use anyhow::Result;
use std::path::Path;
use std::process::Command;
use colored::*;

use crate::sdk::SdkConfig;

#[derive(Debug)]
pub struct SystemHealth {
    pub java_ok: bool,
    pub java_version: Option<String>,
    pub ftc_sdk_ok: bool,
    pub ftc_sdk_version: Option<String>,
    pub android_sdk_ok: bool,
    pub adb_ok: bool,
    pub adb_version: Option<String>,
    pub gradle_ok: bool,
    pub gradle_version: Option<String>,
}

impl SystemHealth {
    pub fn is_healthy(&self) -> bool {
        // Required: Java, FTC SDK, Android SDK
        // Optional: ADB in PATH (can be in Android SDK), Gradle (projects have wrapper)
        self.java_ok && self.ftc_sdk_ok && self.android_sdk_ok
    }
}

/// Run system diagnostics and report health status
pub fn run_diagnostics() -> Result<()> {
    println!("{}", "═══════════════════════════════════════════════════════════".bright_cyan());
    println!("{}", "   🩺 Weevil Doctor - System Diagnostics".bright_cyan().bold());
    println!("{}", "═══════════════════════════════════════════════════════════".bright_cyan());
    println!();
    
    let health = check_system_health()?;
    print_diagnostics(&health);
    
    println!();
    println!("{}", "═══════════════════════════════════════════════════════════".bright_cyan());
    
    if health.is_healthy() {
        println!("{}", "   ✓ System is healthy and ready for FTC development".bright_green().bold());
        println!("{}", "═══════════════════════════════════════════════════════════".bright_cyan());
        println!();
        println!("{}", "You can now:".bright_yellow().bold());
        println!("  - Create a new project: {}", "weevil new <project-name>".bright_cyan());
        println!("  - Setup a cloned project: {}", "weevil setup <project-path>".bright_cyan());
    } else {
        println!("{}", "   ⚠ Issues found - setup required".bright_yellow().bold());
        println!("{}", "═══════════════════════════════════════════════════════════".bright_cyan());
        println!();
        println!("{}", "To fix issues, run:".bright_yellow().bold());
        println!("  {}", "weevil setup".bright_cyan());
    }
    
    println!();
    
    Ok(())
}

/// Check system health and return a report
pub fn check_system_health() -> Result<SystemHealth> {
    let sdk_config = SdkConfig::new()?;
    
    // Check Java
    let (java_ok, java_version) = match check_java() {
        Ok(version) => (true, Some(version)),
        Err(_) => (false, None),
    };
    
    // Check FTC SDK
    let (ftc_sdk_ok, ftc_sdk_version) = if sdk_config.ftc_sdk_path.exists() {
        match crate::sdk::ftc::verify(&sdk_config.ftc_sdk_path) {
            Ok(_) => {
                let version = crate::sdk::ftc::get_version(&sdk_config.ftc_sdk_path)
                    .unwrap_or_else(|_| "unknown".to_string());
                (true, Some(version))
            }
            Err(_) => (false, None),
        }
    } else {
        (false, None)
    };
    
    // Check Android SDK
    let android_sdk_ok = if sdk_config.android_sdk_path.exists() {
        crate::sdk::android::verify(&sdk_config.android_sdk_path).is_ok()
    } else {
        false
    };
    
    // Check ADB
    let (adb_ok, adb_version) = match check_adb(&sdk_config.android_sdk_path) {
        Ok(version) => (true, Some(version)),
        Err(_) => (false, None),
    };
    
    // Check Gradle (optional)
    let (gradle_ok, gradle_version) = match check_gradle() {
        Ok(version) => (true, Some(version)),
        Err(_) => (false, None),
    };
    
    Ok(SystemHealth {
        java_ok,
        java_version,
        ftc_sdk_ok,
        ftc_sdk_version,
        android_sdk_ok,
        adb_ok,
        adb_version,
        gradle_ok,
        gradle_version,
    })
}

fn print_diagnostics(health: &SystemHealth) {
    let sdk_config = SdkConfig::new().unwrap();
    
    println!("{}", "Required Components:".bright_yellow().bold());
    println!();
    
