#include "xtc/xtc_processor.h"
#include "xtc/xtc_dsp.h"
#include <float.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
struct xtc_processor {
    xtc_processor_descriptor descriptor;
    void *state;
    float values[XTC_PROCESSOR_PARAMETERS];
    size_t frames;
    uint64_t next;
};
static int text_valid(const char *s, size_t size, int empty)
{
    size_t i;
    if (!empty && !s[0]) return 0;
    for (i = 0; i < size; ++i) {
        if (!s[i]) return 1;
        if ((unsigned char)s[i] < 32 || (unsigned char)s[i] > 126) return 0;
    }
    return 0;
}
xtc_result xtc_processor_validate(const xtc_processor_descriptor *d)
{
    size_t i, j;
    if (!d) return XTC_ERR_INVALID_ARGUMENT;
    if (d->abi_version != XTC_PROCESSOR_ABI || d->struct_size != sizeof(*d)) return XTC_ERR_UNSUPPORTED;
    if (!text_valid(d->identifier, 64, 0) || d->kind < XTC_NATIVE_EFFECT || d->kind > XTC_NATIVE_INSTRUMENT ||
        d->parameter_count > XTC_PROCESSOR_PARAMETERS || !d->prepare || !d->reset || !d->process || !d->destroy ||
        (d->parameter_count && !d->parameter)) return XTC_ERR_INVALID_ARGUMENT;
    for (i = 0; i < d->parameter_count; ++i) {
        const xtc_parameter_info *p = d->parameters + i;
        if (!text_valid(p->name, sizeof(p->name), 0) || !text_valid(p->unit, sizeof(p->unit), 1) ||
            !isfinite(p->minimum) || !isfinite(p->maximum) || !isfinite(p->default_value) ||
            p->minimum > p->maximum || p->default_value < p->minimum || p->default_value > p->maximum)
            return XTC_ERR_INVALID_ARGUMENT;
        for (j = 0; j < i; ++j) if (d->parameters[j].id == p->id) return XTC_ERR_INVALID_ARGUMENT;
    }
    return XTC_OK;
}
static xtc_result create(const xtc_processor_descriptor *d, double rate, size_t frames,
                         const float *values, xtc_processor **out)
{
    xtc_processor *p;
    xtc_result result;
    if (!out) return XTC_ERR_INVALID_ARGUMENT;
    *out = NULL;
    result = xtc_processor_validate(d);
    if (result != XTC_OK) return result;
    if (!isfinite(rate) || rate <= 0 || rate > 768000 || !frames || frames > 65536) return XTC_ERR_INVALID_ARGUMENT;
    p = calloc(1, sizeof(*p));
    if (!p) return XTC_ERR_OUT_OF_MEMORY;
    p->descriptor = *d; p->frames = frames; p->next = UINT64_MAX;
    if (values) memcpy(p->values, values, d->parameter_count * sizeof(float));
    else { size_t i; for (i = 0; i < d->parameter_count; ++i) p->values[i] = d->parameters[i].default_value; }
    result = d->prepare(rate, frames, p->values, d->parameter_count, &p->state);
    if (result != XTC_OK) { xtc_processor_destroy(p); return result; }
    d->reset(p->state);
    *out = p;
    return XTC_OK;
}
xtc_result xtc_processor_create(const xtc_processor_descriptor *d, double rate, size_t frames, xtc_processor **out)
{ return create(d, rate, frames, NULL, out); }
void xtc_processor_destroy(xtc_processor *p)
{ if (p) { p->descriptor.destroy(p->state); free(p); } }
void xtc_processor_reset(xtc_processor *p)
{ if (p) { p->descriptor.reset(p->state); p->next = UINT64_MAX; } }
static size_t parameter_index(const xtc_processor_descriptor *d, unsigned int id)
{
    size_t i;
    for (i = 0; i < d->parameter_count; ++i) if (d->parameters[i].id == id) return i;
    return SIZE_MAX;
}
xtc_result xtc_processor_process(xtc_processor *p, const xtc_native_block *b, const xtc_parameter_event *events, size_t count)
{
    size_t i, cursor = 0, param = 0, midi = 0;
    xtc_result result = XTC_OK;
    if (!p || !b || !b->output || b->position > UINT64_MAX - b->frames || b->frames > p->frames ||
        count > 256 || (count && !events) || b->event_count > 256 || (b->event_count && !b->events) ||
        (b->event_count && p->descriptor.kind != XTC_NATIVE_INSTRUMENT)) return XTC_ERR_INVALID_ARGUMENT;
    for (i = 0; i < count; ++i) {
        size_t index = parameter_index(&p->descriptor, events[i].id);
        if (index == SIZE_MAX || events[i].offset >= b->frames || (i && events[i].offset < events[i-1].offset) ||
            !isfinite(events[i].value) || events[i].value < p->descriptor.parameters[index].minimum ||
            events[i].value > p->descriptor.parameters[index].maximum) return XTC_ERR_INVALID_ARGUMENT;
