/*
 *******************************************************************************
 * Copyright (C) 2009-2012, International Business Machines Corporation and    *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
 */
package com.ibm.icu.impl;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;

import com.ibm.icu.lang.UCharacter;
import com.ibm.icu.lang.UScript;
import com.ibm.icu.text.DisplayContext;
import com.ibm.icu.text.LocaleDisplayNames;
import com.ibm.icu.text.MessageFormat;
import com.ibm.icu.util.ULocale;
import com.ibm.icu.util.UResourceBundle;
import com.ibm.icu.util.UResourceBundleIterator;

public class LocaleDisplayNamesImpl extends LocaleDisplayNames {
    private final ULocale locale;
    private final DialectHandling dialectHandling;
    private final DisplayContext capitalization;
    private final DataTable langData;
    private final DataTable regionData;
    private final Appender appender;
    private final MessageFormat format;
    private final MessageFormat keyTypeFormat;

    private static final Cache cache = new Cache();

    /**
     * Capitalization context usage types for locale display names
     */
    private enum CapitalizationContextUsage {
        LANGUAGE, 
        SCRIPT, 
        TERRITORY,
        VARIANT, 
        KEY, 
        TYPE 
    }
     /**
     * Capitalization transforms. For each usage type, the first array element indicates
     * whether to titlecase for uiListOrMenu context, the second indicates whether to
     * titlecase for stand-alone context.
     */
    private Map<CapitalizationContextUsage,boolean[]> capitalizationUsage = null;
    /**
     * Map from resource key to CapitalizationContextUsage value
     */
    private static final Map<String, CapitalizationContextUsage> contextUsageTypeMap;
    static {
        contextUsageTypeMap=new HashMap<String, CapitalizationContextUsage>();
        contextUsageTypeMap.put("languages", CapitalizationContextUsage.LANGUAGE);
        contextUsageTypeMap.put("script",    CapitalizationContextUsage.SCRIPT);
        contextUsageTypeMap.put("territory", CapitalizationContextUsage.TERRITORY);
        contextUsageTypeMap.put("variant",   CapitalizationContextUsage.VARIANT);
        contextUsageTypeMap.put("key",       CapitalizationContextUsage.KEY);
        contextUsageTypeMap.put("type",      CapitalizationContextUsage.TYPE);
    }

    public static LocaleDisplayNames getInstance(ULocale locale, DialectHandling dialectHandling) {
        synchronized (cache) {
            return cache.get(locale, dialectHandling);
        }
    }

    public static LocaleDisplayNames getInstance(ULocale locale, DisplayContext... contexts) {
        synchronized (cache) {
            return cache.get(locale, contexts);
        }
    }

    public LocaleDisplayNamesImpl(ULocale locale, DialectHandling dialectHandling) {
        this(locale, (dialectHandling==DialectHandling.STANDARD_NAMES)? DisplayContext.STANDARD_NAMES: DisplayContext.DIALECT_NAMES,
             DisplayContext.CAPITALIZATION_NONE);
    }

    public LocaleDisplayNamesImpl(ULocale locale, DisplayContext... contexts) {
        DialectHandling dialectHandling = DialectHandling.STANDARD_NAMES;
        DisplayContext capitalization = DisplayContext.CAPITALIZATION_NONE;
        for (DisplayContext contextItem : contexts) {
            switch (contextItem.type()) {
                case DIALECT_HANDLING:
                    dialectHandling = (contextItem.value()==DisplayContext.STANDARD_NAMES.value())?
                                      DialectHandling.STANDARD_NAMES: DialectHandling.DIALECT_NAMES;
                    break;
                case CAPITALIZATION:
                    capitalization = contextItem;
                    break;
                default:
                    break;
            }
        }

        this.dialectHandling = dialectHandling;
        this.capitalization = capitalization;
        this.langData = LangDataTables.impl.get(locale);
        this.regionData = RegionDataTables.impl.get(locale);
        this.locale = ULocale.ROOT.equals(langData.getLocale()) ? regionData.getLocale() :
            langData.getLocale();

