light_sampler.c

/*
 * Light Sampler LV2 Plugin - Sampler plugin
 * Copyright (C) 2026 Simon Delaruotte
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 */

#include "light_sampler_uris.h"
#include "light_sampler_peaks.h"
#include "atom_sink.h"

/* LV2 includes - use the paths that match your system */
#include <lv2/core/lv2.h>
#include <lv2/atom/atom.h>
#include <lv2/atom/forge.h>
#include <lv2/atom/util.h>
#include <lv2/midi/midi.h>
#include <lv2/urid/urid.h>
#include <lv2/state/state.h>
#include <lv2/worker/worker.h>
#include <lv2/log/log.h>
#include <lv2/log/logger.h>
#include <lv2/patch/patch.h>
#include <sndfile.h>
#include <math.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>

#define LIGHT_SAMPLER_URI "urn:simdott:light_sampler"

/* Missing LV2 utility functions */
#ifndef HAVE_LV2_FEATURES_QUERY
static inline const char*
lv2_features_query(const LV2_Feature* const* features,
                   const char* uri, void** data, bool required, ...)
{
    va_list args;
    va_start(args, required);
    
    for (int i = 0; features[i]; ++i) {
        if (!strcmp(features[i]->URI, uri)) {
            if (data) *data = features[i]->data;
            va_end(args);
            return NULL;
        }
    }
    
    while (1) {
        const char* next_uri = va_arg(args, const char*);
        if (!next_uri) break;
        
        void** next_data = va_arg(args, void**);
        bool next_required = (bool)va_arg(args, int);
        
        for (int i = 0; features[i]; ++i) {
            if (!strcmp(features[i]->URI, next_uri)) {
                if (next_data) *next_data = features[i]->data;
                va_end(args);
                return NULL;
            }
        }
        
        if (next_required) {
            va_end(args);
            return next_uri;
        }
    }
    
    va_end(args);
    if (data) *data = NULL;
    return NULL;
}
#endif

#ifndef HAVE_LV2_FEATURES_DATA
static inline void*
lv2_features_data(const LV2_Feature* const* features, const char* uri)
{
    for (int i = 0; features[i]; ++i) {
        if (!strcmp(features[i]->URI, uri)) {
            return features[i]->data;
        }
    }
    return NULL;
}
#endif

typedef enum {
    CONTROL_IN   = 0,
    NOTIFY_OUT   = 1,
    AUDIO_OUT_L  = 2,
    AUDIO_OUT_R  = 3,
    PLAY_BACKWARD= 4,    
    HUMANIZE     = 5,    
    STEREO       = 6,    
    MIDI_CHANNEL = 7,    
    MIDI_NOTE    = 8,    
    PITCH_SHIFT  = 9,    
    VOICE_MODE   = 10,
    ATTACK       = 11,
    HOLD         = 12,    
    DECAY        = 13,
    SUSTAIN      = 14,
    RELEASE      = 15,
    VOLUME       = 16
} PortIndex;

typedef struct {
    SF_INFO    info;
    float*     data;
    char*      path;
    uint32_t   path_len;
} Sample;

typedef struct {
    float      position;
    float      gain;
    bool       play;
    float      envelope;
    float      attack_rate;
    float      hold_frames;        
    float      decay_rate;
    float      sustain_level;
    float      release_rate;
    float      current_attack_rate;
    uint32_t   current_hold_frames; 
    float      current_decay_rate;
    float      current_sustain_level;
    float      current_release_rate;
    uint8_t    current_note;
    float      velocity_gain;
    float      pitch_shift_value;
    float      humanize_offset;
    float      humanize_volume;
    uint32_t   hold_counter;        
    int        envelope_state;      
} Voice;

typedef struct {
    // Features
    LV2_URID_Map*        map;
    LV2_Worker_Schedule* schedule;
    LV2_Log_Logger       logger;

    // Ports
    const LV2_Atom_Sequence* control_port;
    LV2_Atom_Sequence*       notify_port;
    float*                   output_port_l;
    float*                   output_port_r;
    const float*             midi_channel;
    const float*             midi_note;
    const float*             play_backward;
    const float*             humanize;
    const float*             pitch_shift;
    const float*             voice_mode;
    const float*             attack;
    const float*             hold;            
    const float*             decay;
    const float*             sustain;
    const float*             release;
    const float*             volume;
    const float*             stereo;

    LV2_Atom_Forge       forge;
    LightSamplerURIs     uris;
    PeaksSender          peaks_sender;

