use std::sync::Arc;

use async_trait::async_trait;
use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
use insta::{assert_snapshot, with_settings};
use owlen_core::{
    Config, Mode, Provider,
    session::SessionController,
    storage::StorageManager,
    types::{Message, ToolCall},
    ui::{NoOpUiController, UiController},
};
use owlen_tui::ChatApp;
use owlen_tui::events::Event;
use owlen_tui::ui::render_chat;
use ratatui::{Terminal, backend::TestBackend};
use tempfile::tempdir;
use tokio::sync::mpsc;

struct StubProvider;

#[async_trait]
impl Provider for StubProvider {
    fn name(&self) -> &str {
        "stub-provider"
    }

    async fn list_models(&self) -> owlen_core::Result<Vec<owlen_core::types::ModelInfo>> {
        Ok(vec![owlen_core::types::ModelInfo {
            id: "stub-model".into(),
            name: "Stub Model".into(),
            description: Some("Stub model for golden snapshot tests".into()),
            provider: self.name().into(),
            context_window: Some(8192),
            capabilities: vec!["chat".into(), "tool-use".into()],
            supports_tools: true,
        }])
    }

    async fn send_prompt(
        &self,
        _request: owlen_core::types::ChatRequest,
    ) -> owlen_core::Result<owlen_core::types::ChatResponse> {
        Ok(owlen_core::types::ChatResponse {
            message: Message::assistant("stub completion".into()),
            usage: None,
            is_streaming: false,
            is_final: true,
        })
    }

    async fn stream_prompt(
        &self,
        _request: owlen_core::types::ChatRequest,
    ) -> owlen_core::Result<owlen_core::ChatStream> {
        Ok(Box::pin(futures_util::stream::empty()))
    }

    async fn health_check(&self) -> owlen_core::Result<()> {
        Ok(())
    }

    fn as_any(&self) -> &(dyn std::any::Any + Send + Sync) {
        self
    }
}

fn buffer_to_string(buffer: &ratatui::buffer::Buffer) -> String {
    let mut output = String::new();

    for y in 0..buffer.area.height {
        output.push('"');
        for x in 0..buffer.area.width {
            output.push_str(buffer[(x, y)].symbol());
        }
        output.push('"');
        output.push('\n');
    }

    output
}

async fn build_chat_app<F>(configure: F) -> ChatApp
where
    F: FnOnce(&mut SessionController),
{
    let temp_dir = tempdir().expect("temp dir");
    let storage =
        StorageManager::with_database_path(temp_dir.path().join("owlen-tui-snapshots.db"))
            .await
            .expect("storage");
    let storage = Arc::new(storage);

    let mut config = Config::default();
    config.general.default_model = Some("stub-model".into());
    config.general.enable_streaming = true;
    config.privacy.encrypt_local_data = false;
    config.privacy.require_consent_per_session = false;
    config.ui.show_onboarding = false;
    config.ui.show_timestamps = false;
    let provider: Arc<dyn Provider> = Arc::new(StubProvider);
    let ui: Arc<dyn UiController> = Arc::new(NoOpUiController);
    let (event_tx, controller_event_rx) = mpsc::unbounded_channel();

    let mut session = SessionController::new(
        Arc::clone(&provider),
        config,
        Arc::clone(&storage),
        ui,
        true,
        Some(event_tx),
    )
    .await
    .expect("session controller");

    session
        .set_operating_mode(Mode::Chat)
        .await
        .expect("chat mode");

    configure(&mut session);

    let (app, mut session_rx) = ChatApp::new(session, controller_event_rx)
        .await
        .expect("chat app");
    session_rx.close();

    app
}

fn render_snapshot(app: &mut ChatApp, width: u16, height: u16) -> String {
    let backend = TestBackend::new(width, height);
    let mut terminal = Terminal::new(backend).expect("terminal");

    terminal
        .draw(|frame| render_chat(frame, app))
        .expect("render chat");

    let buffer = terminal.backend().buffer();
    buffer_to_string(buffer)
}

#[tokio::test(flavor = "multi_thread")]
async fn render_chat_idle_snapshot() {
    let mut app = build_chat_app(|_| {}).await;

    with_settings!({ snapshot_suffix => "100x35" }, {
        let snapshot = render_snapshot(&mut app, 100, 35);
        assert_snapshot!("chat_idle_snapshot", snapshot);
    });
}

#[tokio::test(flavor = "multi_thread")]
async fn render_chat_tool_call_snapshot() {
    let mut app = build_chat_app(|session| {
        let conversation = session.conversation_mut();
        conversation.push_user_message("What happened in the Rust ecosystem today?");

        let stream_id = conversation.start_streaming_response();
        conversation
            .set_stream_placeholder(stream_id, "Consulting the knowledge base…")
            .expect("placeholder");

        let tool_call = ToolCall {
            id: "call-search-1".into(),
            name: "web_search".into(),
            arguments: serde_json::json!({ "query": "Rust language news" }),
        };
        conversation
            .set_tool_calls_on_message(stream_id, vec![tool_call.clone()])
            .expect("tool call metadata");
        conversation
            .append_stream_chunk(stream_id, "Found multiple articles…", false)
            .expect("stream chunk");

        let tool_message = Message::tool(
            tool_call.id.clone(),
            "Rust 1.85 released with generics cleanups and faster async compilation.".to_string(),
        );
        conversation.push_message(tool_message);

        let assistant_summary = Message::assistant(
            "Summarising the latest Rust release and the async runtime updates.".into(),
        );
        conversation.push_message(assistant_summary);
    })
    .await;

    // Surface quota toast to exercise header/status rendering.
    app.push_toast(
        owlen_tui::toast::ToastLevel::Warning,
        "Cloud usage is at 82% of the hourly quota.",
    );

    with_settings!({
        snapshot_suffix => "80x24"
    }, {
        let snapshot = render_snapshot(&mut app, 80, 24);
        assert_snapshot!("chat_tool_call_snapshot", snapshot);
    });
}

#[tokio::test(flavor = "multi_thread")]
async fn render_command_palette_focus_snapshot() {
    let mut app = build_chat_app(|_| {}).await;

    app.handle_event(Event::Key(KeyEvent::new(
        KeyCode::Char(':'),
        KeyModifiers::NONE,
    )))
    .await
    .expect("enter command mode");

    for ch in ['f', 'o', 'c', 'u', 's'] {
        app.handle_event(Event::Key(KeyEvent::new(
            KeyCode::Char(ch),
            KeyModifiers::NONE,
        )))
        .await
        .expect("type query");
    }

    // Highlight the second suggestion (typically the model picker preview).
    app.handle_event(Event::Key(KeyEvent::new(KeyCode::Down, KeyModifiers::NONE)))
        .await
        .expect("move selection");

    with_settings!({ snapshot_suffix => "80x20" }, {
        let snapshot = render_snapshot(&mut app, 80, 20);
        assert_snapshot!("command_palette_focus", snapshot);
    });
}