use std::cell::RefCell;
use std::rc::Rc;

use gpui::{
    AppContext as _, Context, Entity, IntoElement, ParentElement as _, Render, SharedString,
    Styled as _, TestAppContext, VisualTestContext, Window, div,
};
use gpui_native_core::command_palette::{Command, CommandPalette, CommandPaletteState};
use gpui_native_core::init;

fn commands() -> Vec<Command> {
    vec![
        Command::new("open-file", "Open File").hint("Cmd+O"),
        Command::new("close-tab", "Close Tab"),
        Command::new("save-all", "Save All").hint("Cmd+Alt+S"),
        Command::new("toggle-theme", "Toggle Theme"),
    ]
}

/// The caller-owned matcher: case-insensitive substring. `reverse` flips the
/// match order, exercising that ranking belongs to the caller.
fn substring_matcher(reverse: bool) -> impl Fn(&str, &[Command]) -> Vec<Command> {
    move |query, commands| {
        let query = query.to_lowercase();
        let matched: Vec<Command> = commands
            .iter()
            .filter(|command| command.label.to_lowercase().contains(&query))
            .cloned()
            .collect();
        if reverse {
            matched.into_iter().rev().collect()
        } else {
            matched
        }
    }
}

struct Host {
    palette: Entity<CommandPaletteState>,
}

impl Render for Host {
    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
        div().size_full().child(self.palette.clone())
    }
}

type Executed = Rc<RefCell<Vec<SharedString>>>;

struct PaletteHost {
    cx: TestAppContext,
    state: Entity<CommandPaletteState>,
    executed: Executed,
    visual: VisualTestContext,
}

fn palette_host(reverse: bool) -> PaletteHost {
    let cx = TestAppContext::single();
    // `init` registers the input bindings and then the palette's, in the
    // load-bearing order.
    cx.update(init);
    let executed: Executed = Rc::new(RefCell::new(Vec::new()));
    let state_cell: Rc<RefCell<Option<Entity<CommandPaletteState>>>> = Rc::new(RefCell::new(None));
    let window = cx.update(|cx| {
        let executed_for_builder = executed.clone();
        let cell = state_cell.clone();
        cx.open_window(gpui::WindowOptions::default(), |window, cx| {
            let palette =
                CommandPalette::new("test-palette", commands(), substring_matcher(reverse))
                    .on_execute(move |command: &Command, _, _| {
                        executed_for_builder.borrow_mut().push(command.id.clone())
                    });
            let state = cx.new(|cx| CommandPaletteState::new(palette, window, cx));
            cell.borrow_mut().replace(state.clone());
            cx.new(|_| Host { palette: state })
        })
        .unwrap()
    });
    let state = state_cell.borrow().clone().expect("state captured");
    let mut visual = VisualTestContext::from_window(window.into(), &cx);
    draw(&mut visual);
    PaletteHost {
        cx,
        state,
        executed,
        visual,
    }
}

fn draw(visual: &mut VisualTestContext) {
    visual.update(|window, cx| {
        window.draw(cx).clear(cx);
    });
}

fn open(host: &mut PaletteHost) {
    let state = host.state.clone();
    host.visual.update(|window, cx| {
        state.update(cx, |state, cx| state.open(window, cx));
    });
}

fn type_text(host: &mut PaletteHost, text: &str) {
    for letter in text.chars() {
        host.visual.simulate_keystrokes(&letter.to_string());
    }
    draw(&mut host.visual);
}

#[test]
fn open_lists_the_callers_commands() {
    let mut host = palette_host(false);
    open(&mut host);
    draw(&mut host.visual);

    assert!(host.visual.debug_bounds("test-palette-command-0").is_some());
    assert!(host.visual.debug_bounds("test-palette-command-3").is_some());
    assert!(host.visual.debug_bounds("test-palette-panel").is_some());
    assert!(host.cx.update(|cx| host.state.read(cx).is_open()));
}

#[test]
fn enter_runs_the_highlighted_command_and_closes() {
    let mut host = palette_host(false);
    open(&mut host);
    host.visual.simulate_keystrokes("enter");
    draw(&mut host.visual);

    assert_eq!(
        *host.executed.borrow(),
        vec![SharedString::from("open-file")],
        "the first row starts highlighted"
    );
    assert!(host.visual.debug_bounds("test-palette-panel").is_none());
}