    Sample*    sample;
    uint64_t   frame_offset;
    float      global_gain;
    bool       gain_changed;
    bool       sample_changed;
    bool       activated;
    
    Voice      voice0;
    Voice      voice1;
    bool       active_voice_count;
    uint8_t    last_note;
    uint64_t   last_note_frame;
    
    uint32_t   random_state;
    uint32_t   host_rate;
    float      sample_rate_ratio;
} LightSampler;

typedef struct {
    LV2_Atom atom;
    Sample*  sample;
} SampleMessage;

/* Helper functions */
static Sample* load_sample(LV2_Log_Logger* logger, const char* path) {
    lv2_log_trace(logger, "Loading %s\n", path);
    const size_t path_len = strlen(path);
    Sample* sample = (Sample*)calloc(1, sizeof(Sample));
    SF_INFO* info = &sample->info;
    SNDFILE* sndfile = sf_open(path, SFM_READ, info);
    float* data = NULL;
    bool error = true;

    if (!sndfile || !info->frames) {
        lv2_log_error(logger, "Failed to open %s\n", path);
    } else if (info->channels != 1 && info->channels != 2) {
        lv2_log_error(logger, "%s has %d channels, need 1 or 2\n", path, info->channels);
    } else if (!(data = (float*)malloc(sizeof(float) * info->frames * info->channels))) {
        lv2_log_error(logger, "Failed to allocate memory for sample\n");
    } else {
        error = false;
    }

    if (error) {
        free(sample);
        free(data);
        if (sndfile) sf_close(sndfile);
        return NULL;
    }

    sf_seek(sndfile, 0ul, SEEK_SET);
    sf_readf_float(sndfile, data, info->frames);
    sf_close(sndfile);

    sample->data = data;
    sample->path = (char*)malloc(path_len + 1);
    sample->path_len = (uint32_t)path_len;
    memcpy(sample->path, path, path_len + 1);
    return sample;
}

static void free_sample(LightSampler* self, Sample* sample) {
    if (sample) {
        lv2_log_trace(&self->logger, "Freeing %s\n", sample->path);
        free(sample->path);
        free(sample->data);
        free(sample);
    }
}

static void init_voice(Voice* v) {
    v->position = 0.0f;
    v->gain = 1.0f;
    v->play = false;
    v->envelope = 0.0f;
    v->envelope_state = 0;
    v->attack_rate = 0.0f;
    v->hold_frames = 0.0f;
    v->decay_rate = 0.0f;
    v->sustain_level = 0.75f;
    v->release_rate = 0.0f;
    v->current_attack_rate = 0.0f;
    v->current_hold_frames = 0;
    v->current_decay_rate = 0.0f;
    v->current_sustain_level = 0.75f;
    v->current_release_rate = 0.0f;
    v->current_note = 60;
    v->velocity_gain = 1.0f;
    v->pitch_shift_value = 0.0f;
    v->humanize_offset = 0.0f;
    v->humanize_volume = 1.0f;
    v->hold_counter = 0;
}

static uint8_t get_midi_channel(uint8_t status_byte) { 
    return status_byte & 0x0F; 
}

static int should_process_message(LightSampler* self, uint8_t status_byte) {
    if (!self->midi_channel) return 1;
    
    int target_channel_param = (int)*(self->midi_channel);
    if (target_channel_param <= 0 || target_channel_param >= 17) return 1;
    
    int target_channel = target_channel_param - 1;
    uint8_t msg_channel = get_midi_channel(status_byte);
    return (msg_channel == target_channel);
}

/* Update envelope rates once per block */
static void update_envelope_rates(LightSampler* self) {
    const float MIN_TIME_SEC = 0.000001f;
    
    float attack_time = self->attack ? *(self->attack) * 0.001f : 0.0f;
    if (attack_time > 0.0f && attack_time < MIN_TIME_SEC) attack_time = MIN_TIME_SEC;
    float attack_rate = (attack_time > 0.0f) ? (1.0f / (attack_time * self->host_rate)) : 1.0f;
    if (attack_rate > 1.0f) attack_rate = 1.0f;
    
    float hold_time = self->hold ? *(self->hold) * 0.001f : 0.0f;
    uint32_t hold_frames = (uint32_t)(hold_time * self->host_rate);
    
