using System;
using System.Collections.Generic;
using System.IO;
using System.Text;

using SabreTools.Library.Data;
using SabreTools.Library.DatItems;
using SabreTools.Library.IO;
using SabreTools.Library.Tools;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace SabreTools.Library.DatFiles
{
    /// <summary>
    /// Represents parsing and writing of a reference JSON DAT
    /// </summary>
    internal class Json : DatFile
    {
        /// <summary>
        /// Constructor designed for casting a base DatFile
        /// </summary>
        /// <param name="datFile">Parent DatFile to copy from</param>
        public Json(DatFile datFile)
            : base(datFile)
        {
        }

        /// <summary>
        /// Parse a reference JSON DAT and return all found games and roms within
        /// </summary>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="keep">True if full pathnames are to be kept, false otherwise (default)</param>
        protected override void ParseFile(
            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            bool keep)
        {
            // Prepare all internal variables
            StreamReader sr = new StreamReader(FileExtensions.TryOpenRead(filename), new UTF8Encoding(false));
            JsonTextReader jtr = new JsonTextReader(sr);

            // If we got a null reader, just return
            if (jtr == null)
                return;

            // Otherwise, read the file to the end
            try
            {
                jtr.Read();
                while (!sr.EndOfStream)
                {
                    // Skip everything not a property name
                    if (jtr.TokenType != JsonToken.PropertyName)
                    {
                        jtr.Read();
                        continue;
                    }

                    switch (jtr.Value)
                    {
                        // Header value
                        case "header":
                            ReadHeader(jtr);
                            jtr.Read();
                            break;

                        // Machine array
                        case "machines":
                            ReadMachines(jtr, filename, indexId);
                            jtr.Read();
                            break;

                        default:
                            jtr.Read();
                            break;
                    }
                }
            }
            catch (Exception ex)
            {
                Globals.Logger.Warning($"Exception found while parsing '{filename}': {ex}");
            }

            jtr.Close();
        }

        /// <summary>
        /// Read header information
        /// </summary>
        /// <param name="jtr">JsonTextReader to use to parse the header</param>
        private void ReadHeader(JsonTextReader jtr)
        {
            // If the reader is invalid, skip
            if (jtr == null)
                return;

            // Read in the header and apply any new fields
            jtr.Read();
            JsonSerializer js = new JsonSerializer();
            DatHeader header = js.Deserialize<DatHeader>(jtr);
            Header.ConditionalCopy(header);
        }

        /// <summary>
        /// Read machine array information
        /// </summary>
        /// <param name="itr">JsonTextReader to use to parse the machine</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        private void ReadMachines(
            JsonTextReader jtr,

            // Standard Dat parsing
            string filename,
            int indexId)
        {
            // If the reader is invalid, skip
            if (jtr == null)
                return;

            // Read in the machine array
            jtr.Read();
            JsonSerializer js = new JsonSerializer();
            JArray machineArray = js.Deserialize<JArray>(jtr);

            // Loop through each machine object and process
            foreach (JObject machineObj in machineArray)
            {
                ReadMachine(machineObj, filename, indexId);
            }
        }

        /// <summary>
        /// Read machine object information
        /// </summary>
        /// <param name="machineObj">JObject representing a single machine</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        private void ReadMachine(
            JObject machineObj,

            // Standard Dat parsing
            string filename,
            int indexId)
        {
            // If object is invalid, skip it
            if (machineObj == null)
                return;

            // Prepare internal variables
            JsonSerializer js = new JsonSerializer();
            Machine machine = null;

            // Read the machine info, if possible
            if (machineObj.ContainsKey("machine"))
                machine = machineObj["machine"].ToObject<Machine>();

            // Read items, if possible
            if (machineObj.ContainsKey("items"))
                ReadItems(machineObj["items"] as JArray, filename, indexId, machine);
        }

        /// <summary>
        /// Read item array information
        /// </summary>
        /// <param name="itemsArr">JArray representing the items list</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="machine">Machine information to add to the parsed items</param>
        private void ReadItems(
            JArray itemsArr,

            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            Machine machine)
        {
            // If the array is invalid, skip
            if (itemsArr == null)
                return;

            // Loop through each datitem object and process
            foreach (JObject itemObj in itemsArr)
            {
                ReadItem(itemObj, filename, indexId, machine);
            }
        }

