use std::ffi::OsStr;
use std::path::{Path, PathBuf};

use serde::{Deserialize, Serialize};
use tokio::sync::Mutex;

use crate::db::agent_driver::{AgentDriverClient, AgentLaunchSpec, AgentMethod};
use crate::models::connection::DatabaseType;

pub const DEFAULT_JRE_KEY: &str = "21";
pub const DOWNLOAD_CACHE_DIR_NAME: &str = "download-cache";
pub const DOWNLOAD_CACHE_MAX_AGE_DAYS: u64 = 7;

fn default_jre_key() -> String {
    DEFAULT_JRE_KEY.to_string()
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AgentRegistry {
    #[serde(default)]
    pub jre: Option<JreInfo>,
    #[serde(default)]
    pub jres: std::collections::HashMap<String, JreInfo>,
    pub drivers: std::collections::HashMap<String, DriverInfo>,
}

impl AgentRegistry {
    pub fn resolve_jre(&self, key: &str) -> Option<&JreInfo> {
        if !self.jres.is_empty() {
            return self.jres.get(key);
        }
        if key == DEFAULT_JRE_KEY {
            self.jre.as_ref()
        } else {
            None
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;

    fn test_manager(name: &str) -> AgentManager {
        let dir = std::env::temp_dir().join(format!("dbx-agent-manager-{name}-{}", uuid::Uuid::new_v4()));
        AgentManager::new_with_base_dir(dir)
    }

    fn touch(path: &Path) {
        if let Some(parent) = path.parent() {
            fs::create_dir_all(parent).unwrap();
        }
        fs::write(path, b"").unwrap();
        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;

            let mut permissions = fs::metadata(path).unwrap().permissions();
            permissions.set_mode(0o755);
            fs::set_permissions(path, permissions).unwrap();
        }
    }

    #[test]
    fn cleanup_pending_jre_removes_stash_dirs_and_persists() {
        let manager = test_manager("pending-cleanup");
        std::fs::create_dir_all(manager.base_dir()).unwrap();
        let stash = manager.base_dir().join("jre-21.old-1700000000-deadbeef");
        std::fs::create_dir_all(&stash).unwrap();
        std::fs::write(stash.join("dummy"), b"x").unwrap();

        let mut state = AgentState::default();
        state.pending_jre_cleanup.push(stash.clone());
        manager.save_state(&state).unwrap();

        // Re-create the manager (simulates app restart).
        let manager2 = AgentManager::new_with_base_dir(manager.base_dir().clone());

        assert!(!stash.exists(), "stash dir should be removed");
        let after = manager2.load_state();
        assert!(after.pending_jre_cleanup.is_empty(), "cleanup should drain the list on success");
    }

    #[test]
    fn cleanup_orphan_jre_dirs_removes_unrecorded_stash() {
        let manager = test_manager("orphan-cleanup");
        std::fs::create_dir_all(manager.base_dir()).unwrap();
        let orphan = manager.base_dir().join("jre-21.old-1234567890-cafe");
        std::fs::create_dir_all(&orphan).unwrap();

        // Re-create manager — it should sweep orphans even without state.
        let _manager2 = AgentManager::new_with_base_dir(manager.base_dir().clone());

        assert!(!orphan.exists(), "orphan stash should be swept");
    }

    #[test]
    fn cleanup_skips_active_jre_dir() {
        let manager = test_manager("orphan-skip-active");
        std::fs::create_dir_all(manager.base_dir()).unwrap();
        let active = manager.jre_dir(DEFAULT_JRE_KEY); // jre-21
        std::fs::create_dir_all(&active).unwrap();

        let _manager2 = AgentManager::new_with_base_dir(manager.base_dir().clone());

        assert!(active.exists(), "active jre-<key> dir must not be touched (no .old- in name)");
    }

