use crate::app::action::Action;
use crate::app::effect::Effect;
use crate::app::state::AppState;
use crate::app::viewport::{calculate_next_column_offset, calculate_prev_column_offset};
pub(super) fn result_row_count(state: &AppState) -> usize {
state
.query
.current_result()
.map(|r| r.rows.len())
.unwrap_or(0)
}
pub(super) fn result_col_count(state: &AppState) -> usize {
state
.query
.current_result()
.map(|r| r.columns.len())
.unwrap_or(0)
}
pub(super) fn result_max_scroll(state: &AppState) -> usize {
let visible = state.result_visible_rows();
result_row_count(state).saturating_sub(visible)
}
fn ensure_row_visible(state: &mut AppState) {
if let Some(row) = state.result_interaction.selection().row() {
let visible = state.result_visible_rows();
if visible == 0 {
return;
}
if row < state.result_interaction.scroll_offset {
state.result_interaction.scroll_offset = row;
} else if row >= state.result_interaction.scroll_offset + visible {
state.result_interaction.scroll_offset = row - visible + 1;
}
}
}
fn move_row_or_scroll(state: &mut AppState, new_row: usize, scroll_fn: impl FnOnce(&mut AppState)) {
if state.result_interaction.selection().row().is_some() {
state.result_interaction.move_row(new_row);
ensure_row_visible(state);
} else {
scroll_fn(state);
}
}
pub fn reduce(state: &mut AppState, action: &Action) -> Option<Vec<Effect>> {
match action {
Action::ResultScrollUp => {
let new_row = state
.result_interaction
.selection()
.row()
.and_then(|r| r.checked_sub(1));
match new_row {
Some(r) => move_row_or_scroll(state, r, |_| {}),
None if state.result_interaction.selection().row().is_none() => {
state.result_interaction.scroll_offset =
state.result_interaction.scroll_offset.saturating_sub(1);
}
_ => {} }
Some(vec![])
}
Action::ResultScrollDown => {
let max_row = result_row_count(state).saturating_sub(1);
let new_row = state
.result_interaction
.selection()
.row()
.map(|r| (r + 1).min(max_row))
.unwrap_or(0);
move_row_or_scroll(state, new_row, |s| {
let max_scroll = result_max_scroll(s);
if s.result_interaction.scroll_offset < max_scroll {
s.result_interaction.scroll_offset += 1;
}
});
Some(vec![])
}
Action::ResultScrollTop => {
move_row_or_scroll(state, 0, |s| s.result_interaction.scroll_offset = 0);
Some(vec![])
}
Action::ResultScrollBottom => {
let max_row = result_row_count(state).saturating_sub(1);
let max_scroll = result_max_scroll(state);
move_row_or_scroll(state, max_row, |s| {
s.result_interaction.scroll_offset = max_scroll
});
Some(vec![])
}
Action::ResultScrollMiddle => {
let visible = state.result_visible_rows();
let mid_viewport = visible / 2;
let mid_row = state.result_interaction.scroll_offset + mid_viewport;
let max_row = result_row_count(state).saturating_sub(1);
let target = mid_row.min(max_row);
move_row_or_scroll(state, target, |s| {
let total = result_row_count(s);
let v = s.result_visible_rows();
let ideal = total / 2;
let max_s = total.saturating_sub(v);
s.result_interaction.scroll_offset = ideal.saturating_sub(v / 2).min(max_s);
});
Some(vec![])
}
Action::ResultScrollHalfPageDown => {
let delta = (state.result_visible_rows() / 2).max(1);
let max_row = result_row_count(state).saturating_sub(1);
let new_row = state
.result_interaction
.selection()
.row()
.map(|r| (r + delta).min(max_row))
.unwrap_or(0);
move_row_or_scroll(state, new_row, |s| {
let max = result_max_scroll(s);
s.result_interaction.scroll_offset =
(s.result_interaction.scroll_offset + delta).min(max);
});
Some(vec![])
}
Action::ResultScrollHalfPageUp => {
let delta = (state.result_visible_rows() / 2).max(1);
let new_row = state
.result_interaction
.selection()
.row()
.map(|r| r.saturating_sub(delta))
.unwrap_or(0);
move_row_or_scroll(state, new_row, |s| {
s.result_interaction.scroll_offset =