        /// <summary>
        /// Read item information
        /// </summary>
        /// <param name="machineObj">JObject representing a single datitem</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="machine">Machine information to add to the parsed items</param>
        private void ReadItem(
            JObject itemObj,

            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            Machine machine)
        {
            // If we have an empty item, skip it
            if (itemObj == null)
                return;

            // Prepare internal variables
            DatItem datItem = null;

            // Read the datitem info, if possible
            if (itemObj.ContainsKey("datitem"))
            {
                JToken datItemObj = itemObj["datitem"];
                switch (datItemObj.Value<string>("type").AsItemType())
                {
                    case ItemType.Archive:
                        datItem = datItemObj.ToObject<Archive>();
                        break;
                    case ItemType.BiosSet:
                        datItem = datItemObj.ToObject<BiosSet>();
                        break;
                    case ItemType.Blank:
                        datItem = datItemObj.ToObject<Blank>();
                        break;
                    case ItemType.Chip:
                        datItem = datItemObj.ToObject<Chip>();
                        break;
                    case ItemType.Disk:
                        datItem = datItemObj.ToObject<Disk>();
                        break;
                    case ItemType.Release:
                        datItem = datItemObj.ToObject<Release>();
                        break;
                    case ItemType.Rom:
                        datItem = datItemObj.ToObject<Rom>();
                        break;
                    case ItemType.Sample:
                        datItem = datItemObj.ToObject<Sample>();
                        break;
                }
            }

            // If we got a valid datitem, copy machine info and add
            if (datItem != null)
            {
                datItem.CopyMachineInformation(machine);
                datItem.Source = new Source { Index = indexId, Name = filename };
                ParseAddHelper(datItem);
            }
        }

        /// <summary>
        /// Create and open an output file for writing direct from a dictionary
        /// </summary>
        /// <param name="outfile">Name of the file to write to</param>
        /// <param name="ignoreblanks">True if blank roms should be skipped on output, false otherwise (default)</param>
        /// <returns>True if the DAT was written correctly, false otherwise</returns>
        public override bool WriteToFile(string outfile, bool ignoreblanks = false)
        {
            try
            {
                Globals.Logger.User($"Opening file for writing: {outfile}");
                FileStream fs = FileExtensions.TryCreate(outfile);

                // If we get back null for some reason, just log and return
                if (fs == null)
                {
                    Globals.Logger.Warning($"File '{outfile}' could not be created for writing! Please check to see if the file is writable");
                    return false;
                }

                StreamWriter sw = new StreamWriter(fs, new UTF8Encoding(false));
                JsonTextWriter jtw = new JsonTextWriter(sw)
                {
                    Formatting = Formatting.Indented,
                    IndentChar = '\t',
                    Indentation = 1
                };

                // Write out the header
                WriteHeader(jtw);

                // Write out each of the machines and roms
                string lastgame = null;

                // Use a sorted list of games to output
                foreach (string key in Items.SortedKeys)
                {
                    List<DatItem> roms = Items[key];

                    // Resolve the names in the block
                    roms = DatItem.ResolveNames(roms);

                    for (int index = 0; index < roms.Count; index++)
                    {
                        DatItem rom = roms[index];

                        // There are apparently times when a null rom can skip by, skip them
                        if (rom.Name == null || rom.Machine.Name == null)
                        {
                            Globals.Logger.Warning("Null rom found!");
                            continue;
                        }

                        // If we have a different game and we're not at the start of the list, output the end of last item
                        if (lastgame != null && lastgame.ToLowerInvariant() != rom.Machine.Name.ToLowerInvariant())
                            WriteEndGame(jtw);

                        // If we have a new game, output the beginning of the new item
                        if (lastgame == null || lastgame.ToLowerInvariant() != rom.Machine.Name.ToLowerInvariant())
                            WriteStartGame(jtw, rom);

                        // If we have a "null" game (created by DATFromDir or something similar), log it to file
                        if (rom.ItemType == ItemType.Rom
                            && ((Rom)rom).Size == -1
                            && ((Rom)rom).CRC == "null")
                        {
                            Globals.Logger.Verbose($"Empty folder found: {rom.Machine.Name}");