    float decay_time = 0.0f;
    if (self->decay) {
        decay_time = *(self->decay) * 0.001f;
        if (decay_time > 0.0f && decay_time < MIN_TIME_SEC) decay_time = MIN_TIME_SEC;
    }
    float decay_rate = (decay_time > 0.0f) ? (1.0f / (decay_time * self->host_rate)) : 1.0f;
    if (decay_rate > 1.0f) decay_rate = 1.0f;
    
    float sustain_level = 0.75f;
    if (self->sustain) {
        float sustain_percent = *(self->sustain);
        if (sustain_percent < 0.0f) sustain_percent = 0.0f;
        if (sustain_percent > 100.0f) sustain_percent = 100.0f;
        sustain_level = sustain_percent / 100.0f;
    }
    
    float release_time = self->release ? *(self->release) * 0.001f : 0.0f;
    if (release_time > 0.0f && release_time < MIN_TIME_SEC) release_time = MIN_TIME_SEC;
    float release_rate = (release_time > 0.0f) ? (1.0f / (release_time * self->host_rate)) : 1.0f;
    if (release_rate > 1.0f) release_rate = 1.0f;
    
    self->voice0.attack_rate = attack_rate;
    self->voice0.hold_frames = hold_frames;
    self->voice0.decay_rate = decay_rate;
    self->voice0.sustain_level = sustain_level;
    self->voice0.release_rate = release_rate;
    
    self->voice1.attack_rate = attack_rate;
    self->voice1.hold_frames = hold_frames;
    self->voice1.decay_rate = decay_rate;
    self->voice1.sustain_level = sustain_level;
    self->voice1.release_rate = release_rate;
}

static inline uint32_t xorshift32(uint32_t* state) {
    uint32_t x = *state;
    x ^= x << 13;
    x ^= x >> 17;
    x ^= x << 5;
    *state = x;
    return x;
}

static inline float xorshift_float_range(uint32_t* state, float min, float max) {
    uint32_t r = xorshift32(state);
    float t = (float)r / 4294967295.0f;
    return min + t * (max - min);
}

static float linear_interpolate(float y1, float y2, float frac) {
    return y1 + frac * (y2 - y1);
}

/* Worker functions */
static LV2_Worker_Status work(LV2_Handle instance,
                              LV2_Worker_Respond_Function respond,
                              LV2_Worker_Respond_Handle handle,
                              uint32_t size, const void* data) {
    LightSampler* self = (LightSampler*)instance;
    const LV2_Atom* atom = (const LV2_Atom*)data;
    
    if (atom->type == self->uris.ls_freeSample) {
        const SampleMessage* msg = (const SampleMessage*)data;
        free_sample(self, msg->sample);
    } else if (atom->type == self->forge.Object) {
        const LV2_Atom_Object* obj = (const LV2_Atom_Object*)data;
        const char* path = read_set_file(&self->uris, obj);
        if (!path) {
            lv2_log_error(&self->logger, "Malformed set file request\n");
            return LV2_WORKER_ERR_UNKNOWN;
        }
        Sample* sample = load_sample(&self->logger, path);
        if (sample) {
            respond(handle, sizeof(Sample*), &sample);
        }
    }
    return LV2_WORKER_SUCCESS;
}

static LV2_Worker_Status work_response(LV2_Handle instance, uint32_t size, const void* data) {
    LightSampler* self = (LightSampler*)instance;
    Sample* old_sample = self->sample;
    Sample* new_sample = *(Sample* const*)data;
    
    if (!new_sample) return LV2_WORKER_SUCCESS;
    
    if (new_sample == old_sample) {
        return LV2_WORKER_SUCCESS;
    }
    
    self->sample = new_sample;
    init_voice(&self->voice0);
    init_voice(&self->voice1);
    self->sample_changed = true;
    
    if (new_sample->info.samplerate > 0) {
        self->sample_rate_ratio = (float)self->host_rate / (float)new_sample->info.samplerate;
    }
    
    if (self->notify_port && self->notify_port->atom.size >= 256) {
        lv2_atom_forge_set_buffer(&self->forge, (uint8_t*)self->notify_port, self->notify_port->atom.size);
        LV2_Atom_Forge_Frame frame;
        lv2_atom_forge_sequence_head(&self->forge, &frame, 0);
        lv2_atom_forge_frame_time(&self->forge, 0);
        write_set_file(&self->forge, &self->uris, new_sample->path, new_sample->path_len);
    }
    
    self->voice0.play = false;
    self->voice0.envelope_state = 0;
    self->voice1.play = false;
    self->voice1.envelope_state = 0;
    
