const std = @import("std"); pub const FooterRows = struct {    /// Outer top of the footer. Matches `banner` when a banner is    /// active, otherwise matches `top_divider`.    top: u16,    top_divider: u16,    /// Row that sits above the top divider for state banners.    banner: u16,    banner_active: bool = false,    banner_rows: u16 = 0,    input_base: u16,    picker_divider: u16,    picker_start: u16,    bottom_divider: u16,    hint: u16,    total_rows: u16,    composer_top_chrome_rows: u16 = 1,}; pub const Input = struct {    footer_top_for_extra: u16,    terminal_rows: u16,    activity_offset: u16,    extra_input_rows: u16,    input_extra: u16,    input_visible: bool = true,    composer_top_chrome_rows: u16 = 1,    picker_rows: u16,    banner_active: bool,    banner_rows: u16 = 0,    allocated_rows: ?u16 = null,}; pub fn reservedBaseRows(input_visible: bool, composer_top_chrome_rows: u16) u16 {    return if (input_visible) 2 +| composer_top_chrome_rows else 3;} pub fn resolve(input: Input) FooterRows {    if (input.allocated_rows) |allocated_rows| {        return resolveAllocated(input, allocated_rows);    }     const composer_top_chrome_rows: u16 = if (input.input_visible) input.composer_top_chrome_rows else 1;    const reserved: u32 = @as(u32, reservedBaseRows(input.input_visible, composer_top_chrome_rows)) + @as(u32, input.extra_input_rows);    const max_top: u16 = if (@as(u32, input.terminal_rows) > reserved)        @intCast(@as(u32, input.terminal_rows) - reserved)    else        1;    const outer_top = @min(input.footer_top_for_extra + input.activity_offset, max_top);    const banner_offset: u16 = if (input.banner_rows > 0)        input.banner_rows    else if (input.banner_active)        1    else        0;    const banner_row = outer_top;    const top_divider = outer_top + banner_offset;    if (!input.input_visible) {        const picker_start = top_divider + 1;        const bottom_divider = picker_start + input.picker_rows;        const hint = bottom_divider + 1;        return .{            .top = outer_top,            .top_divider = top_divider,            .banner = banner_row,            .banner_active = banner_offset > 0,            .banner_rows = banner_offset,            .input_base = top_divider,            .picker_divider = top_divider,            .picker_start = picker_start,            .bottom_divider = bottom_divider,            .hint = hint,            .total_rows = hint - outer_top + 1,            .composer_top_chrome_rows = 1,        };    }    const input_base = top_divider + composer_top_chrome_rows + input.input_extra;    const picker_divider = input_base + 1;    const bottom_divider = if (input.picker_rows > 0) picker_divider + 1 + input.picker_rows else picker_divider;    const hint = bottom_divider + 1;    return .{        .top = outer_top,        .top_divider = top_divider,        .banner = banner_row,        .banner_active = banner_offset > 0,        .banner_rows = banner_offset,        .input_base = input_base,        .picker_divider = picker_divider,        .picker_start = picker_divider + 1,        .bottom_divider = bottom_divider,        .hint = hint,        .total_rows = hint - outer_top + 1,        .composer_top_chrome_rows = composer_top_chrome_rows,    };} fn resolveAllocated(input: Input, requested_rows: u16) FooterRows {    const top = @max(@min(input.footer_top_for_extra, input.terminal_rows), 1);    const available = input.terminal_rows - top + 1;    const allocated_rows = @max(@min(requested_rows, available), 1);    const bottom = top + allocated_rows - 1;    const requested_banner_rows: u16 = if (input.banner_rows > 0)        input.banner_rows    else if (input.banner_active)        1    else        0;    const banner_rows = @min(requested_banner_rows, allocated_rows -| 1);    const top_divider = top + banner_rows;    const approval_rows = allocated_rows - banner_rows;    const picker_start = if (approval_rows > 1) top_divider + 1 else top_divider;    const bottom_divider = if (approval_rows > 1) bottom - 1 else bottom;     return .{        .top = top,        .top_divider = top_divider,        .banner = top,        .banner_active = banner_rows > 0,        .banner_rows = banner_rows,        .input_base = top_divider,        .picker_divider = top_divider,        .picker_start = picker_start,        .bottom_divider = bottom_divider,        .hint = bottom,        .total_rows = allocated_rows,        .composer_top_chrome_rows = 1,    };} test "footer rows anchor to transcript cursor" {    const rows = resolve(.{        .footer_top_for_extra = 8,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 0,        .input_extra = 0,        .picker_rows = 0,        .banner_active = false,    });    try std.testing.expectEqual(@as(u16, 8), rows.top);    try std.testing.expectEqual(@as(u16, 8), rows.top_divider);    try std.testing.expectEqual(@as(u16, 9), rows.input_base);    try std.testing.expectEqual(@as(u16, 10), rows.picker_divider);    try std.testing.expectEqual(@as(u16, 10), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 11), rows.hint);} test "footer rows clamp near window bottom" {    const rows = resolve(.