/*
  LV2 Fifths Example Plugin
  Copyright 2014-2016 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include "./uris.h"

#include "lv2/atom/atom.h"
#include "lv2/atom/util.h"
#include "lv2/core/lv2.h"
#include "lv2/core/lv2_util.h"
#include "lv2/log/log.h"
#include "lv2/log/logger.h"
#include "lv2/midi/midi.h"
#include "lv2/urid/urid.h"

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

enum { FIFTHS_IN = 0, FIFTHS_OUT = 1 };

typedef struct {
  // Features
  LV2_URID_Map*  map;
  LV2_Log_Logger logger;

  // Ports
  const LV2_Atom_Sequence* in_port;
  LV2_Atom_Sequence*       out_port;

  // URIs
  FifthsURIs uris;
} Fifths;

static void
connect_port(LV2_Handle instance, uint32_t port, void* data)
{
  Fifths* self = (Fifths*)instance;
  switch (port) {
  case FIFTHS_IN:
    self->in_port = (const LV2_Atom_Sequence*)data;
    break;
  case FIFTHS_OUT:
    self->out_port = (LV2_Atom_Sequence*)data;
    break;
  default:
    break;
  }
}

static LV2_Handle
instantiate(const LV2_Descriptor*     descriptor,
            double                    rate,
            const char*               path,
            const LV2_Feature* const* features)
{
  // Allocate and initialise instance structure.
  Fifths* self = (Fifths*)calloc(1, sizeof(Fifths));
  if (!self) {
    return NULL;
  }

  // Scan host features for URID map
  // clang-format off
  const char*  missing = lv2_features_query(
    features,
    LV2_LOG__log,  &self->logger.log, false,
    LV2_URID__map, &self->map,        true,
    NULL);
  // clang-format on

  lv2_log_logger_set_map(&self->logger, self->map);
  if (missing) {
    lv2_log_error(&self->logger, "Missing feature <%s>\n", missing);
    free(self);
    return NULL;
  }

  map_fifths_uris(self->map, &self->uris);

  return (LV2_Handle)self;
}

static void
cleanup(LV2_Handle instance)
{
  free(instance);
}

static void
run(LV2_Handle instance, uint32_t sample_count)
{
  Fifths*     self = (Fifths*)instance;
  FifthsURIs* uris = &self->uris;

  // Struct for a 3 byte MIDI event, used for writing notes
  typedef struct {
    LV2_Atom_Event event;
    uint8_t        msg[3];
  } MIDINoteEvent;

  // Initially self->out_port contains a Chunk with size set to capacity

  // Get the capacity
  const uint32_t out_capacity = self->out_port->atom.size;

  // Write an empty Sequence header to the output
  lv2_atom_sequence_clear(self->out_port);
  self->out_port->atom.type = self->in_port->atom.type;

  // Read incoming events
  LV2_ATOM_SEQUENCE_FOREACH (self->in_port, ev) {
    if (ev->body.type == uris->midi_Event) {
      const uint8_t* const msg = (const uint8_t*)(ev + 1);
      switch (lv2_midi_message_type(msg)) {
      case LV2_MIDI_MSG_NOTE_ON:
      case LV2_MIDI_MSG_NOTE_OFF:
        // Forward note to output
        lv2_atom_sequence_append_event(self->out_port, out_capacity, ev);

        if (msg[1] <= 127 - 7) {
          // Make a note one 5th (7 semitones) higher than input
          MIDINoteEvent fifth;

          // Could simply do fifth.event = *ev here instead...
          fifth.event.time.frames = ev->time.frames; // Same time
          fifth.event.body.type   = ev->body.type;   // Same type
          fifth.event.body.size   = ev->body.size;   // Same size

          fifth.msg[0] = msg[0];     // Same status
          fifth.msg[1] = msg[1] + 7; // Pitch up 7 semitones
          fifth.msg[2] = msg[2];     // Same velocity

          // Write 5th event
          lv2_atom_sequence_append_event(
            self->out_port, out_capacity, &fifth.event);
        }
        break;
      default:
        // Forward all other MIDI events directly
        lv2_atom_sequence_append_event(self->out_port, out_capacity, ev);
        break;
      }
    }
  }
}

static const void*
extension_data(const char* uri)
{
  return NULL;
}

static const LV2_Descriptor descriptor = {EG_FIFTHS_URI,
                                          instantiate,
                                          connect_port,
                                          NULL, // activate,
                                          run,
                                          NULL, // deactivate,
                                          cleanup,
                                          extension_data};

LV2_SYMBOL_EXPORT
const LV2_Descriptor*
lv2_descriptor(uint32_t index)
{
  return index == 0 ? &descriptor : NULL;
}