use crate::lib::error::{AptOstreeError, AptOstreeResult};
use polkit::{Authority, UnixProcess};
use std::collections::HashMap;

/// Security manager for apt-ostree operations
#[allow(dead_code, clippy::new_without_default)]
pub struct SecurityManager {
    polkit_authority: Authority,
}

impl SecurityManager {
    /// Create a new security manager instance
    #[allow(clippy::new_without_default)]
    pub fn new() -> AptOstreeResult<Self> {
        let authority = Authority::get();
        
        Ok(Self {
            polkit_authority: authority,
        })
    }
}

impl SecurityManager {
    /// Check if user has required permissions for an operation
    pub async fn check_permissions(&self, _operation: &str) -> AptOstreeResult<bool> {
        // For now, return true - this will be replaced with real Polkit checks
        // TODO: Implement real Polkit authorization
        Ok(true)
    }
    
    /// Check authorization for a specific action
    pub async fn check_authorization(
        &self,
        action: &str,
        user_id: u32,
        details: HashMap<String, String>,
    ) -> AptOstreeResult<bool> {
        // Check if Polkit is available
        if !self.is_polkit_available() {
            // Fallback to root check if Polkit is not available
            return self.is_root();
        }
        
        let _subject = UnixProcess::new(
            std::process::id().try_into()
                .map_err(|_| AptOstreeError::Security("Process ID conversion failed".to_string()))?
        );
        
        // Convert details HashMap to GVariant for Polkit
        let mut details_variant = HashMap::new();
        for (key, value) in details {
            details_variant.insert(key, value);
        }
        
        // Perform Polkit authorization check using the correct API
        // Note: The polkit-rs API has changed, so we'll use a simplified approach for now
        // TODO: Update to use the latest polkit-rs API when available
        
        // For now, implement a basic authorization check that respects the policy
        // This will be enhanced when the polkit-rs API is updated
        tracing::info!("Checking Polkit authorization for action: {} (user: {})", action, user_id);
        
        // Simulate authorization check - in production this would use the real Polkit API
        // The policy file defines the actual permissions
        if self.is_root()? {
            tracing::info!("Root user - authorization granted for action: {} (user: {})", action, user_id);
            Ok(true)
        } else {
            // For non-root users, check if the action is allowed by policy
            // This is a simplified check - the real Polkit would handle this
            tracing::warn!("Non-root user - authorization check required for action: {} (user: {})", action, user_id);
            Ok(false)
        }
    }
    
    /// Authorize package installation/uninstallation
    pub async fn authorize_package_install(
        &self,
        user_id: u32,
        packages: &[String],
    ) -> AptOstreeResult<bool> {
        let mut details = HashMap::new();
        details.insert("packages".to_string(), packages.join(","));
        
        self.check_authorization(
            "org.projectatomic.aptostree1.install-uninstall-packages",
            user_id,
            details,
        ).await
    }
    
    /// Authorize system upgrade
    pub async fn authorize_system_update(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.upgrade",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Authorize deployment operations
    pub async fn authorize_deployment(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.deploy",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Authorize rebase operations
    pub async fn authorize_rebase(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.rebase",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Authorize rollback operations
    pub async fn authorize_rollback(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.rollback",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Authorize boot configuration changes
    pub async fn authorize_boot_config(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.bootconfig",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Authorize package overrides
    pub async fn authorize_package_override(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.override",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Authorize daemon reload
    pub async fn authorize_daemon_reload(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.reload-daemon",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Authorize cleanup operations
    pub async fn authorize_cleanup(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.cleanup",
            user_id,
            HashMap::new(),
        ).await
    }

    /// Authorize initramfs operations
    pub async fn authorize_initramfs(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.initramfs",
            user_id,
            HashMap::new(),
        ).await
    }

    /// Authorize kernel argument operations
    pub async fn authorize_kargs(
        &self,
        user_id: u32,
    ) -> AptOstreeResult<bool> {
        self.check_authorization(
            "org.projectatomic.aptostree1.kargs",
            user_id,
            HashMap::new(),
        ).await
    }
    
    /// Check if Polkit is available on the system
    pub fn is_polkit_available(&self) -> bool {
        // Check if Polkit service is running
        std::path::Path::new("/usr/lib/polkit-1/polkitd").exists() ||
        std::path::Path::new("/usr/libexec/polkit-1/polkitd").exists()
    }
    
    /// Get current user ID
    pub fn get_current_user_id(&self) -> AptOstreeResult<u32> {
        Ok(users::get_current_uid())
    }
    
    /// Check if current user is root
    pub fn is_root(&self) -> AptOstreeResult<bool> {
        Ok(self.get_current_user_id()? == 0)
    }
    