        // Note, by going through DataTable, this uses table lookup rather than straight lookup.
        // That should get us the same data, I think.  This way we don't have to explicitly
        // load the bundle again.  Using direct lookup didn't seem to make an appreciable
        // difference in performance.
        String sep = langData.get("localeDisplayPattern", "separator");
        if ("separator".equals(sep)) {
            sep = ", ";
        }
        this.appender = new Appender(sep);

        String pattern = langData.get("localeDisplayPattern", "pattern");
        if ("pattern".equals(pattern)) {
            pattern = "{0} ({1})";
        }
        this.format = new MessageFormat(pattern);
        
        String keyTypePattern = langData.get("localeDisplayPattern", "keyTypePattern");
        if ("keyTypePattern".equals(keyTypePattern)) {
            keyTypePattern = "{0}={1}";
        }
        this.keyTypeFormat = new MessageFormat(keyTypePattern);

        // Get values from the contextTransforms data
        // (copied from DateFormatSymbols)
        if (capitalization == DisplayContext.CAPITALIZATION_FOR_UI_LIST_OR_MENU ||
                capitalization == DisplayContext.CAPITALIZATION_FOR_STANDALONE) {
            capitalizationUsage = new HashMap<CapitalizationContextUsage,boolean[]>();
            boolean[] noTransforms = new boolean[2];
            noTransforms[0] = false;
            noTransforms[1] = false;
            CapitalizationContextUsage allUsages[] = CapitalizationContextUsage.values();
            for (CapitalizationContextUsage usage: allUsages) {
                capitalizationUsage.put(usage, noTransforms);
            }
            ICUResourceBundle rb = (ICUResourceBundle)UResourceBundle.getBundleInstance(ICUResourceBundle.ICU_BASE_NAME, locale);
            UResourceBundle contextTransformsBundle = null;
            try {
               contextTransformsBundle = (UResourceBundle)rb.getWithFallback("contextTransforms");
            }
            catch (MissingResourceException e) {
                contextTransformsBundle = null; // probably redundant
            }
            if (contextTransformsBundle != null) {
                UResourceBundleIterator ctIterator = contextTransformsBundle.getIterator();
                while ( ctIterator.hasNext() ) {
                    UResourceBundle contextTransformUsage = ctIterator.next();
                    int[] intVector = contextTransformUsage.getIntVector();
                    if (intVector.length >= 2) {
                        String usageKey = contextTransformUsage.getKey();
                        CapitalizationContextUsage usage = contextUsageTypeMap.get(usageKey);
                        if (usage != null) {
                            boolean[] transforms = new boolean[2];
                            transforms[0] = (intVector[0] != 0);
                            transforms[1] = (intVector[1] != 0);
                            capitalizationUsage.put(usage, transforms);
                        }
                    }
                }
            }
        }
    }

    @Override
    public ULocale getLocale() {
        return locale;
    }

    @Override
    public DialectHandling getDialectHandling() {
        return dialectHandling;
    }

    @Override
    public DisplayContext getContext(DisplayContext.Type type) {
        DisplayContext result;
        switch (type) {
            case DIALECT_HANDLING:
                result = (dialectHandling==DialectHandling.STANDARD_NAMES)? DisplayContext.STANDARD_NAMES: DisplayContext.DIALECT_NAMES;
                break;
            case CAPITALIZATION:
                result = capitalization;
                break;
            default:
                result = DisplayContext.STANDARD_NAMES; // hmm, we should do something else here
                break;
        }
        return result;
    }

