// cppcheck-suppress missingIncludeSystem
#include "looper.h"
#include "channel.h"
#include "midi.h"
#include "wav.h"
#include <jack/jack.h>
#include <jack/midiport.h>
#include <math.h>
#include <pthread.h>
#include <stdatomic.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

/* Global state (shared across files) */
struct channel_t channels[MAX_CHANNELS];
atomic_int channel_count = 0;
int next_channel_id = 1;
atomic_int cmd_add = 0;
atomic_int cmd_remove = 0;
atomic_int cmd_load = 0;
atomic_int cmd_save = 0;
jack_port_t *midi_control_port = NULL;
jack_port_t *midi_clock_port = NULL;
atomic_int control_key_active = 0;
atomic_int bind_channel = 0;

/* Deferred removal index (1 second grace) */
static int pending_unregister_idx = -1;

/* writer thread function and sample rate holder */
static void *writer_thread(void *arg);
static int global_sample_rate = 0;

/* ----------------------------------------------------------------
 * process callback
 * ---------------------------------------------------------------- */
int process_callback(jack_nframes_t nframes, void *arg) {
  (void)arg;

  if (midi_control_port) {
    void *midi_ctrl_buf = jack_port_get_buffer(midi_control_port, nframes);
    if (midi_ctrl_buf) {
      midi_handle_events(midi_ctrl_buf, nframes);
    }
  }

  /* process each active channel */
  for (int c = 0; c < MAX_CHANNELS; c++) {
    if (!atomic_load(&channels[c].active))
      continue;

    /* Guard against NULL ports (e.g. if port registration failed) */
    if (!channels[c].audio_in || !channels[c].audio_out) {
      fprintf(stderr, "WARN: channel %d has NULL audio port(s), skipping\n", c);
      continue;
    }

    const jack_default_audio_sample_t *in =
        (const jack_default_audio_sample_t *)jack_port_get_buffer(
            channels[c].audio_in, nframes);
    jack_default_audio_sample_t *out =
        (jack_default_audio_sample_t *)jack_port_get_buffer(
            channels[c].audio_out, nframes);
    if (!out)
      continue;

    int state = atomic_load(&channels[c].state);

    if (state != atomic_load(&channels[c].prev_state)) {
      switch (state) {
      case STATE_RECORD:
        atomic_store(&channels[c].record_pos, 0);
        atomic_store(&channels[c].loop_count, 0);
        break;
      case STATE_LOOPING:
        if (atomic_load(&channels[c].prev_state) == STATE_RECORD &&
            atomic_load(&channels[c].record_pos) > 0)
          atomic_store(&channels[c].loop_count,
                       atomic_load(&channels[c].record_pos));
        atomic_store(&channels[c].playback_pos, 0);
        break;
      default:
        break;
      }
    }

    jack_nframes_t i;
    switch (state) {
    case STATE_RECORD:
      if (in) {
        float *f_out = (float *)out;
        const float *f_in = (const float *)in;
        for (i = 0; i < nframes; i++) {
          int rp = atomic_fetch_add(&channels[c].record_pos, 1);
          if (rp < LOOP_BUF_SIZE)
            channels[c].loop_buffer[rp] = f_in[i];
          f_out[i] = f_in[i];
        }
      } else {
        memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
      }
      break;

    case STATE_LOOPING:
      int lc = atomic_load(&channels[c].loop_count);
      if (lc > 0) {
        float *outf = (float *)out;
        for (i = 0; i < nframes; i++) {
          int pp = atomic_load(&channels[c].playback_pos);
          outf[i] = channels[c].loop_buffer[pp];
          atomic_store(&channels[c].playback_pos, (pp + 1) % lc);
        }
      } else {
        memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
      }
      break;

    case STATE_PAUSED:
      memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
      break;

    default: /* IDLE */
      if (in) {
        memcpy(out, in, sizeof(jack_default_audio_sample_t) * nframes);
      } else {
        memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
      }
      break;
    }