    #[test]
    fn agent_state_back_compat_without_pending_jre_cleanup() {
        // Old state JSON without pending_jre_cleanup must still deserialize.
        let json = r#"{
            "jre_versions": {},
            "installed_drivers": {},
            "java_runtime": {"mode": "managed"}
        }"#;
        let state: AgentState = serde_json::from_str(json).expect("deserialize legacy state");
        assert!(state.pending_jre_cleanup.is_empty());
    }

    #[test]
    fn resolves_managed_java_runtime_by_default() {
        let manager = test_manager("managed");
        let java = manager.jre_java_path(DEFAULT_JRE_KEY);
        touch(&java);

        let state = AgentState::default();

        assert_eq!(manager.resolve_java_runtime(&state, DEFAULT_JRE_KEY).unwrap(), java);
    }

    #[test]
    fn resolves_custom_java_runtime_when_configured() {
        let manager = test_manager("custom");
        let custom_java = manager.base_dir().join("custom").join("bin").join("java");
        touch(&custom_java);
        let state = AgentState {
            java_runtime: JavaRuntimeConfig {
                mode: JavaRuntimeMode::Custom,
                custom_java_path: Some(custom_java.to_string_lossy().to_string()),
            },
            ..AgentState::default()
        };

        assert_eq!(manager.resolve_java_runtime(&state, DEFAULT_JRE_KEY).unwrap(), custom_java);
    }

    #[test]
    fn rejects_missing_custom_java_runtime() {
        let manager = test_manager("missing-custom");
        let state = AgentState {
            java_runtime: JavaRuntimeConfig {
                mode: JavaRuntimeMode::Custom,
                custom_java_path: Some(manager.base_dir().join("missing-java").to_string_lossy().to_string()),
            },
            ..AgentState::default()
        };

        let err = manager.resolve_java_runtime(&state, DEFAULT_JRE_KEY).unwrap_err();

        assert!(err.contains("Custom Java runtime does not exist"));
    }

    #[test]
    fn stores_configured_app_version_for_agent_handshake() {
        let dir = std::env::temp_dir().join(format!("dbx-agent-manager-version-{}", uuid::Uuid::new_v4()));
        let manager = AgentManager::new_with_base_dir_and_app_version(dir, "0.5.13");

        assert_eq!(manager.agent_app_version(), "0.5.13");
    }

    #[test]
    fn resolves_system_java_runtime_from_path() {
        let manager = test_manager("system");
        let system_java = manager.base_dir().join("bin").join(if cfg!(windows) { "java.exe" } else { "java" });
        touch(&system_java);
        let path = std::env::join_paths([system_java.parent().unwrap()]).unwrap();

        assert_eq!(resolve_system_java_path(Some(path.as_os_str())).unwrap(), system_java);
    }

    #[tokio::test]
    async fn runtime_gateway_returns_existing_missing_driver_error() {
        let manager = test_manager("missing-driver");

        let err = match manager.spawn(&DatabaseType::H2, None).await {
            Ok(_) => panic!("missing driver should fail"),
            Err(err) => err,
        };

        assert_eq!(err, "h2 driver is not installed. Please install it from the Driver Manager.");
    }

    #[tokio::test]
    async fn runtime_gateway_returns_existing_missing_java_error() {
        let manager = test_manager("missing-java");
        let jar = manager.driver_jar_path("h2");
        touch(&jar);

        let err = match manager.spawn(&DatabaseType::H2, None).await {
            Ok(_) => panic!("missing Java runtime should fail"),
            Err(err) => err,
        };

        assert_eq!(err, "JRE 21 runtime is not installed. Please install it from the Driver Manager.");
    }

