package org.apidesign.infra.ant;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileReader;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import java.util.Stack;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import org.apache.tools.ant.BuildException;

import org.apache.tools.ant.DirectoryScanner;

import org.apache.tools.ant.Task;

import org.apache.tools.ant.types.FileSet;

import org.apache.tools.ant.types.FilterSet;

/**

 *

 * @author Jaroslav Tulach

 */

public final class GrepFilter extends Task {

    private int len = 80;

    private String id;

    private FileSet fs;

    private Pattern begin = Pattern.compile(".* BEGIN: *(\\p{Graph}+)[-\\> ]*");

    private Pattern end = Pattern.compile(".* (END|FINISH): *(\\p{Graph}+)[-\\> ]*");

    private boolean openoffice;

    public FileSet createFileSet() {

        if (fs != null) {

            throw new BuildException();

        }

        this.fs = new FileSet();

        return fs;

    }

    public void setId(String id) {

        this.id = id;

    }

    public void setMaxLineLength(int len) {

        this.len = len;

    }

    public void setOutputFormat(String f) {

        if (f.equals("opendocument")) {

            openoffice = true;

            return;

        }

        throw new BuildException("Wrong format: " + f);

    }

    final FilterSet createFilterSet() {

        if (fs == null) {

            throw new BuildException();

        }

        FilterSet filter = new FilterSet();

        try {

            DirectoryScanner ds = fs.getDirectoryScanner(getProject());

            Map<String,CharSequence> texts = new HashMap<String, CharSequence>();

            for (String path : ds.getIncludedFiles()) {

                File file = new File(ds.getBasedir(), path);

                BufferedReader r = new BufferedReader(new FileReader(file));

                for (;;) {

                    String line = r.readLine();

                    if (line == null) {

                        break;

                    }

                    {

                        Matcher m = begin.matcher(line);

                        if (m.matches()) {

                            Item sb = new Item(file);

                            CharSequence prev = texts.put(m.group(1), sb);

                            if (prev != null) {

                                throw new BuildException("Same pattern is there twice: " + m.group(1) + " in " + file);

                            }

                            continue;

                        }

                    }

                    {

                        Matcher m = end.matcher(line);

                        if (m.matches()) {

                            CharSequence s = texts.get(m.group(2));

                            if (s instanceof Item) {

                                texts.put(m.group(2), ((Item)s).toString(m.group(1).equals("FINISH")));

                                continue;

                            }

                            if (s == null) {

                                throw new BuildException("Closing unknown section: " + m.group(2) + " in " + file);

                            }

                            throw new BuildException("Closing not opened section: " + m.group(2) + " in " + file);

                        }

                    }

                    for (CharSequence charSequence : texts.values()) {

                        if (charSequence instanceof Item) {

                            Item sb = (Item)charSequence;

                            sb.append(line);

                        }

                    }

                }

                for (Map.Entry<String, CharSequence> entry : texts.entrySet()) {

                    CharSequence v = entry.getValue();

                    if (v instanceof Item) {

                        throw new BuildException("Not closed section " + entry.getKey() + " in " + file);

                    }

                    entry.setValue(v.toString());

                }

            }

            for (Map.Entry<String, CharSequence> entry : texts.entrySet()) {

                String text = entry.getValue().toString();

                String out = linize(text);

                filter.addFilter(entry.getKey(), out); // NOI18N

            }

        } catch (IOException ex) {

            throw new BuildException(ex);

        }

        if (!filter.hasFilters()) {

            throw new BuildException("No filter found!");

        }

        return filter;

    }

    @Override

    public void execute() throws BuildException {

        if (id == null) {

            throw new BuildException();

        }

        FilterSet filter = createFilterSet();

        getProject().addReference(id, filter);

    }

    private String linize(String input) {

        if (!openoffice) {

            return input;

        }

        StringBuilder copy = new StringBuilder();

        for (String l : input.split("\n")) {

            int spaces = 0;

            while (spaces < l.length() && l.charAt(spaces) == ' ') {

                spaces++;

            }

            copy.append("<text:p text:style-name='Code'><text:s text:c='" + spaces + "'/>" + l.substring(spaces) + "</text:p>\n");

        }

        return copy.toString();

    }

    static final int countChar(CharSequence seq, char ch) {

        int cnt = 0;

        for (int i = 0; i < seq.length(); i++) {

            if (ch == seq.charAt(i)) {

                cnt++;

            }

        }

        return cnt;

    }

    private final class Item implements CharSequence {

        private StringBuilder sb = new StringBuilder();

        private int spaces = Integer.MAX_VALUE;

        private Stack<Integer> remove = new Stack<Integer>();

        private final File file;

        public Item(File file) {

            this.file = file;

        }

        public int length() {

            return sb.length();

        }

        public char charAt(int index) {

            return sb.charAt(index);

        }

        public CharSequence subSequence(int start, int end) {

            return sb.subSequence(start, end);

        }

        private void append(String line) {

            for (int sp = 0; sp < line.length(); sp++) {

                if (line.charAt(sp) != ' ') {

                    if (sp < spaces) {

                        spaces = sp;

                        break;

                    }

                }

            }

            remove.push(sb.length());

            sb.append(line);

            sb.append('\n');

        }

        @Override

        public String toString() {

            return toString(false);

        }

        public String toString(boolean finish) {

            if (remove != null) {

                while (!remove.isEmpty()) {

                   Integer pos = remove.pop();

                   for (int i = 0; i < spaces; i++) {

                       if (sb.charAt(pos) == '\n') {

                           break;

                       }

                       sb.deleteCharAt(pos);

                   }

                }

                remove = null;

                int line = 0;

                for (int i = 0; i < sb.length(); i++) {

                    if (sb.charAt(i) == '\n') {

                        line = 0;

                        continue;

                    }

                    if (++line > len) {

                        throw new BuildException("Line is too long in: " + file + "\n" + sb);

                    }

                }

                int open = countChar(sb, '{');

                int end = countChar(sb, '}');

                if (finish) {

                    for (int i = 0; i < open - end; i++) {

                        sb.append("}\n");

                    }

                }

                if (countChar(sb, '{') != countChar(sb, '}')) {

                    throw new BuildException("not paired amount of braces in " + file + "\n" + sb);

                }

            }

            return sb.toString();

        }

    } // end of Item

}