// Claude Desktop — Hook-System
// Zentraler Dispatcher + Audit-Log fuer automatische Aktionen
// (SessionStart, PreToolUse, PostToolUse, BeforeCompacting, AfterCompacting)

use serde::{Deserialize, Serialize};
use std::sync::{Arc, Mutex};
use std::collections::HashMap;
use tauri::{AppHandle, Emitter};

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum HookEvent {
    SessionStart,
    PreToolUse,
    PostToolUse,
    BeforeCompacting,
    AfterCompacting,
    ContextFailure,
    AgentStarted,
}

impl HookEvent {
    pub fn as_str(&self) -> &'static str {
        match self {
            HookEvent::SessionStart => "SessionStart",
            HookEvent::PreToolUse => "PreToolUse",
            HookEvent::PostToolUse => "PostToolUse",
            HookEvent::BeforeCompacting => "BeforeCompacting",
            HookEvent::AfterCompacting => "AfterCompacting",
            HookEvent::ContextFailure => "ContextFailure",
            HookEvent::AgentStarted => "AgentStarted",
        }
    }

    pub fn from_str(s: &str) -> Option<Self> {
        match s {
            "SessionStart" => Some(HookEvent::SessionStart),
            "PreToolUse" => Some(HookEvent::PreToolUse),
            "PostToolUse" => Some(HookEvent::PostToolUse),
            "BeforeCompacting" => Some(HookEvent::BeforeCompacting),
            "AfterCompacting" => Some(HookEvent::AfterCompacting),
            "ContextFailure" => Some(HookEvent::ContextFailure),
            "AgentStarted" => Some(HookEvent::AgentStarted),
            _ => None,
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HookConfig {
    pub name: String,
    pub event: String,
    pub enabled: bool,
    pub description: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HookExecution {
    pub timestamp: String,
    pub event: String,
    pub hook_name: String,
    pub duration_ms: u64,
    pub success: bool,
    pub summary: String,
}

/// Hook-Manager — haelt Registry und Ausfuehrungs-Log
pub struct HookManager {
    pub hooks: HashMap<String, Vec<HookConfig>>,
    pub executions: Vec<HookExecution>,
    pub max_log_size: usize,
}

impl Default for HookManager {
    fn default() -> Self {
        let mut mgr = HookManager {
            hooks: HashMap::new(),
            executions: Vec::new(),
            max_log_size: 500,
        };
        mgr.register_builtin_hooks();
        mgr
    }
}

impl HookManager {
    /// Eingebaute Hooks registrieren
    fn register_builtin_hooks(&mut self) {
        let builtins = vec![
            HookConfig {
                name: "load-sticky-context".into(),
                event: "SessionStart".into(),
                enabled: true,
                description: "Laedt Sticky-Context bei Session-Start".into(),
            },
            HookConfig {
                name: "inject-knowledge-hints".into(),
                event: "PreToolUse".into(),
                enabled: true,
                description: "Injiziert relevante KB-Eintraege vor Tool-Ausfuehrung".into(),
            },
            HookConfig {
                name: "save-failure-pattern".into(),
                event: "PostToolUse".into(),
                enabled: true,
                description: "Speichert Fehler-Pattern nach fehlgeschlagenen Tools".into(),
            },
            HookConfig {
                name: "extract-critical-context".into(),
                event: "BeforeCompacting".into(),
                enabled: true,
                description: "Extrahiert kritischen Kontext vor Compacting".into(),
            },
            HookConfig {
                name: "reinject-context".into(),
                event: "AfterCompacting".into(),
                enabled: true,
                description: "Injiziert Sticky+Project-Context nach Compacting".into(),
            },
        ];

        for hook in builtins {
            self.hooks
                .entry(hook.event.clone())
                .or_default()
                .push(hook);
        }
    }

    pub fn fire(&mut self, event: &HookEvent, summary: String) -> Vec<String> {
        let event_name = event.as_str().to_string();
        let mut fired_names = Vec::new();

        if let Some(hooks) = self.hooks.get(&event_name) {
            for hook in hooks.iter().filter(|h| h.enabled) {
                fired_names.push(hook.name.clone());