    #[tokio::test]
    async fn runtime_gateway_resolves_profile_specific_keys() {
        let manager = test_manager("profile-key");

        assert_eq!(AgentManager::db_type_to_agent_key(&DatabaseType::Oracle, Some("oracle-10g")), Some("oracle"));
        assert_eq!(AgentManager::db_type_to_agent_key(&DatabaseType::Oracle, Some("oracle-legacy")), Some("oracle"));
        assert_eq!(AgentManager::db_type_to_agent_key(&DatabaseType::Oracle, None), Some("oracle"));
        assert_eq!(AgentManager::db_type_to_agent_key(&DatabaseType::Gbase, Some("gbase8s")), Some("gbase8s"));
        assert_eq!(AgentManager::db_type_to_agent_key(&DatabaseType::Gbase, None), Some("gbase8a"));
        manager.stop_daemon_by_key("oracle-legacy").await;
        manager.stop_daemon_by_key("oracle-10g").await;
        manager.stop_daemon_by_key("gbase8s").await;
    }

    #[test]
    fn resolves_native_agent_launch_when_agent_executable_exists() {
        let manager = test_manager("native-agent");
        let native = manager.driver_native_path("dameng");
        touch(&native);

        let launch = manager
            .resolve_agent_launch_spec(&AgentState::default(), "dameng", DEFAULT_JRE_KEY)
            .expect("native launch should resolve");

        assert_eq!(launch.program, native);
        assert_eq!(launch.args, Vec::<String>::new());
        assert_eq!(launch.working_dir.as_deref(), Some(manager.driver_dir("dameng").as_path()));
    }

    #[test]
    fn resolves_manifest_agent_launch_with_driver_dir_templates() {
        let manager = test_manager("manifest-agent");
        let driver_dir = manager.driver_dir("dameng-go");
        fs::create_dir_all(driver_dir.join("bin")).unwrap();
        fs::write(
            manager.driver_launch_config_path("dameng-go"),
            r#"{
                "command": "bin/dameng-agent",
                "args": ["--config", "{driver_dir}/config.json"],
                "working_dir": "{driver_dir}"
            }"#,
        )
        .unwrap();

        let launch = manager
            .resolve_agent_launch_spec(&AgentState::default(), "dameng-go", DEFAULT_JRE_KEY)
            .expect("manifest launch should resolve");

        assert_eq!(launch.program, driver_dir.join("bin").join("dameng-agent"));
        assert_eq!(
            launch.args,
            vec!["--config".to_string(), driver_dir.join("config.json").to_string_lossy().to_string()]
        );
        assert_eq!(launch.working_dir.as_deref(), Some(driver_dir.as_path()));
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct JreInfo {
    pub version: String,
    pub platforms: std::collections::HashMap<String, ArtifactInfo>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DriverInfo {
    pub version: String,
    pub label: String,
    pub min_app_version: String,
    #[serde(default)]
    pub jar: Option<ArtifactInfo>,
    #[serde(default)]
    pub native: std::collections::HashMap<String, ArtifactInfo>,
    #[serde(default = "default_jre_key")]
    pub jre: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ArtifactInfo {
    pub url: String,
    pub size: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct AgentState {
    #[serde(default)]
    pub jre_version: Option<String>,
    #[serde(default)]
    pub jre_versions: std::collections::HashMap<String, String>,
    #[serde(default)]
    pub installed_drivers: std::collections::HashMap<String, InstalledDriver>,
    #[serde(default)]
    pub java_runtime: JavaRuntimeConfig,
    /// Old JRE directories that could not be deleted in-place during a
    /// reinstall on Windows; renamed aside (`<name>.old-<ts>-<rand>`) and
    /// cleaned up best-effort on next `AgentManager::new`.
    #[serde(default)]
    pub pending_jre_cleanup: Vec<PathBuf>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InstalledDriver {
    pub version: String,
    pub installed_at: String,
    #[serde(default = "default_jre_key")]
    pub jre: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AgentLaunchConfig {
    pub command: String,
    #[serde(default)]
    pub args: Vec<String>,
    #[serde(default)]
    pub working_dir: Option<String>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
#[serde(rename_all = "snake_case")]
pub enum JavaRuntimeMode {
    #[default]
    Managed,
    System,
    Custom,
}

