ruscrypt 0.3.2

//! # Command Dispatcher Module
//!
//! This module handles the routing and execution of CLI commands. It takes parsed
//! command-line arguments and dispatches them to the appropriate cryptographic
//! functions while providing user interaction and formatted output.
//!
//! ## Architecture
//!
//! The dispatcher follows a pattern where:
//! 1. Commands are parsed and displayed to the user
//! 2. Interactive prompts gather necessary parameters
//! 3. Appropriate cryptographic functions are called
//! 4. Results are formatted and displayed
//!
//! ## Error Handling
//!
//! All functions return `Result<()>` to enable proper error propagation
//! and user-friendly error messages.

use anyhow::Result;
use colored::*;

use crate::asym::{dh, rsa};
use crate::block::{aes, des};
use crate::classical::{caesar, playfair, rail_fence, vigenere};
use crate::cli::{
    Commands, EncryptionAlgorithm, ExchangeProtocol, HashAlgorithm, KeygenAlgorithm,
    SigningAlgorithm,
};
use crate::hash::{md5, sha1, sha256};
use crate::stream::rc4;
use crate::{cli, interactive};

/// Dispatch and execute the appropriate command based on parsed CLI arguments
pub fn dispatch_command(args: cli::Args) -> Result<()> {
    match args.command {
        Commands::Encrypt { algorithm } => {
            let algo_name = cli::get_algorithm_name(&algorithm);
            println!(
                "{} {}",
                "🔒 Encrypting with".green(),
                algo_name.yellow().bold()
            );
            handle_encryption(algorithm)?;
        }
        Commands::Decrypt { algorithm } => {
            let algo_name = cli::get_algorithm_name(&algorithm);
            println!(
                "{} {}",
                "🔓 Decrypting with".blue(),
                algo_name.yellow().bold()
            );
            handle_decryption(algorithm)?;
        }
        Commands::Hash { algorithm } => {
            let algo_name = cli::get_hash_algorithm_name(&algorithm);
            println!(
                "{} {}",
                "🔢 Hashing with".magenta(),
                algo_name.yellow().bold()
            );
            handle_hashing(algorithm)?;
        }
        Commands::Exchange { protocol } => {
            let protocol_name = cli::get_keyexchange_protocol_name(&protocol);
            println!(
                "{} {}",
                "🔑 Key Exchange with".purple(),
                protocol_name.yellow().bold()
            );
            handle_key_exchange(protocol)?;
        }
        Commands::Keygen { algorithm } => {
            let algo_name = cli::get_keygen_algorithm_name(&algorithm);
            println!(
                "{} {}",
                "🔑 Generating key for".cyan(),
                algo_name.yellow().bold()
            );
            handle_keygen(algorithm)?;
        }
        Commands::Sign { algorithm } => {
            let algo_name = cli::get_signing_algorithm_name(&algorithm);
            println!("✍️ Signing with {algo_name} algorithm...");

            if algorithm.rsa {
                handle_sign(algorithm)?;
            }
        }
        Commands::Verify { algorithm } => {
            let algo_name = cli::get_signing_algorithm_name(&algorithm);
            println!("🔍 Verifying {algo_name} signature...");

            if algorithm.rsa {
                handle_verify(algorithm)?;
            }
        }
    }

    Ok(())
}

/// Handle encryption operations for all supported algorithms
///
/// This function manages the encryption workflow by:
/// 1. Prompting for input text
/// 2. Gathering algorithm-specific parameters (keys, shifts, etc.)
/// 3. Calling the appropriate encryption function
/// 4. Displaying the encrypted result
///
/// # Arguments
///
/// * `algorithm` - The encryption algorithm configuration specifying which algorithm to use
///
/// # Returns
///
/// Returns `Ok(())` on successful encryption, or an error if the operation fails.
///
/// # Interactive Prompts
///
/// Depending on the algorithm, this function may prompt for:
/// - Shift values (Caesar cipher)
/// - Keywords (Vigenère, Playfair)
/// - Keys and passwords (RC4, AES, DES, RSA)
/// - Encoding preferences (base64, hex)
/// - Algorithm parameters (key sizes, modes)
///
/// # Errors
///
/// Can return errors from:
/// - Invalid user input
/// - Cryptographic operation failures
/// - I/O errors during prompts
/// - Algorithm-specific validation failures
fn handle_encryption(algorithm: EncryptionAlgorithm) -> Result<()> {
    let input = interactive::prompt_for_input("Enter text to encrypt")?;

