @ToString
-public final class User {
-    /**
-     * The snowflake id of this user.
-     */
-    @EqualsAndHashCode.Include private final long id;
-
-    /**
-     * This user's username.
-     */
-    @NonNull private final String username;
-
-    /**
-     * The password for this user.
-     */
-    @NonNull private final String password;
-
-    /**
-     * The salt for this user's password.
-     */
-    @NonNull private final String passwordSalt;
-
-    /**
-     * The date this user last logged in.
-     */
-    @NonNull private final Date lastLogin;
-}

src/main/java/cc/pulseapp/api/model/org/Organization.java

@@ -0,0 +1,33 @@
+package cc.pulseapp.api.model.org;
+
+import cc.pulseapp.api.model.user.User;
+import lombok.*;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.index.Indexed;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+/**
+ * An organization owned by a {@link User}.
+ *
+ * @author Braydon
+ */
+@AllArgsConstructor @Getter
+@EqualsAndHashCode(onlyExplicitlyIncluded = true) @ToString
+@Document("organizations")
+public final class Organization {
+    /**
+     * The snowflake id of this organization.
+     */
+    @Id @EqualsAndHashCode.Include private final long id;
+
+    /**
+     * The name of this organization.
+     */
+    @Indexed @NonNull private final String name;
+
+    /**
+     * The snowflake of the {@link User}
+     * that owns this organization.
+     */
+    @Indexed private final long ownerSnowflake;
+}

src/main/java/cc/pulseapp/api/model/page/StatusPage.java

@@ -0,0 +1,61 @@
+package cc.pulseapp.api.model.page;
+
+import cc.pulseapp.api.model.org.Organization;
+import lombok.*;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.index.Indexed;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+/**
+ * @author Braydon
+ */
+@AllArgsConstructor @Getter
+@EqualsAndHashCode(onlyExplicitlyIncluded = true) @ToString
+@Document("pages")
+public final class StatusPage {
+    /**
+     * The snowflake id of this status page.
+     */
+    @Id @EqualsAndHashCode.Include private final long id;
+
+    /**
+     * The name of this status page.
+     */
+    @Indexed @NonNull private final String name;
+
+    /**
+     * The description of this status page, if any.
+     */
+    private final String description;
+
+    /**
+     * The slug of this status page.
+     */
+    @NonNull private final String slug;
+
+    /**
+     * The id to the logo of this status page, if any.
+     */
+    private final String logo;
+
+    /**
+     * The id to the banner of this status page, if any.
+     */
+    private final String banner;
+
+    /**
+     * The theme of this status page.
+     */
+    @NonNull private final StatusPageTheme theme;
+
+    /**
+     * Whether this status page is visible in search engines.
+     */
+    private final boolean visibleInSearchEngines;
+
+    /**
+     * The snowflake of the {@link Organization}
+     * that owns this status page.
+     */
+    private final long orgSnowflake;
+}

src/main/java/cc/pulseapp/api/model/page/StatusPageTheme.java

@@ -0,0 +1,23 @@
+package cc.pulseapp.api.model.page;
+
+/**
+ * The theme of a {@link StatusPage}.
+ *
+ * @author Braydon
+ */
+public enum StatusPageTheme {
+    /**
+     * The theme is automatically chosen based on the user's OS.
+     */
+    AUTO,
+
+    /**
+     * The theme is forced to be dark.
+     */
+    DARK,
+
+    /**
+     * The theme is forced to be light.
+     */
+    LIGHT
+}

src/main/java/cc/pulseapp/api/model/user/AuthToken.java

@@ -0,0 +1,45 @@
+package cc.pulseapp.api.model.user;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NonNull;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.redis.core.RedisHash;
+import org.springframework.data.redis.core.index.Indexed;
+
+import java.util.UUID;
+
+/**
+ * An authentication token for a {@link User}.
+ *
+ * @author Braydon
+ */
+@AllArgsConstructor @Getter
+@RedisHash(value = "auth_token", timeToLive = 30 * 24 * 60 * 60) // Expire in 30 days (days, hours, mins, secs)
+public final class AuthToken {
+    /**
+     * The ID of this token.
+     */
+    @Id @JsonIgnore @NonNull private final UUID id;
+
+    /**
+     * The snowflake of the user this token is for.
+     */
+    @JsonIgnore private final long userSnowflake;
+
+    /**
+     * The access token for the user.
+     */
+    @Indexed @NonNull private final String accessToken;
+
+    /**
+     * The refresh token for the user.
+     */
+    @Indexed @NonNull private final String refreshToken;
+
+    /**
+     * The unix timestamp of when this token expires.
+     */
+    private final long expires;
+}