#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct JavaRuntimeConfig {
    #[serde(default)]
    pub mode: JavaRuntimeMode,
    #[serde(default)]
    pub custom_java_path: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AgentDriverInfo {
    pub db_type: String,
    pub label: String,
    pub version: String,
    pub size: u64,
    pub installed: bool,
    pub installed_version: Option<String>,
    pub update_available: bool,
    pub jre: String,
    pub jre_installed: bool,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DriverStoreUsageItem {
    pub id: String,
    pub bytes: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DriverStoreUsage {
    pub total_bytes: u64,
    pub jre_bytes: u64,
    pub agent_driver_bytes: u64,
    #[serde(default)]
    pub download_cache_bytes: u64,
    pub jdbc_plugin_bytes: u64,
    pub jdbc_driver_bytes: u64,
    pub jres: Vec<DriverStoreUsageItem>,
    pub agent_drivers: Vec<DriverStoreUsageItem>,
}

pub struct AgentManager {
    base_dir: PathBuf,
    app_version: String,
    pub(crate) daemons: Mutex<std::collections::HashMap<String, AgentDriverClient>>,
}

impl Default for AgentManager {
    fn default() -> Self {
        Self::new()
    }
}

impl AgentManager {
    pub fn new() -> Self {
        let home =
            std::env::var(if cfg!(windows) { "USERPROFILE" } else { "HOME" }).unwrap_or_else(|_| ".".to_string());
        Self::new_with_base_dir(PathBuf::from(home).join(".dbx").join("agents"))
    }

    pub fn new_with_base_dir(base_dir: PathBuf) -> Self {
        Self::new_with_base_dir_and_app_version(base_dir, env!("CARGO_PKG_VERSION"))
    }

    pub fn new_with_base_dir_and_app_version(base_dir: PathBuf, app_version: impl Into<String>) -> Self {
        let mgr =
            Self { base_dir, app_version: app_version.into(), daemons: Mutex::new(std::collections::HashMap::new()) };
        mgr.migrate_legacy_jre();
        mgr.cleanup_pending_jre_dirs();
        mgr.cleanup_orphan_jre_dirs();
        mgr
    }

    fn migrate_legacy_jre(&self) {
        let legacy = self.base_dir.join("jre");
        let versioned = self.jre_dir(DEFAULT_JRE_KEY);
        if legacy.exists() && !versioned.exists() {
            let _ = std::fs::rename(&legacy, &versioned);
        }
    }

    /// Best-effort cleanup of `pending_jre_cleanup` paths recorded by previous
    /// runs that fell back to renaming an old JRE aside on Windows. Successful
    /// removals are pruned from the persisted state. Failures are kept for the
    /// next launch and never block startup. (Issue #1100, D6.)
    fn cleanup_pending_jre_dirs(&self) {
        let mut state = self.load_state();
        if state.pending_jre_cleanup.is_empty() {
            return;
        }
        let mut remaining = Vec::new();
        for path in std::mem::take(&mut state.pending_jre_cleanup) {
            if !path.exists() {
                continue;
            }
            match std::fs::remove_dir_all(&path) {
                Ok(()) => log::info!("Cleaned up pending JRE stash: {}", path.display()),
                Err(err) => {
                    log::warn!("Pending JRE cleanup failed for {}: {err}", path.display());
                    remaining.push(path);
                }
            }
        }
        state.pending_jre_cleanup = remaining;
        if let Err(err) = self.save_state(&state) {
            log::warn!("Failed to persist post-cleanup AgentState: {err}");
        }
    }

