//! Framework update command with safety guarantees
//!
//! This module implements safe framework updates that:
//! - Never overwrite user code
//! - Create backups before changes
//! - Support different update policies
//! - Handle dependency strategy configuration
//! - Preserve local customizations

use std::collections::HashMap;
use std::fs;
use std::path::{Path, PathBuf};

use rustelo_core::{Result, RusteloError};
use serde::{Deserialize, Serialize};

/// Dependency configuration loaded from rustelo-deps.toml
#[derive(Debug, Deserialize, Serialize)]
pub struct RusteloDepsConfig {
    pub dependencies: DependencyConfig,
    pub versions: HashMap<String, String>,
    pub features: HashMap<String, Vec<String>>,
    pub assets: Option<AssetsConfig>,
    pub development: Option<DevelopmentConfig>,
    pub update: UpdateConfig,
    pub contributions: Option<ContributionsConfig>,
    pub notifications: Option<NotificationsConfig>,
    pub ci_cd: Option<CiCdConfig>,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct DependencyConfig {
    pub strategy: String, // "git", "crates-io", "path", "auto"
    pub git: Option<GitConfig>,
    pub crates_io: Option<CratesIoConfig>,
    pub path: Option<PathConfig>,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct GitConfig {
    pub repository: String,
    pub branch: Option<String>,
    pub tag: Option<String>,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct CratesIoConfig {}

#[derive(Debug, Deserialize, Serialize)]
pub struct PathConfig {
    pub base_path: String,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct UpdateConfig {
    pub policy: String, // "conservative", "aggressive", "manual"
    pub automation: Option<UpdateAutomation>,
    pub regenerate: Vec<String>,
    pub protected: Vec<String>,
    pub backup: bool,
    pub backup_dir: String,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct UpdateAutomation {
    pub enabled: bool,
    pub check_frequency: String,
    pub check_targets: Vec<String>,
    pub notify_methods: Vec<String>,
    pub auto_update_policy: String,
    pub fail_on_critical_updates: bool,
    pub update_log_file: String,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct AssetsConfig {
    pub source: String, // "local", "embedded", "download", "auto"
    pub local: Option<LocalAssetsConfig>,
    pub download: Option<DownloadAssetsConfig>,
    pub embedded: Option<EmbeddedAssetsConfig>,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct LocalAssetsConfig {
    pub framework_path: String,
    pub watch_changes: bool,
    pub sync_assets: Vec<String>,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct DownloadAssetsConfig {
    pub base_url: String,
    pub cache_enabled: bool,
    pub cache_dir: String,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct EmbeddedAssetsConfig {
    pub fallback_enabled: bool,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct DevelopmentConfig {
    pub enabled: bool,
    pub auto_detect_changes: bool,
    pub auto_sync_assets: bool,
    pub validate_assets: bool,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct ContributionsConfig {
    pub enabled: bool,
    pub scan_frequency: String,
    pub detect_types: Vec<String>,
    pub auto_package: bool,
    pub package_directory: String,
    pub notify_methods: Vec<String>,
    pub confidence_threshold: f64,
}

#[derive(Debug, Deserialize, Serialize)]
pub struct NotificationsConfig {
    pub enabled: bool,
    // Could extend with channels config later
}

#[derive(Debug, Deserialize, Serialize)]
pub struct CiCdConfig {
    pub enabled: bool,
    // Could extend with exit codes, cache config, etc.
}

/// Update policy determines how aggressive the update process is
#[derive(Debug, Clone)]
pub enum UpdatePolicy {
    /// Only update dependencies, never touch project files
    Conservative,
    /// Update dependencies + regenerate safe files (justfile, package.json,
    /// etc.)
    Aggressive,
    /// Interactive mode - ask user for each change
    Manual,
}

impl UpdatePolicy {
    fn from_str(s: &str) -> Self {
        match s {
            "conservative" => Self::Conservative,
            "aggressive" => Self::Aggressive,
            "manual" => Self::Manual,
            _ => Self::Conservative, // Default to safest option
        }
    }
}

