using System.Collections.Generic;
using System.Globalization;
using System.Text;

public class HtmlBuilder
{
    public static string GetSettingsPage(List<Setting> settings)
    {
        return Decorate(GetSettingsString(settings), title: "Настройки Фишки");
    }

    public static string GetLoginPage()
    {
        string content = @"
<div class='login-root'>
  <h1>Вход</h1>
  <div class='form-group'>
    <label for='pass'>Пароль</label>
    <input id='pass' type='password' autocomplete='current-password' />
  </div>
  <button id='loginBtn' type='button'>Войти</button>
  <p id='loginStatus' style='margin-top:12px;'></p>
</div>

<script>
(function(){
  const pass = document.getElementById('pass');
  const btn = document.getElementById('loginBtn');
  const st  = document.getElementById('loginStatus');

  async function doLogin(){
    st.textContent = '';
    try{
      const r = await fetch('/api/login', {
        method:'POST',
        headers:{'Content-Type':'application/json'},
        body: JSON.stringify({ password: pass.value || '' })
      });
      const t = await r.text();
      if(!r.ok){
        st.textContent = 'Ошибка входа';
        try{
          const j = JSON.parse(t);
          if(j && j.message) st.textContent = j.message;
        }catch(e){}
        return;
      }
      window.location.href = '/';
    }catch(e){
      st.textContent = 'Сервер недоступен';
    }
  }

  btn.addEventListener('click', doLogin);
  pass.addEventListener('keydown', (e)=>{ if(e.key === 'Enter') doLogin(); });
})();
</script>
";
        return Decorate(content, title: "Вход");
    }

    public static string GetSettingsString(List<Setting> settings)
    {
        var sb = new StringBuilder();

        sb.AppendLine("<h1>Настройки фишки</h1>");

        // блок монет
        sb.AppendLine(@"
<div class='panel'>
  <h2>Монеты</h2>
  <div class='coins-row'>
    <input id='coinsAmount' type='number' value='10' min='1' step='1' class='coins-input'/>
    <button id='addCoinsBtn' type='button' class='coins-btn'>Добавить монеты</button>
  </div>
  <div id='coinsStatus' class='status'></div>
</div>
");

        sb.AppendLine("<div class='panel'>");
        sb.AppendLine("<h2>Параметры</h2>");

        foreach (Setting setting in settings)
        {
            string view = setting.Type switch
            {
                SettingType.Bool => GetBoolView(setting),
                SettingType.Float => GetFloatView(setting),
                SettingType.String => GetStringView(setting),
                SettingType.Int => GetIntView(setting),
                _ => $"<p>{Escape(setting.Alias)}: (unknown)</p>"
            };
            sb.AppendLine(view);
        }

        sb.AppendLine("</div>");

        // JS для realtime отправки
        sb.AppendLine(@"
<script>
(function(){
  const status = (txt)=>{ 
    const el = document.getElementById('globalStatus');
    if(!el) return;
    el.textContent = txt || '';
    if(txt){ setTimeout(()=>{ el.textContent=''; }, 1200); }
  };

  const debounceMap = new Map();
  function debounce(key, fn, ms){
    if(debounceMap.has(key)) clearTimeout(debounceMap.get(key));
    debounceMap.set(key, setTimeout(fn, ms));
  }

  async function sendSetting(id, value){
    try{
      const r = await fetch('/api/setting', {
        method:'POST',
        headers:{'Content-Type':'application/json'},
        body: JSON.stringify({ id, value })
      });
      if(!r.ok){
        status('Ошибка применения');
        return;
      }
      status('Сохранено');
    }catch(e){
      status('Сервер недоступен');
    }
  }

  // Все элементы настроек
  document.querySelectorAll('[data-setting-id]').forEach(el=>{
    const id = el.getAttribute('data-setting-id');

    if(el.type === 'checkbox'){
      el.addEventListener('change', ()=>{
        sendSetting(id, el.checked ? 'on' : 'off');
      });
      return;
    }

    if(el.type === 'range'){
      const valueSpanId = el.getAttribute('data-value-span');
      const valueSpan = valueSpanId ? document.getElementById(valueSpanId) : null;

      const apply = ()=>{
        if(valueSpan) valueSpan.textContent = el.value;
        // range шлём с небольшой задержкой, чтобы не заспамить
        debounce('rng_'+id, ()=>sendSetting(id, el.value), 120);
      };

      el.addEventListener('input', apply);
      el.addEventListener('change', apply);
      return;
    }

    if(el.type === 'radio'){
      el.addEventListener('change', ()=>{
        if(el.checked) sendSetting(id, el.value);
      });
      return;
    }

