#include <in_gb.h>
#include <kb.h>
#include <malloc.h>
#include <minmax.h>
#include <mprintf.h>
#include <process.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) {
  memset(buffer, 0, 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(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);
}