src/main/java/cc/pulseapp/api/model/user/User.java

@@ -0,0 +1,66 @@
+package cc.pulseapp.api.model.user;
+
+import lombok.*;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.index.Indexed;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+import java.util.Date;
+
+/**
+ * @author Braydon
+ */
+@AllArgsConstructor @Getter
+@EqualsAndHashCode(onlyExplicitlyIncluded = true) @ToString
+@Document("users")
+public final class User {
+    /**
+     * The snowflake id of this user.
+     */
+    @Id @EqualsAndHashCode.Include private final long id;
+
+    /**
+     * This user's email.
+     */
+    @Indexed @NonNull private final String email;
+
+    /**
+     * This user's username.
+     */
+    @Indexed @NonNull private final String username;
+
+    /**
+     * The password for this user.
+     */
+    @NonNull private final String password;
+
+    /**
+     * The salt for this user's password.
+     */
+    @NonNull private final String passwordSalt;
+
+    /**
+     * The tier of this user.
+     */
+    @NonNull private final UserTier tier;
+
+    /**
+     * The flags for this user.
+     */
+    private final int flags;
+
+    /**
+     * The date this user last logged in.
+     */
+    @NonNull private final Date lastLogin;
+
+    /**
+     * Check if this user has a given flag.
+     *
+     * @param flag the flag to check
+     * @return whether this user has the flag
+     */
+    public boolean hasFlag(@NonNull UserFlag flag) {
+        return (flags & flag.ordinal()) != 0;
+    }
+}

src/main/java/cc/pulseapp/api/model/user/UserDTO.java

@@ -0,0 +1,64 @@
+package cc.pulseapp.api.model.user;
+
+import lombok.*;
+import org.springframework.data.mongodb.core.index.Indexed;
+
+import java.util.Date;
+
+/**
+ * The DTO for a {@link User}.
+ *
+ * @author Braydon
+ */
+@AllArgsConstructor(access = AccessLevel.PRIVATE) @Getter
+@EqualsAndHashCode(onlyExplicitlyIncluded = true) @ToString
+public final class UserDTO {
+    /**
+     * The snowflake id of this user.
+     */
+    @EqualsAndHashCode.Include private final long id;
+
+    /**
+     * This user's email.
+     */
+    @Indexed @NonNull private final String email;
+
+    /**
+     * This user's username.
+     */
+    @Indexed @NonNull private final String username;
+
+    /**
+     * The tier of this user.
+     */
+    @NonNull private final UserTier tier;
+
+    /**
+     * The date this user last logged in.
+     */
+    @NonNull private final Date lastLogin;
+
+    /**
+     * The flags for this user.
+     */
+    private final int flags;
+
+    /**
+     * The date this user was created.
+     */
+    @NonNull private final Date created;
+
+    /**
+     * Create a DTO from the given user.
+     *
+     * @param user         the user
+     * @param creationTime the user's creation time
+     * @return the user dto
+     */
+    @NonNull
+    public static UserDTO asDTO(@NonNull User user, @NonNull Date creationTime) {
+        return new UserDTO(user.getId(), user.getEmail(), user.getUsername(), user.getTier(),
+                user.getLastLogin(), user.getFlags(), creationTime
+        );
+    }
+}

src/main/java/cc/pulseapp/api/model/user/UserFlag.java

@@ -0,0 +1,18 @@
+package cc.pulseapp.api.model.user;
+
+/**
+ * Flags for a {@link User}.
+ *
+ * @author Braydon
+ */
+public enum UserFlag {
+    /**
+     * The user is disabled.
+     */
+    DISABLED,
+
+    /**
+     * The user completed the onboarding process.
+     */
+    COMPLETED_ONBOARDING
+}

