using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;

namespace KeepersCompound.LGS;

public enum ResourceType
{
    Mission,
    Object,
    ObjectTexture,
    Texture,
}

public class ResourcePathManager
{
    private record CampaignResources
    {
        public Dictionary<string, string> missionPathMap;
        public Dictionary<string, string> texturePathMap;
        public Dictionary<string, string> objectPathMap;
        public Dictionary<string, string> objectTexturePathMap;

        public List<string> GetResourceNames(ResourceType type)
        {
            List<string> keys = type switch
            {
                ResourceType.Mission => [.. missionPathMap.Keys],
                ResourceType.Object => [.. objectPathMap.Keys],
                ResourceType.ObjectTexture => [.. objectTexturePathMap.Keys],
                ResourceType.Texture => [.. texturePathMap.Keys],
                _ => throw new ArgumentOutOfRangeException(nameof(type)),
            };
            keys.Sort();
            return keys;
        }

        public string GetResourcePath(ResourceType type, string name)
        {
            var map = type switch
            {
                ResourceType.Mission => missionPathMap,
                ResourceType.Object => objectPathMap,
                ResourceType.ObjectTexture => objectTexturePathMap,
                ResourceType.Texture => texturePathMap,
                _ => throw new ArgumentOutOfRangeException(nameof(type)),
            };
            return map.TryGetValue(name, out var resourcePath) ? resourcePath : null;
        }
    }

    private bool _initialised = false;
    private readonly string _extractionPath;
    private string _fmsDir;
    private CampaignResources _omResources;
    private Dictionary<string, CampaignResources> _fmResources;

    public ResourcePathManager(string extractionPath)
    {
        _extractionPath = extractionPath;
    }

    public bool Init(string installPath)
    {
        // TODO: This can be done less awkwardly with the resource paths
        if (DirContainsThiefExe(installPath) &&
            TryGetInstallCfgPath(installPath, out var installCfgPath) &&
            TryBuildOmsPathMap(installPath, installCfgPath, out var omsMap) &&
            TryBuildFmsPathMap(installPath, out var fmsMap, out var fmsDir) &&
            TryGetPath(installPath, "fam.crf", out var famPath) &&
            TryGetPath(installPath, "obj.crf", out var objPath))
        {
            // Register OM resources
            {
                var famExtractPath = Path.Join(_extractionPath, "fam");
                if (Directory.Exists(famExtractPath))
                {
                    Directory.Delete(famExtractPath, true);
                }
                ZipFile.OpenRead(famPath).ExtractToDirectory(famExtractPath);
                var texturePathMap = GetTexturePaths(_extractionPath);

                var objExtractPath = Path.Join(_extractionPath, "obj");
                if (Directory.Exists(objExtractPath))
                {
                    Directory.Delete(objExtractPath, true);
                }
                ZipFile.OpenRead(objPath).ExtractToDirectory(objExtractPath);
                var objectPathMap = GetObjectPaths(_extractionPath);
                var objectTexturePathMap = GetObjectTexturePaths(_extractionPath);

                _omResources = new CampaignResources
                {
                    missionPathMap = omsMap,
                    texturePathMap = texturePathMap,
                    objectPathMap = objectPathMap,
                    objectTexturePathMap = objectTexturePathMap,
                };
            }

            {
                _fmResources = new Dictionary<string, CampaignResources>();
                foreach (var (campaign, missionPathMap) in fmsMap)
                {
                    var root = Path.Join(fmsDir, campaign);
                    var texturePathMap = GetTexturePaths(root);
                    var objectPathMap = GetObjectPaths(root);
                    var objectTexturePathMap = GetObjectTexturePaths(root);

                    var resource = new CampaignResources
                    {
                        missionPathMap = missionPathMap,
                        texturePathMap = texturePathMap,
                        objectPathMap = objectPathMap,
                        objectTexturePathMap = objectTexturePathMap,
                    };
                    _fmResources.Add(campaign, resource);
                    _fmsDir = fmsDir;
                }
            }

            _initialised = true;
            return true;
        }

        return false;
    }

    public List<string> GetCampaignNames()
    {
        if (!_initialised) return null;

        var names = new List<string>(_fmResources.Keys);
        names.Sort();
        return names;
    }

    public List<string> GetResourceNames(ResourceType type, string campaignName)
    {
        if (!_initialised)
        {
            throw new InvalidOperationException("Resource Path Manager hasn't been initialised.");
        }

        if (campaignName == null || campaignName == "")
        {
            return _omResources.GetResourceNames(type);
        }
        else if (_fmResources.TryGetValue(campaignName, out var campaign))
        {
            return campaign.GetResourceNames(type);
        }

        throw new ArgumentException("No campaign found with given name", nameof(campaignName));
    }

    public (string, string) GetResourcePath(
        ResourceType type,
        string campaignName,
        string resourceName)
    {
        if (!_initialised)
        {
            throw new InvalidOperationException("Resource Path Manager hasn't been initialised.");
        }

        resourceName = resourceName.ToLower();
        var omResourcePath = _omResources.GetResourcePath(type, resourceName);

        if (campaignName == null || campaignName == "" && omResourcePath != null)
        {
            return ("", omResourcePath);
        }
        else if (_fmResources.TryGetValue(campaignName, out var campaign))
        {
            var fmResourcePath = campaign.GetResourcePath(type, resourceName);
            if (fmResourcePath != null)
            {
                return (campaignName, fmResourcePath);
            }
            else if (omResourcePath != null)
            {
                return ("", omResourcePath);
            }
        }