    // Java
    if health.java_ok {
        println!("  {} Java JDK {}", 
            "✓".green(), 
            health.java_version.as_ref().unwrap()
        );
    } else {
        println!("  {} Java JDK {}", 
            "✗".red(), 
            "not found".red()
        );
    }
    
    // FTC SDK
    if health.ftc_sdk_ok {
        println!("  {} FTC SDK {} at {}", 
            "✓".green(),
            health.ftc_sdk_version.as_ref().unwrap(),
            sdk_config.ftc_sdk_path.display()
        );
    } else {
        println!("  {} FTC SDK {} (expected at {})", 
            "✗".red(),
            "not found".red(),
            sdk_config.ftc_sdk_path.display()
        );
    }
    
    // Android SDK
    if health.android_sdk_ok {
        println!("  {} Android SDK at {}", 
            "✓".green(),
            sdk_config.android_sdk_path.display()
        );
    } else {
        println!("  {} Android SDK {} (expected at {})", 
            "✗".red(),
            "not found".red(),
            sdk_config.android_sdk_path.display()
        );
    }
    
    println!();
    println!("{}", "Optional Components:".bright_yellow().bold());
    println!();
    
    // ADB
    if health.adb_ok {
        println!("  {} ADB {}", 
            "✓".green(),
            health.adb_version.as_ref().unwrap()
        );
    } else {
        println!("  {} ADB {}", 
            "⚠".yellow(),
            "not in PATH (included in Android SDK)".yellow()
        );
    }
    
    // Gradle
    if health.gradle_ok {
        println!("  {} Gradle {}", 
            "✓".green(),
            health.gradle_version.as_ref().unwrap()
        );
    } else {
        println!("  {} Gradle {}", 
            "⚠".yellow(),
            "not in PATH (projects include wrapper)".yellow()
        );
    }
}

fn check_java() -> Result<String> {
    let output = Command::new("java")
        .arg("-version")
        .output();
    
    match output {
        Ok(out) => {
            let stderr = String::from_utf8_lossy(&out.stderr);
            for line in stderr.lines() {
                if line.contains("version") {
                    if let Some(version_str) = line.split('"').nth(1) {
                        return Ok(version_str.to_string());
                    }
                }
            }
            Ok("installed (version unknown)".to_string())
        }
        Err(_) => anyhow::bail!("Java JDK not found in PATH"),
    }
}

fn check_adb(android_sdk_path: &Path) -> Result<String> {
    // First try system PATH
    let output = Command::new("adb")
        .arg("version")
        .output();
    
    if let Ok(out) = output {
        if out.status.success() {
            let stdout = String::from_utf8_lossy(&out.stdout);
            for line in stdout.lines() {
                if line.starts_with("Android Debug Bridge version") {
                    return Ok(line.replace("Android Debug Bridge version ", ""));
                }
            }
            return Ok("installed (version unknown)".to_string());
        }
    }
    
    // Try Android SDK location
    let adb_path = if cfg!(target_os = "windows") {
        android_sdk_path.join("platform-tools").join("adb.exe")
    } else {
        android_sdk_path.join("platform-tools").join("adb")
    };
    
    if adb_path.exists() {
        anyhow::bail!("ADB found in Android SDK but not in PATH")
    } else {
        anyhow::bail!("ADB not found")
    }
}

fn check_gradle() -> Result<String> {
    let output = Command::new("gradle")
        .arg("--version")
        .output();
    
    match output {
        Ok(out) => {
            let stdout = String::from_utf8_lossy(&out.stdout);
            for line in stdout.lines() {
                if line.starts_with("Gradle") {
                    return Ok(line.replace("Gradle ", ""));
                }
            }
            Ok("installed (version unknown)".to_string())
        }
        Err(_) => anyhow::bail!("Gradle not found in PATH"),
    }
}