/// Main update command entry point
pub async fn run(
    version: Option<String>,
    force: bool,
    interactive: bool,
    check_only: bool,
) -> Result<()> {
    let current_dir = std::env::current_dir().map_err(RusteloError::Io)?;

    // Check if this is an automated check
    if let Ok(auto_check) = std::env::var("RUSTELO_AUTO_CHECK") {
        if auto_check == "true" {
            return run_automated_check(&current_dir).await;
        }
    }

    println!("🔄 Starting Rustelo framework update...");
    println!("📁 Project: {}", current_dir.display());

    // Load project configuration
    let deps_config = load_deps_config(&current_dir)?;
    let mut policy = UpdatePolicy::from_str(&deps_config.update.policy);

    // Override policy if interactive mode requested
    if interactive {
        policy = UpdatePolicy::Manual;
    }

    println!("🛡️  Update policy: {:?}", policy);

    if check_only {
        return check_updates(&current_dir, &deps_config).await;
    }

    // Create backup if enabled
    if deps_config.update.backup {
        create_backup(&current_dir, &deps_config.update.backup_dir)?;
    }

    // Perform update based on policy
    match policy {
        UpdatePolicy::Conservative => {
            update_dependencies_only(&current_dir, &deps_config, version, force).await
        }
        UpdatePolicy::Aggressive => {
            update_dependencies_and_files(&current_dir, &deps_config, version, force).await
        }
        UpdatePolicy::Manual => {
            interactive_update(&current_dir, &deps_config, version, force).await
        }
    }
}

/// Load dependency configuration from rustelo-deps.toml
pub fn load_deps_config(project_dir: &Path) -> Result<RusteloDepsConfig> {
    let config_path = project_dir.join("rustelo-deps.toml");

    if !config_path.exists() {
        return Err(RusteloError::generic(format!(
            "rustelo-deps.toml not found in {}. This project may not be a Rustelo framework \
             project.",
            project_dir.display()
        )));
    }

    let content = fs::read_to_string(&config_path).map_err(RusteloError::Io)?;
    let config: RusteloDepsConfig = toml::from_str(&content)
        .map_err(|e| RusteloError::generic(format!("Invalid rustelo-deps.toml: {}", e)))?;

    Ok(config)
}

/// Create backup of critical files
fn create_backup(project_dir: &Path, backup_dir: &str) -> Result<()> {
    use chrono::Utc;

    let timestamp = Utc::now().format("%Y%m%d_%H%M%S");
    let backup_path = project_dir
        .join(backup_dir)
        .join(format!("backup_{}", timestamp));

    println!("💾 Creating backup: {}", backup_path.display());

    fs::create_dir_all(&backup_path).map_err(RusteloError::Io)?;

    // Backup critical files
    let files_to_backup = [
        "Cargo.toml",
        "rustelo-deps.toml",
        "justfile",
        "package.json",
        "unocss.config.ts",
        "config/rustelo.toml",
    ];

    for file_name in &files_to_backup {
        let source = project_dir.join(file_name);
        if source.exists() {
            let target = backup_path.join(file_name);
            if let Some(parent) = target.parent() {
                fs::create_dir_all(parent).map_err(RusteloError::Io)?;
            }
            fs::copy(&source, &target).map_err(RusteloError::Io)?;
            println!("  ✅ Backed up: {}", file_name);
        }
    }

    println!("💾 Backup created successfully");
    Ok(())
}

/// Check what updates are available without applying them
async fn check_updates(project_dir: &Path, config: &RusteloDepsConfig) -> Result<()> {
    println!("🔍 Checking for available updates...");

    // Check current Cargo.toml for dependency versions
    let cargo_toml_path = project_dir.join("Cargo.toml");
    let _cargo_content = fs::read_to_string(&cargo_toml_path).map_err(RusteloError::Io)?;

    println!(
        "📋 Current dependency strategy: {}",
        config.dependencies.strategy
    );

    match config.dependencies.strategy.as_str() {
        "git" => {
            if let Some(git_config) = &config.dependencies.git {
                println!("📦 Git repository: {}", git_config.repository);
                if let Some(branch) = &git_config.branch {
                    println!("🌿 Branch: {}", branch);
                }
            }
            println!("🔄 Updates: Git dependencies will pull latest commits");
        }
        "crates-io" => {
            println!("📦 Strategy: crates.io");
            println!("🔄 Updates: Check crates.io for newer versions");
        }
        "path" => {
            println!("⚠️  Strategy: path dependencies");
            println!("🔄 Updates: Use local framework development version");
        }
        _ => {
            println!("❓ Unknown strategy: {}", config.dependencies.strategy);
        }
    }

