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

#include <xas/object.h>
#include <xas/bank.h>
#include <xas/synth.h>
#include <xas/script.h>

xas_script *xas_script_new(xas_spatial_scene *scene, size_t buffer_size) {
    xas_script *script;

    if ((script = malloc(sizeof(*script))) == NULL) {
        goto error_malloc_script;
    }

    script->scene       = scene;
    script->first       = NULL;
    script->buffer_size = buffer_size;

    return script;

error_malloc_script:
    return NULL;
}

void xas_script_destroy(xas_script *script) {
    xas_script_event *event = script->first;

    while (event) {
        xas_script_event *next = event->next;

        free(event);

        event = next;
    }

    free(script);
}

static void add_event(xas_script *script, xas_script_event *ev) {
    xas_script_event *current = script->first;

    if (script->first == NULL) {
        script->first = ev;

        return;
    }

    while (current) {
        xas_script_event *next = current->next;

        if (next == NULL) {
            current->next = ev;

            return;
        }

        if (!timercmp(&current->timestamp, &ev->timestamp,   <)
         &&  timercmp(&current->timestamp, &next->timestamp, <)) {
            current->next = ev;
            ev->next      = next;

            return;
        }

        current = next;
    }
}

int xas_script_add_event_off(xas_script *script,
                               xas_spatial_object *object,
                               struct timeval timestamp) {
    xas_script_event *ev;

    if ((ev = malloc(sizeof(*ev))) == NULL) {
        goto error_malloc_ev;
    }

    ev->type      = XAS_SCRIPT_EVENT_OFF;
    ev->objtype   = XAS_SCRIPT_OBJECT_ANY;
    ev->object    = object;
    ev->timestamp = timestamp;
    ev->next      = NULL;

    add_event(script, ev);

    return 0;

error_malloc_ev:
    return -1;
}

int xas_script_add_event_on(xas_script *script,
                              xas_spatial_object *object,
                              struct timeval timestamp) {
    xas_script_event *ev;

    if ((ev = malloc(sizeof(*ev))) == NULL) {
        goto error_malloc_ev;
    }

    ev->type      = XAS_SCRIPT_EVENT_ON;
    ev->objtype   = XAS_SCRIPT_OBJECT_ANY;
    ev->object    = object;
    ev->timestamp = timestamp;
    ev->next      = NULL;

    add_event(script, ev);

    return 0;

error_malloc_ev:
    return -1;
}

int xas_script_add_set_position(xas_script *script,
                                  xas_spatial_object *object,
                                  struct timeval timestamp,
                                  xas_spatial_coord point) {
    xas_script_event *ev;

    if ((ev = malloc(sizeof(*ev))) == NULL) {
        goto error_malloc_ev;
    }

    ev->type      = XAS_SCRIPT_EVENT_SET_POSITION;
    ev->objtype   = XAS_SCRIPT_OBJECT_ANY;
    ev->object    = object;
    ev->timestamp = timestamp;
    ev->point     = point;
    ev->next      = NULL;

    add_event(script, ev);

    return 0;

error_malloc_ev:
    return -1;
}

int xas_script_add_set_gain(xas_script *script,
                              xas_spatial_object *object,
                              struct timeval timestamp,
                              float gain) {
    xas_script_event *ev;

    if ((ev = malloc(sizeof(*ev))) == NULL) {
        goto error_malloc_ev;
    }

    ev->type      = XAS_SCRIPT_EVENT_ON;
    ev->objtype   = XAS_SCRIPT_OBJECT_ANY;
    ev->object    = object;
    ev->timestamp = timestamp;
    ev->gain      = gain;
    ev->next      = NULL;

    add_event(script, ev);

    return 0;

error_malloc_ev:
    return -1;
}

int xas_script_add_set_bank(xas_script *script,
                              xas_spatial_object *object,
                              struct timeval timestamp,
                              size_t index) {
    xas_script_event *ev;

