use std::process::{Command, Output};
use std::error::Error;
use std::fmt;
use std::collections::HashMap;
use redis::Cmd;
use serde::{Deserialize, Serialize};

use crate::env;
use crate::git::git::parse_git_url;

// Define a custom error type for GitExecutor operations
#[derive(Debug)]
pub enum GitExecutorError {
    GitCommandFailed(String),
    CommandExecutionError(std::io::Error),
    RedisError(redis::RedisError),
    JsonError(serde_json::Error),
    AuthenticationError(String),
    SshAgentNotLoaded,
    InvalidAuthConfig(String),
}

// Implement Display for GitExecutorError
impl fmt::Display for GitExecutorError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            GitExecutorError::GitCommandFailed(e) => write!(f, "Git command failed: {}", e),
            GitExecutorError::CommandExecutionError(e) => write!(f, "Command execution error: {}", e),
            GitExecutorError::RedisError(e) => write!(f, "Redis error: {}", e),
            GitExecutorError::JsonError(e) => write!(f, "JSON error: {}", e),
            GitExecutorError::AuthenticationError(e) => write!(f, "Authentication error: {}", e),
            GitExecutorError::SshAgentNotLoaded => write!(f, "SSH agent is not loaded"),
            GitExecutorError::InvalidAuthConfig(e) => write!(f, "Invalid authentication configuration: {}", e),
        }
    }
}

// Implement Error trait for GitExecutorError
impl Error for GitExecutorError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        match self {
            GitExecutorError::CommandExecutionError(e) => Some(e),
            GitExecutorError::RedisError(e) => Some(e),
            GitExecutorError::JsonError(e) => Some(e),
            _ => None,
        }
    }
}

// From implementations for error conversion
impl From<redis::RedisError> for GitExecutorError {
    fn from(err: redis::RedisError) -> Self {
        GitExecutorError::RedisError(err)
    }
}

impl From<serde_json::Error> for GitExecutorError {
    fn from(err: serde_json::Error) -> Self {
        GitExecutorError::JsonError(err)
    }
}

impl From<std::io::Error> for GitExecutorError {
    fn from(err: std::io::Error) -> Self {
        GitExecutorError::CommandExecutionError(err)
    }
}

// Status enum for GitConfig
#[derive(Debug, Serialize, Deserialize, PartialEq)]
pub enum GitConfigStatus {
    #[serde(rename = "error")]
    Error,
    #[serde(rename = "ok")]
    Ok,
}

// Auth configuration for a specific git server
#[derive(Debug, Serialize, Deserialize)]
pub struct GitServerAuth {
    pub sshagent: Option<bool>,
    pub key: Option<String>,
    pub username: Option<String>,
    pub password: Option<String>,
}

// Main configuration structure from Redis
#[derive(Debug, Serialize, Deserialize)]
pub struct GitConfig {
    pub status: GitConfigStatus,
    pub auth: HashMap<String, GitServerAuth>,
}

// GitExecutor struct
pub struct GitExecutor {
    config: Option<GitConfig>,
}

impl GitExecutor {
    // Create a new GitExecutor
    pub fn new() -> Self {
        GitExecutor { config: None }
    }

    // Initialize by loading configuration from Redis
    pub fn init(&mut self) -> Result<(), GitExecutorError> {
        // Try to load config from Redis
        match self.load_config_from_redis() {
            Ok(config) => {
                self.config = Some(config);
                Ok(())
            }
            Err(e) => {
                // If Redis error, we'll proceed without config
                // This is not a fatal error as we might use default git behavior
                eprintln!("Warning: Failed to load git config from Redis: {}", e);
                self.config = None;
                Ok(())
            }
        }
    }

    // Load configuration from Redis
    fn load_config_from_redis(&self) -> Result<GitConfig, GitExecutorError> {
        // Create Redis command to get the herocontext:git key
        let mut cmd = Cmd::new();
        cmd.arg("GET").arg("herocontext:git");

        // Execute the command
        let result: redis::RedisResult<String> = env::execute(&mut cmd);
        
        match result {
            Ok(json_str) => {
                // Parse the JSON string into GitConfig
                let config: GitConfig = serde_json::from_str(&json_str)?;
                
                // Validate the config
                if config.status == GitConfigStatus::Error {
                    return Err(GitExecutorError::InvalidAuthConfig("Config status is error".to_string()));
                }
                
                Ok(config)
            }
            Err(e) => Err(GitExecutorError::RedisError(e)),
        }
    }

    // Check if SSH agent is loaded
    fn is_ssh_agent_loaded(&self) -> bool {
        let output = Command::new("ssh-add")
            .arg("-l")
            .output();
        
        match output {
            Ok(output) => output.status.success() && !output.stdout.is_empty(),
            Err(_) => false,
        }
    }

    // Get authentication configuration for a git URL
    fn get_auth_for_url(&self, url: &str) -> Option<&GitServerAuth> {
        if let Some(config) = &self.config {
            let (server, _, _) = parse_git_url(url);
            if !server.is_empty() {
                return config.auth.get(&server);
            }
        }
        None
    }

    // Validate authentication configuration
    fn validate_auth_config(&self, auth: &GitServerAuth) -> Result<(), GitExecutorError> {
        // Rule: If sshagent is true, other fields should be empty
        if let Some(true) = auth.sshagent {
            if auth.key.is_some() || auth.username.is_some() || auth.password.is_some() {
                return Err(GitExecutorError::InvalidAuthConfig(
                    "When sshagent is true, key, username, and password must be empty".to_string()
                ));
            }
            // Check if SSH agent is actually loaded
            if !self.is_ssh_agent_loaded() {
                return Err(GitExecutorError::SshAgentNotLoaded);
            }
        }
        
