const QuitText = struct {
    const text = "Press ctrl+c to quit.";

    pub fn element(this: *@This()) App.Element {
        return .{ .ptr = this, .vtable = &.{ .content = content } };
    }

    fn content(ctx: *anyopaque, _: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
        _ = ctx;
        assert(cells.len == @as(usize, size.x) * @as(usize, size.y));

        const row = 2;
        const col = size.x / 2 -| (text.len / 2);
        const anchor = (row * size.x) + col;

        for (text, 0..) |cp, idx| {
            cells[anchor + idx].style.fg = .white;
            cells[anchor + idx].style.bg = .black;
            cells[anchor + idx].cp = cp;

            // NOTE do not write over the contents of this `Container`'s `Size`
            if (anchor + idx == cells.len - 1) break;
        }
    }
};

const TableText = struct {
    pub fn element(this: *@This()) App.Element {
        return .{
            .ptr = this,
            .vtable = &.{
                .content = content,
            },
        };
    }

    fn content(ctx: *anyopaque, _: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
        _ = ctx;
        _ = size;
        var idx: usize = 0;
        {
            const text = "Normal ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Bold   ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Dim    ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Italic ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Underl ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Blink  ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Invert ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Hidden ";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
        {
            const text = "Strikethrough";
            for (text) |cp| {
                cells[idx].cp = cp;
                idx += 1;
            }
        }
    }
};

const TextStyles = struct {
    const text = "Example";

    pub fn element(this: *@This()) App.Element {
        return .{
            .ptr = this,
            .vtable = &.{
                .minSize = minSize,
                .content = content,
            },
        };
    }

    fn minSize(ctx: *anyopaque, _: *const App.Model, size: zterm.Point) zterm.Point {
        _ = ctx;
        _ = size;
        return .{
            .x = std.meta.fields(zterm.Style.Emphasis).len * TextStyles.text.len,
            .y = (std.meta.fields(zterm.Color).len - 1) * (std.meta.fields(zterm.Color).len - 2),
        };
    }

    fn content(ctx: *anyopaque, _: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
        @setEvalBranchQuota(10000);
        _ = ctx;
        assert(cells.len == @as(usize, size.x) * @as(usize, size.y));

        var row: usize = 0;
        var col: usize = 0;

        // Color
        inline for (std.meta.fields(zterm.Color)) |bg_field| {
            if (bg_field.value == 0) continue; // zterm.Color.default == 0 -> skip

            inline for (std.meta.fields(zterm.Color)) |fg_field| {
                if (fg_field.value == 0) continue; // zterm.Color.default == 0 -> skip
                if (fg_field.value == bg_field.value) continue;

                // witouth any emphasis
                for (text) |cp| {
                    cells[(row * size.x) + col].style.bg = @enumFromInt(bg_field.value);
                    cells[(row * size.x) + col].style.fg = @enumFromInt(fg_field.value);
                    cells[(row * size.x) + col].cp = cp;
                    col += 1;
                }

                // emphasis (no combinations)
                inline for (std.meta.fields(zterm.Style.Emphasis)) |emp_field| {
                    if (emp_field.value == 0) continue; // zterm.Style.Emphasis.reset == 0 -> skip
                    const emphasis: zterm.Style.Emphasis = @enumFromInt(emp_field.value);

                    for (text) |cp| {
                        cells[(row * size.x) + col].style.bg = @enumFromInt(bg_field.value);
                        cells[(row * size.x) + col].style.fg = @enumFromInt(fg_field.value);
                        cells[(row * size.x) + col].style.emphasis = &.{emphasis};
                        cells[(row * size.x) + col].cp = cp;
                        col += 1;
                    }
                }
                row += 1;
                col = 0;
            }
        }
    }
};

pub fn main() !void {
    errdefer |err| log.err("Application Error: {any}", .{err});

    var gpa: std.heap.DebugAllocator(.{}) = .init;
    defer if (gpa.deinit() == .leak) log.err("memory leak", .{});

    const allocator = gpa.allocator();

    var app: App = .init(allocator, .{}, .{});
    var renderer = zterm.Renderer.Buffered.init(allocator);
    defer renderer.deinit();

    var quit_text: QuitText = .{};
    const element = quit_text.element();

    var text_styles: TextStyles = .{};

    var container = try App.Container.init(allocator, .{
        .layout = .{
            // .gap = 2,
            .padding = .{ .top = 5, .bottom = 3, .left = 3, .right = 3 },
            .direction = .vertical,
        },
    }, element);
    defer container.deinit();

    var table_head: TableText = .{};
    try container.append(try .init(allocator, .{
        .size = .{
            .dim = .{ .y = 1 },
            .grow = .horizontal,
        },
    }, table_head.element()));

    var scrollable: App.Scrollable = .init(try .init(allocator, .{
        .layout = .{ .direction = .vertical },
    }, text_styles.element()), .enabled(.white, true));
    try container.append(try App.Container.init(allocator, .{}, scrollable.element()));

    try app.start(.full);
    defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});

    // event loop
    loop: while (true) {
        // batch events since last iteration
        const len = blk: {
            app.queue.poll();
            app.queue.lock();
            defer app.queue.unlock();
            break :blk app.queue.len();
        };

        // handle events
        for (0..len) |_| {
            const event = app.queue.pop();
            log.debug("handling event: {s}", .{@tagName(event)});
            // pre event handling
            switch (event) {
                .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
                .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
                else => {},
            }

            container.handle(&app.model, event) catch |err| app.postEvent(.{
                .err = .{
                    .err = err,
                    .msg = "Container Event handling failed",
                },
            });

            // post event handling
            switch (event) {
                .quit => break :loop,
                else => {},
            }
        }

        container.resize(&app.model, try renderer.resize());
        container.reposition(&app.model, .{});
        try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
        try renderer.flush();
    }
}

pub const panic = App.panic_handler;
const log = std.log.scoped(.default);

const std = @import("std");
const assert = std.debug.assert;
const zterm = @import("zterm");

const App = zterm.App(struct {}, union(enum) {});