    /// Sweep `base_dir` for orphan `*.old-*` JRE stash directories left behind
    /// by previous runs (e.g. process crashed before the stash was recorded).
    /// Best-effort — failures are ignored.
    fn cleanup_orphan_jre_dirs(&self) {
        let entries = match std::fs::read_dir(&self.base_dir) {
            Ok(e) => e,
            Err(_) => return,
        };
        for entry in entries.flatten() {
            let Some(name) = entry.file_name().to_str().map(str::to_string) else {
                continue;
            };
            // Match `<...>.old-<digits>-<...>` (typically `jre-21.old-...`),
            // which is the suffix scheme used by stash_old_jre_dir.
            if !name.starts_with("jre-") || !name.contains(".old-") {
                continue;
            }
            let path = entry.path();
            if !path.is_dir() {
                continue;
            }
            match std::fs::remove_dir_all(&path) {
                Ok(()) => log::info!("Cleaned up orphan JRE stash: {}", path.display()),
                Err(err) => log::warn!("Orphan JRE cleanup failed for {}: {err}", path.display()),
            }
        }
    }

    pub fn base_dir(&self) -> &PathBuf {
        &self.base_dir
    }

    pub fn agent_app_version(&self) -> &str {
        &self.app_version
    }

    pub fn jre_dir(&self, jre_key: &str) -> PathBuf {
        self.base_dir.join(format!("jre-{jre_key}"))
    }

    pub fn jre_java_path(&self, jre_key: &str) -> PathBuf {
        let dir = self.jre_dir(jre_key);
        let java_name = if cfg!(windows) { "java.exe" } else { "java" };
        let flat = dir.join("bin").join(java_name);
        if flat.exists() {
            return flat;
        }
        // macOS Adoptium JRE 8 uses Contents/Home/ layout
        let macos = dir.join("Contents").join("Home").join("bin").join(java_name);
        if macos.exists() {
            return macos;
        }
        flat
    }

    pub fn driver_dir(&self, db_type: &str) -> PathBuf {
        self.base_dir.join("drivers").join(db_type)
    }

    pub fn driver_jar_path(&self, db_type: &str) -> PathBuf {
        self.driver_dir(db_type).join("agent.jar")
    }

    pub fn driver_native_path(&self, db_type: &str) -> PathBuf {
        let executable_name = if cfg!(windows) { "agent.exe" } else { "agent" };
        self.driver_dir(db_type).join(executable_name)
    }

    pub fn driver_launch_config_path(&self, db_type: &str) -> PathBuf {
        self.driver_dir(db_type).join("agent-launch.json")
    }

    pub fn download_cache_dir(&self) -> PathBuf {
        self.base_dir.join(DOWNLOAD_CACHE_DIR_NAME)
    }

    pub fn download_cache_max_age_days(&self) -> u64 {
        DOWNLOAD_CACHE_MAX_AGE_DAYS
    }

    fn state_path(&self) -> PathBuf {
        self.base_dir.join("state.json")
    }

    pub fn load_state(&self) -> AgentState {
        std::fs::read_to_string(self.state_path()).ok().and_then(|s| serde_json::from_str(&s).ok()).unwrap_or_default()
    }

    pub fn save_state(&self, state: &AgentState) -> Result<(), String> {
        let dir = self.base_dir.clone();
        std::fs::create_dir_all(&dir).map_err(|e| e.to_string())?;
        let json = serde_json::to_string_pretty(state).map_err(|e| e.to_string())?;
        std::fs::write(self.state_path(), json).map_err(|e| e.to_string())
    }

    pub fn is_jre_installed(&self, jre_key: &str) -> bool {
        self.jre_java_path(jre_key).exists()
    }

    pub fn is_driver_installed(&self, db_type: &str) -> bool {
        self.driver_jar_path(db_type).exists()
            || self.driver_native_path(db_type).exists()
            || self.driver_launch_config_path(db_type).exists()
    }

    pub fn driver_requires_java_runtime(&self, db_type: &str) -> bool {
        self.driver_jar_path(db_type).exists()
            && !self.driver_native_path(db_type).exists()
            && !self.driver_launch_config_path(db_type).exists()
    }