    // number/text (int)
    el.addEventListener('change', ()=>{
      sendSetting(id, el.value);
    });
  });

  // Монеты
  const coinsAmount = document.getElementById('coinsAmount');
  const addBtn = document.getElementById('addCoinsBtn');
  const coinsStatus = document.getElementById('coinsStatus');

  async function addCoins(){
    coinsStatus.textContent = '';
    const v = parseInt(coinsAmount.value || '0', 10);
    if(!Number.isFinite(v) || v <= 0){
      coinsStatus.textContent = 'Введи число > 0';
      return;
    }
    try{
      const r = await fetch('/api/coins', {
        method:'POST',
        headers:{'Content-Type':'application/json'},
        body: JSON.stringify({ amount: v })
      });
      if(!r.ok){
        coinsStatus.textContent = 'Ошибка запроса';
        return;
      }
      coinsStatus.textContent = 'Ок';
      setTimeout(()=>{ coinsStatus.textContent=''; }, 1200);
    }catch(e){
      coinsStatus.textContent = 'Сервер недоступен';
    }
  }

  addBtn.addEventListener('click', addCoins);
})();
</script>

<div id='globalStatus' class='status'></div>
");

        return sb.ToString();
    }

    private static string GetBoolView(Setting setting)
    {
        string name = setting.Id;
        string id = name + "ID";

        string isChecked = setting.BoolValue ? "checked" : "";

        return $@"
<div class='form-group'>
  <label for='{id}'>{Escape(setting.Alias)}</label>
  <input type='checkbox' id='{id}' data-setting-id='{EscapeAttr(name)}' {isChecked}>
</div>";
    }

    private static string GetFloatView(Setting setting)
    {
        string name = setting.Id;
        string id = name + "ID";
        string spanId = id + "_VAL";

        string min = setting.FloatMin.ToString(CultureInfo.InvariantCulture);
        string max = setting.FloatMax.ToString(CultureInfo.InvariantCulture);
        string value = setting.FloatValue.ToString(CultureInfo.InvariantCulture);
        string step = setting.FloatStep.ToString(CultureInfo.InvariantCulture);

        return $@"
<div class='form-group'>
  <label for='{id}'>{Escape(setting.Alias)}: <span id='{spanId}'>{value}</span></label>
  <input id='{id}' type='range' min='{min}' max='{max}' value='{value}' step='{step}'
         data-setting-id='{EscapeAttr(name)}' data-value-span='{spanId}'>
</div>";
    }

    private static string GetStringView(Setting setting)
    {
        var sb = new StringBuilder();
        sb.AppendLine("<div class='form-group'>");
        sb.AppendLine($"<p>{Escape(setting.Alias)}</p>");

        for (int i = 0; i < setting.AllowedValues.Count; i++)
        {
            string stringValue = setting.AllowedValues[i];
            string name = setting.Id;
            string id = name + "ID" + i;

            bool isChecked = setting.StringValue == stringValue;
            string Checked = isChecked ? "checked" : "";

            sb.AppendLine("<div class='radio-row'>");
            sb.AppendLine($"<label for='{EscapeAttr(id)}'>{Escape(stringValue)}</label>");
            sb.AppendLine(
                $"<input type='radio' id='{EscapeAttr(id)}' " +
                $"name='{EscapeAttr(name)}' value='{EscapeAttr(stringValue)}' {Checked} data-setting-id='{EscapeAttr(name)}'>"
            );
            sb.AppendLine("</div>");
        }

        sb.AppendLine("</div>");
        return sb.ToString();
    }

    private static string GetIntView(Setting setting)
    {
        string name = setting.Id;
        string id = name + "ID";

        return $@"
<div class='form-group'>
  <label for='{id}'>{Escape(setting.Alias)}</label>
  <input id='{id}' type='number' value='{setting.IntValue}' step='1'
         data-setting-id='{EscapeAttr(name)}'>
</div>";
    }

    private static string Decorate(string content, string title)
    {
        string res = "<!DOCTYPE html>"
            + "<html lang='ru'>"
            + "<head>"
            + "<meta charset='utf-8'>"
            + "<meta name='viewport' content='width=device-width, initial-scale=1'>"
            + "<link rel='stylesheet' href='style.css'>"
            + $"<title>{Escape(title)}</title>"
            + "</head>"
            + "<body>";

        res += content;

        res += "</body></html>";
        return res;
    }

    // минимальная защита от мусора в html
    private static string Escape(string s)
    {
        if (string.IsNullOrEmpty(s)) return "";
        return s.Replace("&", "&amp;").Replace("<", "&lt;").Replace(">", "&gt;").Replace("\"", "&quot;");
    }

    private static string EscapeAttr(string s) => Escape(s).Replace("'", "&#39;");
}