    let result = match true {
        _ if algorithm.caesar => {
            let shift = interactive::prompt_for_number("Enter shift value (1-25)", 1, 25)?;
            let encrypted = caesar::encrypt(&input, shift as u8)?;
            format!("Encrypted text: {encrypted}")
        }
        _ if algorithm.vigenere => {
            let keyword = interactive::prompt_for_input("Enter keyword")?;
            let encrypted = vigenere::encrypt(&input, &keyword)?;
            format!("Encrypted text: {encrypted}")
        }
        _ if algorithm.playfair => {
            let keyword = interactive::prompt_for_input("Enter keyword for matrix")?;
            let encrypted = playfair::encrypt(&input, &keyword)?;
            format!("Encrypted text: {encrypted}")
        }
        _ if algorithm.railfence => {
            let rails = interactive::prompt_for_number("Enter number of rails (2-10)", 2, 10)?;
            let encrypted = rail_fence::encrypt(&input, rails as usize)?;
            format!("Encrypted text: {encrypted}")
        }
        _ if algorithm.rc4 => {
            let key = interactive::prompt_for_password("Enter encryption key")?;
            let encoding =
                interactive::prompt_for_choices("Select output encoding", &["base64", "hex"])?;
            let encrypted = rc4::encrypt(&input, &key, &encoding)?;
            format!("Encrypted text ({encoding}): {encrypted}")
        }
        _ if algorithm.aes => {
            let password = interactive::prompt_for_password("Enter password")?;
            let key_size =
                interactive::prompt_for_choices("Select AES key size", &["128", "192", "256"])?;
            let mode = interactive::prompt_for_choices("Select encryption mode", &["ECB", "CBC"])?;
            let encoding =
                interactive::prompt_for_choices("Select output encoding", &["base64", "hex"])?;
            let encrypted = aes::encrypt(&input, &password, &key_size, &mode, &encoding)?;
            format!("Encrypted text (AES-{key_size}, {mode}, {encoding}): {encrypted}")
        }
        _ if algorithm.des => {
            let key = interactive::prompt_for_input("Enter key (exactly 8 characters)")?;
            if key.len() != 8 {
                return Err(anyhow::anyhow!("DES key must be exactly 8 characters long"));
            }
            let mode = interactive::prompt_for_choices("Select encryption mode", &["ECB", "CBC"])?;
            let encoding =
                interactive::prompt_for_choices("Select output encoding", &["base64", "hex"])?;
            let encrypted = des::encrypt(&input, &key, &mode, &encoding)?;
            format!("Encrypted text (DES, {mode}, {encoding}): {encrypted}")
        }
        _ if algorithm.rsa => {
            let key_size =
                interactive::prompt_for_choices("Select RSA key size", &["512", "1024", "2048"])?;
            let encoding =
                interactive::prompt_for_choices("Select output encoding", &["base64", "hex"])?;
            let privkey_format = interactive::prompt_for_choices(
                "Select private key output format",
                &["n:d", "PEM"],
            )?;
            let (encrypted, private_key) =
                rsa::encrypt(&input, &key_size, &encoding, &privkey_format)?;

            println!("\n🔐 RSA Encryption Complete!");
            println!("📤 Encrypted data: {encrypted}");
            println!("🔑 Private key (SAVE THIS!): {private_key}");
            println!("⚠️  Keep your private key secure - you'll need it for decryption!");

            format!("RSA-{key_size} encryption successful. Encrypted data and private key provided above.")
        }
        _ => return Err(anyhow::anyhow!("Unknown algorithm")),
    };

