package macros;

#if macro
import haxe.macro.Context;
import haxe.macro.Expr;
import sys.FileSystem;
import sys.io.File;
import haxe.Json;
using StringTools;

/**
 * Macro for processing @:Assets meta tags and building asset manifests
 */
@:keep
class AssetMacro {
    // Track all assets processed
    private static var assetMap:Map<String, Array<{id:String, path:String, size:Int, type:String}>> = new Map();

    /** Force Assets to be typed, which invokes its @:build macro. */
    public static function includeAssets():Void {
        Context.getType("Assets");
    }
    
    /**
     * Entry point for the macro - called during compilation
     */
    public static function build():Array<Field> {
        #if macro
        Sys.println("AssetMacro.build() called - macro is running");
        Context.warning("AssetMacro is running", Context.currentPos());
        #end
        
        // A compilation server can retain macro statics between builds.
        assetMap = new Map();

        // Get current build context
        var fields = Context.getBuildFields();
        var localClass = Context.getLocalClass().get();
        
        #if macro
        Sys.println("Processing class: " + localClass.name);
        #end
        
        // Get the output directory from build.hxml
        var outputDir = getOutputDir();
        var manifestDir = outputDir + "/manifest";
        var assetsOutputDir = outputDir + "/assets";
        
        // These directories are owned by this macro. Recreate them so removed or
        // renamed source assets cannot survive as stale build output.
        removeDirectory(manifestDir);
        removeDirectory(assetsOutputDir);
        createDirectory(manifestDir);
        createDirectory(assetsOutputDir);
        copyLimeNativeLibrary(outputDir);
        
        // Process asset fields
        for (field in fields) {
            processField(field, assetsOutputDir);
        }
        
        // Build the manifest files
        buildManifests(manifestDir);
        
        return fields;
    }
    
    /**
     * Process a field for @:Assets meta
     */
    private static function processField(field:Field, assetsOutputDir:String) {
        // Look for our custom meta
        var assetsMeta = findAssetsMeta(field.meta);
        if (assetsMeta == null) return;
        
        var params = assetsMeta.params;
        if (params.length < 2) {
            Context.error("@:Assets meta requires at least 2 parameters: source path and library name", assetsMeta.pos);
            return;
        }
        
        // Extract parameters
        var sourcePath = extractString(params[0]);
        var libraryName = extractString(params[1]);
        var targetPath = params.length > 2 ? extractString(params[2]) : null;
        
        // Process directory or single file
        if (FileSystem.exists(sourcePath)) {
            if (FileSystem.isDirectory(sourcePath)) {
                processDirectory(sourcePath, libraryName, assetsOutputDir);
            } else {
                processSingleFile(sourcePath, libraryName, targetPath, assetsOutputDir);
            }
        } else {
            Context.warning('Asset source not found: ${sourcePath}', field.pos);
        }
    }
    
    /**
     * Process a directory of assets
     */
    private static function processDirectory(sourcePath:String, libraryName:String, assetsOutputDir:String) {
        if (!sourcePath.endsWith("/")) sourcePath += "/";
        var targetDir = assetsOutputDir + "/" + libraryName + "/";
        createDirectory(targetDir);
        
        function scanDir(path:String, relPath:String = "") {
            if (!FileSystem.exists(path)) return;
            
            for (entry in FileSystem.readDirectory(path)) {
                var fullPath = path + entry;
                var relAssetPath = relPath + entry;
                
                if (FileSystem.isDirectory(fullPath)) {
                    var newRelPath = relPath + entry + "/";
                    var newTargetDir = targetDir + newRelPath;
                    createDirectory(newTargetDir);
                    scanDir(fullPath + "/", newRelPath);
                } else {
                    // Copy file and register in asset map
                    var targetPath = targetDir + relAssetPath;
                    try {
                        File.copy(fullPath, targetPath);
                        
                        // Register asset
                        if (!assetMap.exists(libraryName)) {
                            assetMap.set(libraryName, []);
                        }
                        
                        assetMap.get(libraryName).push({
                            id: relAssetPath,
                            path: relAssetPath,
                            size: FileSystem.stat(fullPath).size,
                            type: getAssetType(fullPath)
                        });
                    } catch (e) {
                        Context.warning('Failed to copy asset: ${fullPath} -> ${targetPath}. Error: ${e}', Context.currentPos());
                    }
                }
            }
        }
        
        scanDir(sourcePath);
    }
    
    /**
     * Process a single file asset
     */
    private static function processSingleFile(sourcePath:String, libraryName:String, targetPath:String, assetsOutputDir:String) {
        var targetDir = assetsOutputDir + "/" + libraryName + "/";
        createDirectory(targetDir);
        
        var fileName = targetPath != null ? targetPath : sourcePath.split("/").pop();
        var destPath = targetDir + fileName;
        
        try {
            File.copy(sourcePath, destPath);
            