    pub fn resolve_agent_launch_spec(
        &self,
        state: &AgentState,
        driver_key: &str,
        jre_key: &str,
    ) -> Result<AgentLaunchSpec, String> {
        let driver_dir = self.driver_dir(driver_key);
        let config_path = self.driver_launch_config_path(driver_key);
        if config_path.exists() {
            return self.resolve_configured_agent_launch_spec(driver_key, &driver_dir, &config_path);
        }

        let native_path = self.driver_native_path(driver_key);
        if native_path.exists() {
            return Ok(AgentLaunchSpec::new(native_path).with_working_dir(driver_dir));
        }

        let jar_path = self.driver_jar_path(driver_key);
        if jar_path.exists() {
            let java = self.resolve_java_runtime(state, jre_key)?;
            return Ok(AgentLaunchSpec::java_jar(java, jar_path));
        }

        Err(format!("{driver_key} driver is not installed. Please install it from the Driver Manager."))
    }

    fn resolve_configured_agent_launch_spec(
        &self,
        driver_key: &str,
        driver_dir: &Path,
        config_path: &Path,
    ) -> Result<AgentLaunchSpec, String> {
        let json = std::fs::read_to_string(config_path)
            .map_err(|e| format!("Failed to read {driver_key} agent launch config: {e}"))?;
        let config: AgentLaunchConfig = serde_json::from_str(&json)
            .map_err(|e| format!("Failed to parse {driver_key} agent launch config: {e}"))?;
        let command = config.command.trim();
        if command.is_empty() {
            return Err(format!("{driver_key} agent launch config command is empty"));
        }
        let working_dir = config
            .working_dir
            .as_deref()
            .map(|value| self.resolve_driver_launch_path(driver_dir, value))
            .transpose()?
            .unwrap_or_else(|| driver_dir.to_path_buf());
        let program = self.resolve_driver_launch_path(driver_dir, command)?;
        let args = config.args.iter().map(|arg| self.expand_agent_launch_template(driver_dir, arg)).collect::<Vec<_>>();
        Ok(AgentLaunchSpec::new(program).with_args(args).with_working_dir(working_dir))
    }

    fn resolve_driver_launch_path(&self, driver_dir: &Path, value: &str) -> Result<PathBuf, String> {
        let expanded = self.expand_agent_launch_template(driver_dir, value);
        let path = PathBuf::from(&expanded);
        if path.is_absolute() || expanded.contains('/') || expanded.contains('\\') || expanded.starts_with('.') {
            return Ok(if path.is_absolute() { path } else { driver_dir.join(path) });
        }
        Ok(path)
    }

    fn expand_agent_launch_template(&self, driver_dir: &Path, value: &str) -> String {
        value
            .replace("{driver_dir}", &driver_dir.to_string_lossy())
            .replace("{agent_dir}", &self.base_dir.to_string_lossy())
            .replace("{platform}", Self::current_platform())
    }

    pub fn collect_driver_store_usage(&self, plugin_root: &Path) -> DriverStoreUsage {
        let mut jres = Vec::new();
        let mut jre_bytes = 0u64;
        if let Ok(entries) = std::fs::read_dir(&self.base_dir) {
            for entry in entries.flatten() {
                let path = entry.path();
                if !path.is_dir() {
                    continue;
                }
                let Some(name) = path.file_name().and_then(|v| v.to_str()) else {
                    continue;
                };
                if !name.starts_with("jre-") {
                    continue;
                }
                let key = name.trim_start_matches("jre-").to_string();
                let bytes = path_size_bytes(&path);
                jre_bytes = jre_bytes.saturating_add(bytes);
                jres.push(DriverStoreUsageItem { id: key, bytes });
            }
        }
        jres.sort_by(|left, right| left.id.cmp(&right.id));