    println!("\n{} {}", "Result:".cyan().bold(), result.white());
    Ok(())
}

/// Handle decryption operations for all supported algorithms
///
/// This function manages the decryption workflow by:
/// 1. Prompting for encrypted text
/// 2. Gathering algorithm-specific parameters (keys, shifts, etc.)
/// 3. Calling the appropriate decryption function
/// 4. Displaying the decrypted result
///
/// # Arguments
///
/// * `algorithm` - The encryption algorithm configuration specifying which algorithm to use
///
/// # Returns
///
/// Returns `Ok(())` on successful decryption, or an error if the operation fails.
///
/// # Interactive Prompts
///
/// Similar to encryption, but may include additional prompts for:
/// - Private keys (RSA)
/// - Initialization vectors (block ciphers)
/// - Input encoding formats (base64, hex)
///
/// # Errors
///
/// Can return errors from:
/// - Invalid encrypted text format
/// - Incorrect keys or parameters
/// - Cryptographic operation failures
/// - Encoding/decoding errors
fn handle_decryption(algorithm: EncryptionAlgorithm) -> Result<()> {
    let input = interactive::prompt_for_input("Enter text to decrypt")?;

    let result = match true {
        _ if algorithm.caesar => {
            let shift = interactive::prompt_for_number("Enter shift value (1-25)", 1, 25)?;
            let decrypted = caesar::decrypt(&input, shift as u8)?;
            format!("Decrypted text: {decrypted}")
        }
        _ if algorithm.vigenere => {
            let keyword = interactive::prompt_for_input("Enter keyword")?;
            let decrypted = vigenere::decrypt(&input, &keyword)?;
            format!("Decrypted text: {decrypted}")
        }
        _ if algorithm.playfair => {
            let keyword = interactive::prompt_for_input("Enter keyword for matrix")?;
            let decrypted = playfair::decrypt(&input, &keyword)?;
            format!("Decrypted text: {decrypted}")
        }
        _ if algorithm.railfence => {
            let rails = interactive::prompt_for_number("Enter number of rails (2-10)", 2, 10)?;
            let decrypted = rail_fence::decrypt(&input, rails as usize)?;
            format!("Decrypted text: {decrypted}")
        }
        _ if algorithm.rc4 => {
            let key = interactive::prompt_for_password("Enter decryption key")?;
            let encoding =
                interactive::prompt_for_choices("Select input encoding", &["base64", "hex"])?;
            let decrypted = rc4::decrypt(&input, &key, &encoding)?;
            format!("Decrypted text: {decrypted}")
        }
        _ if algorithm.aes => {
            let password = interactive::prompt_for_password("Enter password")?;
            let key_size =
                interactive::prompt_for_choices("Select AES key size", &["128", "192", "256"])?;
            let mode = interactive::prompt_for_choices("Select encryption mode", &["ECB", "CBC"])?;
            let encoding =
                interactive::prompt_for_choices("Select input encoding", &["base64", "hex"])?;
            let decrypted = aes::decrypt(&input, &password, &key_size, &mode, &encoding)?;
            format!("Decrypted text: {decrypted}")
        }
        _ if algorithm.des => {
            let key = interactive::prompt_for_input("Enter key (exactly 8 characters)")?;
            if key.len() != 8 {
                return Err(anyhow::anyhow!("DES key must be exactly 8 characters long"));
            }
            let mode = interactive::prompt_for_choices("Select encryption mode", &["ECB", "CBC"])?;
            let encoding =
                interactive::prompt_for_choices("Select input encoding", &["base64", "hex"])?;
            let decrypted = des::decrypt(&input, &key, &mode, &encoding)?;
            format!("Decrypted text: {decrypted}")
        }
        _ if algorithm.rsa => {
            let private_key = interactive::prompt_for_multiline_input(
                "Enter private key (format: n:d or PEM block, end with empty line)",
            )?;
            let encoding =
                interactive::prompt_for_choices("Select input encoding", &["base64", "hex"])?;
            let decrypted = rsa::decrypt(&input, &private_key, &encoding)?;
            format!("Decrypted text: {decrypted}")
        }
        _ => return Err(anyhow::anyhow!("Unknown algorithm")),
    };

