// Claude Desktop — Änderungs-Log (Audit Trail)
// Protokolliert alle Änderungen an Einstellungen, Guard-Rails, Hooks, Skills, etc.

use serde::{Deserialize, Serialize};
use std::sync::{Arc, Mutex};
use tauri::{AppHandle, Manager};

use crate::db;

/// Kategorie der Änderung
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AuditCategory {
    GuardRail,   // Freigabe-Regeln
    Pattern,     // Vorgehensweisen
    Hook,        // Claude Hooks
    Skill,       // Claude Skills
    Setting,     // App-Einstellungen
    MCP,         // MCP-Server Konfiguration
    Memory,      // Gedächtnis-Einträge
}

/// Art der Aktion
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AuditAction {
    Create,
    Update,
    Delete,
    Enable,
    Disable,
}

/// Ein Audit-Eintrag
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuditEntry {
    pub id: String,
    pub timestamp: String,
    pub category: AuditCategory,
    pub action: AuditAction,
    pub item_id: String,
    pub item_name: String,
    pub old_value: Option<serde_json::Value>,
    pub new_value: Option<serde_json::Value>,
    pub reason: Option<String>,
    pub auto_corrected: bool,
    pub session_id: Option<String>,
}

/// Audit-Log Manager (für zukünftige In-Memory-Nutzung)
#[allow(dead_code)]
#[derive(Debug, Default)]
pub struct AuditLog {
    entries: Vec<AuditEntry>,
}

#[allow(dead_code)]
impl AuditLog {
    pub fn new() -> Self {
        Self { entries: vec![] }
    }

    /// Fügt einen Eintrag hinzu
    pub fn log(&mut self, entry: AuditEntry) {
        println!(
            "📋 Audit: {:?} {:?} - {} ({})",
            entry.action, entry.category, entry.item_name,
            entry.reason.as_deref().unwrap_or("keine Begründung")
        );
        self.entries.push(entry);
    }

    /// Holt die letzten N Einträge
    pub fn recent(&self, limit: usize) -> Vec<&AuditEntry> {
        self.entries.iter().rev().take(limit).collect()
    }

    /// Holt Einträge nach Kategorie
    pub fn by_category(&self, category: &AuditCategory) -> Vec<&AuditEntry> {
        self.entries
            .iter()
            .filter(|e| std::mem::discriminant(&e.category) == std::mem::discriminant(category))
            .collect()
    }

    /// Holt auto-korrigierte Einträge
    pub fn auto_corrected(&self) -> Vec<&AuditEntry> {
        self.entries.iter().filter(|e| e.auto_corrected).collect()
    }

    /// Statistiken
    pub fn stats(&self) -> AuditStats {
        AuditStats {
            total: self.entries.len(),
            auto_corrected: self.entries.iter().filter(|e| e.auto_corrected).count(),
            today: self.entries.iter().filter(|e| {
                // Vereinfachte Prüfung - in echt: Datum vergleichen
                e.timestamp.starts_with(&chrono::Local::now().format("%Y-%m-%d").to_string())
            }).count(),
        }
    }
}

#[derive(Debug, Serialize, Deserialize)]
pub struct AuditStats {
    pub total: usize,
    pub auto_corrected: usize,
    pub today: usize,
}

// Tauri-Commands

/// Holt die letzten Audit-Einträge
#[tauri::command]
pub async fn get_audit_log(app: AppHandle, limit: Option<usize>) -> Result<Vec<AuditEntry>, String> {
    let limit = limit.unwrap_or(50);
    let state = app.state::<Arc<Mutex<db::Database>>>();
    let db_lock = state.lock().unwrap();
    db_lock.load_audit_log(limit).map_err(|e| e.to_string())
}

/// Fügt einen Audit-Eintrag hinzu
#[tauri::command]
pub async fn add_audit_entry(
    app: AppHandle,
    category: String,
    action: String,
    item_id: String,
    item_name: String,
    old_value: Option<serde_json::Value>,
    new_value: Option<serde_json::Value>,
    reason: Option<String>,
    auto_corrected: bool,
) -> Result<(), String> {
    let category = match category.as_str() {
        "guard_rail" => AuditCategory::GuardRail,
        "pattern" => AuditCategory::Pattern,
        "hook" => AuditCategory::Hook,
        "skill" => AuditCategory::Skill,
        "setting" => AuditCategory::Setting,
        "mcp" => AuditCategory::MCP,
        "memory" => AuditCategory::Memory,
        _ => return Err(format!("Unbekannte Kategorie: {}", category)),
    };

    let action = match action.as_str() {
        "create" => AuditAction::Create,
        "update" => AuditAction::Update,
        "delete" => AuditAction::Delete,
        "enable" => AuditAction::Enable,
        "disable" => AuditAction::Disable,
        _ => return Err(format!("Unbekannte Aktion: {}", action)),
    };

    let entry = AuditEntry {
        id: uuid::Uuid::new_v4().to_string(),
        timestamp: chrono::Local::now().to_rfc3339(),
        category,
        action,
        item_id,
        item_name,
        old_value,
        new_value,
        reason,
        auto_corrected,
        session_id: None,
    };

    // In SQLite speichern
    let state = app.state::<Arc<Mutex<db::Database>>>();
    let db_lock = state.lock().unwrap();
    db_lock.save_audit_entry(&entry).map_err(|e| e.to_string())?;

    println!("📋 Audit: {:?} {:?} - {}", entry.action, entry.category, entry.item_name);

    Ok(())
}

/// Holt Audit-Statistiken
#[tauri::command]
pub async fn get_audit_stats(app: AppHandle) -> Result<AuditStats, String> {
    let state = app.state::<Arc<Mutex<db::Database>>>();
    let db_lock = state.lock().unwrap();
    db_lock.audit_stats().map_err(|e| e.to_string())
}