{        .footer_top_for_extra = 19,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 2,        .input_extra = 2,        .picker_rows = 0,        .banner_active = false,    });    try std.testing.expectEqual(@as(u16, 19), rows.top);    try std.testing.expectEqual(@as(u16, 19), rows.top_divider);    try std.testing.expectEqual(@as(u16, 22), rows.input_base);    try std.testing.expectEqual(@as(u16, 23), rows.picker_divider);    try std.testing.expectEqual(@as(u16, 23), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 24), rows.hint);} test "footer rows reserve vertical picker block below input" {    const rows = resolve(.{        .footer_top_for_extra = 17,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 4,        .input_extra = 0,        .picker_rows = 3,        .banner_active = false,    });    try std.testing.expectEqual(@as(u16, 17), rows.top);    try std.testing.expectEqual(@as(u16, 17), rows.top_divider);    try std.testing.expectEqual(@as(u16, 18), rows.input_base);    try std.testing.expectEqual(@as(u16, 19), rows.picker_divider);    try std.testing.expectEqual(@as(u16, 20), rows.picker_start);    try std.testing.expectEqual(@as(u16, 23), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 24), rows.hint);} test "footer rows collapse visible tint top chrome" {    const rows = resolve(.{        .footer_top_for_extra = 20,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 0,        .input_extra = 0,        .composer_top_chrome_rows = 0,        .picker_rows = 0,        .banner_active = false,    });    try std.testing.expectEqual(@as(u16, 20), rows.top);    try std.testing.expectEqual(@as(u16, 20), rows.top_divider);    try std.testing.expectEqual(@as(u16, 20), rows.input_base);    try std.testing.expectEqual(@as(u16, 21), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 22), rows.hint);    try std.testing.expectEqual(@as(u16, 3), rows.total_rows);    try std.testing.expectEqual(@as(u16, 0), rows.composer_top_chrome_rows);} test "footer rows keep tint multiline and picker offsets coherent" {    const rows = resolve(.{        .footer_top_for_extra = 18,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 5,        .input_extra = 1,        .composer_top_chrome_rows = 0,        .picker_rows = 3,        .banner_active = false,    });    try std.testing.expectEqual(@as(u16, 17), rows.top);    try std.testing.expectEqual(@as(u16, 17), rows.top_divider);    try std.testing.expectEqual(@as(u16, 18), rows.input_base);    try std.testing.expectEqual(@as(u16, 19), rows.picker_divider);    try std.testing.expectEqual(@as(u16, 20), rows.picker_start);    try std.testing.expectEqual(@as(u16, 23), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 24), rows.hint);} test "footer rows keep tint queued banner above input" {    const rows = resolve(.{        .footer_top_for_extra = 20,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 1,        .input_extra = 0,        .composer_top_chrome_rows = 0,        .picker_rows = 0,        .banner_active = true,        .banner_rows = 1,    });    try std.testing.expectEqual(@as(u16, 20), rows.top);    try std.testing.expectEqual(@as(u16, 20), rows.banner);    try std.testing.expectEqual(@as(u16, 21), rows.top_divider);    try std.testing.expectEqual(@as(u16, 21), rows.input_base);    try std.testing.expectEqual(@as(u16, 22), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 23), rows.hint);} test "footer rows can replace input row with picker panel" {    const rows = resolve(.{        .footer_top_for_extra = 17,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 7,        .input_extra = 0,        .input_visible = false,        .composer_top_chrome_rows = 0,        .picker_rows = 7,        .banner_active = false,    });    try std.testing.expectEqual(@as(u16, 14), rows.top);    try std.testing.expectEqual(@as(u16, 14), rows.top_divider);    try std.testing.expectEqual(@as(u16, 14), rows.input_base);    try std.testing.expectEqual(@as(u16, 14), rows.picker_divider);    try std.testing.expectEqual(@as(u16, 15), rows.picker_start);    try std.testing.expectEqual(@as(u16, 22), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 23), rows.hint);} test "footer rows reserve a banner row when queued prompt is active" {    const rows = resolve(.{        .footer_top_for_extra = 8,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 1,        .input_extra = 0,        .picker_rows = 0,        .banner_active = true,    });    try std.testing.expectEqual(@as(u16, 8), rows.top);    try std.testing.expectEqual(@as(u16, 8), rows.banner);    try std.testing.expect(rows.banner_active);    try std.testing.expectEqual(@as(u16, 9), rows.top_divider);    try std.testing.expectEqual(@as(u16, 10), rows.input_base);    try std.testing.expectEqual(@as(u16, 11), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 12), rows.hint);} test "footer rows reserve explicit multi-row banner" {    const rows = resolve(.{        .footer_top_for_extra = 8,        .terminal_rows = 24,        .activity_offset = 0,        .extra_input_rows = 6,        .input_extra = 0,        .picker_rows = 0,        .banner_active = true,        .banner_rows = 6,    });    try std.testing.expectEqual(@as(u16, 8), rows.top);    try std.testing.expectEqual(@as(u16, 8), rows.banner);    try std.testing.expect(rows.banner_active);    try std.testing.expectEqual(@as(u16, 6), rows.banner_rows);    try std.testing.expectEqual(@as(u16, 14), rows.top_divider);    try std.testing.expectEqual(@as(u16, 15), rows.input_base);    try std.testing.expectEqual(@as(u16, 16), rows.bottom_divider);    try std.testing.expectEqual(@as(u16, 17), rows.hint);}