        // throw new ArgumentException($"No resource found with given type and name: {type}, {resourceName}", nameof(resourceName));
        return (null, null);
    }

    private static Dictionary<string, string> GetObjectTexturePaths(string root)
    {
        string[] validExtensions = { ".dds", ".png", ".tga", ".pcx", ".gif", ".bmp", ".cel", };

        var dirOptions = new EnumerationOptions { MatchCasing = MatchCasing.CaseInsensitive };
        var texOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true,
        };

        var pathMap = new Dictionary<string, string>();
        foreach (var dir in Directory.EnumerateDirectories(root, "obj", dirOptions))
        {
            foreach (var path in Directory.EnumerateFiles(dir, "*", texOptions))
            {
                var ext = Path.GetExtension(path);
                if (validExtensions.Contains(ext.ToLower()))
                {
                    var key = Path.GetFileNameWithoutExtension(path).ToLower();
                    pathMap.TryAdd(key, path);
                }
            }
        }

        return pathMap;
    }

    private static Dictionary<string, string> GetTexturePaths(string root)
    {
        string[] validExtensions = { ".dds", ".png", ".tga", ".pcx", ".gif", ".bmp", ".cel", };

        var famOptions = new EnumerationOptions { MatchCasing = MatchCasing.CaseInsensitive };
        var textureOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true,
        };

        var pathMap = new Dictionary<string, string>();
        foreach (var dir in Directory.EnumerateDirectories(root, "fam", famOptions))
        {
            foreach (var path in Directory.EnumerateFiles(dir, "*", textureOptions))
            {
                var ext = Path.GetExtension(path);
                if (validExtensions.Contains(ext.ToLower()))
                {
                    var key = Path.GetRelativePath(root, path)[..^ext.Length].ToLower();
                    pathMap.TryAdd(key, path);
                }
            }
        }

        return pathMap;
    }

    private static Dictionary<string, string> GetObjectPaths(string root)
    {
        var dirOptions = new EnumerationOptions { MatchCasing = MatchCasing.CaseInsensitive };
        var binOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true,
        };

        var pathMap = new Dictionary<string, string>();
        foreach (var dir in Directory.EnumerateDirectories(root, "obj", dirOptions))
        {
            foreach (var path in Directory.EnumerateFiles(dir, "*.bin", binOptions))
            {
                var key = Path.GetRelativePath(dir, path).ToLower();
                pathMap.TryAdd(key, path);
            }
        }

        return pathMap;
    }

    private static bool TryBuildOmsPathMap(string root, string cfgPath, out Dictionary<string, string> map)
    {
        map = new Dictionary<string, string>();

        var omsPath = "";
        foreach (var line in File.ReadLines(cfgPath))
        {
            if (line.StartsWith("load_path"))
            {
                // TODO: Do we only need to replace on systems with a different path separator?
                var path = line.Split(" ")[1].Replace("\\", "/");
                omsPath = Path.GetFullPath(root + path);
                break;
            }
        }
        if (omsPath == "")
        {
            return false;
        }

        var searchOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
        };
        foreach (var path in Directory.GetFiles(omsPath, "*.mis", searchOptions))
        {
            var baseName = Path.GetFileName(path).ToLower();
            map.Add(baseName, path);
        }

        return true;
    }

    private static bool TryBuildFmsPathMap(
        string root,
        out Dictionary<string, Dictionary<string, string>> fmsMap,
        out string fmsPath)
    {
        fmsMap = new Dictionary<string, Dictionary<string, string>>();
        fmsPath = root + "/FMs";

        var searchOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true
        };

        // Cam Mod tells us where any FMs are installed (alongside other things)
        // If it doesn't exist then something is wrong with the install directory
        if (!TryGetPath(root, "cam_mod.ini", out var camModPath))
        {
            return false;
        }

        // We're looking for an uncommented line defining an fm_path, but its
        // find if we don't find one because there's a default path.
        foreach (var line in File.ReadLines(camModPath))
        {
            if (line.StartsWith("fm_path"))
            {
                // TODO: I think this can technically contain multiple paths
                var path = line.Split(" ")[1].Replace("\\", "/");
                fmsPath = Path.GetFullPath(root + path);
                break;
            }
        }

        // Now we can iterate through all the FM directories and map their mission paths
        // if they have any.
        string[] extensions = { ".mis", ".cow" };
        searchOptions.RecurseSubdirectories = false;
        foreach (var dir in Directory.GetDirectories(fmsPath))
        {
            var campaignMap = new Dictionary<string, string>();
            foreach (var path in Directory.GetFiles(dir))
            {
                if (extensions.Contains(Path.GetExtension(path).ToLower()))
                {
                    var baseName = Path.GetFileName(path).ToLower();
                    campaignMap.Add(baseName, path);
                }
            }

            if (campaignMap.Count != 0)
            {
                fmsMap.Add(Path.GetFileName(dir), campaignMap);
            }
        }

        return true;
    }

    private static bool DirContainsThiefExe(string dir)
    {
        var searchOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
        };

        foreach (var path in Directory.GetFiles(dir, "*.exe", searchOptions))
        {
            var baseName = Path.GetFileName(path).ToLower();
            if (baseName.Contains("thief"))
            {
                return true;
            }
        }

        return false;
    }

    private static bool TryGetInstallCfgPath(string dir, out string installCfgPath)
    {
        var searchOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true
        };

        foreach (var path in Directory.GetFiles(dir, "*.cfg", searchOptions))
        {
            var baseName = Path.GetFileName(path).ToLower();
            if (baseName == "install.cfg" || baseName == "darkinst.cfg")
            {
                installCfgPath = path;
                return true;
            }
        }

        installCfgPath = "";
        return false;
    }

    private static bool TryGetPath(string dir, string searchPattern, out string path)
    {
        var searchOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true
        };

        var paths = Directory.GetFiles(dir, searchPattern, searchOptions);
        if (paths.Length > 0)
        {
            path = paths[0];
            return true;
        }

        path = "";
        return false;
    }
}