// cppcheck-suppress missingIncludeSystem
#include "looper.h"
#include "channel.h"
#include "midi.h"
#include "pipe.h"
#include "queue.h"
#include "wav.h"
#include <fcntl.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 <sys/stat.h>
#include <unistd.h>

/* Global command queues (used by midi.c and pipe.c) */
spsc_queue_t cmd_queue;
spsc_queue_t cmd_queue_main_midi;
spsc_queue_t cmd_queue_main_fifo;

#define STATUS_FIFO "/tmp/looper_status"

/* writer status fd */
static int status_fd = -1;

static void looper_write_status(void) {
  if (status_fd < 0)
    return;
  char buf[256];
  for (int ch = 0; ch < MAX_CHANNELS; ch++) {
    if (!atomic_load(&channels[ch].active))
      continue;
    int sc_idx = atomic_load(&channels[ch].current_scene);
    int state = atomic_load(&channels[ch].scenes[sc_idx].state);
    const char *state_str;
    switch (state) {
    case STATE_IDLE:
      state_str = "IDLE";
      break;
    case STATE_RECORD:
      state_str = "RECORD";
      break;
    case STATE_LOOPING:
      state_str = "LOOPING";
      break;
    case STATE_PAUSED:
      state_str = "PAUSED";
      break;
    default:
      state_str = "UNKNOWN";
    }
    int n = snprintf(buf, sizeof(buf), "CH=%d SC=%d STATE=%s\n", ch, sc_idx,
                     state_str);
    if (n > 0) {
      int ret = write(status_fd, buf, n);
      (void)ret;
    }
  }
}

/* Global state (shared across files) */
struct channel_t channels[MAX_CHANNELS];
atomic_int channel_count = 0;
atomic_int channel_capacity = MAX_CHANNELS;
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;

/* sample rate holder */
static int global_sample_rate = 0;

/* execute a single command (called from looper_process_commands) */
static void exec_command(command_t cmd, jack_client_t *client) {
  int ch = cmd.channel;
  if (ch < 0 || ch >= MAX_CHANNELS)
    ch = 0;

  switch (cmd.type) {
  case CMD_CYCLE: {
    int ch = cmd.channel;
    if (ch < 0 || ch >= MAX_CHANNELS)
      ch = 0;

    // Save the desired scene (may have been set by CMD_SET_SCENE)
    int requested_scene = atomic_load(&channels[ch].current_scene);
    // Clamp requested_scene to valid range
    if (requested_scene < 0) requested_scene = 0;
    if (requested_scene >= MAX_SCENES) requested_scene = MAX_SCENES - 1;

    // Auto-create channel if it doesn't exist
    if (!channels[ch].active) {
      channel_add(client, ch);
    }

    // Ensure enough scenes exist to satisfy requested_scene
    int sc_count = atomic_load(&channels[ch].scene_count);
    while (requested_scene >= sc_count && sc_count < MAX_SCENES) {
      channel_add_scene(client, ch);
      sc_count = atomic_load(&channels[ch].scene_count);
    }
    // Clamp requested_scene if MAX_SCENES prevents adding enough scenes
    if (requested_scene >= sc_count) requested_scene = sc_count - 1;
    // Restore the requested scene (channel_add or add_scene may have reset current_scene)
    atomic_store(&channels[ch].current_scene, requested_scene);


    int sc_idx = atomic_load(&channels[ch].current_scene);
    scene_t *sc_ptr = &channels[ch].scenes[sc_idx];
    int state = atomic_load(&sc_ptr->state);
    fprintf(stderr, "CMD_CYCLE: ch=%d old_state=%d\n", ch, state);
    switch (state) {
    case STATE_IDLE:
      atomic_store(&sc_ptr->state, STATE_RECORD);
      break;
    case STATE_RECORD:
      atomic_store(&sc_ptr->state, STATE_LOOPING);
      break;
    case STATE_LOOPING:
      atomic_store(&sc_ptr->state, STATE_PAUSED);
      break;
    case STATE_PAUSED:
      atomic_store(&sc_ptr->state, STATE_LOOPING);
      break;
    }
    break;
  }
  case CMD_STOP:
    for (int s = 0; s < atomic_load(&channels[ch].scene_count); s++) {
      atomic_store(&channels[ch].scenes[s].state, STATE_IDLE);
      atomic_store(&channels[ch].scenes[s].prev_state, -1);
    }
    break;