        // Rule: If key is set, other fields should be empty
        if let Some(_) = &auth.key {
            if auth.sshagent.unwrap_or(false) || auth.username.is_some() || auth.password.is_some() {
                return Err(GitExecutorError::InvalidAuthConfig(
                    "When key is set, sshagent, username, and password must be empty".to_string()
                ));
            }
        }
        
        // Rule: If username is set, password should be set and other fields empty
        if let Some(_) = &auth.username {
            if auth.sshagent.unwrap_or(false) || auth.key.is_some() {
                return Err(GitExecutorError::InvalidAuthConfig(
                    "When username is set, sshagent and key must be empty".to_string()
                ));
            }
            if auth.password.is_none() {
                return Err(GitExecutorError::InvalidAuthConfig(
                    "When username is set, password must also be set".to_string()
                ));
            }
        }
        
        Ok(())
    }

    // Execute a git command with authentication
    pub fn execute(&self, args: &[&str]) -> Result<Output, GitExecutorError> {
        // Extract the git URL if this is a command that needs authentication
        let url_arg = self.extract_git_url_from_args(args);
        
        // If we have a URL and authentication config, use it
        if let Some(url) = url_arg {
            if let Some(auth) = self.get_auth_for_url(&url) {
                // Validate the authentication configuration
                self.validate_auth_config(auth)?;
                
                // Execute with the appropriate authentication method
                return self.execute_with_auth(args, auth);
            }
        }
        
        // No special authentication needed, execute normally
        self.execute_git_command(args)
    }

    // Extract git URL from command arguments
    fn extract_git_url_from_args<'a>(&self, args: &[&'a str]) -> Option<&'a str> {
        // Commands that might contain a git URL
        if args.contains(&"clone") || args.contains(&"fetch") || args.contains(&"pull") || args.contains(&"push") {
            // The URL is typically the last argument for clone, or after remote for others
            for (i, &arg) in args.iter().enumerate() {
                if arg == "clone" && i + 1 < args.len() {
                    return Some(args[i + 1]);
                }
                if (arg == "fetch" || arg == "pull" || arg == "push") && i + 1 < args.len() {
                    // For these commands, the URL might be specified as a remote name
                    // We'd need more complex logic to resolve remote names to URLs
                    // For now, we'll just return None
                    return None;
                }
            }
        }
        None
    }

    // Execute git command with authentication
    fn execute_with_auth(&self, args: &[&str], auth: &GitServerAuth) -> Result<Output, GitExecutorError> {
        // Handle different authentication methods
        if let Some(true) = auth.sshagent {
            // Use SSH agent (already validated that it's loaded)
            self.execute_git_command(args)
        } else if let Some(key) = &auth.key {
            // Use SSH key
            self.execute_with_ssh_key(args, key)
        } else if let Some(username) = &auth.username {
            // Use username/password
            if let Some(password) = &auth.password {
                self.execute_with_credentials(args, username, password)
            } else {
                // This should never happen due to validation
                Err(GitExecutorError::AuthenticationError("Password is required when username is set".to_string()))
            }
        } else {
            // No authentication method specified, use default
            self.execute_git_command(args)
        }
    }

    // Execute git command with SSH key
    fn execute_with_ssh_key(&self, args: &[&str], key: &str) -> Result<Output, GitExecutorError> {
        // Create a command with GIT_SSH_COMMAND to specify the key
        let ssh_command = format!("ssh -i {} -o IdentitiesOnly=yes", key);
        
        let mut command = Command::new("git");
        command.env("GIT_SSH_COMMAND", ssh_command);
        command.args(args);
        
        let output = command.output()?;
        
        if output.status.success() {
            Ok(output)
        } else {
            let error = String::from_utf8_lossy(&output.stderr);
            Err(GitExecutorError::GitCommandFailed(error.to_string()))
        }
    }

    // Execute git command with username/password
    fn execute_with_credentials(&self, args: &[&str], username: &str, password: &str) -> Result<Output, GitExecutorError> {
        // Helper method to execute a command and handle the result
        fn execute_command(command: &mut Command) -> Result<Output, GitExecutorError> {
            let output = command.output()?;
            
            if output.status.success() {
                Ok(output)
            } else {
                let error = String::from_utf8_lossy(&output.stderr);
                Err(GitExecutorError::GitCommandFailed(error.to_string()))
            }
        }
        // For HTTPS authentication, we need to modify the URL to include credentials
        // Create a new vector to hold our modified arguments
        let modified_args: Vec<String> = args.iter().map(|&arg| {
            if arg.starts_with("https://") {
                // Replace https:// with https://username:password@
                format!("https://{}:{}@{}", 
                    username, 
                    password, 
                    &arg[8..]) // Skip the "https://" part
            } else {
                arg.to_string()
            }
        }).collect();
        
        // Execute the command
        let mut command = Command::new("git");
        
        // Add the modified arguments to the command
        for arg in &modified_args {
            command.arg(arg.as_str());
        }

        // Execute the command and handle the result
        let output = command.output()?;
        if output.status.success() { Ok(output) } else { Err(GitExecutorError::GitCommandFailed(String::from_utf8_lossy(&output.stderr).to_string())) }
    }

    // Basic git command execution
    fn execute_git_command(&self, args: &[&str]) -> Result<Output, GitExecutorError> {
        let mut command = Command::new("git");
        command.args(args);
        
        let output = command.output()?;
        
        if output.status.success() {
            Ok(output)
        } else {
            let error = String::from_utf8_lossy(&output.stderr);
            Err(GitExecutorError::GitCommandFailed(error.to_string()))
        }
    }
}

// Implement Default for GitExecutor
impl Default for GitExecutor {
    fn default() -> Self {
        Self::new()
    }
}