const std = @import("std");
const dvui = @import("dvui");
const icons = @import("../icons.zig");
const WindowContext = @import("../WindowContext.zig");

const DocCallback = union(enum) {
    select: usize,
    close: usize,
};

fn documentTab(ctx: *WindowContext, index: usize, callback: *?DocCallback) void {
    const row_id: usize = index;
    const is_selected = if (ctx.active_document_index) |active| active == index else false;
    const focus_color = dvui.themeGet().focus;

    var row = dvui.box(
        @src(),
        .{ .dir = .horizontal },
        .{
            .id_extra = row_id,
            .expand = .none,
            .gravity_y = 0.5,
        },
    );
    {
        var hovered: bool = false;
        var select_row: bool = false;
        const row_data = row.data();

        // Ручная обработка hover/click по строке без пометки события как handled,
        // чтобы кнопка закрытия могла нормально получать свои события.
        for (dvui.events()) |*e| {
            switch (e.evt) {
                .mouse => |*mouse| {
                    if (!dvui.eventMatchSimple(e, row_data)) continue;
                    hovered = true;
                    if (mouse.action == .press and mouse.button == .left) {
                        select_row = true;
                    }
                },
                else => {},
            }
        }

        var overlay = dvui.overlay(@src(), .{
            .margin = dvui.Rect{ .x = 4, .w = 4 },
            .padding = dvui.Rect{ .x = 12, .y = 0, .w = 0, .h = 0 },
            .background = is_selected or hovered,
            .color_fill = if (is_selected) focus_color.opacity(0.35) else if (hovered) focus_color.opacity(0.18) else null,
            .corner_radius = dvui.Rect.all(4),
        });
        {
            var buf: [32]u8 = undefined;
            const label = std.fmt.bufPrint(&buf, "Doc {d}", .{index + 1}) catch "Doc";
            dvui.labelNoFmt(@src(), label, .{}, .{
                .gravity_x = 0.5,
                .gravity_y = 0.5,
                .margin = .{ .w = 24 },
            });

            if (hovered) {
                if (dvui.buttonIcon(@src(), "Close", icons.cross, .{}, .{}, .{
                    .id_extra = row_id +% 1,
                    .margin = dvui.Rect{ .x = 8, .w = 6 },
                    .padding = dvui.Rect.all(2),
                    .gravity_x = 1,
                    .gravity_y = 0.5,
                })) {
                    callback.* = .{ .close = index };
                }
            }
        }
        overlay.deinit();

        if (select_row) {
            callback.* = .{ .select = index };
        }
    }
    row.deinit();
}

pub fn tabBar(ctx: *WindowContext) void {
    var bar = dvui.box(
        @src(),
        .{ .dir = .horizontal },
        .{
            .expand = .horizontal,
            .background = true,
            .padding = .{
                .x = 12,
                .w = 12,
            },
        },
    );
    {
        var callback: ?DocCallback = null;
        for (ctx.documents.items, 0..) |_, i| {
            documentTab(ctx, i, &callback);
        }
        if (callback) |action| {
            switch (action) {
                .select => |index| ctx.setActiveDocument(index),
                .close => |index| ctx.closeDocument(index),
            }
        }

        if (dvui.buttonIcon(@src(), "Create", icons.plus, .{}, .{}, .{
            .gravity_y = 0,
        })) {
            ctx.addNewDocument() catch |err| {
                std.debug.print("addNewDocument error: {}\n", .{err});
            };
        }
    }
    bar.deinit();
}