#include <stdlib.h>
#include <string.h>

#include <xas/bank.h>

xas_bank *xas_bank_new(size_t sample_size,
                           size_t sample_rate,
                           size_t entry_size,
                           size_t entry_count) {
    xas_bank *bank;

    size_t entry_size_total = sizeof(xas_bank_entry) + sample_size
                                                       * entry_size;

    size_t total = sizeof(xas_bank) + entry_count
                                      * entry_size_total;

    if ((bank = malloc(total)) == NULL) {
        goto error_malloc_bank;
    }

    memset(bank, '\0', total);

    bank->sample_size = sample_size;
    bank->sample_rate = sample_rate;
    bank->entry_size  = entry_size;
    bank->entry_count = entry_count;

    return bank;

error_malloc_bank:
    return NULL;
}

void xas_bank_destroy(xas_bank *bank) {
    free(bank);
}

int xas_bank_play(xas_bank *bank, size_t entry, float force) {
    bank->flags |= XAS_BANK_ACTIVE;
    bank->force  = force;
    bank->entry  = entry;
    bank->index  = 0;

    return 0;
}

void xas_bank_stop(xas_bank *bank) {
    bank->flags &= ~XAS_BANK_ACTIVE;
    bank->force  = 0.0;
    bank->entry  = 0;
    bank->index  = 0;
}

int xas_bank_active(xas_bank *bank) {
    return bank->flags & XAS_BANK_ACTIVE;
}

static inline void *ptr(xas_audio_stream *stream, void *buf, size_t index) {
    return ((uint8_t *)buf) + stream->channels * stream->sample_size * index;
}

ssize_t xas_bank_record(xas_bank *bank,
                          xas_audio_stream *input,
                          size_t entry_index,
                          size_t count) {
    xas_bank_entry *entry = &((xas_bank_entry *)(bank + 1))[entry_index];

    size_t left    = count,
           index_o = 0;

    if (count > bank->entry_size) {
        count = bank->entry_size;
    }

    while (left) {
        ssize_t readlen,
                amount = left > count? count: left;

        void *buf;

        if ((readlen = xas_audio_stream_read(input, &buf, amount)) < 0) {
            goto error_audio_stream_read;
        }

        memcpy(ptr(input, entry + 1, index_o),
               ptr(input, buf,       0),
               readlen * bank->sample_size);

        left    -= readlen;
        index_o += readlen;
    }

    return entry->duration = index_o;

error_audio_stream_read:
    return -1;
}

static ssize_t stream_fill(xas_bank *bank,
                           int16_t *dest,
                           size_t count,
                           xas_audio_stream *stream) {
        size_t index_o = 0,
               left    = count;

    while (left) {
        if (bank->flags & XAS_BANK_ACTIVE) {
            xas_bank_entry *entry =
                &((xas_bank_entry *)(bank + 1))[bank->entry];

            int16_t *src = (int16_t *)(entry + 1);

            size_t remaining = entry->duration - bank->index,
                   amount    = remaining < left? remaining: left;

            size_t i;

            for (i=0; i<amount; i++) {
                dest[index_o + i] = bank->force * src[bank->index + i];
            }

            left        -= amount;
            bank->index += amount;
            index_o     += amount;

            if (bank->index == entry->duration) {
                xas_bank_stop(bank);
            }
        } else {
            memset(ptr(stream, dest, index_o),
                   '\0',
                   left * stream->channels * stream->sample_size);

            index_o += left;
            left     = 0;
        }
    }

    return count;
}

void stream_cleanup(xas_bank *bank, xas_audio_stream *stream) {
    return;
}

xas_audio_stream *xas_bank_stream_new(xas_bank *bank) {
    return xas_audio_stream_new_source((xas_audio_fill)stream_fill,
                                         (xas_audio_cleanup)stream_cleanup,
                                         bank,
                                         XAS_AUDIO_MONO,
                                         bank->sample_size,
                                         bank->sample_rate,
                                         bank->entry_size);
}