    private String adjustForUsageAndContext(CapitalizationContextUsage usage, String name) {
        String result = name;
        boolean titlecase = false;
        switch (capitalization) {
            case CAPITALIZATION_FOR_BEGINNING_OF_SENTENCE:
                titlecase = true;
                break;
            case CAPITALIZATION_FOR_UI_LIST_OR_MENU:
            case CAPITALIZATION_FOR_STANDALONE:
                if (capitalizationUsage != null) {
                    boolean[] transforms = capitalizationUsage.get(usage);
                    titlecase = (capitalization==DisplayContext.CAPITALIZATION_FOR_UI_LIST_OR_MENU)?
                                transforms[0]: transforms[1];
                }
                break;
            default:
                break;
        }
        if (titlecase) {
            // TODO: Fix this titlecase hack when we figure out something better to do.
            // We don't want to titlecase the whole text, only something like the first word,
            // of the first segment long enough to have a complete cluster, whichever is
            // shorter. We could have keep a word break iterator around, but I am not sure
            // that will do the ight thing for the purposes here. For now we assume that in
            // languages for which titlecasing makes a difference, we can stop at non-letter
            // characters in 0x0000-0x00FF and only titlecase up to the first occurrence of
            // any of those, or to a small number of chars, whichever comes first.
            int stopPos, stopPosLimit = 8, len = name.length();
            if ( stopPosLimit > len ) {
                stopPosLimit = len;
            }
            for ( stopPos = 0; stopPos < stopPosLimit; stopPos++ ) {
                int ch = name.codePointAt(stopPos);
                if ( (ch < 0x41) || (ch > 0x5A && ch < 0x61) || (ch > 0x7A && ch < 0xC0) ) {
                    break;
                }
                if (ch >= 0x10000) {
                    stopPos++;
                }
            }
            if ( stopPos > 0 && stopPos < len ) {
                String firstWord = name.substring(0, stopPos);
                String firstWordTitleCase = UCharacter.toTitleCase(locale, firstWord, null,
                                            UCharacter.TITLECASE_NO_LOWERCASE | UCharacter.TITLECASE_NO_BREAK_ADJUSTMENT);
                result = firstWordTitleCase.concat(name.substring(stopPos));
            } else {
                // no stopPos, titlecase the whole text
                result = UCharacter.toTitleCase(locale, name, null,
                         UCharacter.TITLECASE_NO_LOWERCASE | UCharacter.TITLECASE_NO_BREAK_ADJUSTMENT);
            }
        }
        return result;
    }

    @Override
    public String localeDisplayName(ULocale locale) {
        return localeDisplayNameInternal(locale);
    }

    @Override
    public String localeDisplayName(Locale locale) {
        return localeDisplayNameInternal(ULocale.forLocale(locale));
    }

    @Override
    public String localeDisplayName(String localeId) {
        return localeDisplayNameInternal(new ULocale(localeId));
    }

    // TOTO: implement use of capitalization
    private String localeDisplayNameInternal(ULocale locale) {
        // lang
        // lang (script, country, variant, keyword=value, ...)
        // script, country, variant, keyword=value, ...

        String resultName = null;

        String lang = locale.getLanguage();

        // Empty basename indicates root locale (keywords are ignored for this).
        // Our data uses 'root' to access display names for the root locale in the
        // "Languages" table.
        if (locale.getBaseName().length() == 0) {
            lang = "root";
        }
        String script = locale.getScript();
        String country = locale.getCountry();
        String variant = locale.getVariant();

        boolean hasScript = script.length() > 0;
        boolean hasCountry = country.length() > 0;
        boolean hasVariant = variant.length() > 0;

