//! App 级会话持久化的测试（临时数据目录，零网络）。
//! App-level session persistence tests (temp data dir, zero network).

use crossterm::event::{KeyModifiers, MouseEvent, MouseEventKind};
use focus_core::model::Message;
use focus_harness::session::SessionStore;
use focus_tui::app::App;
use std::path::PathBuf;
use std::sync::atomic::{AtomicUsize, Ordering};

static DIR_SEQ: AtomicUsize = AtomicUsize::new(0);

fn temp_data_dir(tag: &str) -> PathBuf {
    let seq = DIR_SEQ.fetch_add(1, Ordering::SeqCst);
    let d = std::env::temp_dir().join(format!(
        "focus-tui-app-{}-{}-{}",
        tag,
        std::process::id(),
        seq
    ));
    let _ = std::fs::remove_dir_all(&d);
    std::fs::create_dir_all(&d).unwrap();
    d
}

/// 构造一个使用临时数据目录的 App（避免环境变量在并行测试间竞争）。
/// Build an App on a temp data dir (avoids env-var races in parallel tests).
fn app_on(dir: &PathBuf) -> App {
    let mut app = App::new();
    app.store = SessionStore::new(dir);
    app
}

#[test]
fn persist_and_reload_session() {
    let dir = temp_data_dir("persist");

    let mut app = app_on(&dir);
    assert_eq!(app.session_id, None);
    app.ensure_session();
    let sid = app.session_id.clone().unwrap();

    app.persist_entries(&[Message::user_text("first")]);
    app.persist_entries(&[Message::user_text("second")]);
    assert_eq!(app.persisted, 2);
    assert_eq!(app.last_entry_id.as_deref(), Some("e2"));

    // 另一个 App 实例加载同一会话。
    // Another App instance loads the same session.
    let mut app2 = app_on(&dir);
    app2.load_session(&sid);
    assert_eq!(app2.transcript.len(), 2);
    assert_eq!(app2.persisted, 2);
    let text = match &app2.transcript[1] {
        Message::User(u) => u.content[0].as_text().map(|t| t.text.clone()),
        _ => None,
    };
    assert_eq!(text.as_deref(), Some("second"));

    // 续写：追加消息（parentId 链延续到 e3）。
    // Continue: appending continues the parentId chain at e3.
    app2.persist_entries(&[Message::user_text("third")]);
    assert_eq!(app2.last_entry_id.as_deref(), Some("e3"));
    let sessions = app2.store.list_sessions().unwrap();
    assert_eq!(sessions, vec![sid.clone()]);
}

#[test]
fn new_session_resets_state() {
    let dir = temp_data_dir("new");

    let mut app = app_on(&dir);
    app.ensure_session();
    let sid1 = app.session_id.clone().unwrap();
    app.persist_entries(&[Message::user_text("hi")]);
    assert_eq!(app.persisted, 1);

    app.new_session();
    assert_eq!(app.session_id, None);
    assert_eq!(app.transcript.len(), 0);
    assert_eq!(app.persisted, 0);
    assert_eq!(app.last_entry_id, None);

    app.ensure_session();
    let sid2 = app.session_id.clone().unwrap();
    assert_ne!(sid1, sid2);
}

/// 滚轮方向与逐行滚动（回归：此前 ScrollUp/ScrollDown 方向写反，且贴底时
/// 上滚被钳回底部导致滚轮失灵）。
/// Wheel direction and line-by-line scrolling (regression: both wheel
/// directions used to scroll down, and scrolling up at the bottom was clamped
/// back, killing the wheel).
#[test]
fn wheel_scrolls_line_by_line_in_correct_direction() {
    let mut app = app_on(&temp_data_dir("wheel"));
    // 模拟内容 100 行、视口 10 行的几何。
    // Simulate geometry: 100 content lines, 10-line viewport.
    app.content_lines = 100;
    app.view_height = 10;

    // 贴底时向上滚：偏移减 1、取消 follow。
    // At the bottom, scrolling up: offset -1, follow cleared.
    app.scroll = 90;
    app.follow = true;
    app.handle_mouse(scroll_event(MouseEventKind::ScrollUp));
    assert_eq!(app.scroll, 89, "wheel up must move up one line");
    assert!(!app.follow);

    // 向下滚：偏移 +1，逐行。
    // Wheel down: offset +1, line by line.
    app.handle_mouse(scroll_event(MouseEventKind::ScrollDown));
    assert_eq!(app.scroll, 90);
    assert!(app.follow, "reaching the bottom restores follow");

    // 从顶部向下滚一次只动一行（不是直接跳到底部）。
    // From the top, one notch moves exactly one line (no jump to the bottom).
    app.scroll = 0;
    app.follow = false;
    app.handle_mouse(scroll_event(MouseEventKind::ScrollDown));
    assert_eq!(app.scroll, 1);

    // 顶部再向上滚不会下溢。
    // Scrolling up at the top does not underflow.
    app.handle_mouse(scroll_event(MouseEventKind::ScrollUp));
    assert_eq!(app.scroll, 0);
}

fn scroll_event(kind: MouseEventKind) -> MouseEvent {
    MouseEvent {
        kind,
        column: 0,
        row: 0,
        modifiers: KeyModifiers::NONE,
    }
}