mod client;
mod history;

pub use client::{
    ChatMessage, ConfigError, LlmBackend, LlmClient, LlmError,
    DEFAULT_BASE_URL, DEFAULT_MODEL, ENV_BASE_URL, ENV_MODEL, ENV_TOKEN,
    OLLAMA_DEFAULT_BASE_URL, OLLAMA_DEFAULT_MODEL,
};
pub use history::ConversationHistory;

use once_cell::sync::Lazy;
use parking_lot::RwLock;
use std::sync::Arc;

// ─── Shared conversation history ───────────────────────────────────────────
//
// Single global history so the LLM fallback chat, the Lua reset/repeat helpers,
// and any future IPC handler all operate on the same buffer. Initialised on
// boot via `init_history(system_prompt, max_turns)`.

static HISTORY: Lazy<RwLock<Option<ConversationHistory>>> = Lazy::new(|| RwLock::new(None));

pub fn init_history(system_prompt: impl Into<String>, max_turns: usize) {
    *HISTORY.write() = Some(ConversationHistory::new(system_prompt, max_turns));
}

pub fn history_push_user(content: impl Into<String>) {
    if let Some(h) = HISTORY.write().as_mut() {
        h.push_user(content);
    }
}

pub fn history_push_assistant(content: impl Into<String>) {
    if let Some(h) = HISTORY.write().as_mut() {
        h.push_assistant(content);
    }
}

pub fn history_snapshot() -> Vec<ChatMessage> {
    HISTORY.read().as_ref().map(|h| h.snapshot()).unwrap_or_default()
}

pub fn history_clear() {
    if let Some(h) = HISTORY.write().as_mut() {
        h.clear();
    }
}

pub fn history_pop_last_user() {
    if let Some(h) = HISTORY.write().as_mut() {
        h.pop_last_user();
    }
}

/// Return the most recent assistant message text, or None.
pub fn history_last_assistant() -> Option<String> {
    HISTORY.read().as_ref()
        .and_then(|h| h.last_assistant().map(|m| m.content.clone()))
}

/// Shared mutable LLM client. Modules read via `current()`; the user can
/// hot-swap backends at runtime via `swap_to(LlmBackend::Ollama)` etc.
///
/// `None` means LLM is disabled (no GROQ_TOKEN and no Ollama reachable, or
/// `init_global()` was never called).
static GLOBAL: Lazy<RwLock<Option<Arc<LlmClient>>>> = Lazy::new(|| RwLock::new(None));

/// Initialise the global client. Precedence:
///   1. Settings DB `llm_backend` field (if non-empty)
///   2. `JARVIS_LLM` env var
///   3. Auto-detect (Groq if `GROQ_TOKEN`, else Ollama)
///
/// Idempotent — replaces any previous global. Returns Ok even when the chosen
/// backend can't be probed: an Ollama server may not be running yet but we
/// stash the client anyway and let calls fail on first request.
pub fn init_global() -> Result<(), ConfigError> {
    // Try DB-persisted choice first.
    let persisted = crate::DB.get().and_then(|db| {
        let s = db.read();
        let backend = s.llm_backend.trim().to_string();
        if backend.is_empty() { None } else { parse_backend(&backend) }
    });

    let c = match persisted {
        Some(LlmBackend::Groq) => LlmClient::groq()?,
        Some(LlmBackend::Ollama) => LlmClient::ollama(),
        None => LlmClient::from_env()?,
    };

    log::info!("LLM global initialised: backend={}, model={}", c.backend().name(), c.model());
    *GLOBAL.write() = Some(Arc::new(c));
    Ok(())
}

/// Return a clone of the active client. Cheap (Arc).
pub fn current() -> Option<Arc<LlmClient>> {
    GLOBAL.read().clone()
}

/// Name of the currently active backend, or "none" if not initialised.
pub fn current_backend_name() -> &'static str {
    match GLOBAL.read().as_ref().map(|c| c.backend()) {
        Some(LlmBackend::Groq) => "groq",
        Some(LlmBackend::Ollama) => "ollama",
        None => "none",
    }
}

/// Hot-swap to a different backend. Returns the new backend's name on success.
/// Persists the choice to the settings DB so it survives restart.
pub fn swap_to(backend: LlmBackend) -> Result<&'static str, ConfigError> {
    let c = match backend {
        LlmBackend::Groq => LlmClient::groq()?,
        LlmBackend::Ollama => LlmClient::ollama(),
    };
    let name = c.backend().name();
    log::info!("LLM swapped → backend={}, model={}", name, c.model());
    *GLOBAL.write() = Some(Arc::new(c));

    // Persist to settings DB (best-effort — log on failure, don't propagate).
    if let Some(db) = crate::DB.get() {
        let snapshot = {
            let mut s = db.write();
            s.llm_backend = name.to_string();
            s.clone()
        };
        if let Err(e) = crate::db::save_settings(&snapshot) {
            log::warn!("LLM swap: failed to persist to settings DB: {}", e);
        } else {
            log::info!("LLM choice persisted: {}", name);
        }
    }

    Ok(name)
}

/// Parse a backend name (case-insensitive) into the enum.
pub fn parse_backend(name: &str) -> Option<LlmBackend> {
    match name.trim().to_lowercase().as_str() {
        "groq" | "cloud" | "облако" | "клауд" => Some(LlmBackend::Groq),
        "ollama" | "local" | "локал" | "локальн" | "локальный" => Some(LlmBackend::Ollama),
        _ => None,
    }
}