#include <in_gb.h>
#include <kb.h>
#include <malloc.h>
#include <minmax.h>
#include <mprintf.h>
#include <process_self.h>
#include <stddef.h>
#include <stdint.h>
#include <streams.h>
#include <string.h>
#include <system.h>
#include <tcursor.h>
#include <tscreen.h>

static void* in_wmalloc (void* ctx, size_t size) {
  (void)ctx;
  return malloc (size);
}

static void in_wfree (void* ctx, void* mem) {
  (void)ctx;
  free (mem);
}

static void* in_wrealloc (void* ctx, void* mem, size_t old, size_t new) {
  (void)ctx, (void)old;
  return realloc (mem, new);
}

struct edit_line {
  struct in_gb gb;
  size_t cursor;
};

void in_stream_read_line (const char* prompt, char* buffer, size_t max) {
  struct edit_line edit_line;
  memset (&edit_line, 0, sizeof (edit_line));
  const char* render = NULL;

  in_gb_init (&in_wmalloc, NULL, &edit_line.gb, max);
  edit_line.cursor = 0;

  mprintf ("%s", prompt);

  for (;;) {
    uint8_t ch;

    if (stream_read (process_get_pgid (), STREAM_IN, &ch, 1) <= 0) {
      sched ();
      continue;
    }

    if (ch == '\n')
      break;

    in_gb_move (&edit_line.gb, edit_line.cursor);

    switch (ch) {
    case '\b':
      if (edit_line.cursor > 0) {
        edit_line.cursor--;
        in_gb_backspace (&edit_line.gb);

        mprintf (ANSIQ_CUR_LEFT (1));

        char* tail = in_gb_string_at (&in_wmalloc, NULL, &edit_line.gb, edit_line.cursor);
        mprintf ("%s" ANSIQ_SCR_CLR2LEND, tail);

        int move_back = strlen (tail);
        if (move_back > 0)
          mprintf (ANSIQ_DYN_CUR_LEFT, move_back);
      }
      break;
    case KB_DELETE:
      if (edit_line.cursor < in_gb_length (&edit_line.gb)) {
        edit_line.gb.gap_end++;

        char* tail = in_gb_string_at (&in_wmalloc, NULL, &edit_line.gb, edit_line.cursor);
        mprintf ("%s" ANSIQ_SCR_CLR2LEND, tail);

        int move_back = strlen (tail);
        if (move_back > 0)
          mprintf (ANSIQ_DYN_CUR_LEFT, move_back);
      }
      break;
    case KB_LEFT:
      if (edit_line.cursor > 0) {
        edit_line.cursor--;
        mprintf (ANSIQ_CUR_LEFT (1));
      }
      break;
    case KB_RIGHT:
      if (edit_line.cursor < in_gb_length (&edit_line.gb)) {
        edit_line.cursor++;
        mprintf (ANSIQ_CUR_RIGHT (1));
      }
      break;
    default:
      if (isprint (ch)) {
        in_gb_insert (&in_wrealloc, NULL, &edit_line.gb, ch);
        edit_line.cursor++;

        if (edit_line.cursor == in_gb_length (&edit_line.gb)) {
          mprintf ("%c", ch);
        } else {
          char* tail = in_gb_string_at (&in_wmalloc, NULL, &edit_line.gb, edit_line.cursor - 1);
          size_t move_back = strlen (tail) - 1;
          mprintf ("%s" ANSIQ_DYN_CUR_LEFT, tail, move_back);
        }
      }
      break;
    }
  }

  mprintf ("\n");

  render = in_gb_string_at (&in_wmalloc, NULL, &edit_line.gb, 0);

  if (render != NULL) {
    size_t len_render = strlen (render);
    memcpy (buffer, render, min (len_render, max));
  }

  in_gb_fini (&in_wfree, NULL, &edit_line.gb);
}