    // push loop output into save ring if saving (atomic load)
    RingBuf *r = (RingBuf *)atomic_load_explicit(&channels[c].save_ring,
                                                 memory_order_acquire);
    if (r != NULL) {
      if (state == STATE_LOOPING && atomic_load(&channels[c].loop_count) > 0) {
        const float *outf = (const float *)out;
        ring_write(r, outf, nframes);
      }
    }

    atomic_store(&channels[c].prev_state, state);
  }

  /* MIDI clock events – affect channel 0 only */
  if (midi_clock_port) {
    void *midi_clock_buf = jack_port_get_buffer(midi_clock_port, nframes);
    if (midi_clock_buf) {
      jack_nframes_t n_clock_events = jack_midi_get_event_count(midi_clock_buf);
      jack_midi_event_t cev;
      for (jack_nframes_t j = 0; j < n_clock_events; j++) {
        if (jack_midi_event_get(&cev, midi_clock_buf, j) != 0)
          continue;
        if (cev.size >= 1) {
          unsigned char msg = cev.buffer[0];
          switch (msg) {
          case 0xFA: {
            int s = atomic_load(&channels[0].state);
            if (s == STATE_IDLE)
              atomic_store(&channels[0].state, STATE_RECORD);
            break;
          }
          case 0xFC:
            atomic_store(&channels[0].state, STATE_IDLE);
            break;
          case 0xFB: {
            int s = atomic_load(&channels[0].state);
            if (s == STATE_PAUSED)
              atomic_store(&channels[0].state, STATE_LOOPING);
            break;
          }
          default:
            break;
          }
        }
      }
    }
  }

  return 0;
}

/* ----------------------------------------------------------------
 * shutdown callback
 * ---------------------------------------------------------------- */
void jack_shutdown_cb(void *arg) {
  (void)arg;
  fprintf(stderr, "JACK shutdown\n");
  exit(0);
}

/* ----------------------------------------------------------------
 * looper initialisation
 * ---------------------------------------------------------------- */
int looper_init(jack_client_t *client) {
  /* store sample rate for writer thread */
  global_sample_rate = jack_get_sample_rate(client);

  /* channel 0 */
  channels[0].active = 1;
  atomic_store(&channels[0].state, STATE_IDLE);
  atomic_store(&channels[0].prev_state, -1);
  channels[0].loop_count = 0;
  atomic_store(&channels[0].record_pos, 0);
  atomic_store(&channels[0].playback_pos, 0);
  atomic_store_explicit(&channels[0].save_ring, NULL, memory_order_release);

  channels[0].audio_in = jack_port_register(
      client, "input", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
  channels[0].audio_out = jack_port_register(
      client, "output", JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
  if (!channels[0].audio_in || !channels[0].audio_out) {
    fprintf(stderr, "Could not create audio ports for channel 0\n");
    return -1;
  }
  channel_count = 1;

  midi_control_port = jack_port_register(
      client, "control", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);
  midi_clock_port = jack_port_register(client, "clock", JACK_DEFAULT_MIDI_TYPE,
                                       JackPortIsInput, 0);
  if (!midi_control_port || !midi_clock_port) {
    fprintf(stderr, "Could not create MIDI ports\n");
    return -1;
  }

  return 0;
}

/* ----------------------------------------------------------------
 * writer thread – consumes the save ring and writes WAV file
 * ---------------------------------------------------------------- */
static void *writer_thread(void *arg) {
  struct channel_t *ch = (struct channel_t *)arg;
  RingBuf *ring = (RingBuf *)ch->save_ring;
  if (!ring)
    return NULL;

  static const char *path = "save.wav";
  unsigned sr = (unsigned)global_sample_rate;
  if (sr == 0)
    sr = 48000;