#[test]
fn rows_follow_the_callers_match_order() {
    let mut host = palette_host(true);
    open(&mut host);
    host.visual.simulate_keystrokes("enter");
    draw(&mut host.visual);

    assert_eq!(
        *host.executed.borrow(),
        vec![SharedString::from("toggle-theme")],
        "enter runs the first row, and the caller's matcher owns the row order"
    );
}

#[test]
fn typing_filters_through_the_caller_matcher() {
    let mut host = palette_host(false);
    open(&mut host);
    type_text(&mut host, "save");

    assert!(host.visual.debug_bounds("test-palette-command-0").is_some());
    assert!(
        host.visual.debug_bounds("test-palette-command-1").is_none(),
        "only the matching command stays listed"
    );

    host.visual.simulate_keystrokes("enter");
    draw(&mut host.visual);
    assert_eq!(
        *host.executed.borrow(),
        vec![SharedString::from("save-all")]
    );
}

#[test]
fn escape_closes_without_running() {
    let mut host = palette_host(false);
    open(&mut host);
    host.visual.simulate_keystrokes("escape");
    draw(&mut host.visual);

    assert!(host.visual.debug_bounds("test-palette-panel").is_none());
    assert!(host.executed.borrow().is_empty());
    assert!(!host.cx.update(|cx| host.state.read(cx).is_open()));
}

#[test]
fn arrow_keys_move_the_highlight() {
    let mut host = palette_host(false);
    open(&mut host);
    host.visual.simulate_keystrokes("down");
    host.visual.simulate_keystrokes("enter");
    draw(&mut host.visual);
    assert_eq!(
        *host.executed.borrow(),
        vec![SharedString::from("close-tab")]
    );

    // Up from the top wraps to the last row.
    open(&mut host);
    host.visual.simulate_keystrokes("up");
    host.visual.simulate_keystrokes("enter");
    draw(&mut host.visual);
    assert_eq!(
        *host.executed.borrow(),
        vec![
            SharedString::from("close-tab"),
            SharedString::from("toggle-theme")
        ]
    );
}

#[test]
fn clicking_a_row_runs_it() {
    let mut host = palette_host(false);
    open(&mut host);
    let row = host
        .visual
        .debug_bounds("test-palette-command-2")
        .expect("save-all row missing");
    host.visual
        .simulate_click(row.center(), gpui::Modifiers::default());
    draw(&mut host.visual);

    assert_eq!(
        *host.executed.borrow(),
        vec![SharedString::from("save-all")]
    );
    assert!(host.visual.debug_bounds("test-palette-panel").is_none());
}

#[test]
fn clicking_the_scrim_closes() {
    let mut host = palette_host(false);
    open(&mut host);
    draw(&mut host.visual);
    host.visual.simulate_click(
        gpui::point(gpui::px(10.), gpui::px(10.)),
        gpui::Modifiers::default(),
    );
    draw(&mut host.visual);

    assert!(host.visual.debug_bounds("test-palette-panel").is_none());
    assert!(host.executed.borrow().is_empty());
}

#[test]
fn reopen_starts_from_a_fresh_query() {
    let mut host = palette_host(false);
    open(&mut host);
    type_text(&mut host, "zzzz");
    assert!(
        host.visual.debug_bounds("test-palette-command-0").is_none(),
        "nothing matches nonsense"
    );

    host.visual.simulate_keystrokes("escape");
    open(&mut host);
    draw(&mut host.visual);
    assert!(
        host.visual.debug_bounds("test-palette-command-0").is_some(),
        "a fresh open clears the query"
    );
}

#[test]
fn set_commands_replaces_the_registry() {
    let mut host = palette_host(false);
    host.cx.update(|cx| {
        host.state.update(cx, |state, cx| {
            state.set_commands(vec![Command::new("only", "Only Command")], cx)
        });
    });
    open(&mut host);
    draw(&mut host.visual);

    assert!(host.visual.debug_bounds("test-palette-command-0").is_some());
    assert!(host.visual.debug_bounds("test-palette-command-1").is_none());

    host.visual.simulate_keystrokes("enter");
    draw(&mut host.visual);
    assert_eq!(*host.executed.borrow(), vec![SharedString::from("only")]);
}