#![allow(dead_code)]

//! Constants module for the DML Launcher.
//!
//! This module defines immutable configuration values and defaults
//! used throughout the launcher. These constants provide a single
//! source of truth for URLs, download behavior, memory settings,
//! JVM defaults, download concurrency, directory names, and version selection.
//!
//! Centralizing these constants ensures consistency across the
//! application and simplifies maintenance when defaults need to change.

use std::time::Duration;

/// URL to the Minecraft version manifest.
///
/// This manifest contains metadata for all available Minecraft
/// releases, including release dates, type (release, snapshot),
/// and download URLs for the client and server distributions.
pub const VERSION_MANIFEST_URL: &str =
    "https://launchermeta.mojang.com/mc/game/version_manifest.json";

/// Number of times to retry a failed download.
///
/// Used by asset and library download routines to tolerate
/// transient network failures. Downloads will be retried
/// up to this number of attempts before returning an error.
pub const DOWNLOAD_RETRIES: usize = 3;

/// Duration to wait between download retries.
///
/// Provides fixed delay for network resilience when fetching
/// game assets. Specified in milliseconds.
pub const DOWNLOAD_BACKOFF: Duration = Duration::from_millis(400);

/// Default maximum memory allocation for the Minecraft JVM process in
/// megabytes.
///
/// If the user does not specify memory settings via configuration
/// or JVM arguments, this value will be applied as the default heap size.
pub const DEFAULT_MAX_MEMORY_MB: u32 = 4048;

/// Default path to the Java executable.
///
/// Used when launching the Minecraft client. Can be overridden
/// via configuration or environment variables if a custom Java
/// installation is required.
pub const DEFAULT_JAVA_PATH: &str = "java";

/// Default Minecraft version to launch when no specific version is provided.
///
/// The launcher will resolve "latest" to the most recent stable release
/// according to the version manifest.
pub const DEFAULT_VERSION: &str = "latest";

/// Default Java major version for launching Minecraft.
///
/// This value is used when generating the JVM runtime configuration
/// for the launcher.
pub const DEFAULT_JAVA_MAJOR: u8 = 8;

/// Default number of concurrent downloads for libraries.
///
/// Limits the number of simultaneous HTTP requests when fetching
/// Minecraft libraries to avoid saturating network or file handles.
pub const DEFAULT_LIBRARY_CONCURRENCY: usize = 20;

/// Default number of concurrent downloads for assets.
///
/// Limits the number of simultaneous HTTP requests when fetching
/// Minecraft assets to optimize throughput without overloading the system.
pub const DEFAULT_ASSET_CONCURRENCY: usize = 20;

/// Default launcher cache directory name.
///
/// Used as the base subdirectory for downloaded assets, libraries,
/// versions, and configuration.
pub const DEFAULT_LAUNCHER_DIR: &str = "dml";

/// Default environment variable names for overriding configuration.
pub const ENV_USERNAME: &str = "MC_USERNAME";
pub const ENV_VERSION: &str = "MC_VERSION";
pub const ENV_JAVA_PATH: &str = "MC_JAVA_PATH";
pub const ENV_MAX_MEMORY_MB: &str = "MC_MAX_MEMORY_MB";

/// Default project/platform constants for `directories::ProjectDirs`.
pub const DEFAULT_COMPANY: &str = "com";
pub const DEFAULT_PROJECT_GROUP: &str = "example";
pub const DEFAULT_PROJECT_NAME: &str = "dml";

/// Default error messages for common failures.
pub const DEFAULT_ERR_PLATFORM_DIR: &str = "cannot determine config dir";
pub const DEFAULT_ERR_CREATE_DIR: &str = "failed to create directory";

/// Default configuration filename within the launcher directory.
pub const DEFAULT_CONFIG_FILENAME: &str = "config.toml";

/// Default username if none is provided by environment or config.
pub const DEFAULT_USERNAME: &str = "phil";

/// Default subdirectory names within the launcher directory.
pub mod directory {
    /// Directory for Minecraft versions.
    pub const VERSIONS: &str = "versions";

    /// Directory for downloaded libraries.
    pub const LIBRARIES: &str = "libraries";

    /// Directory for Minecraft assets.
    pub const ASSETS: &str = "assets";

    /// Subdirectory for asset indexes.
    pub const INDEXES: &str = "indexes";

    /// Subdirectory for asset objects.
    pub const OBJECTS: &str = "objects";

    /// Directory for native libraries.
    pub const NATIVES: &str = "natives";

    /// Directory for saved worlds.
    pub const SAVES: &str = "saves";
}