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

#include <xas/riff.h>
#include <xas/bank.h>

xas_bank *xas_bank_new(xas_audio_format format,
                           size_t entry_size,
                           size_t entry_count) {
    xas_bank *bank;

    size_t entry_size_total = sizeof(xas_bank_entry) + format.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->format.channels    = XAS_AUDIO_MONO;
    bank->format.sample_size = format.sample_size;
    bank->format.sample_rate = format.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);
}

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 (!xas_audio_format_eq(bank->format, input->format)) {
        errno = EINVAL;

        goto error_invalid_format;
    }

    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;
        } else if (readlen == 0) {
            break;
        }

        xas_audio_copy(bank->format,
                         entry + 1,
                         buf,
                         index_o,
                         0,
                         readlen);

        left    -= readlen;
        index_o += readlen;
    }

    return entry->duration = index_o;

error_audio_stream_read:
error_invalid_format:
    return -1;
}

ssize_t xas_bank_load_file(xas_bank *bank,
                             size_t entry_index,
                             const char *path) {
    ssize_t ret;

    xas_audio_stream *riff;

    if ((riff = xas_riff_open_file(path, O_RDONLY)) == NULL) {
        goto error_riff_open_file;
    }

    if ((ret = xas_bank_record(bank,
                                 riff,
                                 entry_index,
                                 bank->entry_size)) < 0) {
        goto error_record;
    }

    xas_audio_stream_destroy(riff);

    return ret;

error_record:
    xas_audio_stream_destroy(riff);

error_riff_open_file:
    return -1;
}

static int set_gain(xas_bank_player *player, float gain) {
    xas_bank_player_set_gain(player, gain);

    return 0;
}

xas_bank_player *xas_bank_player_new(xas_bank *bank) {
    xas_bank_player *player;

    if ((player = malloc(sizeof(*player))) == NULL) {
        goto error_malloc_player;
    }

    player->obj.start      = (xas_object_start_callback)xas_bank_player_start;
    player->obj.stop       = (xas_object_stop_callback)xas_bank_player_stop;
    player->obj.set_gain   = (xas_object_set_gain_callback)set_gain;
    player->obj.stream_new = (xas_object_stream_new_callback)xas_bank_player_stream_new;
    player->obj.destroy    = (xas_object_destroy_callback)xas_bank_player_destroy;

    player->bank   = bank;
    player->status = XAS_BANK_PLAYER_STOPPED;
    player->gain   = XAS_BANK_PLAYER_DEFAULT_GAIN;
    player->entry  = 0;
    player->index  = 0;

    return player;

error_malloc_player:
    return NULL;
}

void xas_bank_player_destroy(xas_bank_player *player) {
    free(player);
}

int xas_bank_player_set_entry(xas_bank_player *player, size_t entry) {
    if (entry > player->bank->entry_count) {
        errno = EINVAL;

        goto error_invalid_entry;
    }

    player->entry = entry;

    return 0;

error_invalid_entry:
    return -1;
}

void xas_bank_player_set_gain(xas_bank_player *player, float gain) {
    player->gain = gain;
}

int xas_bank_player_start(xas_bank_player *player) {
    if (player->status == XAS_BANK_PLAYER_PLAYING) {
        return 0;
    }

    player->status = XAS_BANK_PLAYER_PLAYING;
    player->index  = 0;

    return 0;
}

int xas_bank_player_stop(xas_bank_player *player) {
    if (player->status == XAS_BANK_PLAYER_STOPPED) {
        return 0;
    }

    player->status = XAS_BANK_PLAYER_STOPPED;
    player->gain   = 0.0;
    player->entry  = 0;
    player->index  = 0;

    return 1;
}

int xas_bank_player_playing(xas_bank_player *player) {
    return player->status == XAS_BANK_PLAYER_PLAYING;
}

static ssize_t stream_fill(xas_bank_player *player,
                           int16_t *dest,
                           size_t count,
                           xas_audio_stream *stream) {
    xas_bank *bank = player->bank;

    size_t index_o = 0,
            left   = count;

    while (left) {
        if (player->status == XAS_BANK_PLAYER_PLAYING) {
            xas_bank_entry *entry =
                &((xas_bank_entry *)(bank + 1))[player->entry];

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

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

            size_t i;

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

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

            if (player->index == entry->duration) {
                xas_bank_player_stop(player);
            }
        } else {
            xas_audio_zero(bank->format, dest, index_o, left);

            index_o += left;
            left     = 0;
        }
    }

    return count;
}

void stream_cleanup(xas_bank_player *player, xas_audio_stream *stream) {
    return;
}

xas_audio_stream *xas_bank_player_stream_new(xas_bank_player *player) {
    return xas_audio_stream_new_source((xas_audio_fill)stream_fill,
                                         (xas_audio_cleanup)stream_cleanup,
                                         player->bank->format,
                                         player->bank->entry_size,
                                         player);
}