/*
 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.sun.tools.jextract;

import java.util.Map;
import java.util.Set;
import com.sun.tools.jextract.tree.FunctionTree;

/**
 * A helper class to generate header interface class in source form.
 * After aggregating various constituents of a .java source, build
 * method is called to get overall generated source string.
 */
class JavaSourceBuilder {
    // buffer
    protected StringBuffer sb;
    // current line alignment (number of 4-spaces)
    protected int align;

    JavaSourceBuilder(int align) {
        this.align = align;
        this.sb = new StringBuffer();
    }

    JavaSourceBuilder() {
        this(0);
    }

    protected int align() {
        return align;
    }

    protected void addPackagePrefix(String pkgName) {
        sb.append("// Generated by jextract\n\n");
        if (!pkgName.isEmpty()) {
            sb.append("package ");
            sb.append(pkgName);
            sb.append(";\n\n");
        }
        addImportSection();
    }

    protected void addImportSection() {
        sb.append("import java.foreign.*;\n");
        sb.append("import java.foreign.annotations.*;\n");
        sb.append("import java.foreign.memory.*;\n");
        sb.append("import java.lang.annotation.*;\n\n");
    }

    protected void interfaceBegin(String name, boolean isStatic) {
        interfaceBegin(name, isStatic, false);
    }

    protected void interfaceBegin(String name, boolean isStatic, boolean isAnnotation) {
        check();
        indent();
        sb.append("public ");
        if (isStatic) {
            sb.append("static ");
        }
        if (isAnnotation) {
            sb.append('@');
        }
        sb.append("interface ");
        sb.append(name);
        sb.append(" {\n\n");
    }

    protected void interfaceEnd() {
        check();
        indent();
        sb.append("}\n\n");
    }

    protected void addAnnotation(String annoName, Map<String, Object> fields) {
        addAnnotation(true, annoName, fields);
    }

    protected void addAnnotation(boolean incrAlign, String annoName, Map<String, Object> fields) {
        check();
        if (incrAlign) {
            incrAlign();
        }

        indent();
        sb.append('@');
        sb.append(annoName);
        if (fields.isEmpty()) {
            sb.append('\n');
            return;
        }
        boolean singleProperty = (fields.size() == 1);

        if (singleProperty) {
            sb.append('(');
        } else {
            sb.append("(\n");
            incrAlign();
        }
        Set<String> keys = fields.keySet();
        int size = keys.size();
        for (String key : keys) {
            if (!singleProperty) {
                indent();
            }

            if (!singleProperty || !key.equals("value")) {
                sb.append(key);
                sb.append('=');
            }

            Object value = fields.get(key);
            if (value instanceof String) {
                sb.append('"');
                sb.append(value.toString());
                sb.append('"');
            } else if (value instanceof Enum) {
                sb.append(value.getClass().getSimpleName());
                sb.append('.');
                sb.append(((Enum)value).name());
            } else if (value instanceof Long) {
                sb.append(value);
                sb.append("L");
            } else if (value instanceof String[]) {
                sb.append("{ ");
                String[] strs = (String[])value;
                for (int i = 0; i < strs.length; i++) {
                    sb.append('"');
                    sb.append(strs[i]);
                    sb.append('"');
                    if (i != strs.length - 1) {
                        sb.append(", ");
                    }
                }
                sb.append(" }");
            } else if (value instanceof JType.ClassType[]) {
                sb.append("{ ");
                JType.ClassType[] types = (JType.ClassType[])value;
                for (int i = 0; i < types.length; i++) {
                    sb.append(types[i].externalName);
                    sb.append(".class");
                    if (i != types.length - 1) {
                        sb.append(", ");
                    }
                }
                sb.append(" }");
            } else {
                sb.append(value);
            }
            if (!singleProperty && size > 1) {
                sb.append(",\n");
            }
            size--;
        }

        if (!singleProperty) {
            decrAlign();
            sb.append("\n");
            indent();
        }
        sb.append(")\n");

        if (incrAlign) {
            decrAlign();
        }
    }

    protected void addGetter(String name, JType jt) {
        check();
        incrAlign();
        indent();
        sb.append("public ");
        sb.append(jt.getSourceSignature(false));
        sb.append(' ');
        sb.append(name);
        sb.append("();\n\n");
        decrAlign();
    }

    protected void addSetter(String name, JType jt) {
        check();
        incrAlign();
        indent();
        sb.append("public ");
        sb.append("void ");
        sb.append(name);
        sb.append('(');
        sb.append(jt.getSourceSignature(true));
        sb.append(" value");
        sb.append(");\n\n");
        decrAlign();
    }

    protected void fillArgTypes(JType.Function fn, String[] argTypes) {
        for (int i = 0; i < fn.args.length; i++) {
            argTypes[i] = fn.args[i].getSourceSignature(true);
        }
        if (fn.isVarArgs) {
            argTypes[argTypes.length - 1] = "Object...";
        }
    }

    protected void fillArgNames(JType.Function fn, FunctionTree funcTree, String[] argNames) {
        for (int i = 0; i < fn.args.length; i++) {
            String name = funcTree != null? funcTree.paramName(i) : null;
            argNames[i] = (name == null || name.isEmpty())? ("$arg" + i) : name;
        }
        if (fn.isVarArgs) {
            argNames[argNames.length - 1] = "$args";
        }
    }

    private void addMethod(String name, JType.Function fn, FunctionTree funcTree) {
        final int numArgs = fn.isVarArgs? fn.args.length + 1 : fn.args.length;
        final String[] argTypes = new String[numArgs];
        final String[] argNames = new String[numArgs];
        fillArgTypes(fn, argTypes);
        fillArgNames(fn, funcTree, argNames);

        check();
        incrAlign();
        indent();
        sb.append("public ");
        sb.append(fn.returnType.getSourceSignature(false));
        sb.append(' ');
        sb.append(name);
        sb.append('(');
        for (int i = 0; i < numArgs; i++) {
            sb.append(argTypes[i]);
            sb.append(' ');
            sb.append(argNames[i]);
            if (i != argTypes.length - 1) {
                sb.append(", ");
            }
        }
        sb.append(");\n\n");
        decrAlign();
    }

    protected void addMethod(String name, JType.Function fn) {
        addMethod(name, fn, null);
    }

    protected void addMethod(FunctionTree funcTree, JType.Function fn) {
        addMethod(funcTree.name(), fn, funcTree);
    }

    protected void addNestedType(JavaSourceBuilder jsb) {
        check();
        sb.append(jsb.build());
    }

    protected String build() {
        check();
        String res = sb.toString();
        this.sb = null;
        return res.toString();
    }

    protected void indent() {
        for (int i = 0; i < align; i++) {
            sb.append("    ");
        }
    }

    protected void incrAlign() {
        align++;
    }

    protected void decrAlign() {
        align--;
    }

    protected void check() {
        if (sb == null) {
            throw new IllegalStateException("source already built");
        }
    }
}