        // always have a value for lang
        if (dialectHandling == DialectHandling.DIALECT_NAMES) {
            do { // loop construct is so we can break early out of search
                if (hasScript && hasCountry) {
                    String langScriptCountry = lang + '_' + script + '_' + country;
                    String result = localeIdName(langScriptCountry);
                    if (!result.equals(langScriptCountry)) {
                        resultName = result;
                        hasScript = false;
                        hasCountry = false;
                        break;
                    }
                }
                if (hasScript) {
                    String langScript = lang + '_' + script;
                    String result = localeIdName(langScript);
                    if (!result.equals(langScript)) {
                        resultName = result;
                        hasScript = false;
                        break;
                    }
                }
                if (hasCountry) {
                    String langCountry = lang + '_' + country;
                    String result = localeIdName(langCountry);
                    if (!result.equals(langCountry)) {
                        resultName = result;
                        hasCountry = false;
                        break;
                    }
                }
            } while (false);
        }

        if (resultName == null) {
            resultName = localeIdName(lang);
        }

        StringBuilder buf = new StringBuilder();
        if (hasScript) {
            // first element, don't need appender
            buf.append(scriptDisplayNameInContext(script));
        }
        if (hasCountry) {
            appender.append(regionDisplayName(country), buf);
        }
        if (hasVariant) {
            appender.append(variantDisplayName(variant), buf);
        }

        Iterator<String> keys = locale.getKeywords();
        if (keys != null) {
            while (keys.hasNext()) {
                String key = keys.next();
                String value = locale.getKeywordValue(key);
                String keyDisplayName = keyDisplayName(key);
                String valueDisplayName = keyValueDisplayName(key, value);
                if (!valueDisplayName.equals(value)) {
                    appender.append(valueDisplayName, buf);
                } else if (!key.equals(keyDisplayName)) {
                    String keyValue = keyTypeFormat.format(
                        new String[] { keyDisplayName, valueDisplayName });
                    appender.append(keyValue, buf);
                } else {
                    appender.append(keyDisplayName, buf)
                        .append("=")
                        .append(valueDisplayName);
                }
            }
        }

        String resultRemainder = null;
        if (buf.length() > 0) {
            resultRemainder = buf.toString();
        }

        if (resultRemainder != null) {
            resultName =  format.format(new Object[] {resultName, resultRemainder});
        }

        return adjustForUsageAndContext(CapitalizationContextUsage.LANGUAGE, resultName);
    }

    private String localeIdName(String localeId) {
        return langData.get("Languages", localeId);
    }

    @Override
    public String languageDisplayName(String lang) {
        // Special case to eliminate non-languages, which pollute our data.
        if (lang.equals("root") || lang.indexOf('_') != -1) {
            return lang;
        }
        return adjustForUsageAndContext(CapitalizationContextUsage.LANGUAGE, langData.get("Languages", lang));
    }

    @Override
    public String scriptDisplayName(String script) {
        String str = langData.get("Scripts%stand-alone", script);
        if (str.equals(script) ) {
            str = langData.get("Scripts", script);
        }
        return adjustForUsageAndContext(CapitalizationContextUsage.SCRIPT, str);
    }

    @Override
    public String scriptDisplayNameInContext(String script) {
        return adjustForUsageAndContext(CapitalizationContextUsage.SCRIPT, langData.get("Scripts", script));
    }

    @Override
    public String scriptDisplayName(int scriptCode) {
        return adjustForUsageAndContext(CapitalizationContextUsage.SCRIPT, scriptDisplayName(UScript.getShortName(scriptCode)));
    }

    @Override
    public String regionDisplayName(String region) {
        return adjustForUsageAndContext(CapitalizationContextUsage.TERRITORY, regionData.get("Countries", region));
    }

    @Override
    public String variantDisplayName(String variant) {
        return adjustForUsageAndContext(CapitalizationContextUsage.VARIANT, langData.get("Variants", variant));
    }

    @Override
    public String keyDisplayName(String key) {
        return adjustForUsageAndContext(CapitalizationContextUsage.KEY, langData.get("Keys", key));
    }

    @Override
    public String keyValueDisplayName(String key, String value) {
        return adjustForUsageAndContext(CapitalizationContextUsage.TYPE, langData.get("Types", key, value));
    }

    public static class DataTable {
        ULocale getLocale() {
            return ULocale.ROOT;
        }

        String get(String tableName, String code) {
            return get(tableName, null, code);
        }

