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

/* Global state (shared across files) */
struct channel_t *_Atomic channels = NULL;
atomic_int channel_capacity = 0;
atomic_int channel_count = 0;
int next_channel_id = 1;
spsc_queue_t cmd_queue_main_midi;
spsc_queue_t cmd_queue_main_fifo;
atomic_int global_rt_cycles = 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;
spsc_queue_t cmd_queue;

/* Deferred removal index and cycle counter */
static int pending_unregister_idx = -1;
static int pending_unregister_cycle = 0;

/* Deferred free of old channel array (must not free while RT thread may hold
 * pointer) */
static struct channel_t *pending_old = NULL;
static int pending_old_cycle = 0;

/* Helper: grow the channel array so that index idx is valid */
static int ensure_capacity(jack_client_t *client, int idx) {
  (void)client;
  int cur_cap = atomic_load(&channel_capacity);
  if (idx < cur_cap)
    return 0;
  int new_cap = cur_cap == 0 ? 8 : cur_cap;
  while (new_cap <= idx)
    new_cap *= 2;
  struct channel_t *new_arr = calloc(new_cap, sizeof(struct channel_t));
  if (!new_arr)
    return -1;
  /* copy existing channels */
  if (cur_cap > 0)
    memcpy(new_arr, atomic_load(&channels), cur_cap * sizeof(struct channel_t));
  /* atomically publish new array, defer free of old */
  struct channel_t *old = atomic_exchange(&channels, new_arr);
  atomic_store(&channel_capacity, new_cap);
  /* schedule old pointer for later deallocation (after RT cycle) */
  pending_old = old;
  pending_old_cycle = atomic_load(&global_rt_cycles);
  return 0;
}

static void apply_command(command_t cmd) {
  struct channel_t *cur = get_channels_array();
  int cap = atomic_load(&channel_capacity);

  switch (cmd.type) {
  case CMD_CYCLE:
    if (cmd.channel >= 0 && cmd.channel < cap) {
      int sc_idx = cur[cmd.channel].current_scene;
      scene_t *sc = &cur[cmd.channel].scenes[sc_idx];
      int cst = atomic_load(&sc->state);
      int next;
      switch (cst) {
      case STATE_IDLE:
        next = STATE_RECORD;
        break;
      case STATE_RECORD:
        next = STATE_LOOPING;
        break;
      case STATE_LOOPING:
        next = STATE_PAUSED;
        break;
      case STATE_PAUSED:
        next = STATE_LOOPING;
        break;
      default:
        next = STATE_IDLE;
        break;
      }
      atomic_store(&sc->state, next);
    }
    break;
  case CMD_STOP:
    if (cmd.channel >= 0 && cmd.channel < cap) {
      struct channel_t *ch = &cur[cmd.channel];
      for (int s = 0; s < ch->scene_count; s++) {
        atomic_store(&ch->scenes[s].state, STATE_IDLE);
        ch->scenes[s].loop_count = 0;
        ch->scenes[s].record_pos = 0;
        ch->scenes[s].playback_pos = 0;
        ch->scenes[s].prev_state = -1;
      }
    } else {
      for (int i = 0; i < cap; i++) {
        struct channel_t *ch = &cur[i];
        for (int s = 0; s < ch->scene_count; s++) {
          atomic_store(&ch->scenes[s].state, STATE_IDLE);
          ch->scenes[s].loop_count = 0;
          ch->scenes[s].record_pos = 0;
          ch->scenes[s].playback_pos = 0;
          ch->scenes[s].prev_state = -1;
        }
      }
    }
    break;
  case CMD_BIND_CHANNEL:
    atomic_store(&bind_channel, cmd.data);
    break;
  case CMD_UNBIND:
    atomic_store(&bind_channel, 0);
    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);
    }
  }

  /* drain RT‑safe commands */
  command_t cmd;
  while (queue_pop(&cmd_queue, &cmd)) {
    apply_command(cmd);
  }

  /* process each active channel */
  struct channel_t *active_channels = get_channels_array();
  int cap = atomic_load(&channel_capacity);
  for (int c = 0; c < cap; c++) {
    if (!atomic_load(&active_channels[c].active))
      continue;

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

    /* Obtain current scene pointer */
    int sc_idx = active_channels[c].current_scene;
    scene_t *sc = &active_channels[c].scenes[sc_idx];

