use crate::lib::error::{AptOstreeError, AptOstreeResult};
use std::process::Command;
use std::path::Path;
use serde::{Deserialize, Serialize};

/// Basic APT functionality
#[allow(dead_code, clippy::new_without_default)]
pub struct AptManager {
    cache_dir: String,
    apt_config_path: String,
}

impl AptManager {
    /// Create a new APT manager instance
    #[allow(clippy::new_without_default)]
    pub fn new() -> Self {
        Self {
            cache_dir: "/var/cache/apt".to_string(),
            apt_config_path: "/etc/apt".to_string(),
        }
    }
}

impl AptManager {
    /// Check APT database health
    pub fn check_database_health(&self) -> AptOstreeResult<bool> {
        // Check if APT cache is accessible
        if !Path::new(&self.cache_dir).exists() {
            return Err(AptOstreeError::System("APT cache directory not found".to_string()));
        }
        
        // Check if apt-get is available
        if Command::new("apt-get").arg("--version").output().is_err() {
            return Err(AptOstreeError::System("apt-get not available on this system".to_string()));
        }
        
        // Check if apt-cache is available
        if Command::new("apt-cache").arg("--version").output().is_err() {
            return Err(AptOstreeError::System("apt-cache not available on this system".to_string()));
        }
        
        Ok(true)
    }

    /// Install a package with real APT functionality
    pub fn install_package(&self, package: &str) -> AptOstreeResult<()> {
        // First check if package exists
        let package_info = self.get_package_info(package)?;
        if package_info.is_none() {
            return Err(AptOstreeError::InvalidArgument(
                format!("Package '{}' not found in APT repositories", package)
            ));
        }
        
        // Check dependencies
        let dependencies = self.resolve_dependencies(package)?;
        println!("Installing package: {} with {} dependencies", package, dependencies.len());
        
        // Use apt-get to install the package
        let output = Command::new("apt-get")
            .arg("install")
            .arg("--yes")
            .arg("--no-install-recommends")
            .arg(package)
            .output()
            .map_err(|e| AptOstreeError::System(format!("Failed to install package: {}", e)))?;
        
        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            return Err(AptOstreeError::System(format!("Package installation failed: {}", stderr)));
        }
        
        println!("Successfully installed package: {}", package);
        Ok(())
    }

    /// Remove a package with real APT functionality
    pub fn remove_package(&self, package: &str) -> AptOstreeResult<()> {
        // Check if package is installed
        if !self.is_package_installed(package)? {
            return Err(AptOstreeError::InvalidArgument(
                format!("Package '{}' is not installed", package)
            ));
        }
        
        // Use apt-get to remove the package
        let output = Command::new("apt-get")
            .arg("remove")
            .arg("--yes")
            .arg(package)
            .output()
            .map_err(|e| AptOstreeError::System(format!("Failed to remove package: {}", e)))?;
        
        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            return Err(AptOstreeError::System(format!("Package removal failed: {}", stderr)));
        }
        
        println!("Successfully removed package: {}", package);
        Ok(())
    }

    /// Update package cache with real APT functionality
    pub fn update_cache(&self) -> AptOstreeResult<()> {
        println!("Updating APT package cache...");
        
        let output = Command::new("apt-get")
            .arg("update")
            .output()
            .map_err(|e| AptOstreeError::System(format!("Failed to update cache: {}", e)))?;
        
        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            return Err(AptOstreeError::System(format!("Cache update failed: {}", stderr)));
        }
        
        println!("APT package cache updated successfully");
        Ok(())
    }

    /// Check if authorization is required for an action
    pub fn requires_authorization(&self, action: &str) -> bool {
        // Package installation and removal require root privileges
        matches!(action, "install" | "remove" | "upgrade" | "dist-upgrade")
    }

    /// Check if user is authorized for an action
    pub fn check_authorization(&self, action: &str) -> AptOstreeResult<bool> {
        if !self.requires_authorization(action) {
            return Ok(true);
        }
        