src/main/java/cc/pulseapp/api/model/user/UserTier.java

@@ -0,0 +1,35 @@
+package cc.pulseapp.api.model.user;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.ToString;
+
+/**
+ * The tier of a {@link User}.
+ *
+ * @author Braydon
+ */
+@AllArgsConstructor @Getter @ToString
+public enum UserTier {
+    FREE(1, 2, false, 10);
+
+    /**
+     * The maximum number of organizations a user can have.
+     */
+    private final int maxOrganizations;
+
+    /**
+     * The maximum number of status pages a user can have.
+     */
+    private final int maxStatusPages;
+
+    /**
+     * Whether this tier has banners on status pages.
+     */
+    private final boolean statusPageBanners;
+
+    /**
+     * The maximum number of components a user can have on a status page.
+     */
+    private final int maxStatusPageComponents;
+}

src/main/java/cc/pulseapp/api/model/user/input/UserRegistrationInput.java

@@ -0,0 +1,51 @@
+package cc.pulseapp.api.model.user.input;
+
+import cc.pulseapp.api.model.user.User;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.ToString;
+
+/**
+ * Input to register a new {@link User}.
+ *
+ * @author Braydon
+ */
+@AllArgsConstructor @Getter @ToString
+public final class UserRegistrationInput {
+    /**
+     * The name of the user to create.
+     */
+    private final String email;
+
+    /**
+     * The username of the user to create.
+     */
+    private final String username;
+
+    /**
+     * The password of the user to create.
+     */
+    private final String password;
+
+    /**
+     * The confirmation password of the user to create.
+     */
+    private final String passwordConfirmation;
+
+    /**
+     * The captcha response token to validate.
+     */
+    private final String captchaResponse;
+
+    /**
+     * Check if this input is valid.
+     *
+     * @return whether this input is valid
+     */
+    public boolean isValid() {
+        return email != null && (!email.isBlank())
+                && password != null && (!password.isBlank())
+                && passwordConfirmation != null && (!passwordConfirmation.isBlank())
+                && captchaResponse != null && (!captchaResponse.isBlank());
+    }
+}

src/main/java/cc/pulseapp/api/repository/AuthTokenRepository.java

@@ -0,0 +1,20 @@
+package cc.pulseapp.api.repository;
+
+import cc.pulseapp.api.model.user.AuthToken;
+import lombok.NonNull;
+import org.springframework.data.repository.CrudRepository;
+
+/**
+ * The repository for {@link AuthToken}'s.
+ *
+ * @author Braydon
+ */
+public interface AuthTokenRepository extends CrudRepository<AuthToken, String> {
+    /**
+     * Find an auth token by the access token.
+     *
+     * @param accessToken the access token to search by
+     * @return the auth token, null if none
+     */
+    AuthToken findByAccessToken(@NonNull String accessToken);
+}

src/main/java/cc/pulseapp/api/repository/UserRepository.java

@@ -0,0 +1,20 @@
+package cc.pulseapp.api.repository;
+
+import cc.pulseapp.api.model.user.User;
+import lombok.NonNull;
+import org.springframework.data.mongodb.repository.MongoRepository;
+
+/**
+ * The repository for interacting with {@link User}'s.
+ *
+ * @author Braydon
+ */
+public interface UserRepository extends MongoRepository<User, Long> {
+    /**
+     * Find a user by their email.
+     *
+     * @param email the email of the user
+     * @return the user with the email
+     */
+    User findByEmailIgnoreCase(@NonNull String email);
+}

