//! Pop-up Menu widget to show the available keybindings

const std = @import("std");
const vaxis = @import("vaxis");

const widget = @import("../widget.zig");

const Event = widget.Event;

allocator: std.mem.Allocator = undefined,
unicode: *const vaxis.Unicode = undefined,

pub fn init(allocator: std.mem.Allocator, unicode: *const vaxis.Unicode) @This() {
    return .{
        .allocator = allocator,
        .unicode = unicode,
    };
}

pub fn deinit(this: *@This()) void {
    this.* = undefined;
}

/// Update loop for a given widget to react to the provided `Event`. It may
/// change its internal state, update variables, react to user input, etc.
pub fn update(this: *@This(), event: Event) ?Event {
    _ = this;
    switch (event) {
        .key_press => |key| {
            if (key.matches('a', .{})) {
                // About
                return .{ .path = "./doc/about.md" };
            }
            if (key.matches('h', .{})) {
                // Home
                return .{ .path = "./doc/home.md" };
            }
        },
        else => {},
    }
    return null;
}

/// Draw a given widget using the provided `vaxis.Window`. The window controls
/// the dimension one widget may take on the screen. The widget itself has no
/// control over this.
pub fn draw(this: *@This(), win: vaxis.Window) void {
    var view = vaxis.widgets.View.init(this.allocator, this.unicode, .{ .width = win.width, .height = win.height }) catch @panic("OOM");
    defer view.deinit();

    const msg =
        \\# Goto
        \\
        \\*a* about
        \\*h* home
    ;
    var col: usize = 0;
    var row: usize = 0;
    for (msg, 0..) |_, i| {
        const cell: vaxis.Cell = .{
            // each cell takes a _grapheme_ as opposed to a single
            // codepoint. This allows Vaxis to handle emoji properly,
            // particularly with terminals that the Unicode Core extension
            // (IE Mode 2027)
            .char = .{ .grapheme = msg[i .. i + 1] },
            .style = .{
                .fg = .{ .index = 6 },
                .bold = true,
            },
        };
        view.writeCell(col, row, cell);
        if (std.mem.eql(u8, cell.char.grapheme, "\n")) {
            col = 0;
            row += 1;
        } else {
            col += 1;
        }
    }
    view.draw(win, .{});
}