    // Check which files would be regenerated
    if !config.update.regenerate.is_empty() {
        println!("\n📄 Files that can be safely regenerated:");
        for file in &config.update.regenerate {
            let exists = project_dir.join(file).exists();
            println!(
                "  {} {} ({})",
                if exists { "✅" } else { "❌" },
                file,
                if exists { "exists" } else { "missing" }
            );
        }
    }

    // Check protected files
    if !config.update.protected.is_empty() {
        println!("\n🛡️  Protected files (never overwritten):");
        for pattern in &config.update.protected {
            println!("  🔒 {}", pattern);
        }
    }

    println!("\n✅ Update check complete. Run without --check to apply updates.");
    Ok(())
}

/// Conservative update - only update dependencies in Cargo.toml
async fn update_dependencies_only(
    project_dir: &Path,
    config: &RusteloDepsConfig,
    _version: Option<String>,
    _force: bool,
) -> Result<()> {
    println!("🛡️  Conservative update: Only updating dependencies...");

    let cargo_toml_path = project_dir.join("Cargo.toml");
    let _cargo_content = fs::read_to_string(&cargo_toml_path).map_err(RusteloError::Io)?;

    // Update dependencies based on strategy
    match config.dependencies.strategy.as_str() {
        "git" => {
            if let Some(git_config) = &config.dependencies.git {
                println!(
                    "📦 Updating git dependencies from: {}",
                    git_config.repository
                );
                // In a real implementation, we would parse and update the TOML
                println!("ℹ️  Run 'cargo update' to pull latest commits");
            }
        }
        "crates-io" => {
            println!("📦 Updating from crates.io...");
            println!("ℹ️  Run 'cargo update' to get latest published versions");
        }
        "path" => {
            println!("📦 Using path dependencies - no update needed");
        }
        _ => {
            return Err(RusteloError::generic(format!(
                "Unknown dependency strategy: {}",
                config.dependencies.strategy
            )));
        }
    }

    println!("✅ Dependencies updated. Run 'cargo check' to verify.");
    Ok(())
}

/// Aggressive update - update dependencies and regenerate safe files
async fn update_dependencies_and_files(
    project_dir: &Path,
    config: &RusteloDepsConfig,
    version: Option<String>,
    force: bool,
) -> Result<()> {
    println!("⚡ Aggressive update: Updating dependencies and regenerating files...");

    // First do conservative update
    update_dependencies_only(project_dir, config, version.clone(), force).await?;

    // Then regenerate safe files
    // Note: Template regeneration now happens through remote asset system
    for file_name in &config.update.regenerate {
        let file_path = project_dir.join(file_name);

        // Check if file was modified by user
        if file_was_modified(&file_path)? {
            println!(
                "⚠️  Skipping {} - appears to be modified by user",
                file_name
            );
            continue;
        }

        // In production, this would fetch templates from remote source
        // For now, skip regeneration as templates are managed remotely
        println!(
            "  ℹ️  {} - template regeneration through remote system",
            file_name
        );
    }

    println!("✅ Aggressive update complete!");
    Ok(())
}

/// Interactive update - ask user for each change
async fn interactive_update(
    project_dir: &Path,
    config: &RusteloDepsConfig,
    version: Option<String>,
    force: bool,
) -> Result<()> {
    println!("🤔 Interactive update: You'll be prompted for each change...");

    // Update dependencies
    if prompt_user("Update framework dependencies?")? {
        update_dependencies_only(project_dir, config, version, force).await?;
    }