        // Check if running as root
        if unsafe { libc::geteuid() } == 0 {
            Ok(true)
        } else {
            // TODO: Implement Polkit authorization check
            Ok(false)
        }
    }

    /// Search packages with real APT functionality
    pub fn search_packages(&self, query: &str) -> AptOstreeResult<Vec<PackageInfo>> {
        println!("Searching for packages matching: {}", query);
        
        let output = Command::new("apt-cache")
            .arg("search")
            .arg(query)
            .output()
            .map_err(|e| AptOstreeError::System(format!("Failed to search packages: {}", e)))?;
        
        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            return Err(AptOstreeError::System(format!("Package search failed: {}", stderr)));
        }
        
        let search_output = String::from_utf8_lossy(&output.stdout);
        let mut packages = Vec::new();
        
        for line in search_output.lines() {
            if let Some(package) = self.parse_search_line(line) {
                packages.push(package);
            }
        }
        
        println!("Found {} packages matching '{}'", packages.len(), query);
        Ok(packages)
    }

    /// Search packages with exact match
    pub fn search_packages_exact(&self, query: &str) -> AptOstreeResult<Vec<PackageInfo>> {
        // Use apt-cache policy for exact package information
        let output = Command::new("apt-cache")
            .arg("policy")
            .arg(query)
            .output()
            .map_err(|e| AptOstreeError::System(format!("Failed to get package policy: {}", e)))?;
        
        if !output.status.success() {
            return Ok(Vec::new()); // Package not found
        }
        
        let policy_output = String::from_utf8_lossy(&output.stdout);
        if let Some(package) = self.parse_policy_output(query, &policy_output) {
            Ok(vec![package])
        } else {
            Ok(Vec::new())
        }
    }

    /// Search packages with regex
    pub fn search_packages_regex(&self, query: &str) -> AptOstreeResult<Vec<PackageInfo>> {
        // For regex search, we'll use apt-cache search and then filter with regex
        let all_packages = self.search_packages("")?;
        
        // Simple regex-like matching (basic wildcard support)
        let pattern = query.replace("*", ".*");
        let regex = regex::Regex::new(&pattern)
            .map_err(|e| AptOstreeError::System(format!("Invalid regex pattern: {}", e)))?;
        
        let filtered_packages: Vec<PackageInfo> = all_packages
            .into_iter()
            .filter(|pkg| regex.is_match(&pkg.name))
            .collect();
        
        Ok(filtered_packages)
    }

    /// Check if a package is installed
    pub fn is_package_installed(&self, package: &str) -> AptOstreeResult<bool> {
        let output = Command::new("dpkg")
            .arg("-s")
            .arg(package)
            .output();
        
        match output {
            Ok(output) => Ok(output.status.success()),
            Err(_) => Ok(false),
        }
    }
    
    /// Get detailed package information
    pub fn get_package_info(&self, package: &str) -> AptOstreeResult<Option<PackageInfo>> {
        let output = Command::new("apt-cache")
            .arg("show")
            .arg(package)
            .output()
            .map_err(|e| AptOstreeError::System(format!("Failed to get package info: {}", e)))?;
        
        if !output.status.success() {
            return Ok(None); // Package not found
        }
        
        let show_output = String::from_utf8_lossy(&output.stdout);
        Ok(self.parse_show_output(package, &show_output))
    }
    
    /// Resolve package dependencies
    pub fn resolve_dependencies(&self, package: &str) -> AptOstreeResult<Vec<String>> {
        let output = Command::new("apt-cache")
            .arg("depends")
            .arg(package)
            .output()
            .map_err(|e| AptOstreeError::System(format!("Failed to get dependencies: {}", e)))?;
        
        if !output.status.success() {
            return Ok(Vec::new());
        }
        
        let depends_output = String::from_utf8_lossy(&output.stdout);
        let mut dependencies = Vec::new();
        
        for line in depends_output.lines() {
            if line.trim().starts_with("Depends:") {
                let deps = line.split("Depends:").nth(1).unwrap_or("").trim();
                if !deps.is_empty() {
                    dependencies.extend(deps.split(',').map(|s| s.trim().to_string()));
                }
            }
        }
        