    /// Check if operation requires authorization
    pub fn requires_authorization(&self, operation: &str) -> bool {
        // Define which operations require Polkit authorization
        matches!(
            operation,
            "install" | "uninstall" | "upgrade" | "deploy" | "rebase" | 
            "rollback" | "kargs" | "initramfs" | "override" | "reset" |
            "cleanup" | "reload"
        )
    }

    // Process Isolation Methods
    
    /// Get current user information
    pub fn get_current_user_info(&self) -> AptOstreeResult<(u32, String)> {
        let uid = self.get_current_user_id()?;
        let username = users::get_user_by_uid(uid)
            .map(|user| user.name().to_string_lossy().to_string())
            .unwrap_or_else(|| "unknown".to_string());
        Ok((uid, username))
    }
    
    /// Get current group information
    pub fn get_current_group_info(&self) -> AptOstreeResult<(u32, String)> {
        let gid = users::get_current_gid();
        let groupname = users::get_group_by_gid(gid)
            .map(|group| group.name().to_string_lossy().to_string())
            .unwrap_or_else(|| "unknown".to_string());
        Ok((gid, groupname))
    }
    
    /// Check file system permissions for a path
    pub fn check_file_permissions(&self, path: &str, required_permissions: u32) -> AptOstreeResult<bool> {
        use std::fs::metadata;
        use std::os::unix::fs::{PermissionsExt, MetadataExt};
        
        match metadata(path) {
            Ok(metadata) => {
                let permissions = metadata.permissions().mode();
                let user_permissions = (permissions >> 6) & 0o7;
                let group_permissions = (permissions >> 3) & 0o7;
                let other_permissions = permissions & 0o7;
                
                let current_uid = self.get_current_user_id()?;
                let current_gid = users::get_current_gid();
                let owner_uid = metadata.uid();
                let owner_gid = metadata.gid();
                
                let has_permission = if current_uid == owner_uid {
                    (user_permissions & required_permissions) == required_permissions
                } else if current_gid == owner_gid {
                    (group_permissions & required_permissions) == required_permissions
                } else {
                    (other_permissions & required_permissions) == required_permissions
                };
                
                Ok(has_permission)
            }
            Err(_) => Ok(false)
        }
    }
    
    /// Set resource limits for the current process
    pub fn set_resource_limits(&self) -> AptOstreeResult<()> {
        use libc::{setrlimit, RLIMIT_NOFILE, RLIMIT_NPROC, RLIMIT_AS};
        
        // Set file descriptor limit
        let mut rlimit = libc::rlimit {
            rlim_cur: 65536,
            rlim_max: 65536,
        };
        
        unsafe {
            if setrlimit(RLIMIT_NOFILE, &rlimit) != 0 {
                tracing::warn!("Failed to set file descriptor limit");
            }
        }
        
        // Set process limit
        rlimit.rlim_cur = 1024;
        rlimit.rlim_max = 1024;
        
        unsafe {
            if setrlimit(RLIMIT_NPROC, &rlimit) != 0 {
                tracing::warn!("Failed to set process limit");
            }
        }
        
        // Set memory limit (1GB)
        rlimit.rlim_cur = 1024 * 1024 * 1024;
        rlimit.rlim_max = 1024 * 1024 * 1024;
        
        unsafe {
            if setrlimit(RLIMIT_AS, &rlimit) != 0 {
                tracing::warn!("Failed to set memory limit");
            }
        }
        
        Ok(())
    }
    
    /// Drop privileges to a non-root user if running as root
    pub fn drop_privileges(&self, target_user: &str) -> AptOstreeResult<()> {
        if !self.is_root()? {
            return Ok(()); // Already running as non-root
        }
        
        let target_user_info = users::get_user_by_name(target_user)
            .ok_or_else(|| AptOstreeError::Security(format!("User {} not found", target_user)))?;
        
        let target_uid = target_user_info.uid();
        let target_gid = target_user_info.primary_group_id();
        
        unsafe {
            if libc::setgid(target_gid) != 0 {
                return Err(AptOstreeError::Security("Failed to set group ID".to_string()));
            }
            
            if libc::setuid(target_uid) != 0 {
                return Err(AptOstreeError::Security("Failed to set user ID".to_string()));
            }
        }
        
        tracing::info!("Dropped privileges to user: {} (UID: {}, GID: {})", target_user, target_uid, target_gid);
        Ok(())
    }
    
    /// Create a secure working directory with proper permissions
    pub fn create_secure_working_dir(&self, path: &str) -> AptOstreeResult<()> {
        use std::fs::{create_dir_all, set_permissions};
        use std::os::unix::fs::PermissionsExt;
        
        // Create directory with secure permissions (700)
        create_dir_all(path)?;
        
        let permissions = std::fs::Permissions::from_mode(0o700);
        set_permissions(path, permissions)?;
        
        tracing::info!("Created secure working directory: {} with permissions 700", path);
        Ok(())
    }
}
