package de.srsoftware.widerhall.data;

import de.srsoftware.widerhall.Configuration;
import de.srsoftware.widerhall.Util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.internet.InternetAddress;
import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

import static de.srsoftware.widerhall.Constants.*;
import static de.srsoftware.widerhall.Constants.VARCHAR;

public class Post {
    public static final Logger LOG = LoggerFactory.getLogger(Post.class);
    public static final String TABLE_NAME = "Posts";
    private static final String FROM_ADDR = "from_addr";
    private static final String FROM_NAME = "from_name";
    private static final String PARENT = "parent";
    private static final String LONG = "LONG";
    private static final String DATE = "date";
    private static final String FILE = "file";
    private static HashMap<String, Post> cache = new HashMap<>();

    private String id, fromAddr, fromName, subject, filename;
    private MailingList list;
    private Post parent;
    private Long timestamp;

    public Post(String id, MailingList list, String fromAddr, String fromName, String subject, Long timestamp){
        this.id = id;
        this.list = list;
        this.fromAddr = fromAddr;
        this.fromName = fromName;
        this.subject = subject;
        this.timestamp = timestamp;
        this.filename = generateFilename();
    }


    public static Post create(MailingList list, Message message){
        try {
            var id = message.getHeader("Message-ID")[0].replace("<", "").replace(">", "");
            var addr = ((InternetAddress) message.getFrom()[0]);
            var fromEmail = addr.getAddress();
            var fromName = addr.getPersonal();
            if (fromName == null || fromName.isBlank()) fromName = fromEmail.split("@")[0] + "@xxxxxx";
            var subject = message.getSubject();
            var text = Util.getText(message);
            var time = message.getSentDate().getTime();

            Post post = new Post(id,list,fromEmail,fromName,subject,time);
            var file = post.file();
            file.getParentFile().mkdirs();
            Files.writeString(file.toPath(),text, StandardCharsets.UTF_8);
            return post.save();
        } catch (MessagingException | IOException | SQLException e) {
            LOG.warn("Failed to create post from {}",message);
        }
        return null;
    }

    /**
     * create posts table
     * @throws SQLException
     */
    public static void createTable() throws SQLException {
        var sql = new StringBuilder()
                .append("CREATE TABLE ").append(TABLE_NAME)
                .append(" (")
                .append(ID).append(" ").append(VARCHAR).append(" NOT NULL PRIMARY KEY, ")
                .append(LIST).append(" ").append(VARCHAR).append(", ")
                .append(FROM_ADDR).append(" ").append(VARCHAR).append(", ")
                .append(FROM_NAME).append(" ").append(VARCHAR).append(", ")
                .append(PARENT).append(" ").append(VARCHAR).append(", ")
                .append(SUBJECT).append(" ").append(VARCHAR).append(", ")
                .append(DATE).append(" ").append(LONG).append(", ")
                .append(FILE).append(" ").append(VARCHAR)

                .append(");");
        Database.open().query(sql).compile().run();
    }


    public File file(){
        return new File(filename);
    }

    public static ArrayList<Post> find(MailingList list, String month) throws SQLException {
        var rs = Database.open()
                .select(TABLE_NAME,"*","strftime('%Y-%m',date/1000,'unixepoch') as month")
                .where(LIST,list.email())
                .where(MONTH,month)
                .sort(DATE)
                .compile()
                .exec();
        try {
            var result = new ArrayList<Post>();
            while (rs.next()) result.add(Post.from(rs));
            return result;
        } finally {
            rs.close();
        }
    }

    private static Post from(ResultSet rs) {
        try {
            var id = rs.getString(ID);
            var post = cache.get(id);
            if (post == null) {
                var list = MailingList.load(rs.getString(LIST));
                post = new Post(id, list, rs.getString(FROM_ADDR), rs.getString(FROM_NAME), rs.getString(SUBJECT), rs.getLong(DATE));
                post.filename = rs.getString(FILE);
                cache.put(id,post);
            }
            return post;
        } catch (SQLException e){
            LOG.debug("Failed to load Post from database!",e);
        }
        return null;
    }


    private String generateFilename() {
        return Configuration.instance().archiveDir()+File.separator+id+".txt";
    }

    public String id() {
        return id;
    }

    public static Post load(String id) throws SQLException {
        var rs = Database.open().select(TABLE_NAME).where(ID,id).compile().exec();
        try {
            if (rs.next()) return Post.from(rs);
        } finally {
            rs.close();
        }
        return null;
    }

    public Map<String,Object> map() {
        return Map.of(ID,id,
                LIST,list.email(),
                FROM_ADDR,fromAddr,
                FROM_NAME,fromName,
                SUBJECT,subject,
                DATE,timestamp,
                FILE,filename);
    }

    public Map<String,Object> safeMap() {
        return Map.of(ID,id,
                LIST,list.name(),
                FROM_NAME,fromName,
                SUBJECT,Util.dropEmail(subject),
                DATE, new Timestamp(timestamp).toString());
    }

    private Post save() throws SQLException {
        Database.open().insertInto(TABLE_NAME).values(map()).compile().run();
        return this;
    }

    public static Map<String, Object> summarize(MailingList list) throws SQLException {
        var sql = new StringBuilder("SELECT count(*) as count,strftime('%Y-%m',date/1000,'unixepoch') as month FROM Posts WHERE list = ? GROUP BY month ORDER BY month;");
        var map = new TreeMap<String,Object>();
        var rs = Database.open().query(sql).compile(list.email()).exec();
        while (rs.next()) map.put(rs.getString("month"),rs.getInt("count"));
        rs.close();
        return map;
    }

    public long timestamp(){
        return timestamp;
    }

}