//! Pure presentation maths. Anything that touches a `Ui` is covered by the
//! manual screenshot pass; these are the calculations a pixel test cannot
//! express.

use std::f32::consts::TAU;

use eframe::egui::{Pos2, Rect, pos2, vec2};
use zagan_bet::roulette::{BetTarget, Outside};
use zagan_bet_gui::roulette::{Felt, number_under, size_for, target_name};
use zagan_bet_gui::theme::{group_digits, money};

#[test]
fn money_is_grouped_in_threes() {
    assert_eq!(group_digits(0), "0");
    assert_eq!(group_digits(999), "999");
    assert_eq!(group_digits(1000), "1 000");
    assert_eq!(group_digits(1234567), "1 234 567");
    assert_eq!(group_digits(-1500), "-1 500");
    assert_eq!(money(1000), "1 000 Kr");
}

#[test]
fn the_wheel_pointer_reads_the_number_at_the_top() {
    let segment = TAU / 37.0;
    assert_eq!(number_under(0.0), 0);

    // Rotating by -i segments puts wheel entry i under the pointer.
    for number in [0u8, 32, 17, 26] {
        let index = zagan_bet::roulette::WHEEL
            .iter()
            .position(|candidate| *candidate == number)
            .expect("number is on the wheel");
        let rotation = -(index as f32) * segment;
        assert_eq!(number_under(rotation), number);
    }

    // One full turn changes nothing.
    assert_eq!(number_under(-TAU), 0);
}

#[test]
fn table_size_keeps_the_felt_aspect_and_fits() {
    let available = eframe::egui::vec2(1300.0, 900.0);
    let size = size_for(available);
    assert!(size.x <= available.x + 0.01, "{size:?} overflows");
    assert!(size.y <= available.y + 0.01, "{size:?} overflows");

    // 13 cells wide and 4.89 cells tall, plus the felt border on every side.
    let cell = (size.x - 12.0) / 13.0;
    assert!((cell - (size.y - 12.0) / 4.89).abs() < 0.01);
}

fn felt() -> Felt {
    Felt::new(Rect::from_min_size(
        Pos2::ZERO,
        size_for(vec2(1300.0, 900.0)),
    ))
}

#[test]
fn the_pointer_snaps_to_straights_splits_and_corners() {
    let felt = felt();
    let cell = felt.cell_size();
    let center = felt.number_rect(17).center();

    // The inner half of a cell is a straight, even slightly off centre.
    assert_eq!(
        felt.target_at(center + vec2(cell * 0.2, 0.0)),
        Some(BetTarget::Straight { number: 17 })
    );

    // A quarter cell from the centre is the line: right of 17 is 20, above is 18.
    assert_eq!(
        felt.target_at(center + vec2(cell * 0.3, 0.0)),
        Some(BetTarget::Split { a: 17, b: 20 })
    );
    assert_eq!(
        felt.target_at(center + vec2(0.0, -cell * 0.3)),
        Some(BetTarget::Split { a: 17, b: 18 })
    );

    // Near both lines at once is the corner of the four cells.
    assert_eq!(
        felt.target_at(center + vec2(cell * 0.3, -cell * 0.3)),
        Some(BetTarget::Corner {
            numbers: [17, 18, 20, 21]
        })
    );

    // Zero is a straight and nothing else.
    assert_eq!(
        felt.target_at(felt.number_rect(0).center()),
        Some(BetTarget::Straight { number: 0 })
    );
}

#[test]
fn the_pointer_finds_the_wide_bets_below_the_grid() {
    let felt = felt();
    let cell = felt.cell_size();
    let x = felt.number_rect(17).center().x;
    let grid_bottom = felt.number_rect(16).bottom();

    // 17 sits in the second dozen (13-24).
    assert_eq!(
        felt.target_at(pos2(x, grid_bottom + cell * 0.3)),
        Some(BetTarget::Dozen { index: 1 })
    );

    // Below the dozens is the column row; 17 is in column 2 (2,5,...,17).
    assert_eq!(
        felt.target_at(pos2(x, grid_bottom + cell * (0.72 + 0.3))),
        Some(BetTarget::Column { index: 1 })
    );

    // And below that, the outside row: 17's column lands on RED.
    assert_eq!(
        felt.target_at(pos2(x, grid_bottom + cell * (0.72 + 0.55 + 0.3))),
        Some(BetTarget::Outside { kind: Outside::Red })
    );

    // Outside the board is not a bet.
    assert_eq!(felt.target_at(pos2(-1.0, -1.0)), None);
}

#[test]
fn targets_read_as_bet_slips() {
    assert_eq!(
        target_name(&BetTarget::Straight { number: 17 }),
        "Straight 17"
    );
    assert_eq!(
        target_name(&BetTarget::Split { a: 26, b: 29 }),
        "Split 26/29"
    );
    assert_eq!(
        target_name(&BetTarget::Corner {
            numbers: [17, 18, 20, 21]
        }),
        "Corner 17/18/20/21"
    );
    assert_eq!(target_name(&BetTarget::Dozen { index: 1 }), "2nd 12");
    assert_eq!(target_name(&BetTarget::Column { index: 2 }), "Column 3");
    assert_eq!(
        target_name(&BetTarget::Outside {
            kind: Outside::High
        }),
        "19-36"
    );
    assert_eq!(
        target_name(&BetTarget::Outside {
            kind: Outside::Black
        }),
        "Black"
    );
}