                            rom.Name = (rom.Name == "null" ? "-" : rom.Name);
                            ((Rom)rom).Size = Constants.SizeZero;
                            ((Rom)rom).CRC = ((Rom)rom).CRC == "null" ? Constants.CRCZero : null;
                            ((Rom)rom).MD5 = ((Rom)rom).MD5 == "null" ? Constants.MD5Zero : null;
#if NET_FRAMEWORK
                            ((Rom)rom).RIPEMD160 = ((Rom)rom).RIPEMD160 == "null" ? Constants.RIPEMD160Zero : null;
#endif
                            ((Rom)rom).SHA1 = ((Rom)rom).SHA1 == "null" ? Constants.SHA1Zero : null;
                            ((Rom)rom).SHA256 = ((Rom)rom).SHA256 == "null" ? Constants.SHA256Zero : null;
                            ((Rom)rom).SHA384 = ((Rom)rom).SHA384 == "null" ? Constants.SHA384Zero : null;
                            ((Rom)rom).SHA512 = ((Rom)rom).SHA512 == "null" ? Constants.SHA512Zero : null;
                        }

                        // Now, output the rom data
                        WriteDatItem(jtw, rom, ignoreblanks);

                        // Set the new data to compare against
                        lastgame = rom.Machine.Name;
                    }
                }

                // Write the file footer out
                WriteFooter(jtw);

                Globals.Logger.Verbose("File written!" + Environment.NewLine);
                jtw.Close();
                fs.Dispose();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out DAT header using the supplied JsonTextWriter
        /// </summary>
        /// <param name="jtw">JsonTextWriter to output to</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteHeader(JsonTextWriter jtw)
        {
            try
            {
                jtw.WriteStartObject();

                // Write the DatHeader
                jtw.WritePropertyName("header");
                JsonSerializer js = new JsonSerializer() { Formatting = Formatting.Indented };
                js.Serialize(jtw, Header);

                jtw.WritePropertyName("machines");
                jtw.WriteStartArray();

                jtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out Game start using the supplied JsonTextWriter
        /// </summary>
        /// <param name="jtw">JsonTextWriter to output to</param>
        /// <param name="datItem">DatItem object to be output</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteStartGame(JsonTextWriter jtw, DatItem datItem)
        {
            try
            {
                // No game should start with a path separator
                datItem.Machine.Name = datItem.Machine.Name.TrimStart(Path.DirectorySeparatorChar);

                // Build the state
                jtw.WriteStartObject();

                // Write the Machine
                jtw.WritePropertyName("machine");
                JsonSerializer js = new JsonSerializer() { Formatting = Formatting.Indented };
                js.Serialize(jtw, datItem.Machine);

                jtw.WritePropertyName("items");
                jtw.WriteStartArray();

                jtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out Game end using the supplied JsonTextWriter
        /// </summary>
        /// <param name="jtw">JsonTextWriter to output to</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteEndGame(JsonTextWriter jtw)
        {
            try
            {
                // End items
                jtw.WriteEndArray();

                // End machine
                jtw.WriteEndObject();

                jtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out DatItem using the supplied JsonTextWriter
        /// </summary>
        /// <param name="jtw">JsonTextWriter to output to</param>
        /// <param name="datItem">DatItem object to be output</param>
        /// <param name="ignoreblanks">True if blank roms should be skipped on output, false otherwise (default)</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteDatItem(JsonTextWriter jtw, DatItem datItem, bool ignoreblanks = false)
        {
            // If we are in ignore blanks mode AND we have a blank (0-size) rom, skip
            if (ignoreblanks && (datItem.ItemType == ItemType.Rom && ((datItem as Rom).Size == 0 || (datItem as Rom).Size == -1)))
                return true;

            // If we have the blank item type somehow, skip
            if (datItem.ItemType == ItemType.Blank)
                return true;

            try
            {
                // Pre-process the item name
                ProcessItemName(datItem, true);

                // Build the state
                jtw.WriteStartObject();

                // Write the DatItem
                jtw.WritePropertyName("datitem");
                JsonSerializer js = new JsonSerializer() { ContractResolver = new BaseFirstContractResolver(), Formatting = Formatting.Indented };
                js.Serialize(jtw, datItem);

                // End item
                jtw.WriteEndObject();

                jtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out DAT footer using the supplied JsonTextWriter
        /// </summary>
        /// <param name="jtw">JsonTextWriter to output to</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteFooter(JsonTextWriter jtw)
        {
            try
            {
                // End items
                jtw.WriteEndArray();

                // End machine
                jtw.WriteEndObject();

                // End machines
                jtw.WriteEndArray();

                // End file
                jtw.WriteEndObject();

                jtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }
    }
}