widgets: added table widget

- Added `Table.zig` under the `src/widgets` directory and `widgets.zig` module.
- Created the `drawTable()` function to draw a Table to the provided parent Window based on the provided ArrayList.
- Created the `TableContext` struct to manage state and attributes for the `drawTable()` function.

src/widgets.zig

@@ -1,3 +1,4 @@
 pub const border = @import("widgets/border.zig");
 pub const alignment = @import("widgets/alignment.zig");
 pub const TextInput = @import("widgets/TextInput.zig");
+pub const Table = @import("widgets/Table.zig");

src/widgets/Table.zig

@@ -0,0 +1,150 @@
+const std = @import("std");
+const ascii = std.ascii;
+const fmt = std.fmt;
+const fs = std.fs;
+const heap = std.heap;
+const log = std.log;
+const mem = std.mem;
+const meta = std.meta;
+
+const vaxis = @import("../main.zig");
+
+/// Table Context for maintaining state and drawing Tables with `drawTable()`.
+pub const TableContext = struct {
+    /// Current selected Row of the Table.
+    row: usize = 0,
+    /// Current selected Column of the Table.
+    col: usize = 0,
+    /// Starting point within the Data List.
+    start: usize = 0,
+
+    /// Active status of the Table.
+    active: bool = false,
+
+    /// The Background Color for Selected Rows and Column Headers.
+    selected_bg: vaxis.Cell.Color,
+    /// First Column Header Background Color
+    hdr_bg_1: vaxis.Cell.Color = .{ .rgb = [_]u8{ 64, 64, 64 } },
+    /// Second Column Header Background Color
+    hdr_bg_2: vaxis.Cell.Color = .{ .rgb = [_]u8{ 8, 8, 24 } },
+    /// First Row Background Color
+    row_bg_1: vaxis.Cell.Color = .{ .rgb = [_]u8{ 32, 32, 32 } },
+    /// Second Row Background Color
+    row_bg_2: vaxis.Cell.Color = .{ .rgb = [_]u8{ 8, 8, 8 } },
+
+    /// Y Offset for drawing to the parent Window.
+    y_off: usize = 0,
+};
+
+/// Draw a Table for the TUI.
+pub fn drawTable(
+    /// This should be an ArenaAllocator that can be deinitialized after each event call.
+    /// The Allocator is only used if a row field is a non-String.
+    /// If the Allocator is not provided, those fields will show "[unsupported (TypeName)]".
+    alloc: ?mem.Allocator,
+    /// The parent Window to draw to.
+    win: vaxis.Window,
+    /// Headers for the Table
+    headers: []const []const u8,
+    /// This must be an ArrayList.
+    data_list: anytype,
+    // The Table Context for this Table.
+    table_ctx: *TableContext,
+) !void {
+    const table_win = win.initChild(
+        0,
+        table_ctx.y_off,
+        .{ .limit = win.width },
+        .{ .limit = win.height },
+    );
+
+    var item_width = table_win.width / headers.len;
+    if (item_width % 2 != 0) item_width += 1;
+
+    if (table_ctx.col > headers.len - 1) table_ctx.*.col = headers.len - 1;
+    for (headers[0..], 0..) |hdr_txt, idx| {
+        const hdr_bg =
+            if (table_ctx.active and idx == table_ctx.col) table_ctx.selected_bg else if (idx % 2 == 0) table_ctx.hdr_bg_1 else table_ctx.hdr_bg_2;
+        const hdr_win = table_win.initChild(
+            idx * item_width,
+            0,
+            .{ .limit = item_width },
+            .{ .limit = 1 },
+        );
+        var hdr = vaxis.widgets.alignment.center(hdr_win, @min(item_width - 1, hdr_txt.len), 1);
+        hdr_win.fill(.{ .style = .{ .bg = hdr_bg } });
+        var seg = [_]vaxis.Cell.Segment{.{
+            .text = hdr_txt,
+            .style = .{
+                .bg = hdr_bg,
+                .bold = true,
+                .ul_style = if (idx == table_ctx.col) .single else .dotted,
+            },
+        }};
+        try hdr.wrap(seg[0..]);
+    }
+
+    const max_items = if (data_list.items.len > table_win.height - 1) table_win.height - 1 else data_list.items.len;
+    var end = table_ctx.*.start + max_items;
+    if (end > data_list.items.len) end = data_list.items.len;
+    table_ctx.*.start = tableStart: {
+        if (table_ctx.row == 0)
+            break :tableStart 0;
+        if (table_ctx.row < table_ctx.start)
+            break :tableStart table_ctx.start - (table_ctx.start - table_ctx.row);
+        if (table_ctx.row >= data_list.items.len - 1)
+            table_ctx.*.row = data_list.items.len - 1;
+        if (table_ctx.row >= end)
+            break :tableStart table_ctx.start + (table_ctx.row - end + 1);
+        break :tableStart table_ctx.start;
+    };
+    end = table_ctx.*.start + max_items;
+    if (end > data_list.items.len) end = data_list.items.len;
+    for (data_list.items[table_ctx.start..end], 0..) |data, idx| {
+        const row_bg =
+            if (table_ctx.active and table_ctx.start + idx == table_ctx.row) table_ctx.selected_bg else if (idx % 2 == 0) table_ctx.row_bg_1 else table_ctx.row_bg_2;
+
+        const row_win = table_win.initChild(
+            0,
+            1 + idx,
+            .{ .limit = table_win.width },
+            .{ .limit = 1 },
+        );
+        const DataT = @TypeOf(data);
+        const item_fields = meta.fields(DataT);
+        inline for (item_fields[0..], 0..) |item_field, item_idx| {
+            const item = @field(data, item_field.name);
+            const ItemT = @TypeOf(item);
+            const item_win = row_win.initChild(
+                item_idx * item_width,
+                0,
+                .{ .limit = item_width },
+                .{ .limit = 1 },
+            );
+            item_win.fill(.{ .style = .{ .bg = row_bg } });
+            var seg = [_]vaxis.Cell.Segment{.{
+                .text = switch (ItemT) {
+                    []const u8 => item,
+                    else => nonStr: {
+                        switch (@typeInfo(ItemT)) {
+                            .Optional => {
+                                const opt_item = item orelse break :nonStr "-";
+                                switch (@typeInfo(ItemT).Optional.child) {
+                                    []const u8 => break :nonStr opt_item,
+                                    else => {
+                                        break :nonStr if (alloc) |_alloc| try fmt.allocPrint(_alloc, "{any}", .{opt_item}) else fmt.comptimePrint("[unsupported ({s})]", .{@typeName(DataT)});
+                                    },
+                                }
+                            },
+                            else => {
+                                break :nonStr if (alloc) |_alloc| try fmt.allocPrint(_alloc, "{any}", .{item}) else fmt.comptimePrint("[unsupported ({s})]", .{@typeName(DataT)});
+                            },
+                        }
+                    },
+                },
+                .style = .{ .bg = row_bg },
+            }};
+            try item_win.wrap(seg[0..]);
+        }
+    }
+}