    if ((ev = malloc(sizeof(*ev))) == NULL) {
        goto error_malloc_ev;
    }

    ev->type      = XAS_SCRIPT_EVENT_SET_BANK_INDEX;
    ev->objtype   = XAS_SCRIPT_OBJECT_BANK_PLAYER;
    ev->object    = object;
    ev->timestamp = timestamp;
    ev->next      = NULL;
    ev->index     = index;

    add_event(script, ev);

    return 0;

error_malloc_ev:
    return -1;
}

int xas_script_add_set_frequency(xas_script *script,
                                   xas_spatial_object *object,
                                   struct timeval timestamp,
                                   size_t frequency) {
    xas_script_event *ev;

    if ((ev = malloc(sizeof(*ev))) == NULL) {
        goto error_malloc_ev;
    }

    ev->type      = XAS_SCRIPT_EVENT_SET_FREQUENCY;
    ev->objtype   = XAS_SCRIPT_OBJECT_SYNTH;
    ev->object    = object;
    ev->timestamp = timestamp;
    ev->next      = NULL;
    ev->frequency = frequency;

    add_event(script, ev);

    return 0;

error_malloc_ev:
    return -1;
}

static inline void timerupdate(struct timeval *tv,
                               suseconds_t interval,
                               size_t frame) {
    struct timeval zero  = { 0, 0 },
                   timer = { 0, frame * interval };

    timeradd(&zero, &timer, tv);
}

static int event_trigger(xas_spatial_scene *scene, xas_script_event *ev) {
    switch (ev->type) {
        case XAS_SCRIPT_EVENT_OFF:
            return xas_spatial_object_stop(ev->object);

        case XAS_SCRIPT_EVENT_ON:
            return xas_spatial_object_start(ev->object);

        case XAS_SCRIPT_EVENT_SET_POSITION:
            xas_spatial_scene_position_object(scene,
                                                ev->object,
                                                ev->point);

            break;

        case XAS_SCRIPT_EVENT_SET_GAIN:
            xas_object_set_gain(ev->object->ctx, ev->gain);

            break;

        case XAS_SCRIPT_EVENT_SET_FREQUENCY:
            if (ev->objtype != XAS_SCRIPT_OBJECT_SYNTH) {
                goto error_invalid_event;
            }

            xas_synth_set_frequency(ev->object->ctx, ev->frequency);

            break;

        case XAS_SCRIPT_EVENT_SET_BANK_INDEX:
            if (ev->objtype != XAS_SCRIPT_OBJECT_BANK_PLAYER) {
                goto error_invalid_event;
            }

            xas_bank_player_set_entry(ev->object->ctx, ev->gain);

            break;
    }

    return 0;

error_invalid_event:
    return -1;
}

int xas_script_play(xas_script *script, xas_audio_stream *sink) {
    xas_script_event *ev = script->first;
    xas_audio_stream *source;

    size_t frame       = 0,
           sample_rate = script->scene->format.sample_rate,
           buffer_size = script->buffer_size;

    suseconds_t interval = 1000000 / (sample_rate / buffer_size);

    int16_t *samples;

    if ((source = xas_spatial_scene_new_stream(script->scene,
                                                 script->buffer_size)) == NULL) {
        goto error_spatial_scene_new_stream;
    }

    while (ev) {
        xas_script_event *next = ev->next;
        struct timeval tv;

        ssize_t readlen;

        timerupdate(&tv, interval, frame);

        if (timercmp(&ev->timestamp, &tv, >)) {
            if (event_trigger(script->scene, ev) < 0) {
                goto error_event_trigger;
            }

            ev = next;
        }

        if ((readlen = xas_audio_stream_read(source,
                                               (void **)&samples,
                                               buffer_size)) < 0) {
            goto error_audio_stream_io;
        } else if (readlen == 0) {
            break;
        }

        if (xas_audio_stream_write(sink, samples, readlen) < 0) {
            goto error_audio_stream_io;
        }

        frame++;
    }

    return frame * buffer_size;

error_audio_stream_io:
error_event_trigger:
    xas_audio_stream_destroy(source);

error_spatial_scene_new_stream:
    return -1;
}