//! Renderer which holds the screen to compare with the previous screen for efficient rendering.
const std = @import("std");
const terminal = @import("terminal.zig");

const Contents = std.ArrayList(u8);
const Position = terminal.Position;
const Size = terminal.Size;

pub fn Buffered(comptime fullscreen: bool) type {
    return struct {
        refresh: bool = false,
        size: terminal.Size = undefined,
        screen: Contents = undefined,

        pub fn init(allocator: std.mem.Allocator) @This() {
            return .{
                .fullscreen = fullscreen,
                .screen = Contents.init(allocator),
            };
        }

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

        pub fn resize(this: *@This(), size: Size) void {
            // TODO: are there size changes which impact the corresponding rendered content?
            // -> can I even be sure nothing needs to be re-rendered?
            this.size = size;
            this.refresh = true;
        }

        pub fn render(this: *@This(), content: *Contents) !void {
            // TODO: put the corresponding screen to the terminal
            // -> determine diff between screen and new content and only update the corresponding characters of the terminal
            _ = this;
            _ = content;
            @panic("Not yet implemented.");
        }
    };
}

pub fn Plain(comptime _: bool) type {
    return struct {
        pub fn clear(this: @This(), anchor: Position, size: Size) !void {
            _ = this;
            _ = size;
            // NOTE: clear entire screen for the first content (derived from the anchor being at the very left-top)
            if (anchor.col == 1 and anchor.row == 1) {
                try terminal.clearScreen();
            }
        }

        pub fn render(this: @This(), anchor: Position, size: Size, contents: *Contents) !void {
            _ = this;
            _ = size;
            // FIXME: this should respect the given `size`
            try terminal.setCursorPosition(anchor);
            _ = try terminal.write(contents.items);
        }
    };
}