scritcher/src/image.zig

const std = @import("std");
const lv2 = @import("lv2_helpers.zig");
const c = lv2.c;

const plugins = @import("plugin.zig");

pub const ImageError = error{
    OpenFail,
    InvalidPlugin,
    UnknownPlugin,
    InvalidSymbol,
};

/// Low level integration function with libsndfile.
fn sopen(
    allocator: *std.mem.Allocator,
    path: []const u8,
    mode: i32,
    fmt: *c.SF_INFO,
) !*c.SNDFILE {
    var cstr_path = try std.cstr.addNullByte(allocator, path);
    defer allocator.free(cstr_path);

    var file = c.sf_open(cstr_path.ptr, mode, fmt);
    const st: i32 = c.sf_error(file);

    if (st != 0) {
        std.debug.warn(
            "Failed to open {} ({})\n",
            path,
            c.sf_error_number(st),
        );

        return ImageError.OpenFail;
    }

    return file.?;
}

pub const Image = struct {
    allocator: *std.mem.Allocator,
    sndfile: *c.SNDFILE,
    path: []const u8,

    /// Open a BMP file.
    pub fn open(allocator: *std.mem.Allocator, path: []const u8) !*Image {
        var in_fmt = c.SF_INFO{
            .frames = c_int(0),
            .samplerate = c_int(44100),
            .channels = c_int(1),
            .format = c.SF_FORMAT_ULAW | c.SF_FORMAT_RAW | c.SF_ENDIAN_BIG,
            .sections = c_int(0),
            .seekable = c_int(0),
        };

        var sndfile = try sopen(allocator, path, c.SFM_READ, &in_fmt);
        var image = try allocator.create(Image);

        image.* = Image{
            .allocator = allocator,
            .sndfile = sndfile,
            .path = path,
        };

        return image;
    }

    pub fn close(self: *Image) void {
        var st: i32 = c.sf_close(self.sndfile);

        if (st != 0) {
            std.debug.warn(
                "Failed to close {} ({})\n",
                self.path,
                c.sf_error_number(st),
            );
        }
    }

    pub fn read(self: *Image, file_chans: c_int, buf: []f32) bool {
        var file = file_opt.?;

        const n_read: c.sf_count_t = c.sf_readf_float(file, buf.ptr, 1);
        const buf_chans = @intCast(c_int, buf.len);

        var i = file_chans - 1;
        while (i < buf_chans) : (i += 1) {
            //buf[@intCast(usize, i)] = buf[i % file_chans];
            buf[@intCast(usize, i)] = buf[@intCast(usize, @mod(i, file_chans))];
        }

        return n_read == 1;
    }

    pub fn runPlugin(
        self: *Image,
        plugin_uri: []const u8,
        pos: plugins.Position,
        params: plugins.ParamList,
    ) !void {
        var ctx = try plugins.makeContext(self.allocator, plugin_uri);
        std.debug.warn("\tworld: {}\n", ctx.world);
        std.debug.warn("\tplugin: {}\n", ctx.plugin);

        var ports = try lv2.setupPorts(&ctx);

        if (ctx.n_audio_in != 1) {
            std.debug.warn("plugin <{}> does not accept mono input.\n", plugin_uri);
            return ImageError.InvalidPlugin;
        }

        // now, for each param for the plugin, we find its port, and set
        // the value for the port there.
        var it = params.iterator();

        while (it.next()) |param| {
            var sym_cstr = try std.cstr.addNullByte(self.allocator, param.sym);
            defer self.allocator.free(sym_cstr);

            var sym = c.lilv_new_string(ctx.world, sym_cstr.ptr);
            const port = c.lilv_plugin_get_port_by_symbol(ctx.plugin, sym) orelse blk: {
                std.debug.warn("assert fail: symbol not found on port");
                return ImageError.InvalidSymbol;
            };

            c.lilv_node_free(sym);

            var idx = c.lilv_port_get_index(ctx.plugin, port);
            std.debug.warn(
                "sym={}, idx={} to val={}\n",
                param.sym,
                idx,
                param.value,
            );
            ports[idx].value = param.value;
        }
    }
};