    println!("\n{} {}", "Result:".cyan().bold(), result.white());
    Ok(())
}

/// Handle hashing operations for all supported hash functions
///
/// This function manages the hashing workflow by:
/// 1. Prompting for input text
/// 2. Computing the hash using the selected algorithm
/// 3. Displaying the hash value in hexadecimal format
///
/// # Arguments
///
/// * `algorithm` - The hash algorithm configuration specifying which function to use
///
/// # Returns
///
/// Returns `Ok(())` on successful hashing, or an error if the operation fails.
///
/// # Output Format
///
/// Hash values are displayed as hexadecimal strings:
/// - MD5: 32 characters
/// - SHA-1: 40 characters  
/// - SHA-256: 64 characters
///
/// # Errors
///
/// Can return errors from:
/// - Hash computation failures
/// - I/O errors during prompts
/// - Memory allocation issues for large inputs
fn handle_hashing(algorithm: HashAlgorithm) -> Result<()> {
    let input = interactive::prompt_for_input("Enter text to hash")?;

    let result = match true {
        _ if algorithm.md5 => {
            let hash_value = md5::hash(&input)?;
            format!("MD5 hash: {hash_value}")
        }
        _ if algorithm.sha1 => {
            let hash_value = sha1::hash(&input)?;
            format!("SHA-1 hash: {hash_value}")
        }
        _ if algorithm.sha256 => {
            let hash_value = sha256::hash(&input)?;
            format!("SHA-256 hash: {hash_value}")
        }
        _ => return Err(anyhow::anyhow!("Unknown algorithm")),
    };

    println!("\n{} {}", "Result:".blue().bold(), result.white());
    Ok(())
}

/// Handle key exchange protocol operations
///
/// This function manages key exchange workflows by:
/// 1. Presenting protocol-specific options
/// 2. Managing interactive or manual exchange modes
/// 3. Facilitating secure key establishment
/// 4. Displaying shared secrets and educational information
///
/// # Arguments
///
/// * `protocol` - The key exchange protocol configuration
///
/// # Returns
///
/// Returns `Ok(())` on successful key exchange, or an error if the operation fails.
///
/// # Supported Modes
///
/// For Diffie-Hellman:
/// - **Interactive Simulation**: Demonstrates Alice & Bob exchange
/// - **Manual Exchange - Start Session**: Real-world usage with other parties
/// - **Manual Exchange - Complete with Other's Key**: Complete the exchange with a given key
/// - **Mathematical Demo**: Shows the underlying mathematics
///
/// # Security Considerations
///
/// The function provides educational warnings about:
/// - Parameter selection importance
/// - Man-in-the-middle attack risks
/// - Proper implementation requirements
///
/// # Errors
///
/// Can return errors from:
/// - Invalid protocol selection
/// - Mathematical computation failures
/// - User input validation errors
/// - Network communication issues (future implementations)
fn handle_key_exchange(protocol: ExchangeProtocol) -> Result<()> {
    let result = match true {
        _ if protocol.dh => {
            let choice = interactive::prompt_for_choices(
                "Select Diffie-Hellman operation",
                &[
                    "Interactive Simulation (Alice & Bob)",
                    "Manual Exchange - Start Session",
                    "Manual Exchange - Complete with Other's Key",
                    "Mathematical Concept Demo",
                ],
            )?;

            match choice.as_str() {
                "Interactive Simulation (Alice & Bob)" => dh::key_exchange("interactive")?,
                "Manual Exchange - Start Session" => {
                    println!("\n🚀 Starting manual key exchange session...");
                    dh::key_exchange("manual")?
                }
                "Manual Exchange - Complete with Other's Key" => {
                    let other_public_key =
                        interactive::prompt_for_input("Enter other party's public key")?
                            .parse::<u64>()
                            .map_err(|_| {
                                anyhow::anyhow!("Invalid public key format. Must be a number.")
                            })?;

                    let my_private_key = interactive::prompt_for_input("Enter your private key")?
                        .parse::<u64>()
                        .map_err(|_| {
                            anyhow::anyhow!("Invalid private key format. Must be a number.")
                        })?;

                    dh::complete_manual_key_exchange(other_public_key, my_private_key)?
                }
                "Mathematical Concept Demo" => dh::key_exchange("demo")?,
                _ => return Err(anyhow::anyhow!("Invalid choice")),
            }
        }
        _ if protocol.ecdh => "ECDH key exchange is not yet implemented. Coming soon!".to_string(),
        _ => return Err(anyhow::anyhow!("Unknown key exchange protocol")),
    };