    if (old_sample) {
        SampleMessage msg = {{sizeof(Sample*), self->uris.ls_freeSample}, old_sample};
        if (self->schedule) {
            self->schedule->schedule_work(self->schedule->handle, sizeof(msg), &msg);
        } else {
            free_sample(self, old_sample);
        }
    }
    
    return LV2_WORKER_SUCCESS;
}

static void start_voice(LightSampler* self, Voice* v, uint8_t note, uint8_t vel) {
    if (!self->sample || !self->sample->data) return;
    
    if (v->play) {
        v->envelope_state = 4;
    }
    
    v->position = 0.0f;
    v->play = true;
    v->current_note = note;
    v->envelope = 0.0f;
    v->envelope_state = 1;
    v->hold_counter = 0;
    
    if (v->attack_rate >= 1.0f) {
        v->envelope = 1.0f;
        if (v->hold_frames > 0) {
            v->envelope_state = 2;
            v->hold_counter = v->hold_frames;
        } else {
            v->envelope_state = 3;
        }
    }
    
    if (*(self->play_backward) > 0.5f) {
        v->position = (float)(self->sample->info.frames - 1);
    }
    
    v->pitch_shift_value = *(self->pitch_shift);
    
    if (*(self->humanize) > 0.5f) {
        v->humanize_offset = xorshift_float_range(&self->random_state, -0.2f, 0.2f);
        v->humanize_volume = xorshift_float_range(&self->random_state, 0.94f, 1.06f);
    } else {
        v->humanize_offset = 0.0f;
        v->humanize_volume = 1.0f;
    }
    
    float total_pitch = v->pitch_shift_value + v->humanize_offset;
    v->gain = exp2f(total_pitch / 12.0f) * self->sample_rate_ratio;
    
    if (*(self->play_backward) > 0.5f) {
        v->gain = -fabsf(v->gain);
    }
    
    v->velocity_gain = (float)vel / 127.0f;
    
    v->current_attack_rate = v->attack_rate;
    v->current_hold_frames = v->hold_frames;
    v->current_decay_rate = v->decay_rate;
    v->current_sustain_level = v->sustain_level;
    v->current_release_rate = v->release_rate;
}

static void stop_voice(Voice* v, uint8_t note) {
    if (note == v->current_note && (v->envelope_state == 1 || v->envelope_state == 2 || v->envelope_state == 3)) {
        v->envelope_state = 4;
    }
}

static void handle_event(LightSampler* self, LV2_Atom_Event* ev) {
    if (!self) return;
    
    if (ev->body.type == self->uris.midi_Event) {
        const uint8_t* const msg = (const uint8_t*)(ev + 1);
        const uint8_t status = msg[0] & 0xF0;
        const uint8_t note = msg[1];
        const uint8_t vel = msg[2];
        
        if (!should_process_message(self, msg[0])) {
            return;
        }
        
        if (status == LV2_MIDI_MSG_NOTE_ON && vel > 0) {
            int target_note = (int)*(self->midi_note);
            if (target_note < 0) target_note = 0;
            if (target_note > 127) target_note = 127;
            if (note != target_note) {
                return;
            }
            
            if (ev->time.frames == self->last_note_frame && note == self->last_note) {
                return;
            }
            self->last_note = note;
            self->last_note_frame = ev->time.frames;
            
            bool dual_mode = self->voice_mode && (*(self->voice_mode) > 0.5f);
            
            if (dual_mode) {
                int voice_to_use = 0;
                
                if (!self->voice0.play && self->voice1.play) {
                    voice_to_use = 0;
                } else if (self->voice0.play && !self->voice1.play) {
                    voice_to_use = 1;
                } else if (!self->voice0.play && !self->voice1.play) {
                    voice_to_use = 0;
                } else {
                    if (self->voice0.envelope_state == 3 && self->voice1.envelope_state != 3) {
                        voice_to_use = 0;
                    } else if (self->voice1.envelope_state == 3 && self->voice0.envelope_state != 3) {
                        voice_to_use = 1;
                    } else {
                        voice_to_use = (self->voice0.envelope <= self->voice1.envelope) ? 0 : 1;
                    }
                }
                