    // Check each file that could be regenerated
    // Note: Template regeneration now happens through remote asset system
    for file_name in &config.update.regenerate {
        let file_path = project_dir.join(file_name);

        let question = if file_path.exists() {
            format!(
                "Regenerate {}? (This will overwrite existing file)",
                file_name
            )
        } else {
            format!("Create missing {}?", file_name)
        };

        if prompt_user(&question)? {
            println!(
                "  ℹ️  {} - would be regenerated through remote asset system",
                file_name
            );
            // In production, this would fetch templates from remote source
        }
    }

    println!("✅ Interactive update complete!");
    Ok(())
}

/// Simple file modification detection (basic heuristic)
fn file_was_modified(file_path: &Path) -> Result<bool> {
    if !file_path.exists() {
        return Ok(false);
    }

    let content = fs::read_to_string(file_path).map_err(RusteloError::Io)?;

    // Check for absence of generation markers
    let has_generation_marker = content.contains("Generated by cargo rustelo")
        || content.contains("_generated_by")
        || content.contains("# This file is automatically generated");

    // If no generation marker, assume it was modified
    Ok(!has_generation_marker)
}

/// Simple user prompt for interactive updates
fn prompt_user(question: &str) -> Result<bool> {
    use std::io::{self, Write};

    print!("{} [y/N]: ", question);
    io::stdout().flush().map_err(RusteloError::Io)?;

    let mut input = String::new();
    io::stdin()
        .read_line(&mut input)
        .map_err(RusteloError::Io)?;

    Ok(input.trim().to_lowercase() == "y" || input.trim().to_lowercase() == "yes")
}

// =============================================================================
// AUTOMATED UPDATE CHECKING & NOTIFICATION SYSTEM
// =============================================================================

/// Run automated update check (called by cron/scheduler)
pub async fn run_automated_check(project_dir: &Path) -> Result<()> {
    let config = load_deps_config(project_dir)?;

    if let Some(automation) = &config.update.automation {
        if !automation.enabled {
            return Ok(());
        }

        println!("🤖 Running automated update check...");

        // Check for updates
        let update_status = check_for_updates(project_dir, &config).await?;

        // Send notifications if updates are available
        if update_status.has_updates {
            send_notifications(project_dir, &config, &update_status).await?;
        }

        // Log results
        log_update_check(project_dir, &config, &update_status).await?;

        // Set exit code for CI/CD integration
        if automation.fail_on_critical_updates && update_status.has_critical_updates {
            std::process::exit(1);
        }
    }

    Ok(())
}

/// Update status information
#[derive(Debug)]
pub struct UpdateStatus {
    pub has_updates: bool,
    pub has_critical_updates: bool,
    pub framework_version: String,
    pub available_version: String,
    pub outdated_dependencies: Vec<String>,
    pub new_features: Vec<String>,
    pub breaking_changes: Vec<String>,
    pub security_updates: Vec<String>,
    pub check_timestamp: chrono::DateTime<chrono::Utc>,
}

/// Check for available updates
async fn check_for_updates(project_dir: &Path, config: &RusteloDepsConfig) -> Result<UpdateStatus> {
    let mut status = UpdateStatus {
        has_updates: false,
        has_critical_updates: false,
        framework_version: env!("CARGO_PKG_VERSION").to_string(),
        available_version: env!("CARGO_PKG_VERSION").to_string(),
        outdated_dependencies: Vec::new(),
        new_features: Vec::new(),
        breaking_changes: Vec::new(),
        security_updates: Vec::new(),
        check_timestamp: chrono::Utc::now(),
    };

    // Check based on dependency strategy
    match config.dependencies.strategy.as_str() {
        "git" => {
            if let Some(git_config) = &config.dependencies.git {
                status = check_git_updates(project_dir, git_config, status).await?;
            }
        }
        "crates-io" => {
            status = check_crates_io_updates(project_dir, status).await?;
        }
        "path" => {
            // For path dependencies, check if local framework has updates
            if let Some(path_config) = &config.dependencies.path {
                status = check_local_framework_updates(project_dir, path_config, status).await?;
            }
        }
        _ => {}
    }

    // Check for feature updates
    status = check_feature_updates(project_dir, config, status).await?;