  case CMD_ADD_CHANNEL:
  case CMD_ADD_MIDI_CHANNEL: {
    int idx;
    for (idx = 0; idx < MAX_CHANNELS; idx++)
      if (!channels[idx].active)
        break;
    if (idx < MAX_CHANNELS)
      channel_add(client, idx);
    break;
  }

  case CMD_REMOVE_CHANNEL: {
    int remove_idx = -1;
    for (int idx = 1; idx < MAX_CHANNELS; idx++)
      if (channels[idx].active)
        remove_idx = idx;
    if (remove_idx != -1) {
      channel_remove(client, remove_idx);
      pending_unregister_idx = remove_idx;
    }
    break;
  }

  case CMD_BIND_CHANNEL:
    atomic_store(&bind_channel, cmd.data);
    break;

  case CMD_UNBIND:
    atomic_store(&bind_channel, 0);
    break;

  case CMD_LOAD:
    atomic_store(&cmd_load, 1);
    break;

  case CMD_SAVE:
    atomic_store(&cmd_save, 1);
    break;

  case CMD_ADD_SCENE:
    channel_add_scene(client, ch);
    break;

  case CMD_REMOVE_SCENE:
    channel_remove_scene(client, ch);
    break;

  case CMD_NEXT_SCENE:
    channel_next_scene(client, ch);
    break;

  case CMD_PREV_SCENE:
    channel_prev_scene(client, ch);
    break;

  case CMD_SET_SCENE: {
    int sc = cmd.data;
    // Allow any scene index; scenes will be added by CMD_CYCLE if needed
    if (sc >= 0) {
      atomic_store(&channels[ch].current_scene, sc);
    }
    break;
  }

  default:
    break;
  }
}

/* ----------------------------------------------------------------
 * 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;
    }

    /* For each channel, use the current scene */
    int sc_idx = atomic_load(&channels[c].current_scene);
    scene_t *sc = &channels[c].scenes[sc_idx];
    int state = atomic_load(&sc->state);
    int prev = atomic_load(&sc->prev_state);

    if (state != prev) {
      switch (state) {
      case STATE_RECORD:
        atomic_store(&sc->record_pos, 0);
        atomic_store(&sc->loop_count, 0);
        break;
      case STATE_LOOPING:
        if (prev == STATE_RECORD && atomic_load(&sc->record_pos) > 0)
          atomic_store(&sc->loop_count, atomic_load(&sc->record_pos));
        atomic_store(&sc->playback_pos, 0);
        break;
      default:
        break;
      }
    }

    /* Handle MIDI channels separately */
    if (channels[c].type == CHANNEL_MIDI) {
      /* MIDI channel handling */
      void *midi_in_buf = jack_port_get_buffer(channels[c].midi_in, nframes);
      void *midi_out_buf = jack_port_get_buffer(channels[c].midi_out, nframes);
      if (!midi_out_buf)
        continue;

      switch (state) {
      case STATE_RECORD: {
        if (midi_in_buf) {
          jack_nframes_t nevents = jack_midi_get_event_count(midi_in_buf);
          jack_midi_event_t ev;
          for (jack_nframes_t j = 0; j < nevents; j++) {
            if (jack_midi_event_get(&ev, midi_in_buf, j) != 0)
              continue;
            int rp = atomic_load(&sc->record_pos);
            if (rp < MAX_MIDI_EVENTS) {
              sc->loop.midi_events[rp].timestamp = ev.time;
              sc->loop.midi_events[rp].status = ev.buffer[0];
              sc->loop.midi_events[rp].note = (ev.size > 1) ? ev.buffer[1] : 0;
              sc->loop.midi_events[rp].velocity =
                  (ev.size > 2) ? ev.buffer[2] : 0;
              atomic_store(&sc->record_pos, rp + 1);
            }
          }
          /* forward incoming MIDI to output during record */
          jack_midi_clear_buffer(midi_out_buf);
          for (jack_nframes_t j = 0; j < nevents; j++) {
            if (jack_midi_event_get(&ev, midi_in_buf, j) != 0)
              continue;
            jack_midi_event_write(midi_out_buf, ev.time, ev.buffer, ev.size);
          }
        }
        break;
      }
      case STATE_LOOPING: {
        jack_midi_clear_buffer(midi_out_buf);
        int cnt = atomic_load(&sc->loop_count);
        if (cnt > 0) {
          for (int e = 0; e < cnt; e++) {
            unsigned char msg[3];
            msg[0] = sc->loop.midi_events[e].status;
            msg[1] = sc->loop.midi_events[e].note;
            msg[2] = sc->loop.midi_events[e].velocity;
            jack_midi_event_write(midi_out_buf, 0, msg, 3);
          }
        }
        break;
      }
      case STATE_PAUSED:
        jack_midi_clear_buffer(midi_out_buf);
        break;
      default: /* IDLE */
        jack_midi_clear_buffer(midi_out_buf);
        if (midi_in_buf) {
          jack_nframes_t nevents = jack_midi_get_event_count(midi_in_buf);
          jack_midi_event_t ev;
          for (jack_nframes_t j = 0; j < nevents; j++) {
            if (jack_midi_event_get(&ev, midi_in_buf, j) != 0)
              continue;
            jack_midi_event_write(midi_out_buf, ev.time, ev.buffer, ev.size);
          }
        }
        break;
      }
      continue;
    }

