//! Tier 3 integration tests for the walking skeleton (per ADR-0008).
//!
//! These tests drive synthetic crossterm events through `App::update`
//! and assert on the resulting state and rendered buffer. They
//! exercise the full input → state → render path without a real
//! terminal, so they run on every commit and catch regressions in
//! the wiring between modules.

use crossterm::event::{KeyCode, KeyEvent, KeyEventKind, KeyModifiers};
use ratatui::Terminal;
use ratatui::backend::TestBackend;

use rdbms_playground::action::Action;
use rdbms_playground::app::{App, OutputKind};
use rdbms_playground::event::AppEvent;
use rdbms_playground::mode::Mode;
use rdbms_playground::theme::Theme;
use rdbms_playground::ui;

const fn key(code: KeyCode) -> AppEvent {
    AppEvent::Key(KeyEvent {
        code,
        modifiers: KeyModifiers::NONE,
        kind: KeyEventKind::Press,
        state: crossterm::event::KeyEventState::NONE,
    })
}

fn type_str(app: &mut App, s: &str) -> Vec<Action> {
    let mut actions = Vec::new();
    for c in s.chars() {
        actions.extend(app.update(key(KeyCode::Char(c))));
    }
    actions
}

fn submit(app: &mut App) -> Vec<Action> {
    app.update(key(KeyCode::Enter))
}

fn rendered_text(app: &App, theme: &Theme, width: u16, height: u16) -> String {
    let backend = TestBackend::new(width, height);
    let mut terminal = Terminal::new(backend).expect("create terminal");
    terminal
        .draw(|f| ui::render(app, theme, f))
        .expect("draw frame");
    let buffer = terminal.backend().buffer().clone();
    let mut out = String::new();
    for y in 0..buffer.area.height {
        for x in 0..buffer.area.width {
            out.push_str(buffer[(x, y)].symbol());
        }
        out.push('\n');
    }
    out
}

#[test]
fn typing_then_submitting_produces_an_echo_in_the_output_panel() {
    let mut app = App::new();
    let theme = Theme::dark();

    type_str(&mut app, "hello world");
    let pre_render = rendered_text(&app, &theme, 80, 24);
    assert!(
        pre_render.contains("hello world"),
        "input field should display the typed text:\n{pre_render}"
    );

    let actions = submit(&mut app);
    assert!(actions.is_empty());
    assert!(app.input.is_empty(), "input buffer cleared on submit");
    assert_eq!(app.output.len(), 1);

    let post_render = rendered_text(&app, &theme, 80, 24);
    assert!(
        post_render.contains("hello world"),
        "output panel should display the echoed line:\n{post_render}"
    );
    assert!(
        post_render.contains("[simple]"),
        "echo should be tagged with the submission mode:\n{post_render}"
    );
}

#[test]
fn mode_switch_changes_label_and_subsequent_echoes() {
    let mut app = App::new();
    let theme = Theme::dark();

    let initial = rendered_text(&app, &theme, 80, 24);
    assert!(initial.contains("SIMPLE"));
    assert!(!initial.contains("ADVANCED"));

    type_str(&mut app, "mode advanced");
    submit(&mut app);
    assert_eq!(app.mode, Mode::Advanced);

    let after_switch = rendered_text(&app, &theme, 80, 24);
    assert!(after_switch.contains("ADVANCED"));

    type_str(&mut app, "select 1");
    submit(&mut app);
    let last = app.output.back().expect("output present");
    assert_eq!(last.mode_at_submission, Mode::Advanced);
    assert_eq!(last.kind, OutputKind::Echo);
}

#[test]
fn colon_escape_in_simple_mode_is_one_shot() {
    let mut app = App::new();
    type_str(&mut app, ":select 1");
    submit(&mut app);
    assert_eq!(app.mode, Mode::Simple);
    assert_eq!(app.output[0].mode_at_submission, Mode::Advanced);
    assert_eq!(app.output[0].text, "select 1");

    type_str(&mut app, "another line");
    submit(&mut app);
    assert_eq!(app.output[1].mode_at_submission, Mode::Simple);
}

#[test]
fn quit_command_returns_quit_action() {
    let mut app = App::new();
    type_str(&mut app, "quit");
    let actions = submit(&mut app);
    assert_eq!(actions, vec![Action::Quit]);
}

#[test]
fn rendering_works_at_minimum_useful_size() {
    // Sanity check that the layout does not panic at small sizes.
    let app = App::new();
    let theme = Theme::dark();
    let _ = rendered_text(&app, &theme, 40, 12);
}

#[test]
fn typing_colon_in_simple_mode_flips_prompt_to_advanced() {
    let mut app = App::new();
    let theme = Theme::dark();

    // No `:` yet — prompt shows SIMPLE.
    type_str(&mut app, "sel");
    let before = rendered_text(&app, &theme, 80, 24);
    assert!(before.contains("SIMPLE"));
    assert!(!before.contains("Advanced:"));

    // Reset and type `:` first — prompt should flip immediately.
    app.input.clear();
    type_str(&mut app, ":");
    let after_colon = rendered_text(&app, &theme, 80, 24);
    assert!(
        after_colon.contains("Advanced:"),
        "input panel should show 'Advanced:' once `:` is typed:\n{after_colon}"
    );
    assert!(!after_colon.contains("SIMPLE"));

    // Backspace through both the auto-inserted space and the `:`
    // itself reverts the prompt.
    while !app.input.is_empty() {
        app.update(key(KeyCode::Backspace));
    }
    let after_revert = rendered_text(&app, &theme, 80, 24);
    assert!(after_revert.contains("SIMPLE"));
    assert!(!after_revert.contains("Advanced:"));
}

#[test]
fn status_bar_lists_quit_and_submit_in_all_modes() {
    let mut app = App::new();
    let theme = Theme::dark();

    let simple = rendered_text(&app, &theme, 80, 24);
    assert!(simple.contains("Enter"), "status bar lists Enter");
    assert!(simple.contains("Ctrl-C"), "status bar lists Ctrl-C");
    assert!(simple.contains("mode advanced"));

    type_str(&mut app, "mode advanced");
    submit(&mut app);
    let advanced = rendered_text(&app, &theme, 80, 24);
    assert!(advanced.contains("Enter"));
    assert!(advanced.contains("Ctrl-C"));
    assert!(advanced.contains("mode simple"));
}