src/main/java/cc/pulseapp/api/service/AuthService.java

@@ -0,0 +1,147 @@
+package cc.pulseapp.api.service;
+
+import cc.pulseapp.api.common.EnvironmentUtils;
+import cc.pulseapp.api.common.HashUtils;
+import cc.pulseapp.api.common.StringUtils;
+import cc.pulseapp.api.exception.impl.BadRequestException;
+import cc.pulseapp.api.model.IGenericResponse;
+import cc.pulseapp.api.model.user.AuthToken;
+import cc.pulseapp.api.model.user.User;
+import cc.pulseapp.api.model.user.UserFlag;
+import cc.pulseapp.api.model.user.UserTier;
+import cc.pulseapp.api.model.user.input.UserRegistrationInput;
+import cc.pulseapp.api.repository.AuthTokenRepository;
+import cc.pulseapp.api.repository.UserRepository;
+import lombok.NonNull;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.Base64;
+import java.util.Date;
+import java.util.UUID;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * @author Braydon
+ */
+@Service
+public final class AuthService {
+    /**
+     * The service to use for captcha validation.
+     */
+    @NonNull private final CaptchaService captchaService;
+
+    /**
+     * The service to use for snowflake generation and timestamp extraction.
+     */
+    @NonNull private final SnowflakeService snowflakeService;
+
+    /**
+     * The repository to store and retrieve users.
+     */
+    @NonNull private final UserRepository userRepository;
+
+    /**
+     * The auth token repository for generating and validating auth tokens.
+     */
+    @NonNull private final AuthTokenRepository authTokenRepository;
+
+    @Autowired
+    public AuthService(@NonNull CaptchaService captchaService, @NonNull SnowflakeService snowflakeService,
+                       @NonNull UserRepository userRepository, @NonNull AuthTokenRepository authTokenRepository) {
+        this.captchaService = captchaService;
+        this.snowflakeService = snowflakeService;
+        this.userRepository = userRepository;
+        this.authTokenRepository = authTokenRepository;
+    }
+
+    /**
+     * Register a new user.
+     *
+     * @param input the registration input
+     * @return the registered user's auth token
+     * @throws BadRequestException if the input has an error
+     */
+    @NonNull
+    public AuthToken registerUser(UserRegistrationInput input) throws BadRequestException {
+        validateRegistrationInput(input); // Ensure the input is valid
+
+        // Ensure the given email hasn't been used before
+        if (userRepository.findByEmailIgnoreCase(input.getEmail()) != null) {
+            throw new BadRequestException(Error.EMAIL_ALREADY_USED);
+        }
+
+        // Create the user and return it
+        byte[] salt = HashUtils.generateSalt();
+        Date now = new Date();
+        return generateAuthToken(userRepository.save(new User(
+                snowflakeService.generateSnowflake(), input.getEmail(), input.getUsername(),
+                HashUtils.hash(salt, input.getPassword()), Base64.getEncoder().encodeToString(salt),
+                UserTier.FREE, 0, now
+        )));
+    }
+
+    /**
+     * Generate an auth token for a user.
+     *
+     * @param user the user to generate for
+     * @return the generated auth token
+     * @throws BadRequestException if the user is disabled
+     */
+    @NonNull
+    private AuthToken generateAuthToken(@NonNull User user) throws BadRequestException {
+        // User's account has been disabled
+        if (user.hasFlag(UserFlag.DISABLED)) {
+            throw new BadRequestException(Error.USER_DISABLED);
+        }
+        return authTokenRepository.save(new AuthToken(
+                UUID.randomUUID(), user.getId(),
+                StringUtils.generateRandom(128, true, true, false),
+                StringUtils.generateRandom(128, true, true, false),
+                System.currentTimeMillis() + TimeUnit.DAYS.toMillis(30L)
+        ));
+    }
+
+    /**
+     * Validate the given registration input.
+     *
+     * @param input the registration input
+     * @throws BadRequestException if the input has an error
+     */
+    private void validateRegistrationInput(UserRegistrationInput input) throws BadRequestException {
+        // Ensure the input was provided
+        if (input == null || (!input.isValid())) {
+            throw new BadRequestException(Error.MALFORMED_INPUT);
+        }
+        // Ensure the email is valid
+        if (!StringUtils.isValidEmail(input.getEmail())) {
+            throw new BadRequestException(Error.EMAIL_INVALID);
+        }
+        // Ensure the username is valid
+        if (!StringUtils.isValidUsername(input.getUsername())) {
+            throw new BadRequestException(Error.USERNAME_INVALID);
+        }
+        // Password and confirmed password must match
+        if (!input.getPassword().equals(input.getPasswordConfirmation())) {
+            throw new BadRequestException(Error.PASSWORDS_DO_NOT_MATCH);
+        }
+        // The password must meet the requirements
+        StringUtils.PasswordError passwordError = StringUtils.checkPasswordRequirements(input.getPassword());
+        if (passwordError != null) {
+            throw new BadRequestException(passwordError);
+        }
+        // Finally validate the captcha
+        if (EnvironmentUtils.isProduction()) {
+            captchaService.validateCaptcha(input.getCaptchaResponse());
+        }
+    }
+
+    private enum Error implements IGenericResponse {
+        MALFORMED_INPUT,
+        EMAIL_INVALID,
+        USERNAME_INVALID,
+        PASSWORDS_DO_NOT_MATCH,
+        EMAIL_ALREADY_USED,
+        USER_DISABLED
+    }
+}