    /* Audio channel handling */
    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;

    if (c == 0 && !atomic_load(&channels[c].active)) {
        fprintf(stderr, "CHANNEL0_NOT_ACTIVE during record\n");
    }

    switch (state) {
    case STATE_RECORD:
      if (c == 0 && atomic_load(&sc->record_pos) == 0) {
          if (in) {
              fprintf(stderr, "FIRST_INPUT_SAMPLE = %f\n", ((const float*)in)[0]);
          } else {
              fprintf(stderr, "FIRST_INPUT_SAMPLE = NULL\n");
          }
      }
      if (in) {
        float *f_out = (float *)out;
        const float *f_in = (const float *)in;
        for (jack_nframes_t i = 0; i < nframes; i++) {
          int rp = atomic_fetch_add(&sc->record_pos, 1);
          if (rp < LOOP_BUF_SIZE)
            sc->loop.audio_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 loop_cnt = atomic_load(&sc->loop_count);
      if (loop_cnt > 0) {
        float *outf = (float *)out;
        int pp = atomic_load(&sc->playback_pos);
        for (jack_nframes_t i = 0; i < nframes; i++) {
          outf[i] = sc->loop.audio_buffer[pp];
          pp = (pp + 1) % loop_cnt;
        }
        atomic_store(&sc->playback_pos, pp);
      } 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 && !atomic_load(&channels[c].save_complete)) {
      if (state == STATE_LOOPING && atomic_load(&sc->loop_count) > 0) {
        const float *outf = (const float *)out;
        ring_write(r, outf, nframes);
      }
    }

    atomic_store(&sc->prev_state, state);
  }

  /* MIDI clock events – affect current scene of channel 0 */
  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 sc0 = atomic_load(&channels[0].current_scene);
            int s = atomic_load(&channels[0].scenes[sc0].state);
            if (s == STATE_IDLE)
              atomic_store(&channels[0].scenes[sc0].state, STATE_RECORD);
            break;
          }
          case 0xFC: {
            int sc0 = atomic_load(&channels[0].current_scene);
            atomic_store(&channels[0].scenes[sc0].state, STATE_IDLE);
            break;
          }
          case 0xFB: {
            int sc0 = atomic_load(&channels[0].current_scene);
            int s = atomic_load(&channels[0].scenes[sc0].state);
            if (s == STATE_PAUSED)
              atomic_store(&channels[0].scenes[sc0].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);

  /* create status FIFO (ignore if already exists) */
  mkfifo(STATUS_FIFO, 0666);

  /* open the status FIFO for reading+writing so writes work even without reader
   */
  status_fd = open(STATUS_FIFO, O_RDWR);
  if (status_fd < 0) {
    perror("open status FIFO");
  }

  queue_init(&cmd_queue);
  queue_init(&cmd_queue_main_midi);
  queue_init(&cmd_queue_main_fifo);

  /* start the FIFO reader thread */
  pipe_start_reader();

  /* channel 0 */
  channels[0].active = 1;
  channels[0].type = CHANNEL_AUDIO; /* default */
  channels[0].current_scene = 0;
  channels[0].scene_count = 1;
  init_scene(&channels[0].scenes[0]); /* sets state IDLE, prev_state -1 */
  atomic_store(&channels[0].scenes[0].loop_count, 0);
  atomic_store(&channels[0].scenes[0].record_pos, 0);
  atomic_store(&channels[0].scenes[0].playback_pos, 0);
  atomic_store_explicit(&channels[0].save_ring, NULL, memory_order_release);
  atomic_store(&channels[0].save_complete, 0);

