const c = @import("c.zig");
const gl = @import("gl.zig");
const std = @import("std");

const param_prefix = "/param/";

pub const ControlServer = struct {
    server: c.lo_server,
    shader: gl.ShaderProgram,

    pub fn init(allocator: *std.mem.Allocator) !*ControlServer {
        var self: *ControlServer = try allocator.create(ControlServer);

        self.server = c.lo_server_new("1234", handle_error);
        _ = c.lo_server_add_method(self.server, null, null, handle_method, @ptrCast(*c_void, self));

        return self;
    }

    pub fn update(self: *ControlServer, shader: gl.ShaderProgram) void {
        self.shader = shader;
        while (c.lo_server_recv_noblock(self.server, 0) > 0) {}
    }

    pub fn destroy(self: ControlServer) void {
        c.lo_server_free(self.server);
    }

    fn handle_error(num: c_int, msg: [*c]const u8, where: [*c]const u8) callconv(.C) void {
        std.debug.warn("OSC error {} @ {s}: {s}\n", .{ num, @ptrCast([*:0]const u8, where), @ptrCast([*:0]const u8, msg) });
    }

    fn handle_method(_path: [*c]const u8, _types: [*c]const u8, argv: [*c][*c]c.lo_arg, argc: c_int, msg: c.lo_message, userdata: ?*c_void) callconv(.C) c_int {
        const self = @ptrCast(*ControlServer, @alignCast(@alignOf(ControlServer), userdata.?));
        const path = _path[0..c.strlen(_path)];
        const types = _types[0..@intCast(u32, argc)];

        if (std.mem.startsWith(u8, path, param_prefix)) {
            const param_name = path[param_prefix.len..];

            const uniform = self.shader.uniformLocation(@ptrCast([*]const u8, param_name.ptr)) catch {
                std.debug.warn("param {s} doesn't exist\n", .{param_name});
                return 0;
            };

            if (argc == 0) {
                std.debug.warn("param get: {s}\n", .{param_name});
                return 0;
            }

            if (std.mem.eql(u8, types, "f")) {
                self.shader.setUniform1f(uniform, argv[0].*.f);
            } else if (std.mem.eql(u8, types, "ff")) {
                self.shader.setUniform2f(uniform, argv[0].*.f, argv[1].*.f);
            } else if (std.mem.eql(u8, types, "fff")) {
                self.shader.setUniform3f(uniform, argv[0].*.f, argv[1].*.f, argv[2].*.f);
            } else if (std.mem.eql(u8, types, "ffff")) {
                self.shader.setUniform4f(uniform, argv[0].*.f, argv[1].*.f, argv[2].*.f, argv[3].*.f);
            } else if (std.mem.eql(u8, types, "i")) {
                self.shader.setUniform1i(uniform, argv[0].*.i);
            } else {
                std.debug.warn("unsupported types: {s}\n", .{types});
            }
            return 0;
        }

        std.debug.warn("unhandled OSC message {s} ({s})\n", .{ path, types });
        return 1;
    }

    fn handle_bundle_start(time: c.lo_timetag, userdata: ?*c_void) callconv(.C) c_int {
        return 1;
    }
    fn handle_bundle_end(userdata: ?*c_void) callconv(.C) c_int {
        return 1;
    }
};