                let execution = HookExecution {
                    timestamp: chrono::Utc::now().to_rfc3339(),
                    event: event_name.clone(),
                    hook_name: hook.name.clone(),
                    duration_ms: 0,
                    success: true,
                    summary: summary.clone(),
                };

                self.executions.push(execution);
                if self.executions.len() > self.max_log_size {
                    self.executions.remove(0);
                }
            }
        }

        fired_names
    }

    pub fn set_enabled(&mut self, event: &str, hook_name: &str, enabled: bool) -> bool {
        if let Some(hooks) = self.hooks.get_mut(event) {
            for hook in hooks.iter_mut() {
                if hook.name == hook_name {
                    hook.enabled = enabled;
                    return true;
                }
            }
        }
        false
    }

    pub fn list_all(&self) -> Vec<HookConfig> {
        self.hooks.values().flatten().cloned().collect()
    }

    pub fn recent_executions(&self, limit: usize) -> Vec<HookExecution> {
        let start = self.executions.len().saturating_sub(limit);
        self.executions[start..].to_vec()
    }
}

pub type HookState = Arc<Mutex<HookManager>>;

// ============ Tauri Commands ============

#[tauri::command]
pub async fn list_hooks(state: tauri::State<'_, HookState>) -> Result<Vec<HookConfig>, String> {
    let mgr = state.lock().map_err(|e| e.to_string())?;
    Ok(mgr.list_all())
}

#[tauri::command]
pub async fn set_hook_enabled(
    state: tauri::State<'_, HookState>,
    event: String,
    hook_name: String,
    enabled: bool,
) -> Result<bool, String> {
    let mut mgr = state.lock().map_err(|e| e.to_string())?;
    Ok(mgr.set_enabled(&event, &hook_name, enabled))
}

#[tauri::command]
pub async fn get_hook_executions(
    state: tauri::State<'_, HookState>,
    limit: Option<usize>,
) -> Result<Vec<HookExecution>, String> {
    let mgr = state.lock().map_err(|e| e.to_string())?;
    Ok(mgr.recent_executions(limit.unwrap_or(100)))
}

#[tauri::command]
pub async fn fire_hook(
    app: AppHandle,
    state: tauri::State<'_, HookState>,
    event: String,
    summary: String,
) -> Result<Vec<String>, String> {
    let hook_event = HookEvent::from_str(&event)
        .ok_or_else(|| format!("Unbekanntes Hook-Event: {}", event))?;

    let fired = {
        let mut mgr = state.lock().map_err(|e| e.to_string())?;
        mgr.fire(&hook_event, summary.clone())
    };

    // Event ans Frontend senden (fuer Live-Log im UI)
    let _ = app.emit(
        "hook-fired",
        serde_json::json!({
            "event": event,
            "hooks": fired,
            "summary": summary,
        }),
    );

    // Spezifische Hook-Events dispatchen — Frontend kann gezielt darauf reagieren
    // Summary wird als JSON-Payload durchgereicht (Tool-Name, Argumente, Ergebnis etc.)
    match hook_event {
        HookEvent::SessionStart => {
            let _ = app.emit("hook-session-start", serde_json::json!({
                "hooks": fired,
                "payload": summary,
            }));
        }
        HookEvent::PreToolUse => {
            let _ = app.emit("hook-pre-tool-use", serde_json::json!({
                "hooks": fired,
                "payload": summary,
            }));
        }
        HookEvent::PostToolUse => {
            let _ = app.emit("hook-post-tool-use", serde_json::json!({
                "hooks": fired,
                "payload": summary,
            }));
        }
        HookEvent::BeforeCompacting => {
            let _ = app.emit("hook-before-compacting", serde_json::json!({
                "hooks": fired,
                "payload": summary,
            }));
        }
        HookEvent::AfterCompacting => {
            let _ = app.emit("hook-after-compacting", serde_json::json!({
                "hooks": fired,
                "payload": summary,
            }));
        }
        // ContextFailure + AgentStarted: aktuell kein eigenes Frontend-Event noetig
        _ => {}
    }

    Ok(fired)
}