package io.trygvis.container.compiler;

import io.trygvis.container.compiler.model.ClassG;
import io.trygvis.container.compiler.model.Imports;
import io.trygvis.container.compiler.model.TypeRef;

import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.Element;
import javax.persistence.PersistenceException;
import javax.tools.JavaFileObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringReader;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import static io.trygvis.container.compiler.model.ClassG.addAll;
import static java.lang.Character.isUpperCase;
import static java.lang.Character.toLowerCase;
import static java.lang.Character.toUpperCase;
import static org.apache.commons.lang.StringUtils.stripEnd;

public class Utils {
    public static final String EOL = System.getProperty("line.separator");

    public static String toFieldName(TypeRef type) {
        return toFieldName(type.className);
    }

    public static String toFieldName(String s) {
        if (s.length() < 1) {
            return s.toLowerCase();
        }

        if (s.startsWith("set")) {
            s = s.substring(3, s.length());
        } else if (s.startsWith("get")) {
            s = s.substring(3, s.length());
        }

        char[] chars = s.toCharArray();

        boolean toUpper = false;

        int j = 0;
        for (int i = 0; i < chars.length; i++) {
            char c = chars[i];
            if (c == '_') {
                toUpper = true;
            } else {
                if (j == 0) {
                    chars[j++] = toLowerCase(c);
                } else {
                    chars[j++] = toUpper ? toUpperCase(c) : c;
                }
                toUpper = false;
            }
        }
        return new String(chars, 0, j);
    }

    public static String toClassName(String s) {
        s = toFieldName(s);
        return toUpperCase(s.charAt(0)) + s.substring(1, s.length());
    }

    public static String toSetterName(String s) {
        s = toFieldName(s);
        return "set" + toUpperCase(s.charAt(0)) + s.substring(1, s.length());
    }

    public static String toGetterName(String s) {
        s = toFieldName(s);
        return "get" + toUpperCase(s.charAt(0)) + s.substring(1, s.length());
    }

    public static String toJavaString(String s) {
        try {
            BufferedReader reader = new BufferedReader(new StringReader(s));
            String line = reader.readLine();
            StringBuilder buffer = new StringBuilder();
            while (line != null) {
                buffer.append('"');
                buffer.append(line.replace("\"", "\\\""));
                buffer.append('"');
                line = reader.readLine();
                if (line != null) {
                    buffer.append(" +").append(EOL);
                }
            }

            return buffer.toString();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static void writeFile(ProcessingEnvironment processingEnv, ClassG g, Element element) throws IOException {
        JavaFileObject sourceFile = processingEnv.getFiler().createSourceFile(g.type.fqName, element);
        try (PrintWriter w = new PrintWriter(sourceFile.openWriter())) {
            for (String s : g.generate()) {
                w.println(stripEnd(s, " "));
            }
        }
    }

    public static List<String> tryCatchSqlException(Imports imports, List<String> body) {
        TypeRef sqlException = imports.add(SQLException.class);
        TypeRef persistenceException = imports.add(PersistenceException.class);
        List<String> newBody = new ArrayList<>();
        newBody.add("try {");
        addAll(1, newBody, body);
        newBody.add("} catch (" + sqlException.plainName + " e) {");
        newBody.add("    throw new " + persistenceException.plainName + "(e);"); // TODO: Add context info.
        newBody.add("}");
        return newBody;
    }

    public static String sqlName(String javaName) {
        StringBuilder builder = new StringBuilder();
        for (char c : javaName.toCharArray()) {
            if (isUpperCase(c) && builder.length() > 0) {
                builder.append("_");
            }
            if (Character.isLetterOrDigit(c)) {
                builder.append(toLowerCase(c));
            } else {
                builder.append('_');
            }
        }
        return builder.toString();
    }
}