                if (voice_to_use == 0) {
                    start_voice(self, &self->voice0, note, vel);
                } else {
                    start_voice(self, &self->voice1, note, vel);
                }
            } else {
                start_voice(self, &self->voice0, note, vel);
                if (self->voice1.play) {
                    self->voice1.envelope_state = 3;
                }
            }
        } else if (status == LV2_MIDI_MSG_NOTE_OFF || (status == LV2_MIDI_MSG_NOTE_ON && vel == 0)) {
            int target_note = (int)*(self->midi_note);
            if (target_note < 0) target_note = 0;
            if (target_note > 127) target_note = 127;
            
            if (note == target_note) {
                stop_voice(&self->voice0, note);
                stop_voice(&self->voice1, note);
            }
        }
    } else if (lv2_atom_forge_is_object_type(&self->forge, ev->body.type)) {
        const LV2_Atom_Object* obj = (const LV2_Atom_Object*)&ev->body;
        
        if (obj->body.otype == self->uris.patch_Set) {
            const LV2_Atom* property = NULL;
            const LV2_Atom* value = NULL;
            
            lv2_atom_object_get(obj, self->uris.patch_property, &property,
                                      self->uris.patch_value, &value, 0);
            
            if (!property || property->type != self->uris.atom_URID) {
                return;
            }
            
            const uint32_t key = ((const LV2_Atom_URID*)property)->body;
            
            if (key == self->uris.ls_sample) {
                if (self->schedule) {
                    self->schedule->schedule_work(self->schedule->handle,
                                                 lv2_atom_total_size(&ev->body), &ev->body);
                }
            }
        }
    }
}

static void render_voice(LightSampler* self, Voice* v, uint32_t start, uint32_t end,
                         float* out_l, float* out_r, bool stereo_mode, float volume) {
    if (!v->play && v->envelope_state == 0) {
        v->envelope = 0.0f;
        return;
    }
    
    if (!self->sample || !self->sample->data || self->sample->info.frames == 0) return;
    
    uint32_t total_frames = self->sample->info.frames;
    uint32_t channels = self->sample->info.channels;
    
    float final_volume = volume * v->humanize_volume * v->velocity_gain;
    
    for (uint32_t i = start; i < end; i++) {
        /* Per-sample envelope update */
        if (v->envelope_state == 1) { /* Attack */
            float target = 1.0f;
            v->envelope += (target - v->envelope) * v->current_attack_rate;
            if (v->envelope >= 0.999f) {
                v->envelope = 1.0f;
                if (v->current_hold_frames > 0) {
                    v->envelope_state = 2;
                    v->hold_counter = v->current_hold_frames;
                } else {
                    v->envelope_state = 3;
                }
            }
        }
        else if (v->envelope_state == 2) { /* Hold */
            if (v->hold_counter > 0) {
                v->hold_counter--;
            } else {
                v->envelope_state = 3;
            }
        }
        else if (v->envelope_state == 3) { /* Decay */
            float target = v->current_sustain_level;
            v->envelope += (target - v->envelope) * v->current_decay_rate;
            if (v->envelope <= target + 1e-6f) {
                v->envelope = target;
            }
        }
        else if (v->envelope_state == 4) { /* Release */
            v->envelope *= (1.0f - v->current_release_rate);
            if (v->envelope < 1e-6f) {
                v->envelope = 0.0f;
                v->play = false;
                v->envelope_state = 0;
                return;
            }
        }
        
        float final_gain = v->envelope * final_volume;
        
        /* Position bounds check */
        if (v->gain > 0 && v->position >= total_frames) {
            v->position = (float)(total_frames - 1);
            if (v->envelope_state != 4) {
                v->envelope_state = 4;
                v->play = false;
            }
        }
        if (v->gain < 0 && v->position < 0.0f) {
            v->position = 0.0f;
            if (v->envelope_state != 4) {
                v->envelope_state = 4;
                v->play = false;
            }
        }
        
        float sample_l = 0.0f;
        float sample_r = 0.0f;
        
        if (channels == 1) {
            uint32_t pos0 = (uint32_t)v->position;
            uint32_t pos1 = pos0 + 1;
            if (pos1 >= total_frames) pos1 = pos0;
            
            float frac = v->position - (float)pos0;
            float s0 = self->sample->data[pos0];
            float s1 = self->sample->data[pos1];
            sample_l = linear_interpolate(s0, s1, frac);
            sample_r = sample_l;
        } else if (channels == 2) {
            uint32_t pos0 = (uint32_t)v->position;
            uint32_t pos1 = pos0 + 1;
            if (pos1 >= total_frames) pos1 = pos0;
            