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

    int state = atomic_load(&sc->state);

    if (state != sc->prev_state) {
      switch (state) {
      case STATE_RECORD:
        sc->record_pos = 0;
        sc->loop_count = 0;
        break;
      case STATE_LOOPING:
        if (sc->record_pos > 0)
          sc->loop_count = sc->record_pos;
        sc->playback_pos = 0;
        break;
      default:
        break;
      }
    }

    if (active_channels[c].type == CHANNEL_MIDI) {
      /* MIDI channel handling */
      switch (state) {
      case STATE_RECORD: {
        void *midi_in_buf =
            jack_port_get_buffer(active_channels[c].midi_in, nframes);
        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;
            if (sc->record_pos < MAX_MIDI_EVENTS) {
              sc->loop.midi_events[sc->record_pos].timestamp = ev.time;
              sc->loop.midi_events[sc->record_pos].status = ev.buffer[0];
              sc->loop.midi_events[sc->record_pos].note =
                  (ev.size > 1) ? ev.buffer[1] : 0;
              sc->loop.midi_events[sc->record_pos].velocity =
                  (ev.size > 2) ? ev.buffer[2] : 0;
              sc->record_pos++;
            }
          }
          /* forward incoming MIDI to output during record */
          void *midi_out_buf =
              jack_port_get_buffer(active_channels[c].midi_out, nframes);
          if (midi_out_buf) {
            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: {
        void *midi_out_buf =
            jack_port_get_buffer(active_channels[c].midi_out, nframes);
        if (midi_out_buf) {
          jack_midi_clear_buffer(midi_out_buf);
          int cnt = 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:
        /* no output */
        break;
      default: /* IDLE */
        {
          void *midi_in_buf =
              jack_port_get_buffer(active_channels[c].midi_in, nframes);
          void *midi_out_buf =
              jack_port_get_buffer(active_channels[c].midi_out, nframes);
          if (midi_in_buf && midi_out_buf) {
            jack_midi_clear_buffer(midi_out_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;
      }
      if (state == STATE_LOOPING) {
        sc->loop_count = sc->record_pos;
      }
    } else {
      /* audio channel handling */
      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++) {
            if (sc->record_pos < LOOP_BUF_SIZE)
              sc->loop.audio_buffer[sc->record_pos++] = f_in[i];
            f_out[i] = f_in[i];
          }
        } else {
          memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
        }
        break;

      case STATE_LOOPING:
        if (sc->loop_count > 0) {
          float *outf = (float *)out;
          for (i = 0; i < nframes; i++) {
            outf[i] = sc->loop.audio_buffer[sc->playback_pos];
            sc->playback_pos = (sc->playback_pos + 1) % sc->loop_count;
          }
        } 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;
      }
    }

    sc->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: {
            struct channel_t *cur = atomic_load(&channels);
            int s = atomic_load(&cur[0].state);
            if (s == STATE_IDLE)
              atomic_store(&cur[0].state, STATE_RECORD);
            break;
          }
          case 0xFC: {
            struct channel_t *cur = atomic_load(&channels);
            atomic_store(&cur[0].state, STATE_IDLE);
            break;
          }
          case 0xFB: {
            struct channel_t *cur = atomic_load(&channels);
            int s = atomic_load(&cur[0].state);
            if (s == STATE_PAUSED)
              atomic_store(&cur[0].state, STATE_LOOPING);
            break;
          }
          default:
            break;
          }
        }
      }
    }
  }

  atomic_fetch_add_explicit(&global_rt_cycles, 1, memory_order_release);
  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) {
  queue_init(&cmd_queue);
  queue_init(&cmd_queue_main_midi);
  queue_init(&cmd_queue_main_fifo);

  /* allocate initial array for at least one channel */
  if (ensure_capacity(client, 0) != 0) {
    fprintf(stderr, "Cannot allocate channel array\n");
    return -1;
  }
  struct channel_t *init = atomic_load(&channels);
  /* channel 0 */
  atomic_store(&init[0].active, 1);
  init[0].scene_count = 1;
  init[0].current_scene = 0;
  init[0].scenes[0].loop_count = 0;
  init[0].scenes[0].record_pos = 0;
  init[0].scenes[0].playback_pos = 0;
  atomic_store(&init[0].scenes[0].state, STATE_IDLE);
  init[0].scenes[0].prev_state = -1;

