#include "web_dom.h"
#include "web_opts.h"

#include "comp.h"

#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <emscripten/emscripten.h>

#define PREFIX "dartboat_"

int delay_ms = 1000;

static int difficulty = 32;
static struct { int diff; double stdev; } DIFF_PRESETS[] = {
	{ 0, 66.80}, // 10
	{ 8, 40.24}, // 20
	{16, 28.14}, // 30
	{24, 21.35}, // 40
	{32, 17.20}, // 50
	{40, 14.34}, // 60
	{48, 12.15}, // 70
	{56, 10.36}, // 80
	{64,  8.83}, // 90
	{72,  7.48}, // 100
	{80,  6.32}, // 110
	{88,  5.34}, // 120
	{99,  0.00}, // 167
};
#define NUM_DIFF_PRESETS (sizeof(DIFF_PRESETS) / sizeof(*DIFF_PRESETS))

static void set_delay(char *val)
{
	delay_ms = atoi(val);
}

static void set_stdev(int diff)
{
	if (diff < DIFF_PRESETS[0].diff)
		diff = DIFF_PRESETS[0].diff;
	else if (diff > DIFF_PRESETS[NUM_DIFF_PRESETS - 1].diff)
		diff = DIFF_PRESETS[NUM_DIFF_PRESETS - 1].diff;

	size_t ind = 1;
	while (ind < NUM_DIFF_PRESETS - 1 && DIFF_PRESETS[ind].diff <= diff)
		ind++;

	double step = (DIFF_PRESETS[ind - 1].stdev - DIFF_PRESETS[ind].stdev) /
		(DIFF_PRESETS[ind].diff - DIFF_PRESETS[ind - 1].diff);
	horizontal_stdev = vertical_stdev = DIFF_PRESETS[ind - 1].stdev -
		((diff - DIFF_PRESETS[ind - 1].diff) * step);
}

static void set_difficulty(char *val)
{
	int diff = atoi(val);
	difficulty = diff < 0 ? 0 : diff > 99 ? 99 : diff;

	set_stdev(difficulty);
}

static char *prefix_opt(char *opt)
{
	char len = strlen(opt);
	char *s = malloc(len + sizeof(PREFIX));
	memcpy(s, PREFIX, sizeof(PREFIX) - 1);
	memcpy(s + sizeof(PREFIX) - 1, opt, len + 1);

	return s;
}

static char *read_opt(char *opt)
{
	char *s = prefix_opt(opt);
	char *val = (char *)EM_ASM_INT({return readOpt($0)}, s);
	free(s);
	return val;
}

static bool read_delay()
{
	char *val = read_opt("delay");
	if (!val) return false;

	set_delay(val);
	free(val);
	return true;
}

static bool read_difficulty()
{
	char *val = read_opt("difficulty");
	if (!val) return false;

	set_difficulty(val);
	free(val);
	return true;
}

void opts_init()
{
	read_delay();
	if (!read_difficulty())
		set_stdev(difficulty);

	char buf[64];
	sprintf(buf, "%d", delay_ms);
	dom_set_value("#delay", buf);

	sprintf(buf, "%d", difficulty);
	dom_set_value("#difficulty", buf);
}

static void store_opt(char *opt, char  *val)
{
	char *s = prefix_opt(opt);
	EM_ASM({storeOpt($0, $1)}, s, val);
	free(s);
}

EMSCRIPTEN_KEEPALIVE
void set_opt(char *opt, char *val)
{
	if (!strcmp(opt, "delay"))
		set_delay(val);
	else if (!strcmp(opt, "difficulty"))
		set_difficulty(val);
	else
		return;

	store_opt(opt, val);
}