    println!("\n{} {}", "Result:".cyan().bold(), result.white());
    Ok(())
}

/// Handle key generation operations for supported algorithms
///
/// This function manages the key generation workflow by:
/// 1. Prompting for key size and output format
/// 2. Calling the appropriate key generation function
/// 3. Displaying the generated keys in the selected format
///
/// # Arguments
///
/// * `algorithm` - The key generation algorithm configuration
///
/// # Returns
///
/// Returns `Ok(())` on successful key generation, or an error if the operation fails.
///
/// # Interactive Prompts
///
/// - Key size (e.g., 512, 1024, 2048 for RSA)
/// - Output format (e.g., "n:e" or "PEM")
///
/// # Errors
///
/// Can return errors from:
/// - Invalid user input
/// - Key generation failures
/// - I/O errors during prompts
fn handle_keygen(algorithm: KeygenAlgorithm) -> Result<()> {
    if algorithm.rsa {
        let key_size: String =
            interactive::prompt_for_choices("Select RSA key size", &["512", "1024", "2048"])?;
        let format = interactive::prompt_for_key_output_format()?;
        let key_size_num = key_size
            .parse::<u32>()
            .map_err(|_| anyhow::anyhow!("Invalid key size"))?;
        let (public_key, private_key) = rsa::keygen_and_export(key_size_num, &format)?;
        println!("\n{} {}", "Public Key:".green().bold(), public_key.white());
        println!("{} {}", "Private Key:".yellow().bold(), private_key.white());
        println!("⚠️  Keep your private key secure!");
        Ok(())
    } else {
        Err(anyhow::anyhow!("Unknown key generation algorithm"))
    }
}

/// Handle RSA signing operations
pub fn handle_sign(algorithm: SigningAlgorithm) -> Result<()> {
    if algorithm.rsa {
        println!("📝 RSA Digital Signature");
        println!("========================");

        let data = interactive::prompt_for_input("Enter message to sign")?;
        let private_key =
            interactive::prompt_for_multiline_input("Enter private key (n:d format or PEM)")?;
        let encoding = interactive::prompt_for_encoding("Select output encoding")?;

        match rsa::sign(&data, &private_key, &encoding) {
            Ok(signature) => {
                println!("\n✅ Digital signature created successfully!");
                println!("📝 Original message: {data}");
                println!(
                    "🔏 Digital signature ({}): {}",
                    encoding.to_uppercase(),
                    signature
                );
                println!("\n💡 Save this signature to verify the message authenticity later.");
            }
            Err(e) => {
                eprintln!("❌ Signing failed: {e}");
                return Err(e);
            }
        }

        Ok(())
    } else {
        Err(anyhow::anyhow!("Unknown signing algorithm"))
    }
}

/// Handle RSA signature verification operations
pub fn handle_verify(algorithm: SigningAlgorithm) -> Result<()> {
    if algorithm.rsa {
        println!("🔍 RSA Signature Verification");
        println!("=============================");

        let data = interactive::prompt_for_input("Enter original message")?;
        let signature = interactive::prompt_for_input("Enter signature to verify")?;
        let public_key =
            interactive::prompt_for_multiline_input("Enter public key (n:e format or PEM)")?;
        let encoding = interactive::prompt_for_encoding("Select signature encoding")?;

        match rsa::verify(&data, &signature, &public_key, &encoding) {
            Ok(is_valid) => {
                println!("\n🔍 Signature verification result:");
                println!("📝 Original message: {data}");
                println!("🔏 Signature: {}...", &signature[..signature.len().min(20)]);

                if is_valid {
                    println!("✅ VALID: The signature is authentic!");
                    println!("🔒 The message integrity is verified and the signature is genuine.");
                } else {
                    println!("❌ INVALID: The signature verification failed!");
                    println!(
                        "⚠️  The message may have been tampered with or the signature is forged."
                    );
                }
            }
            Err(e) => {
                eprintln!("❌ Verification failed: {e}");
                return Err(e);
            }
        }

        Ok(())
    } else {
        Err(anyhow::anyhow!("Unknown verification algorithm"))
    }
}