#ifndef XTC_MIX_INTERNAL_H
#define XTC_MIX_INTERNAL_H

#include "../project/project_internal.h"
#include "xtc/xtc_audio.h"

typedef struct {
    uint64_t sample, tick;
    size_t track;
    unsigned int parameter, step;
    float value;
} xtc_mix_point;

typedef struct {
    xtc_track_info tracks[XTC_PROJECT_MAX_TRACKS];
    size_t count, offsets[XTC_PROJECT_MAX_TRACKS][2], lengths[XTC_PROJECT_MAX_TRACKS][2];
    xtc_mix_point points[XTC_MAX_AUTOMATION_POINTS];
    int any_solo;
    size_t bus[XTC_PROJECT_MAX_TRACKS];
} xtc_mix_snapshot;

/**
 * @brief Builds a render-ready snapshot from a project's mix and automation.
 *
 * @param project Project to snapshot; borrowed and not modified.
 * @param rate Sample rate used for automation tick conversion.
 * @param m Receives the snapshot.
 * @return XTC_OK on success, or a validation/conversion error.
 */
xtc_result xtc_mix_prepare(const xtc_project * project, unsigned int rate, xtc_mix_snapshot * m);
/**
 * @brief Finds the dense index of a snapshot track by stable identifier.
 *
 * @param m Mixer snapshot.
 * @param id Stable identifier of the object to find or edit.
 * @return Dense track index, or SIZE_MAX if absent.
 */
size_t xtc_mix_track(const xtc_mix_snapshot * m, uint64_t id);
/* side 0/1 stereo, 2 mono (gain only). */
/**
 * @brief Evaluates track gain, pan, mute, solo, and automation at a sample position.
 *
 * @param m Mixer snapshot.
 * @param track Dense snapshot track index.
 * @param sample Absolute sample position.
 * @param side Output side: 0 for left, 1 for right, 2 for mono gain only.
 * @return Linear level for the chosen side, or zero for an absent or inaudible track.
 */
float xtc_mix_level(const xtc_mix_snapshot * m, size_t track, uint64_t sample, unsigned int side);
float xtc_mix_leaf_level(const xtc_mix_snapshot *m, size_t track, uint64_t sample, unsigned int side);
/* Borrowed control-installed scratch: 2*track_count channels, stride frames.
 * Clear once per callback before audio+MIDI rendering. No pointer changes active. */
void xtc_audio_plan_monitor(xtc_audio_plan *plan, float *samples, size_t stride);
void xtc_midi_plan_monitor(xtc_midi_plan *plan, float *samples, size_t stride);
void xtc_mix_monitor(const xtc_mix_snapshot *mix, float *samples, size_t stride, size_t track,
                     uint64_t position, size_t frame, float sample, int stereo);
#endif