package gudusoft.gsqlparser.compiler.builtinFunction;

import gudusoft.gsqlparser.TBaseType;
import gudusoft.gsqlparser.TLog;

import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.math.RoundingMode;

public class TOracleBuiltFunction {

    public final static String PACKAGE_DELIMITER = "___";

    static TOracleBuiltFunction oracleBuiltFunction;

    public static TOracleBuiltFunction getOracleBuiltFunctionInstance(){
        if (oracleBuiltFunction == null) oracleBuiltFunction = new TOracleBuiltFunction();
        return oracleBuiltFunction;
    }
    public Integer ABS(Integer n){
        return Math.abs(n);
    }

    public Double ABS(Double n){
        return Math.abs(n);
    }

    public Double ACOS(Double n){
        return Math.acos(n);
    }

    public String CHR(Integer n){
        // 目前只转化 ascii 字符
        if (n>256) return "";
        char c = (char) (n % 256);
        return String.valueOf((char)c);
    }

    public String CONCAT(String char1, String char2){
        return char1+char2;
    }

    public Double COS(Double n){
        return Math.cos(n);
    }

    public Double COSH(Double n){
        return Math.cosh(n);
    }

    public void DBMS_OUTPUT___PUT_LINE(String a){
      //  System.out.println(a);
        TBaseType.log(a, TLog.INTERPRETER_MSG);
    }

    public Double LOG(Double d1, Double d2){
        return Math.log(d2) / Math.log(d1);
    }
    public String LOWER(String str){
        if(str==null){
            return "";
        }
        return str.toLowerCase();
    }

    public Integer MOD(Integer n2, Integer n1){
        if(n1==0){
            return n2;
        }
        return n2 % n1;
    }

    public String REPLACE(String str, String search, String replacement){
        if(str==null){
            return "";
        }
        return str.replace(search, replacement);
    }

    public Double ROUND(Double d, Integer newScale) {
        if(newScale>=0){
            BigDecimal bd = new BigDecimal(d).setScale(newScale, RoundingMode.HALF_UP);
            return bd.doubleValue();
        }
        else{
            int scale = -1 * newScale;
            double f = 0.1;
            int b = 10;
            for(int i=0; i<scale; i++){
                f = f * 0.1;
                b = b * 10;
            }
            d = d * f;
            BigDecimal bd = new BigDecimal(d).setScale(scale, RoundingMode.HALF_UP);
            return bd.doubleValue() * b;
        }
    }

    public Double ROUND(Double d) {
        BigDecimal bd = new BigDecimal(d).setScale(0, RoundingMode.HALF_UP);
        return bd.doubleValue();
    }

    public Integer SIGN(Double n){
        if(n>0){
            return 1;
        }
        else if(n==0){
            return 0;
        }
        else{
            return -1;
        }
    }

    public Double SIN(Double n){
        return Math.sin(n);
    }

    public String SUBSTR(String str,  Integer start, Integer size){
        if(start==0){
            start = 1;
        }
        if(start < 0){
            start = str.length() + start + 1;
        }
        return str.substring(start-1, start + size -1);
    }

    public String SUBSTR(String str,  Integer start){
        if(start==0){
            start = 1;
        }
        if(start < 0){
            start = str.length() + start + 1;
        }
        return str.substring(start-1);
    }

    public Double TAN(Double n){
        BigDecimal bd = new BigDecimal(Math.tan(n)).setScale(10, RoundingMode.HALF_UP);
        return bd.doubleValue();
    }

    public String TO_CHAR(Double n){
        return Double.toString(n);
    }

    public String TO_CHAR(Integer n){
        return Integer.toString(n);
    }

    public String TRIM(String str){
        if(str==null){
            return "";
        }
        return str.trim();
    }

    public String UPPER(String str){
        if(str==null){
            return "";
        }
        return str.toUpperCase();
    }

    public static Method searchMethod(String packageName, String functionName, Class[] parameterTypes, Class<?> returnType){
        Method ret = null;


        Class xxxClass = null;
        try {
            xxxClass = Class.forName("gudusoft.gsqlparser.compiler.builtinFunction.TOracleBuiltFunction");
        } catch (ClassNotFoundException e) {
            return null;
        }

        String fullName = functionName.toUpperCase();
        if (packageName != null){
            fullName = packageName.toUpperCase()+PACKAGE_DELIMITER+fullName;
        }


        Method[] allMethods = xxxClass.getDeclaredMethods();

        for (Method m : allMethods) {
           // System.out.println(m.getName());
            if (m.getName().equals(fullName)){
                if (returnType != m.getReturnType()){
                    continue;
                }
                if (parameterTypes.length  != m.getParameterTypes().length){
                    continue;
                }

                if ((parameterTypes.length == 0) && (m.getParameterTypes().length == 0)){
                   // System.out.println("Find function: "+m.getName()+" with no argument");
                    ret = m;
                    break;
                }

                int i=0;
                while (i<parameterTypes.length){
                    if (m.getParameterTypes()[i] != parameterTypes[i]){
                        break;
                    }
                    i++;
                }

                if (i == parameterTypes.length){
                    //System.out.println("Find function: "+m.getName()+" with "+ parameterTypes.length +" arguments");
                    ret =m;
                    break;
                }
            }
        }
        return ret;
    }

}