s.result_interaction.scroll_offset.saturating_sub(delta);
});
Some(vec![])
}
Action::ResultScrollFullPageDown => {
let delta = state.result_visible_rows().max(1);
let max_row = result_row_count(state).saturating_sub(1);
let new_row = state
.result_interaction
.selection()
.row()
.map(|r| (r + delta).min(max_row))
.unwrap_or(0);
move_row_or_scroll(state, new_row, |s| {
let max = result_max_scroll(s);
s.result_interaction.scroll_offset =
(s.result_interaction.scroll_offset + delta).min(max);
});
Some(vec![])
}
Action::ResultScrollFullPageUp => {
let delta = state.result_visible_rows().max(1);
let new_row = state
.result_interaction
.selection()
.row()
.map(|r| r.saturating_sub(delta))
.unwrap_or(0);
move_row_or_scroll(state, new_row, |s| {
s.result_interaction.scroll_offset =
s.result_interaction.scroll_offset.saturating_sub(delta);
});
Some(vec![])
}
Action::ResultScrollLeft => {
state.result_interaction.horizontal_offset =
calculate_prev_column_offset(state.result_interaction.horizontal_offset);
Some(vec![])
}
Action::ResultScrollRight => {
let plan = &state.ui.result_viewport_plan;
let all_widths_len = plan.max_offset + plan.column_count;
state.result_interaction.horizontal_offset = calculate_next_column_offset(
all_widths_len,
state.result_interaction.horizontal_offset,
plan.column_count,
);
Some(vec![])
}
_ => None,
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::sync::Arc;
mod result_page_scroll {
use super::*;
fn state_with_result_rows(rows: usize, pane_height: u16) -> AppState {
let mut state = AppState::new("test".to_string());
state.ui.result_pane_height = pane_height;
let result_rows: Vec<Vec<String>> = (0..rows).map(|i| vec![format!("{}", i)]).collect();
let row_count = result_rows.len();
state
.query
.set_current_result(Arc::new(crate::domain::QueryResult {
query: String::new(),
columns: vec!["id".to_string()],
rows: result_rows,
row_count,
execution_time_ms: 1,
executed_at: std::time::Instant::now(),
source: crate::domain::QuerySource::Preview,
error: None,
command_tag: None,
}));
state
}
#[test]
fn half_page_down_from_top() {
let mut state = state_with_result_rows(100, 25);
let effects = reduce(&mut state, &Action::ResultScrollHalfPageDown);
assert!(effects.is_some());
assert_eq!(state.result_interaction.scroll_offset, 10);
}
#[test]
fn half_page_up_from_middle() {
let mut state = state_with_result_rows(100, 25);
state.result_interaction.scroll_offset = 50;
reduce(&mut state, &Action::ResultScrollHalfPageUp);
assert_eq!(state.result_interaction.scroll_offset, 40);
}
#[test]
fn full_page_down_clamped_at_max() {
let mut state = state_with_result_rows(30, 25);
state.result_interaction.scroll_offset = 5;
reduce(&mut state, &Action::ResultScrollFullPageDown);
assert_eq!(state.result_interaction.scroll_offset, 10);
}
#[test]
fn full_page_up_clamped_at_zero() {
let mut state = state_with_result_rows(100, 25);
state.result_interaction.scroll_offset = 5;
reduce(&mut state, &Action::ResultScrollFullPageUp);
assert_eq!(state.result_interaction.scroll_offset, 0);
}
#[test]
fn zero_height_pane_scrolls_by_one() {
let mut state = state_with_result_rows(100, 0);
reduce(&mut state, &Action::ResultScrollHalfPageDown);
assert_eq!(state.result_interaction.scroll_offset, 1);
}
#[test]
fn scroll_middle_centers_viewport() {
let mut state = state_with_result_rows(100, 25);
reduce(&mut state, &Action::ResultScrollMiddle);
assert_eq!(state.result_interaction.scroll_offset, 40);
}
#[test]
fn scroll_middle_moves_row_to_viewport_center_in_row_active() {
let mut state = state_with_result_rows(100, 25);
state.result_interaction.enter_row(0);
reduce(&mut state, &Action::ResultScrollMiddle);
assert_eq!(state.result_interaction.selection().row(), Some(10));
}
}
}