  int lc = atomic_load(&ch->loop_count);
  float *outbuf = malloc((size_t)lc * sizeof(float));
  if (!outbuf) {
    ring_destroy(ring);
    free(ring);
    ch->save_ring = NULL;
    return NULL;
  }
  size_t collected = 0;
  size_t want = (size_t)lc;
  while (collected < want) {
    size_t got = ring_read(ring, outbuf + collected, want - collected);
    collected += got;
    if (got == 0) {
      struct timespec req = {.tv_sec = 0, .tv_nsec = 10000000};
      nanosleep(&req, NULL);
    }
  }
  wav_write(path, outbuf, (unsigned)lc, sr);
  free(outbuf);

  ring_destroy(ring);
  free(ring);
  atomic_store_explicit(&ch->save_ring, NULL, memory_order_release);
  return NULL;
}

/* ----------------------------------------------------------------
 * main‑loop command processing
 * ---------------------------------------------------------------- */
void looper_process_commands(jack_client_t *client) {
  /* Unregister any ports that were marked for deferred removal.
     By now the real‑time thread has had at least one full cycle
     to see the `active = 0` store. */
  if (pending_unregister_idx != -1) {
    int idx = pending_unregister_idx;
    if (channels[idx].audio_in)
      jack_port_unregister(client, channels[idx].audio_in);
    if (channels[idx].audio_out)
      jack_port_unregister(client, channels[idx].audio_out);
    pending_unregister_idx = -1;
  }

  if (atomic_exchange(&cmd_add, 0)) {
    int idx;
    for (idx = 0; idx < MAX_CHANNELS; idx++)
      if (!channels[idx].active)
        break;
    if (idx < MAX_CHANNELS) {
      channel_add(client, idx);
    }
  }

  if (atomic_exchange(&cmd_remove, 0)) {
    int remove_idx = -1;
    for (int idx = 1; idx < MAX_CHANNELS; idx++)
      if (channels[idx].active)
        remove_idx = idx;
    if (remove_idx != -1) {
      /* Mark inactive now; ports will be unregistered next round */
      channel_remove(client, remove_idx);
      pending_unregister_idx = remove_idx;
    }
  }

  /* ---------- load command ---------- */
  if (atomic_exchange(&cmd_load, 0)) {
    float *buf = NULL;
    unsigned frames = 0;
    printf("LOAD: wav_read called\n");
    if (wav_read("loop.wav", &buf, &frames) == 0 && frames > 0) {
      printf("LOAD: success, frames=%u\n", frames);
      if (frames > LOOP_BUF_SIZE)
        frames = LOOP_BUF_SIZE;
      memcpy(channels[0].loop_buffer, buf, frames * sizeof(float));
      atomic_store(&channels[0].loop_count, (int)frames);
      atomic_store(&channels[0].record_pos, 0);
      atomic_store(&channels[0].playback_pos, 0);
      atomic_store(&channels[0].state, STATE_LOOPING);
      atomic_store(&channels[0].prev_state, -1);
      free(buf);
    } else {
      fprintf(stderr, "Failed to load loop.wav\n");
      printf("LOAD: FAILED\n");
    }
  }

  /* ---------- save command (writer thread) ---------- */
  if (atomic_exchange(&cmd_save, 0)) {
    int lc = atomic_load(&channels[0].loop_count);
    if (atomic_load(&channels[0].state) == STATE_LOOPING && lc > 0 &&
        channels[0].save_ring == NULL) {
      RingBuf *ring = (RingBuf *)malloc(sizeof(RingBuf));
      if (ring) {
        size_t sz = (size_t)lc * 2;
        if (ring_init(ring, sz) == 0) {
          atomic_store_explicit(&channels[0].save_ring, (_Atomic RingBuf *)ring,
                                memory_order_release);
          pthread_t th;
          pthread_create(&th, NULL, writer_thread, &channels[0]);
          pthread_detach(th);
        } else {
          free(ring);
        }
      }
    }
  }
}