        String get(String tableName, String subTableName, String code) {
            return code;
        }
    }

    static class ICUDataTable extends DataTable {
        private final ICUResourceBundle bundle;

        public ICUDataTable(String path, ULocale locale) {
            this.bundle = (ICUResourceBundle) UResourceBundle.getBundleInstance(
                    path, locale.getBaseName());
        }

        public ULocale getLocale() {
            return bundle.getULocale();
        }

        public String get(String tableName, String subTableName, String code) {
            return ICUResourceTableAccess.getTableString(bundle, tableName, subTableName,
                    code);
        }
    }

    static abstract class DataTables {
        public abstract DataTable get(ULocale locale);
        public static DataTables load(String className) {
            try {
                return (DataTables) Class.forName(className).newInstance();
            } catch (Throwable t) {
                final DataTable NO_OP = new DataTable();
                return new DataTables() {
                    public DataTable get(ULocale locale) {
                        return NO_OP;
                    }
                };
            }
        }
    }

    static abstract class ICUDataTables extends DataTables {
        private final String path;

        protected ICUDataTables(String path) {
            this.path = path;
        }

        @Override
        public DataTable get(ULocale locale) {
            return new ICUDataTable(path, locale);
        }
    }

    static class LangDataTables {
        static final DataTables impl = DataTables.load("com.ibm.icu.impl.ICULangDataTables");
    }

    static class RegionDataTables {
        static final DataTables impl = DataTables.load("com.ibm.icu.impl.ICURegionDataTables");
    }

    public static enum DataTableType {
        LANG, REGION;
    }

    public static boolean haveData(DataTableType type) {
        switch (type) {
        case LANG: return LangDataTables.impl instanceof ICUDataTables;
        case REGION: return RegionDataTables.impl instanceof ICUDataTables;
        default:
            throw new IllegalArgumentException("unknown type: " + type);
        }
    }

    static class Appender {
        private final String sep;

        Appender(String sep) {
            this.sep = sep;
        }
        StringBuilder append(String s, StringBuilder b) {
            if (b.length() > 0) {
                b.append(sep);
            }
            b.append(s);
            return b;
        }
    }

    private static class Cache {
        private ULocale locale;
        private DialectHandling dialectHandling;
        private DisplayContext capitalization;
        private LocaleDisplayNames cache;
        public LocaleDisplayNames get(ULocale locale, DialectHandling dialectHandling) {
            if (!(dialectHandling == this.dialectHandling && DisplayContext.CAPITALIZATION_NONE == this.capitalization && locale.equals(this.locale))) {
                this.locale = locale;
                this.dialectHandling = dialectHandling;
                this.capitalization = DisplayContext.CAPITALIZATION_NONE;
                this.cache = new LocaleDisplayNamesImpl(locale, dialectHandling);
            }
            return cache;
        }
        public LocaleDisplayNames get(ULocale locale, DisplayContext... contexts) {
            DialectHandling dialectHandlingIn = DialectHandling.STANDARD_NAMES;
            DisplayContext capitalizationIn = DisplayContext.CAPITALIZATION_NONE;
            for (DisplayContext contextItem : contexts) {
                switch (contextItem.type()) {
                    case DIALECT_HANDLING:
                        dialectHandlingIn = (contextItem.value()==DisplayContext.STANDARD_NAMES.value())?
                                            DialectHandling.STANDARD_NAMES: DialectHandling.DIALECT_NAMES;
                        break;
                    case CAPITALIZATION:
                        capitalizationIn = contextItem;
                        break;
                    default:
                        break;
                }
            }
            if (!(dialectHandlingIn == this.dialectHandling && capitalizationIn == this.capitalization && locale.equals(this.locale))) {
                this.locale = locale;
                this.dialectHandling = dialectHandlingIn;
                this.capitalization = capitalizationIn;
                this.cache = new LocaleDisplayNamesImpl(locale, contexts);
            }
            return cache;
        }
    }
}