        let mut agent_drivers = Vec::new();
        let mut agent_driver_bytes = 0u64;
        let drivers_root = self.base_dir.join("drivers");
        if let Ok(entries) = std::fs::read_dir(&drivers_root) {
            for entry in entries.flatten() {
                let path = entry.path();
                if !path.is_dir() {
                    continue;
                }
                let Some(id) = path.file_name().and_then(|v| v.to_str()) else {
                    continue;
                };
                let bytes = path_size_bytes(&path);
                agent_driver_bytes = agent_driver_bytes.saturating_add(bytes);
                agent_drivers.push(DriverStoreUsageItem { id: id.to_string(), bytes });
            }
        }
        agent_drivers.sort_by(|left, right| left.id.cmp(&right.id));

        let jdbc_root = plugin_root.join("jdbc");
        let jdbc_driver_root = jdbc_root.join("drivers");
        let jdbc_driver_bytes = path_size_bytes(&jdbc_driver_root);
        let jdbc_total_bytes = path_size_bytes(&jdbc_root);
        let jdbc_plugin_bytes = jdbc_total_bytes.saturating_sub(jdbc_driver_bytes);
        let download_cache_bytes = path_size_bytes(&self.download_cache_dir());

        DriverStoreUsage {
            total_bytes: jre_bytes
                .saturating_add(agent_driver_bytes)
                .saturating_add(download_cache_bytes)
                .saturating_add(jdbc_plugin_bytes)
                .saturating_add(jdbc_driver_bytes),
            jre_bytes,
            agent_driver_bytes,
            download_cache_bytes,
            jdbc_plugin_bytes,
            jdbc_driver_bytes,
            jres,
            agent_drivers,
        }
    }

    pub fn resolve_java_runtime(&self, state: &AgentState, jre_key: &str) -> Result<PathBuf, String> {
        match state.java_runtime.mode {
            JavaRuntimeMode::Managed => {
                if !self.is_jre_installed(jre_key) {
                    return Err(format!(
                        "JRE {jre_key} runtime is not installed. Please install it from the Driver Manager."
                    ));
                }
                Ok(self.jre_java_path(jre_key))
            }
            JavaRuntimeMode::System => resolve_system_java_path(None).ok_or_else(|| {
                "System Java runtime was not found on PATH. Please install Java or choose a custom Java executable."
                    .to_string()
            }),
            JavaRuntimeMode::Custom => {
                let path = state
                    .java_runtime
                    .custom_java_path
                    .as_deref()
                    .map(str::trim)
                    .filter(|path| !path.is_empty())
                    .ok_or_else(|| "Custom Java runtime path is empty. Please choose a Java executable.".to_string())?;
                resolve_custom_java_path(path)
            }
        }
    }

    pub async fn stop_daemons(&self) {
        crate::agent_runtime::stop_daemons(self).await;
    }

    pub async fn stop_daemon_by_key(&self, agent_key: &str) {
        crate::agent_runtime::stop_daemon_by_key(self, agent_key).await;
    }

    pub async fn restart_daemon_by_key(&self, agent_key: &str) -> Result<(), String> {
        crate::agent_runtime::restart_daemon_by_key(self, agent_key).await
    }

    pub async fn active_daemon_keys(&self) -> Vec<String> {
        self.daemons.lock().await.keys().cloned().collect()
    }

    pub fn db_type_to_agent_key(db_type: &DatabaseType, driver_profile: Option<&str>) -> Option<&'static str> {
        crate::agent_runtime::db_type_to_agent_key(db_type, driver_profile)
    }

    pub fn is_agent_type(db_type: &DatabaseType) -> bool {
        crate::agent_runtime::is_agent_type(db_type)
    }

    pub async fn spawn(
        &self,
        db_type: &DatabaseType,
        driver_profile: Option<&str>,
    ) -> Result<AgentDriverClient, String> {
        crate::agent_runtime::spawn_connection_client(self, db_type, driver_profile).await
    }

    pub async fn call_daemon<T: serde::de::DeserializeOwned + Send + 'static>(
        &self,
        db_type: &DatabaseType,
        driver_profile: Option<&str>,
        method: &str,
        params: serde_json::Value,
    ) -> Result<T, String> {
        crate::agent_runtime::call_daemon(self, db_type, driver_profile, method, params).await
    }