            float frac = v->position - (float)pos0;
            uint32_t idx0 = pos0 * 2;
            uint32_t idx1 = pos1 * 2;
            
            float left = linear_interpolate(self->sample->data[idx0], self->sample->data[idx1], frac);
            float right = linear_interpolate(self->sample->data[idx0 + 1], self->sample->data[idx1 + 1], frac);
            
            if (stereo_mode) {
                sample_l = left;
                sample_r = right;
            } else {
                float mono = (left + right) * 0.5f;
                sample_l = mono;
                sample_r = mono;
            }
        }
        
        out_l[i] += sample_l * final_gain;
        out_r[i] += sample_r * final_gain;
        
        v->position += v->gain;
    }
    
    if (v->gain > 0 && v->position >= total_frames && v->envelope_state != 4) {
        v->envelope_state = 4;
    } else if (v->gain < 0 && v->position < 0 && v->envelope_state != 4) {
        v->envelope_state = 4;
    }
}

static void render(LightSampler* self, uint32_t start, uint32_t end) {
    if (!self || !self->output_port_l || !self->output_port_r || start >= end) return;
    
    bool stereo_mode = self->stereo && (*(self->stereo) > 0.5f);
    bool dual_mode = self->voice_mode && (*(self->voice_mode) > 0.5f);
    
    float volume = 1.0f;
    if (self->volume) {
        volume = *self->volume / 100.0f;
        volume = volume * volume;
    }
    
    memset(&self->output_port_l[start], 0, (end - start) * sizeof(float));
    memset(&self->output_port_r[start], 0, (end - start) * sizeof(float));
    
    render_voice(self, &self->voice0, start, end,
                 self->output_port_l, self->output_port_r, stereo_mode, volume);
    
    if (dual_mode) {
        render_voice(self, &self->voice1, start, end,
                     self->output_port_l, self->output_port_r, stereo_mode, volume);
    }
}

static LV2_Handle instantiate(const LV2_Descriptor* descriptor,
                              double rate, const char* bundle_path,
                              const LV2_Feature* const* features) {
    LightSampler* self = (LightSampler*)calloc(1, sizeof(LightSampler));
    if (!self) return NULL;
    
    self->map = NULL;
    self->schedule = NULL;
    self->logger.log = NULL;
    self->sample = NULL;
    
    for (int i = 0; features[i]; ++i) {
        const char* uri = features[i]->URI;
        if (!strcmp(uri, LV2_URID__map)) {
            self->map = (LV2_URID_Map*)features[i]->data;
        }
        else if (!strcmp(uri, LV2_WORKER__schedule)) {
            self->schedule = (LV2_Worker_Schedule*)features[i]->data;
        }
        else if (!strcmp(uri, LV2_LOG__log)) {
            self->logger.log = (LV2_Log_Log*)features[i]->data;
        }
    }
    
    if (!self->map) {
        free(self);
        return NULL;
    }
    
    if (self->logger.log) {
        lv2_log_logger_set_map(&self->logger, self->map);
        lv2_log_note(&self->logger, "Light Sampler instantiated\n");
    }
    
    map_light_sampler_uris(self->map, &self->uris);
    lv2_atom_forge_init(&self->forge, self->map);
    peaks_sender_init(&self->peaks_sender, self->map);
    
    self->host_rate = (uint32_t)rate;
    self->global_gain = 1.0f;
    self->random_state = (uint32_t)((uintptr_t)self ^ (uint32_t)rate);
    if (self->random_state == 0) self->random_state = 123456789;
    
    self->sample = NULL;
    self->sample_rate_ratio = 1.0f;
    
    init_voice(&self->voice0);
    init_voice(&self->voice1);
    self->last_note = 0;
    self->last_note_frame = 0;
    
    self->control_port = NULL;
    self->notify_port = NULL;
    self->output_port_l = NULL;
    self->output_port_r = NULL;
    self->midi_channel = NULL;
    self->midi_note = NULL;
    self->play_backward = NULL;
    self->humanize = NULL;
    self->pitch_shift = NULL;
    self->voice_mode = NULL;
    self->attack = NULL;
    self->hold = NULL;
    self->decay = NULL;
    self->sustain = NULL;
    self->release = NULL;
    self->volume = NULL;
    self->stereo = NULL;
    
    self->activated = false;
    self->gain_changed = false;
    self->sample_changed = false;
    self->frame_offset = 0;
    self->active_voice_count = 0;
    