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

/* ----------------------------------------------------------------
 * main‑loop command processing
 * ---------------------------------------------------------------- */
void looper_process_commands(jack_client_t *client) {
  /* Drain main‑loop command queues (add/remove) */
  command_t cmd;
  while (queue_pop(&cmd_queue_main_midi, &cmd)) {
    switch (cmd.type) {
    case CMD_ADD_CHANNEL: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int idx;
      for (idx = 0; idx < cap; idx++)
        if (!atomic_load(&cur[idx].active))
          break;
      if (idx == cap) {
        if (ensure_capacity(client, idx) != 0)
          break;
      }
      channel_add(client, idx);
      break;
    }
    case CMD_ADD_MIDI_CHANNEL: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int idx;
      for (idx = 0; idx < cap; idx++)
        if (!atomic_load(&cur[idx].active))
          break;
      if (idx == cap) {
        if (ensure_capacity(client, idx) != 0)
          break;
      }
      channel_add_midi(client, idx);
      break;
    }
    case CMD_REMOVE_CHANNEL: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int remove_idx = -1;
      for (int idx = 1; idx < cap; idx++)
        if (atomic_load(&cur[idx].active))
          remove_idx = idx;
      if (remove_idx != -1) {
        channel_remove(client, remove_idx);
        pending_unregister_idx = remove_idx;
        pending_unregister_cycle = atomic_load(&global_rt_cycles);
      }
      break;
    }
    case CMD_ADD_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_add_scene(client, ch);
      }
      break;
    }
    case CMD_REMOVE_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_remove_scene(client, ch);
      }
      break;
    }
    case CMD_NEXT_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_next_scene(client, ch);
      }
      break;
    }
    case CMD_PREV_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_prev_scene(client, ch);
      }
      break;
    }
    default:
      break;
    }
  }
  while (queue_pop(&cmd_queue_main_fifo, &cmd)) {
    switch (cmd.type) {
    case CMD_ADD_CHANNEL: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int idx;
      for (idx = 0; idx < cap; idx++)
        if (!atomic_load(&cur[idx].active))
          break;
      if (idx == cap) {
        if (ensure_capacity(client, idx) != 0)
          break;
      }
      channel_add(client, idx);
      break;
    }
    case CMD_ADD_MIDI_CHANNEL: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int idx;
      for (idx = 0; idx < cap; idx++)
        if (!atomic_load(&cur[idx].active))
          break;
      if (idx == cap) {
        if (ensure_capacity(client, idx) != 0)
          break;
      }
      channel_add_midi(client, idx);
      break;
    }
    case CMD_REMOVE_CHANNEL: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int remove_idx = -1;
      for (int idx = 1; idx < cap; idx++)
        if (atomic_load(&cur[idx].active))
          remove_idx = idx;
      if (remove_idx != -1) {
        channel_remove(client, remove_idx);
        pending_unregister_idx = remove_idx;
        pending_unregister_cycle = atomic_load(&global_rt_cycles);
      }
      break;
    }
    case CMD_ADD_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_add_scene(client, ch);
      }
      break;
    }
    case CMD_REMOVE_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_remove_scene(client, ch);
      }
      break;
    }
    case CMD_NEXT_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_next_scene(client, ch);
      }
      break;
    }
    case CMD_PREV_SCENE: {
      int cap = atomic_load(&channel_capacity);
      struct channel_t *cur = get_channels_array();
      int bind = atomic_load(&bind_channel);
      int ch = bind;
      if (ch < cap) {
        channel_prev_scene(client, ch);
      }
      break;
    }
    default:
      break;
    }
  }

  /* Deferred port unregistration – wait until RT thread has seen active=0 */
  if (pending_unregister_idx != -1) {
    int current_cycle = atomic_load(&global_rt_cycles);
    if (current_cycle - pending_unregister_cycle >= 1) {
      int idx = pending_unregister_idx;
      struct channel_t *cur = atomic_load(&channels);
      if (cur[idx].audio_in)
        jack_port_unregister(client, cur[idx].audio_in);
      if (cur[idx].audio_out)
        jack_port_unregister(client, cur[idx].audio_out);
      if (cur[idx].midi_in)
        jack_port_unregister(client, cur[idx].midi_in);
      if (cur[idx].midi_out)
        jack_port_unregister(client, cur[idx].midi_out);
      pending_unregister_idx = -1;
    }
  }

  /* Deferred free of old channel array – wait until RT thread has seen new
   * pointer */
  if (pending_old != NULL) {
    int current_cycle = atomic_load(&global_rt_cycles);
    if (current_cycle - pending_old_cycle >= 1) {
      free(pending_old);
      pending_old = NULL;
    }
  }
}