    pub async fn call_daemon_method<T: serde::de::DeserializeOwned + Send + 'static>(
        &self,
        db_type: &DatabaseType,
        driver_profile: Option<&str>,
        method: AgentMethod,
        params: serde_json::Value,
    ) -> Result<T, String> {
        crate::agent_runtime::call_daemon_method(self, db_type, driver_profile, method, params).await
    }

    pub async fn download_file(url: &str, dest: &Path) -> Result<(), String> {
        if let Some(parent) = dest.parent() {
            std::fs::create_dir_all(parent).map_err(|e| e.to_string())?;
        }
        let resp = reqwest::get(url).await.map_err(|e| format!("Download failed: {e}"))?;
        if !resp.status().is_success() {
            return Err(format!("Download failed with status: {}", resp.status()));
        }
        let bytes = resp.bytes().await.map_err(|e| format!("Download read failed: {e}"))?;
        std::fs::write(dest, &bytes).map_err(|e| format!("Failed to write file: {e}"))
    }

    pub fn current_platform() -> &'static str {
        if cfg!(target_os = "macos") && cfg!(target_arch = "aarch64") {
            "macos-aarch64"
        } else if cfg!(target_os = "macos") && cfg!(target_arch = "x86_64") {
            "macos-x64"
        } else if cfg!(target_os = "linux") && cfg!(target_arch = "aarch64") {
            "linux-aarch64"
        } else if cfg!(target_os = "linux") && cfg!(target_arch = "x86_64") {
            "linux-x64"
        } else if cfg!(target_os = "windows") && cfg!(target_arch = "aarch64") {
            "windows-aarch64"
        } else if cfg!(target_os = "windows") && cfg!(target_arch = "x86_64") {
            "windows-x64"
        } else {
            "unknown"
        }
    }
}

fn path_size_bytes(path: &Path) -> u64 {
    if let Ok(meta) = std::fs::symlink_metadata(path) {
        if meta.is_file() {
            return meta.len();
        }
        if !meta.is_dir() {
            return 0;
        }
    } else {
        return 0;
    }

    let mut total = 0u64;
    if let Ok(entries) = std::fs::read_dir(path) {
        for entry in entries.flatten() {
            total = total.saturating_add(path_size_bytes(&entry.path()));
        }
    }
    total
}

fn java_executable_name() -> &'static str {
    if cfg!(windows) {
        "java.exe"
    } else {
        "java"
    }
}

fn resolve_custom_java_path(path: &str) -> Result<PathBuf, String> {
    let raw = PathBuf::from(path);
    if is_executable_file(&raw) {
        return Ok(raw);
    }

    let flat = raw.join("bin").join(java_executable_name());
    if is_executable_file(&flat) {
        return Ok(flat);
    }

    let macos = raw.join("Contents").join("Home").join("bin").join(java_executable_name());
    if is_executable_file(&macos) {
        return Ok(macos);
    }

    Err(format!("Custom Java runtime does not exist or is not a Java executable: {}", raw.display()))
}

fn resolve_system_java_path(path_var: Option<&OsStr>) -> Option<PathBuf> {
    let path_var = path_var.map(|p| p.to_owned()).or_else(|| std::env::var_os("PATH"))?;
    std::env::split_paths(&path_var)
        .map(|dir| dir.join(java_executable_name()))
        .find(|candidate| is_executable_file(candidate))
}

fn is_executable_file(path: &Path) -> bool {
    if !path.is_file() {
        return false;
    }
    #[cfg(unix)]
    {
        use std::os::unix::fs::PermissionsExt;

        path.metadata().map(|meta| meta.permissions().mode() & 0o111 != 0).unwrap_or(false)
    }
    #[cfg(not(unix))]
    {
        true
    }
}