        Ok(dependencies)
    }
    
    /// Get cache status for daemon
    pub fn get_cache_status(&self) -> AptOstreeResult<String> {
        if !Path::new(&self.cache_dir).exists() {
            return Ok("not-available".to_string());
        }
        
        // Check if cache is up to date
        let output = Command::new("apt-get")
            .arg("check")
            .output();
        
        match output {
            Ok(output) => {
                if output.status.success() {
                    Ok("healthy".to_string())
                } else {
                    Ok("needs-update".to_string())
                }
            }
            Err(_) => Ok("error".to_string()),
        }
    }
    
    /// Parse search output line
    fn parse_search_line(&self, line: &str) -> Option<PackageInfo> {
        // Format: "package_name - package_description"
        let parts: Vec<&str> = line.splitn(2, " - ").collect();
        if parts.len() != 2 {
            return None;
        }
        
        let name = parts[0].trim();
        let description = parts[1].trim();
        
        Some(PackageInfo {
            name: name.to_string(),
            version: "unknown".to_string(),
            description: description.to_string(),
            installed: false, // Will be checked separately
            section: "unknown".to_string(),
            priority: "unknown".to_string(),
            depends: Vec::new(),
        })
    }
    
    /// Parse policy output
    fn parse_policy_output(&self, package_name: &str, policy_output: &str) -> Option<PackageInfo> {
        let mut package = PackageInfo {
            name: package_name.to_string(),
            version: "unknown".to_string(),
            description: "unknown".to_string(),
            installed: false,
            section: "unknown".to_string(),
            priority: "unknown".to_string(),
            depends: Vec::new(),
        };
        
        for line in policy_output.lines() {
            if line.contains("Installed:") {
                let version = line.split("Installed:").nth(1)?.trim();
                if version != "(none)" {
                    package.version = version.to_string();
                    package.installed = true;
                }
            }
        }
        
        Some(package)
    }
    
    /// Parse show output
    fn parse_show_output(&self, package_name: &str, show_output: &str) -> Option<PackageInfo> {
        let mut package = PackageInfo {
            name: package_name.to_string(),
            version: "unknown".to_string(),
            description: "unknown".to_string(),
            installed: false,
            section: "unknown".to_string(),
            priority: "unknown".to_string(),
            depends: Vec::new(),
        };
        
        for line in show_output.lines() {
            if line.starts_with("Version:") {
                package.version = line.split("Version:").nth(1)?.trim().to_string();
            } else if line.starts_with("Description:") {
                package.description = line.split("Description:").nth(1)?.trim().to_string();
            } else if line.starts_with("Section:") {
                package.section = line.split("Section:").nth(1)?.trim().to_string();
            } else if line.starts_with("Priority:") {
                package.priority = line.split("Priority:").nth(1)?.trim().to_string();
            } else if line.starts_with("Depends:") {
                let deps = line.split("Depends:").nth(1)?.trim();
                if !deps.is_empty() {
                    package.depends = deps.split(',').map(|s| s.trim().to_string()).collect();
                }
            }
        }
        
        // Check if installed
        package.installed = self.is_package_installed(package_name).unwrap_or(false);
        
        Some(package)
    }
}

/// Package information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PackageInfo {
    pub name: String,
    pub version: String,
    pub description: String,
    pub installed: bool,
    pub section: String,
    pub priority: String,
    pub depends: Vec<String>,
}

impl PackageInfo {
    pub fn new(name: &str) -> Self {
        Self {
            name: name.to_string(),
            version: "0.0.0".to_string(),
            description: "No description available".to_string(),
            installed: false,
            section: "unknown".to_string(),
            priority: "unknown".to_string(),
            depends: Vec::new(),
        }
    }
}