    Ok(status)
}

/// Check for git-based updates
async fn check_git_updates(
    _project_dir: &Path,
    git_config: &GitConfig,
    mut status: UpdateStatus,
) -> Result<UpdateStatus> {
    println!("🔍 Checking git repository: {}", git_config.repository);

    // In a real implementation, we would:
    // 1. Fetch latest commits from the git repository
    // 2. Compare with current commit hash
    // 3. Parse changelog/release notes for breaking changes
    // 4. Check for security advisories

    // For now, simulate update checking
    status.has_updates = true;
    status.available_version = "0.1.1".to_string();
    status.new_features = vec![
        "Enhanced asset processing".to_string(),
        "Improved error handling".to_string(),
    ];

    Ok(status)
}

/// Check for crates.io updates
async fn check_crates_io_updates(
    _project_dir: &Path,
    mut status: UpdateStatus,
) -> Result<UpdateStatus> {
    println!("🔍 Checking crates.io for updates...");

    // In a real implementation, we would:
    // 1. Query crates.io API for latest versions
    // 2. Compare semantic versions
    // 3. Check for breaking changes in changelog
    // 4. Look for security advisories

    status.has_updates = false; // No updates for now

    Ok(status)
}

/// Check for local framework updates
async fn check_local_framework_updates(
    _project_dir: &Path,
    path_config: &PathConfig,
    mut status: UpdateStatus,
) -> Result<UpdateStatus> {
    let framework_path = PathBuf::from(&path_config.base_path)
        .parent()
        .unwrap()
        .to_path_buf();

    println!("🔍 Checking local framework: {}", framework_path.display());

    // Check if framework directory has uncommitted changes
    if framework_path.join(".git").exists() {
        // In real implementation: check git status, recent commits, etc.
        status.has_updates = true;
        status.new_features = vec!["Local development changes detected".to_string()];
    }

    Ok(status)
}

/// Check for new feature updates
async fn check_feature_updates(
    _project_dir: &Path,
    config: &RusteloDepsConfig,
    mut status: UpdateStatus,
) -> Result<UpdateStatus> {
    // Check if there are new features available in the framework
    // that aren't enabled in this project

    let available_features = get_available_framework_features().await?;
    let enabled_features: Vec<String> = config.features.values().flatten().cloned().collect();

    let new_features: Vec<String> = available_features
        .into_iter()
        .filter(|feature| !enabled_features.contains(feature))
        .collect();

    if !new_features.is_empty() {
        status.has_updates = true;
        status.new_features.extend(new_features);
    }

    Ok(status)
}

/// Get available framework features
async fn get_available_framework_features() -> Result<Vec<String>> {
    // In real implementation, this would query the framework
    // for available features/modules
    Ok(vec![
        "auth".to_string(),
        "content-management".to_string(),
        "real-time".to_string(),
        "analytics".to_string(),
    ])
}

/// Send update notifications
async fn send_notifications(
    project_dir: &Path,
    config: &RusteloDepsConfig,
    status: &UpdateStatus,
) -> Result<()> {
    if let Some(automation) = &config.update.automation {
        for method in &automation.notify_methods {
            match method.as_str() {
                "log" => send_log_notification(status).await?,
                "file" => send_file_notification(project_dir, status).await?,
                "webhook" => send_webhook_notification(config, status).await?,
                "github" => send_github_notification(config, status).await?,
                "slack" => send_slack_notification(config, status).await?,
                _ => println!("⚠️  Unknown notification method: {}", method),
            }
        }
    }
    Ok(())
}

/// Send log notification
async fn send_log_notification(status: &UpdateStatus) -> Result<()> {
    println!("📢 UPDATE NOTIFICATION");
    println!("Current version: {}", status.framework_version);
    println!("Available version: {}", status.available_version);

    if !status.new_features.is_empty() {
        println!("🆕 New features:");
        for feature in &status.new_features {
            println!("  • {}", feature);
        }
    }

    if !status.breaking_changes.is_empty() {
        println!("⚠️  Breaking changes:");
        for change in &status.breaking_changes {
            println!("  • {}", change);
        }
    }

    if !status.security_updates.is_empty() {
        println!("🔒 Security updates:");
        for update in &status.security_updates {
            println!("  • {}", update);
        }
    }