src/main/java/cc/pulseapp/api/service/CaptchaService.java

@@ -0,0 +1,40 @@
+package cc.pulseapp.api.service;
+
+import cc.pulseapp.api.exception.impl.BadRequestException;
+import cc.pulseapp.api.model.IGenericResponse;
+import com.google.gson.JsonObject;
+import kong.unirest.core.HttpResponse;
+import kong.unirest.core.JsonNode;
+import kong.unirest.core.Unirest;
+import lombok.NonNull;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+/**
+ * @author Braydon
+ */
+@Service
+public final class CaptchaService {
+    @Value("${captcha.secret}")
+    private String secretKey;
+
+    /**
+     * Validates the captcha response.
+     *
+     * @param captchaResponse the response to validate
+     * @throws BadRequestException if the response is invalid
+     */
+    public void validateCaptcha(@NonNull String captchaResponse) throws BadRequestException {
+        JsonObject body = new JsonObject();
+        body.addProperty("secret", secretKey);
+        body.addProperty("response", captchaResponse);
+        HttpResponse<JsonNode> response = Unirest.post("https://challenges.cloudflare.com/turnstile/v0/siteverify").body(body).asJson();
+        if (!response.getBody().getObject().getBoolean("success")) {
+            throw new BadRequestException(Error.CAPTCHA_INVALID);
+        }
+    }
+
+    public enum Error implements IGenericResponse {
+        CAPTCHA_INVALID
+    }
+}

src/main/java/cc/pulseapp/api/service/SnowflakeService.java

@@ -0,0 +1,48 @@
+package cc.pulseapp.api.service;
+
+import com.relops.snowflake.Snowflake;
+import lombok.NonNull;
+import org.springframework.stereotype.Service;
+
+/**
+ * The service responsible for generating snowflakes!
+ *
+ * @author Braydon
+ */
+@Service
+public final class SnowflakeService {
+    private static final long TIMESTAMP_SHIFT = Snowflake.NODE_SHIFT + Snowflake.SEQ_SHIFT;
+
+    /**
+     * The snowflake instance to use.
+     */
+    @NonNull private final Snowflake snowflake;
+
+    private SnowflakeService() {
+        snowflake = new Snowflake(7);
+    }
+
+    /**
+     * Generate a new snowflake.
+     *
+     * @return the generated snowflake
+     */
+    public long generateSnowflake() {
+        return snowflake.next();
+    }
+
+    /**
+     * Extract the creation time of the given
+     * snowflake by reversing the snowflake algorithm.
+     * <p>
+     * The snowflake is right-shifted by 22
+     * bits to get the original timestamp.
+     * </p>
+     *
+     * @param snowflake the snowflake
+     * @return the snowflake unix creation time
+     */
+    public long extractCreationTime(long snowflake) {
+        return snowflake >>> TIMESTAMP_SHIFT;
+    }
+}

src/main/resources/application.yml

@@ -8,19 +8,33 @@ logging:
   file:
     path: "./logs"
 
-# Sentry Configuration
-sentry:
-  dsn: "CHANGE_ME"
-  tracesSampleRate: 1.0
-  environment: "development"
+# Cloudflare Captcha Configuration
+captcha:
+  secret: "CHANGE_ME"
 
 # QuestDB Configuration (Metrics)
 questdb:
   enabled: false
   uri: "http::addr=localhost:9000;username=tether;password=p4$$w0rd;auto_flush_interval=5000;"
 
+# Sentry Configuration
+sentry:
+  dsn: "" # Leave blank for no sentry
+  tracesSampleRate: 1.0
+  environment: "development"
+
 # Spring Configuration
 spring:
+  data:
+    # MongoDB Configuration
+    mongodb:
+      uri: "mongodb://pulseapp:p4$$w0rd@localhost:27017/pulseapp?authSource=admin"
+      auto-index-creation: true # Automatically create collection indexes
+
+  # Don't serialize null values by default with Jackson
+  jackson:
+    default-property-inclusion: non_null
+
   # Ignore
   banner:
     location: "classpath:banner.txt"