    return (LV2_Handle)self;
}

static void connect_port(LV2_Handle instance, uint32_t port, void* data) {
    LightSampler* self = (LightSampler*)instance;
    switch ((PortIndex)port) {
        case CONTROL_IN:   self->control_port   = (const LV2_Atom_Sequence*)data; break;
        case NOTIFY_OUT:   self->notify_port    = (LV2_Atom_Sequence*)data;       break;
        case AUDIO_OUT_L:  self->output_port_l  = (float*)data; break;
        case AUDIO_OUT_R:  self->output_port_r  = (float*)data; break;
        case PLAY_BACKWARD:self->play_backward  = (const float*)data; break;
        case HUMANIZE:     self->humanize       = (const float*)data; break;
        case STEREO:       self->stereo         = (const float*)data; break;
        case MIDI_CHANNEL: self->midi_channel   = (const float*)data; break;
        case MIDI_NOTE:    self->midi_note      = (const float*)data; break;
        case PITCH_SHIFT:  self->pitch_shift    = (const float*)data; break;
        case VOICE_MODE:   self->voice_mode     = (const float*)data; break;
        case ATTACK:       self->attack         = (const float*)data; break;
        case HOLD:         self->hold           = (const float*)data; break;
        case DECAY:        self->decay          = (const float*)data; break;
        case SUSTAIN:      self->sustain        = (const float*)data; break;
        case RELEASE:      self->release        = (const float*)data; break;
        case VOLUME:       self->volume         = (const float*)data; break;
    }
}

static void activate(LV2_Handle instance) {
    LightSampler* self = (LightSampler*)instance;
    self->activated = true;
    update_envelope_rates(self);
    
    // Force clean voice state on activation
    init_voice(&self->voice0);
    init_voice(&self->voice1);
    self->voice0.play = false;
    self->voice0.envelope_state = 0;
    self->voice1.play = false;
    self->voice1.envelope_state = 0;
}

static void run(LV2_Handle instance, uint32_t sample_count) {
    LightSampler* self = (LightSampler*)instance;
        
    if (!self || !self->output_port_l || !self->output_port_r) {
        return;
    }
    
    update_envelope_rates(self);
    
    if (self->control_port) {
        if (self->control_port->atom.size <= sizeof(LV2_Atom_Sequence_Body)) {
            render(self, 0, sample_count);
            return;
        }
        
        if (self->notify_port && self->notify_port->atom.size >= 256) {
            lv2_atom_forge_set_buffer(&self->forge, 
                                     (uint8_t*)self->notify_port, 
                                     self->notify_port->atom.size);
            LV2_Atom_Forge_Frame notify_frame;
            lv2_atom_forge_sequence_head(&self->forge, &notify_frame, 0);
            
            if (self->gain_changed || self->sample_changed) {
                lv2_atom_forge_frame_time(&self->forge, 0);
                
                if (self->gain_changed) {
                    write_set_gain(&self->forge, &self->uris, 0.0f);
                    self->gain_changed = false;
                }
                
                if (self->sample_changed && self->sample) {
                    write_set_file(&self->forge, &self->uris, 
                                  self->sample->path, self->sample->path_len);
                    self->sample_changed = false;
                }
            }
        }
        
        if (self->sample_changed) {
    // Sample just loaded, ensure voices are clean
    self->voice0.play = false;
    self->voice0.envelope_state = 0;
    self->voice1.play = false;
    self->voice1.envelope_state = 0;
    self->sample_changed = false;
}
        
        self->frame_offset = 0;
        uint32_t event_count = 0;
        
        self->last_note_frame = UINT64_MAX;
        
        LV2_ATOM_SEQUENCE_FOREACH(self->control_port, ev) {
            event_count++;
            self->frame_offset = ev->time.frames;
            handle_event(self, ev);
        }
        
        if (event_count == 0) {
            if (self->frame_offset == 0) {
                render(self, 0, sample_count);
            } else {
                if (self->frame_offset > 0) {
                    uint32_t zero_frames = (uint32_t)self->frame_offset;
                    if (zero_frames > sample_count) zero_frames = sample_count;
                    memset(self->output_port_l, 0, zero_frames * sizeof(float));
                    memset(self->output_port_r, 0, zero_frames * sizeof(float));
                }
                
                if ((uint32_t)self->frame_offset < sample_count) {
                    render(self, (uint32_t)self->frame_offset, sample_count);
                }
            }
        } else {
            render(self, 0, sample_count);
        }
    } else {
        memset(self->output_port_l, 0, sample_count * sizeof(float));
        memset(self->output_port_r, 0, sample_count * sizeof(float));
    }
    