  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;
  }

  /* Give JACK time to register the ports before clients connect */
  {
    struct timespec req = {.tv_sec = 0, .tv_nsec = 500000000};
    nanosleep(&req, NULL);
  }

  return 0;
}

/* ----------------------------------------------------------------
 * main‑loop command processing
 * ---------------------------------------------------------------- */
void looper_process_commands(jack_client_t *client) {
  /* process commands from the three queues FIRST */
  command_t cmd;
  while (queue_pop(&cmd_queue, &cmd))
    exec_command(cmd, client);
  while (queue_pop(&cmd_queue_main_midi, &cmd))
    exec_command(cmd, client);
  while (queue_pop(&cmd_queue_main_fifo, &cmd))
    exec_command(cmd, 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;
  }

  /* ---------- add channel ---------- */
  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);
    }
  }

  /* ---------- remove channel ---------- */
  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;
    fprintf(stderr, "LOAD: wav_read called\n");
    if (wav_read("loop.wav", &buf, &frames) == 0 && frames > 0) {
      fprintf(stderr, "LOAD: success, frames=%u\n", frames);
      int sc_idx = atomic_load(&channels[0].current_scene);
      scene_t *sc = &channels[0].scenes[sc_idx];
      if (frames > LOOP_BUF_SIZE)
        frames = LOOP_BUF_SIZE;
      memcpy(sc->loop.audio_buffer, buf, frames * sizeof(float));
      atomic_store(&sc->loop_count, (int)frames);
      atomic_store(&sc->record_pos, 0);
      atomic_store(&sc->playback_pos, 0);
      atomic_store(&sc->state, STATE_LOOPING);
      atomic_store(&sc->prev_state, -1);
      free(buf);
    } else {
      fprintf(stderr, "Failed to load loop.wav\n");
      fprintf(stderr, "LOAD: FAILED\n");
    }
  }

  /* ---------- save command (synchronous) ---------- */
  if (atomic_exchange(&cmd_save, 0)) {
    int sc_idx = atomic_load(&channels[0].current_scene);
    scene_t *sc = &channels[0].scenes[sc_idx];
    int lc = atomic_load(&sc->loop_count);
    int rp = atomic_load(&sc->record_pos);
    int state = atomic_load(&sc->state);
    printf("SAVE debug: state=%d loop_count=%d record_pos=%d\n", state, lc, rp);
    /* Allow save from any state where we have data */
    int frames_to_save = 0;
    if ((state == STATE_LOOPING || state == STATE_PAUSED) && lc > 0) {
        frames_to_save = lc;
    } else if (state == STATE_RECORD && rp > 0) {
        frames_to_save = rp;
    }
    if (frames_to_save > 0) {
      /* Deactivate channel to prevent RT thread from reading the buffer */
      int was_active = atomic_load(&channels[0].active);
      if (was_active) {
        atomic_store(&channels[0].active, 0);
        struct timespec req = {.tv_sec = 0, .tv_nsec = 500000000}; /* 500 ms */
        nanosleep(&req, NULL);
      }
      /* Now safe to copy the loop buffer */
      float *data = malloc((size_t)frames_to_save * sizeof(float));
      if (data) {
        memcpy(data, sc->loop.audio_buffer, (size_t)frames_to_save * sizeof(float));
        unsigned sr = (unsigned)global_sample_rate;
        if (sr == 0) sr = 48000;
        char save_path[256];
        snprintf(save_path, sizeof(save_path), "save.wav");
        printf("SAVE: writing %u frames, first sample = %f\n", (unsigned)frames_to_save, data[0]);
        int ret = wav_write(save_path, data, (unsigned)frames_to_save, sr);
        printf("SAVE: wav_write returned %d\n", ret);
        free(data);
      }
      /* Reactivate channel – use a shorter sleep to reduce xrun risk */
      if (was_active) {
        struct timespec req = {.tv_sec = 0, .tv_nsec = 200000000}; /* 200 ms */
        nanosleep(&req, NULL);
        atomic_store(&channels[0].active, 1);
      }
    } else {
      printf("SAVE: condition not met, state=%d lc=%d rp=%d\n", state, lc, rp);
    }
  }

  /* write current state to status FIFO */
  looper_write_status();
}