vs-config 0.0.4

//! Reading and writing persisted `vs` configuration files.

use std::fs;
use std::path::{Path, PathBuf};

use serde_yaml::Value;

use crate::ConfigError;
use crate::types::{AppConfig, ToolVersions};

/// Reads `config.yaml` from the active home.
pub fn read_app_config(home: &Path) -> Result<AppConfig, ConfigError> {
    let path = home.join("config.yaml");
    if !path.exists() {
        return Ok(AppConfig::default());
    }

    let content = fs::read_to_string(&path)?;
    serde_yaml::from_str(&content).map_err(|error| ConfigError::Yaml {
        path,
        message: error.to_string(),
    })
}

/// Writes `config.yaml` to the active home.
pub fn write_app_config(home: &Path, config: &AppConfig) -> Result<(), ConfigError> {
    fs::create_dir_all(home)?;
    let path = home.join("config.yaml");
    let rendered = serde_yaml::to_string(config).map_err(|error| ConfigError::Yaml {
        path: path.clone(),
        message: error.to_string(),
    })?;
    fs::write(path, rendered)?;
    Ok(())
}

/// Reads a TOML tool file.
pub fn read_tool_versions(path: &Path) -> Result<ToolVersions, ConfigError> {
    let content = fs::read_to_string(path)?;
    toml::from_str(&content).map_err(|error| ConfigError::Toml {
        path: path.to_path_buf(),
        message: error.to_string(),
    })
}

/// Writes a TOML tool file.
pub fn write_tool_versions(path: &Path, tools: &ToolVersions) -> Result<(), ConfigError> {
    if let Some(parent) = path.parent() {
        fs::create_dir_all(parent)?;
    }
    let rendered = toml::to_string_pretty(tools).map_err(|error| ConfigError::Toml {
        path: path.to_path_buf(),
        message: error.to_string(),
    })?;
    fs::write(path, rendered)?;
    Ok(())
}

/// Lists user-visible configuration values as strings.
pub fn flatten_app_config(config: &AppConfig) -> Vec<(String, String)> {
    vec![
        (
            String::from("proxy.enable"),
            config.proxy.enable.to_string(),
        ),
        (
            String::from("proxy.url"),
            if config.proxy.url.is_empty() {
                String::from("<unset>")
            } else {
                config.proxy.url.clone()
            },
        ),
        (
            String::from("storage.sdkPath"),
            if config.storage.sdk_path.is_empty() {
                String::from("<unset>")
            } else {
                config.storage.sdk_path.clone()
            },
        ),
        (
            String::from("registry.address"),
            if config.registry.address.is_empty() {
                String::from("<unset>")
            } else {
                config.registry.address.clone()
            },
        ),
        (
            String::from("legacyVersionFile.enable"),
            config.legacy_version_file.enable.to_string(),
        ),
        (
            String::from("legacyVersionFile.strategy"),
            config.legacy_version_file.strategy.clone(),
        ),
        (
            String::from("cache.availableHookDuration"),
            config.cache.available_hook_duration.clone(),
        ),
    ]
}

/// Sets a top-level config value by key.
pub fn set_app_config_value(
    config: &mut AppConfig,
    key: &str,
    value: &str,
) -> Result<(), ConfigError> {
    match key {
        "proxy.enable" => {
            config.proxy.enable = value
                .parse::<bool>()
                .map_err(|_| ConfigError::InvalidValue {
                    key: key.to_string(),
                    value: value.to_string(),
                })?;
        }
        "proxy.url" => {
            config.proxy.url = value.to_string();
        }
        "storage.sdkPath" => {
            config.storage.sdk_path = value.to_string();
        }
        "registry.address" => {
            config.registry.address = value.to_string();
        }
        "legacyVersionFile.enable" => {
            config.legacy_version_file.enable =
                value
                    .parse::<bool>()
                    .map_err(|_| ConfigError::InvalidValue {
                        key: key.to_string(),
                        value: value.to_string(),
                    })?;
        }
        "legacyVersionFile.strategy" => {
            if !is_supported_legacy_strategy(value) {
                return Err(ConfigError::InvalidValue {
                    key: key.to_string(),
                    value: value.to_string(),
                });
            }
            config.legacy_version_file.strategy = value.to_string();
        }
        "cache.availableHookDuration" => {
            if !is_supported_duration(value) {
                return Err(ConfigError::InvalidValue {
                    key: key.to_string(),
                    value: value.to_string(),
                });
            }
            config.cache.available_hook_duration = value.to_string();
        }
        _ => {
            return Err(ConfigError::UnknownKey(key.to_string()));
        }
    }
    Ok(())
}

/// Unsets a top-level config value by key.
pub fn unset_app_config_value(config: &mut AppConfig, key: &str) -> Result<(), ConfigError> {
    match key {
        "proxy.enable" => {
            config.proxy.enable = AppConfig::default().proxy.enable;
        }
        "proxy.url" => {
            config.proxy.url.clear();
        }
        "storage.sdkPath" => {
            config.storage.sdk_path.clear();
        }
        "registry.address" => {
            config.registry.address.clear();
        }
        "legacyVersionFile.enable" => {
            config.legacy_version_file.enable = AppConfig::default().legacy_version_file.enable;
        }
        "legacyVersionFile.strategy" => {
            config.legacy_version_file.strategy = AppConfig::default().legacy_version_file.strategy;
        }
        "cache.availableHookDuration" => {
            config.cache.available_hook_duration =
                AppConfig::default().cache.available_hook_duration;
        }
        _ => {
            return Err(ConfigError::UnknownKey(key.to_string()));
        }
    }
    Ok(())
}

/// Converts an application config to a YAML value for debugging.
pub fn app_config_to_value(config: &AppConfig) -> Result<Value, ConfigError> {
    serde_yaml::to_value(config).map_err(|error| ConfigError::Yaml {
        path: PathBuf::from("config.yaml"),
        message: error.to_string(),
    })
}

fn is_supported_legacy_strategy(value: &str) -> bool {
    matches!(value, "specified" | "latest_installed" | "latest_available")
}

fn is_supported_duration(value: &str) -> bool {
    let trimmed = value.trim();
    if trimmed.is_empty() || trimmed == "0" {
        return true;
    }

    let split_at = trimmed
        .find(|ch: char| !ch.is_ascii_digit())
        .unwrap_or(trimmed.len());
    let (amount, unit) = trimmed.split_at(split_at);
    if amount
        .parse::<u64>()
        .ok()
        .filter(|amount| *amount > 0)
        .is_none()
    {
        return false;
    }

    matches!(unit, "" | "s" | "m" | "h" | "d")
}