    if (self->notify_port && self->notify_port->atom.size >= 256 && 
        self->sample && self->sample->data && 
        (self->voice0.play || self->voice1.play)) {
        peaks_sender_send(&self->peaks_sender, &self->forge,
                         sample_count, self->frame_offset);
    }
}

static void deactivate(LV2_Handle instance) {
    LightSampler* self = (LightSampler*)instance;
    self->activated = false;
    init_voice(&self->voice0);
    init_voice(&self->voice1);
}

static void cleanup(LV2_Handle instance) {
    LightSampler* self = (LightSampler*)instance;
    free_sample(self, self->sample);
    free(self);
}

/* State functions */
static LV2_State_Status save(LV2_Handle instance,
                             LV2_State_Store_Function store,
                             LV2_State_Handle handle,
                             uint32_t flags,
                             const LV2_Feature* const* features) {
    LightSampler* self = (LightSampler*)instance;
    if (!self->sample) return LV2_STATE_SUCCESS;
    
    LV2_State_Map_Path* map_path = (LV2_State_Map_Path*)
        lv2_features_data(features, LV2_STATE__mapPath);
    if (!map_path) return LV2_STATE_ERR_NO_FEATURE;
    
    char* apath = map_path->abstract_path(map_path->handle, self->sample->path);
    store(handle, self->uris.ls_sample, apath, strlen(apath) + 1,
          self->uris.atom_Path, LV2_STATE_IS_POD | LV2_STATE_IS_PORTABLE);
    free(apath);
    
    return LV2_STATE_SUCCESS;
}

static LV2_State_Status restore(LV2_Handle instance,
                                LV2_State_Retrieve_Function retrieve,
                                LV2_State_Handle handle,
                                uint32_t flags,
                                const LV2_Feature* const* features) {
    LightSampler* self = (LightSampler*)instance;
    
    LV2_Worker_Schedule* schedule = NULL;
    LV2_State_Map_Path* paths = NULL;
    const char* missing = lv2_features_query(
        features,
        LV2_STATE__mapPath, (void**)&paths, true,
        LV2_WORKER__schedule, (void**)&schedule, false,
        NULL);
    if (missing) return LV2_STATE_ERR_NO_FEATURE;
    
    size_t size; uint32_t type, valflags;
    const void* value = retrieve(handle, self->uris.ls_sample, &size, &type, &valflags);
    if (!value || type != self->uris.atom_Path) return LV2_STATE_ERR_BAD_TYPE;
    
    const char* apath = (const char*)value;
    char* path = paths->absolute_path(paths->handle, apath);
    
    // Always use worker if available, never load directly
    if (schedule) {
        LV2_Atom_Forge forge;
        LV2_Atom* buf = (LV2_Atom*)calloc(1, strlen(path) + 128);
        lv2_atom_forge_init(&forge, self->map);
        lv2_atom_forge_set_sink(&forge, atom_sink, atom_sink_deref, buf);
        write_set_file(&forge, &self->uris, path, strlen(path));
        
        const uint32_t msg_size = lv2_atom_pad_size(buf->size);
        schedule->schedule_work(self->schedule->handle, msg_size, buf + 1);
        free(buf);
    } else {
        // Fallback to direct load only if no worker
        Sample* sample = load_sample(&self->logger, path);
        if (sample) {
            free_sample(self, self->sample);
            self->sample = sample;
            self->sample_changed = true;
            self->sample_rate_ratio = (float)self->host_rate / (float)sample->info.samplerate;
        }
    }
    
    free(path);
    return LV2_STATE_SUCCESS;
}

static const void* extension_data(const char* uri) {
    static const LV2_State_Interface state = {save, restore};
    static const LV2_Worker_Interface worker = {work, work_response, NULL};
    
    if (!strcmp(uri, LV2_STATE__interface)) return &state;
    if (!strcmp(uri, LV2_WORKER__interface)) return &worker;
    return NULL;
}

static const LV2_Descriptor descriptor = {
    LIGHT_SAMPLER_URI,
    instantiate,
    connect_port,
    activate,
    run,
    deactivate,
    cleanup,
    extension_data
};

LV2_SYMBOL_EXPORT const LV2_Descriptor* lv2_descriptor(uint32_t index) {
    return index == 0 ? &descriptor : NULL;
}