    }
    for (i = 0; i < b->event_count; ++i) {
        const xtc_midi_event *e = b->events + i;
        if (e->offset >= b->frames || (i && e->offset < b->events[i-1].offset) || e->type < XTC_MIDI_NOTE_ON ||
            e->type > XTC_MIDI_BEND || e->pitch > 127 || e->velocity > 127 || e->channel > 15 ||
            (e->type == XTC_MIDI_NOTE_ON && !e->velocity)) return XTC_ERR_INVALID_ARGUMENT;
    }
    if (!b->frames) return XTC_OK;
    if (p->next != b->position) p->descriptor.reset(p->state);
    while (cursor < b->frames) {
        xtc_midi_event local[256];
        size_t end, n = 0;
        xtc_native_block segment;
        while (param < count && events[param].offset == cursor) {
            size_t index = parameter_index(&p->descriptor, events[param].id);
            p->values[index] = events[param].value;
            p->descriptor.parameter(p->state, events[param].id, events[param].value);
            ++param;
        }
        end = param < count ? events[param].offset : b->frames;
        while (midi < b->event_count && b->events[midi].offset < end) {
            local[n] = b->events[midi++]; local[n++].offset -= (unsigned int)cursor;
        }
        segment = (xtc_native_block){b->input ? b->input + cursor : NULL, b->output + cursor,
            end - cursor, b->position + cursor, local, n};
        result = p->descriptor.process(p->state, &segment);
        if (result != XTC_OK) { memset(b->output, 0, b->frames * sizeof(float)); xtc_processor_reset(p); return result; }
        cursor = end;
    }
    for (i = 0; i < b->frames; ++i) b->output[i] = xtc_dsp_finite(b->output[i]);
    p->next = b->position + b->frames;
    return result;
}
static void put(unsigned char *p, uint32_t value)
{ size_t i; for (i = 0; i < 4; ++i) p[i] = (unsigned char)(value >> (i * 8)); }
static uint32_t get(const unsigned char *p)
{ return (uint32_t)p[0] | (uint32_t)p[1]<<8 | (uint32_t)p[2]<<16 | (uint32_t)p[3]<<24; }
xtc_result xtc_processor_save(const xtc_processor *p, void *data, size_t capacity, size_t *written)
{
    unsigned char *bytes = data;
    size_t i, size;
    if (!p || !written) return XTC_ERR_INVALID_ARGUMENT;
    size = 80 + p->descriptor.parameter_count * 8;
    *written = size;
    if (!data || capacity < size) return XTC_ERR_CAPACITY;
    if (sizeof(float) != 4 || FLT_RADIX != 2 || FLT_MANT_DIG != 24 || FLT_MAX_EXP != 128) return XTC_ERR_UNSUPPORTED;
    memset(bytes, 0, size); memcpy(bytes, "XTCN", 4); put(bytes+4, 2);
    memcpy(bytes+8, p->descriptor.identifier, strlen(p->descriptor.identifier));
    put(bytes+72, (uint32_t)p->descriptor.parameter_count);
    for (i = 0; i < p->descriptor.parameter_count; ++i) {
        uint32_t bits; memcpy(&bits, p->values+i, 4);
        put(bytes+80+i*8, p->descriptor.parameters[i].id); put(bytes+84+i*8, bits);
    }
    return XTC_OK;
}
xtc_result xtc_processor_restore(const xtc_processor_descriptor *d, double rate, size_t frames,
                                 const void *data, size_t size, xtc_processor **out)
{
    const unsigned char *bytes = data;
    float values[XTC_PROCESSOR_PARAMETERS] = {0};
    size_t i, j;
    xtc_result result;
    if (!out) return XTC_ERR_INVALID_ARGUMENT;
    *out = NULL;
    result = xtc_processor_validate(d);
    if (result != XTC_OK) return result;
    if (sizeof(float) != 4 || FLT_RADIX != 2 || FLT_MANT_DIG != 24 || FLT_MAX_EXP != 128) return XTC_ERR_UNSUPPORTED;
    if (!bytes || size != 80 + 8*d->parameter_count || memcmp(bytes, "XTCN", 4) || get(bytes+4) != 2 ||
        !memchr(bytes+8, 0, 64) || strcmp((const char *)bytes+8, d->identifier) ||
        get(bytes+72) != d->parameter_count || get(bytes+76)) return XTC_ERR_FORMAT;
    for (i = 0; i < d->parameter_count; ++i) {
        uint32_t bits = get(bytes+84+i*8);
        if (get(bytes+80+i*8) != d->parameters[i].id) return XTC_ERR_UNSUPPORTED;
        memcpy(values+i, &bits, 4);
        if (!isfinite(values[i]) || values[i] < d->parameters[i].minimum || values[i] > d->parameters[i].maximum)
            return XTC_ERR_FORMAT;
    }
    for (j = 8 + strlen((const char *)bytes+8); j < 72; ++j) if (bytes[j]) return XTC_ERR_FORMAT;
    return create(d, rate, frames, values, out);
}