    Ok(())
}

/// Send file notification
async fn send_file_notification(project_dir: &Path, status: &UpdateStatus) -> Result<()> {
    let notification_file = project_dir.join(".rustelo-updates.json");

    let notification = serde_json::json!({
        "timestamp": status.check_timestamp.to_rfc3339(),
        "current_version": status.framework_version,
        "available_version": status.available_version,
        "has_updates": status.has_updates,
        "has_critical_updates": status.has_critical_updates,
        "new_features": status.new_features,
        "breaking_changes": status.breaking_changes,
        "security_updates": status.security_updates,
        "outdated_dependencies": status.outdated_dependencies
    });

    let json_content = serde_json::to_string_pretty(&notification)
        .map_err(|e| RusteloError::generic(format!("JSON error: {}", e)))?;
    fs::write(&notification_file, json_content).map_err(RusteloError::Io)?;

    println!(
        "📄 Update notification written to: {}",
        notification_file.display()
    );

    Ok(())
}

/// Send webhook notification
async fn send_webhook_notification(
    _config: &RusteloDepsConfig,
    _status: &UpdateStatus,
) -> Result<()> {
    // In real implementation, would send HTTP POST to configured webhook URL
    println!("🌐 Sending webhook notification (simulated)");
    Ok(())
}

/// Send GitHub notification
async fn send_github_notification(
    _config: &RusteloDepsConfig,
    _status: &UpdateStatus,
) -> Result<()> {
    // In real implementation, would create GitHub issue or comment
    println!("🐙 Sending GitHub notification (simulated)");
    Ok(())
}

/// Send Slack notification
async fn send_slack_notification(
    _config: &RusteloDepsConfig,
    _status: &UpdateStatus,
) -> Result<()> {
    // In real implementation, would send to Slack webhook
    println!("💬 Sending Slack notification (simulated)");
    Ok(())
}

/// Log update check results
async fn log_update_check(
    project_dir: &Path,
    config: &RusteloDepsConfig,
    status: &UpdateStatus,
) -> Result<()> {
    if let Some(automation) = &config.update.automation {
        let log_file = project_dir.join(&automation.update_log_file);

        let log_entry = format!(
            "{} - Update Check: {} -> {} (Updates: {}, Critical: {})\n",
            status.check_timestamp.to_rfc3339(),
            status.framework_version,
            status.available_version,
            status.has_updates,
            status.has_critical_updates
        );

        // Append to log file
        use std::fs::OpenOptions;
        use std::io::Write;

        let mut file = OpenOptions::new()
            .create(true)
            .append(true)
            .open(&log_file)
            .map_err(RusteloError::Io)?;

        file.write_all(log_entry.as_bytes())
            .map_err(RusteloError::Io)?;
    }

    Ok(())
}

// =============================================================================
// CI/CD INTEGRATION COMMANDS
// =============================================================================

/// Non-interactive update check for CI/CD (with exit codes)
#[allow(dead_code)]
pub async fn run_ci_check() -> Result<()> {
    let current_dir = std::env::current_dir().map_err(RusteloError::Io)?;
    let config = load_deps_config(&current_dir)?;

    if let Some(ci_config) = &config.ci_cd {
        if !ci_config.enabled {
            println!("CI/CD integration disabled");
            return Ok(());
        }
    }

    let status = check_for_updates(&current_dir, &config).await?;

    // Output machine-readable status
    println!("RUSTELO_UPDATE_CHECK=true");
    println!("RUSTELO_HAS_UPDATES={}", status.has_updates);
    println!("RUSTELO_HAS_CRITICAL={}", status.has_critical_updates);
    println!("RUSTELO_CURRENT_VERSION={}", status.framework_version);
    println!("RUSTELO_AVAILABLE_VERSION={}", status.available_version);

    // Exit codes for CI/CD:
    // 0 = No updates
    // 1 = Updates available
    // 2 = Critical/security updates available
    if status.has_critical_updates {
        std::process::exit(2);
    } else if status.has_updates {
        std::process::exit(1);
    }

    Ok(())
}
