package org.zwobble.mammoth;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import org.zwobble.mammoth.internal.DocumentConverter;
import org.zwobble.mammoth.internal.documents.DocumentElement;
import org.zwobble.mammoth.internal.documents.HasChildren;
import org.zwobble.mammoth.internal.documents.Paragraph;
import org.zwobble.mammoth.internal.documents.Text;
import org.zwobble.mammoth.internal.docx.DocxFile;
import org.zwobble.mammoth.internal.docx.InMemoryDocxFile;
import org.zwobble.mammoth.internal.docx.ZippedDocxFile;
import org.zwobble.mammoth.internal.html.Html;
import org.zwobble.mammoth.results.Result;
import org.zwobble.mammoth.internal.styles.*;
import org.zwobble.mammoth.internal.styles.parsing.StyleMapParser;
import org.zwobble.mammoth.internal.util.Casts;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.List;
import java.util.Optional;
import java.util.zip.ZipFile;

import static org.zwobble.mammoth.internal.docx.DocumentReader.readDocument;
import static org.zwobble.mammoth.internal.util.MammothLists.list;

public class Mammoth {
    public static class Options {
        public static final Options DEFAULT = new Options("", false);

        private final String idPrefix;
        private final boolean preserveEmptyParagraphs;

        public Options(String idPrefix, boolean preserveEmptyParagraphs) {
            this.idPrefix = idPrefix;
            this.preserveEmptyParagraphs = preserveEmptyParagraphs;
        }

        public Options idPrefix(String prefix) {
            return new Options(prefix, preserveEmptyParagraphs);
        }

        public Options preserveEmptyParagraphs() {
            return new Options(idPrefix, true);
        }
    }

    private static final StyleMap DEFAULT_STYLE_MAP = StyleMapParser.parse(ImmutableList.of(
        "p.Heading1 => h1:fresh",
        "p.Heading2 => h2:fresh",
        "p.Heading3 => h3:fresh",
        "p.Heading4 => h4:fresh",
        "p[style-name='Heading 1'] => h1:fresh",
        "p[style-name='Heading 2'] => h2:fresh",
        "p[style-name='Heading 3'] => h3:fresh",
        "p[style-name='Heading 4'] => h4:fresh",
        "p[style-name='heading 1'] => h1:fresh",
        "p[style-name='heading 2'] => h2:fresh",
        "p[style-name='heading 3'] => h3:fresh",
        "p[style-name='heading 4'] => h4:fresh",
        "p[style-name='heading 4'] => h4:fresh",

        "r[style-name='Strong'] => strong",

        "p[style-name='footnote text'] => p",
        "r[style-name='footnote reference'] =>",
        "p[style-name='endnote text'] => p",
        "r[style-name='endnote reference'] =>",

        // LibreOffice
        "p[style-name='Footnote'] => p",
        "r[style-name='Footnote anchor'] =>",
        "p[style-name='Endnote'] => p",
        "r[style-name='Endnote anchor'] =>",

        "p:unordered-list(1) => ul > li:fresh",
        "p:unordered-list(2) => ul|ol > li > ul > li:fresh",
        "p:unordered-list(3) => ul|ol > li > ul|ol > li > ul > li:fresh",
        "p:unordered-list(4) => ul|ol > li > ul|ol > li > ul|ol > li > ul > li:fresh",
        "p:unordered-list(5) => ul|ol > li > ul|ol > li > ul|ol > li > ul|ol > li > ul > li:fresh",
        "p:ordered-list(1) => ol > li:fresh",
        "p:ordered-list(2) => ul|ol > li > ol > li:fresh",
        "p:ordered-list(3) => ul|ol > li > ul|ol > li > ol > li:fresh",
        "p:ordered-list(4) => ul|ol > li > ul|ol > li > ul|ol > li > ol > li:fresh",
        "p:ordered-list(5) => ul|ol > li > ul|ol > li > ul|ol > li > ul|ol > li > ol > li:fresh",

        "r[style-name='Hyperlink'] =>",

        "p[style-name='Normal'] => p:fresh"));

    public static Result<String> convertToHtml(InputStream stream) throws IOException {
        return convertToHtml(stream, Options.DEFAULT);
    }

    public static Result<String> convertToHtml(InputStream stream, Options options) throws IOException {
        return withDocxFile(stream, zipFile ->
            convertToHtml(Optional.empty(), zipFile, options));
    }

    public static Result<String> convertToHtml(File file) throws IOException {
        return convertToHtml(file, Options.DEFAULT);
    }

    public static Result<String> convertToHtml(File file, Options options) throws IOException {
        return withDocxFile(file, zipFile ->
            convertToHtml(Optional.of(file.toPath()), zipFile, options));
    }

    private static Result<String> convertToHtml(Optional<Path> path, DocxFile zipFile, Options options) {
        return readDocument(path, zipFile)
            .flatMap(nodes -> DocumentConverter.convertToHtml(options.idPrefix, options.preserveEmptyParagraphs, DEFAULT_STYLE_MAP, nodes))
            .map(Html::stripEmpty)
            .map(Html::collapse)
            .map(Html::write);
    }

    public static Result<String> extractRawText(File file) throws IOException {
        return withDocxFile(file, zipFile ->
            readDocument(Optional.of(file.toPath()), zipFile)
                .map(Mammoth::extractRawTextOfChildren));
    }

    private static <T> T withDocxFile(File file, Function<DocxFile, T> function) throws IOException {
        try (DocxFile zipFile = new ZippedDocxFile(new ZipFile(file))) {
            return function.apply(zipFile);
        }
    }

    private static <T> T withDocxFile(InputStream stream, Function<DocxFile, T> function) throws IOException {
        try (DocxFile zipFile = InMemoryDocxFile.fromStream(stream)) {
            return function.apply(zipFile);
        }
    }

    private static String extractRawTextOfChildren(HasChildren parent) {
        return extractRawText(parent.getChildren());
    }

    private static String extractRawText(List<DocumentElement> nodes) {
        return String.join("", Iterables.transform(nodes, node -> extractRawText(node)));
    }

    private static String extractRawText(DocumentElement node) {
        return Casts.tryCast(Text.class, node)
            .map(Text::getValue)
            .orElseGet(() -> {
                List<DocumentElement> children = Casts.tryCast(HasChildren.class, node)
                    .map(HasChildren::getChildren)
                    .orElse(list());
                String suffix = node instanceof Paragraph ? "\n\n" : "";
                return extractRawText(children) + suffix;
            });
    }
}