            // Register asset
            if (!assetMap.exists(libraryName)) {
                assetMap.set(libraryName, []);
            }
            
            assetMap.get(libraryName).push({
                id: fileName,
                path: fileName,
                size: FileSystem.stat(sourcePath).size,
                type: getAssetType(sourcePath)
            });
        } catch (e) {
            Context.warning('Failed to copy asset: ${sourcePath} -> ${destPath}. Error: ${e}', Context.currentPos());
        }
    }
    
    /**
     * Build manifest JSON files for each library
     */
    private static function buildManifests(manifestDir:String) {
        // Create an array to hold all assets for the default manifest
        var allAssets = [];
        
        // First, process individual library manifests
        for (library in assetMap.keys()) {
            var assets = assetMap.get(library);
            var manifest = {
                name: library,
                assets: assets,
                rootPath: "../assets/" + library + "/"
            };
            
            // Add assets to combined collection with library prefix
            for (asset in assets) {
                allAssets.push({
                    id: library + "/" + asset.id,
                    path: library + "/" + asset.path,
                    size: asset.size,
                    type: asset.type
                });
            }
            
            var manifestPath = manifestDir + "/" + library + ".json";
            try {
                var content = Json.stringify(manifest, null, "  ");
                File.saveContent(manifestPath, content);
                Context.info('Built manifest: ${manifestPath} with ${assets.length} assets', Context.currentPos());
            } catch (e) {
                Context.warning('Failed to write manifest: ${manifestPath}. Error: ${e}', Context.currentPos());
            }
        }
        
        // Create the default manifest with all assets
        var defaultManifest = {
            name: "default",
            assets: allAssets,
            rootPath: "../assets/"
        };
        
        // Save the default manifest
        var defaultManifestPath = manifestDir + "/default.json";
        try {
            var content = Json.stringify(defaultManifest, null, "  ");
            File.saveContent(defaultManifestPath, content);
            Context.info('Built default manifest: ${defaultManifestPath} with ${allAssets.length} assets', Context.currentPos());
        } catch (e) {
            Context.warning('Failed to write default manifest: ${defaultManifestPath}. Error: ${e}', Context.currentPos());
        }
    }
    
    // Helper functions
    
    private static function getOutputDir():String {
        // Try to parse the --cpp argument from the build.hxml
        var args = Sys.args();
        for (i in 0...args.length) {
            if (args[i] == "--cpp" && i < args.length - 1) {
                return args[i + 1];
            }
        }
        return "bin/cpp"; // Default output directory
    }
    
    private static function createDirectory(path:String) {
        if (!FileSystem.exists(path)) {
            try {
                FileSystem.createDirectory(path);
            } catch (e) {
                Context.warning('Failed to create directory: ${path}. Error: ${e}', Context.currentPos());
            }
        }
    }
    
    private static function removeDirectory(path:String):Void {
        if (!FileSystem.exists(path)) return;

        for (entry in FileSystem.readDirectory(path)) {
            var entryPath = path + "/" + entry;
            if (FileSystem.isDirectory(entryPath)) {
                removeDirectory(entryPath);
            } else {
                FileSystem.deleteFile(entryPath);
            }
        }
        FileSystem.deleteDirectory(path);
    }

    /** Stage the Lime CFFI module that matches the selected haxelib version. */
    private static function copyLimeNativeLibrary(outputDir:String):Void {
        var platformDirectory = if (Context.defined("linux")) {
            "Linux64";
        } else if (Context.defined("windows")) {
            "Windows64";
        } else if (Context.defined("mac")) {
            Context.defined("arm64") ? "MacArm64" : "Mac64";
        } else {
            return;
        }

        var limeRoot:String = null;
        for (classPath in Context.getClassPath()) {
            var normalized = classPath.split("\\").join("/");
            if (normalized.indexOf("/lime/") != -1 && normalized.endsWith("/src/")) {
                limeRoot = normalized.substr(0, normalized.length - 4);
                break;
            }
        }
        if (limeRoot == null) {
            Context.warning("Could not locate Lime native library from the compiler class path", Context.currentPos());
            return;
        }

        var source = limeRoot + "ndll/" + platformDirectory + "/lime.ndll";
        if (!FileSystem.exists(source) && platformDirectory.endsWith("64")) {
            platformDirectory = platformDirectory.substr(0, platformDirectory.length - 2);
            source = limeRoot + "ndll/" + platformDirectory + "/lime.ndll";
        }
        if (!FileSystem.exists(source)) {
            Context.warning("Lime native library not found: " + source, Context.currentPos());
            return;
        }

        try {
            File.copy(source, outputDir + "/lime.ndll");
        } catch (e:Dynamic) {
            Context.error("Failed to copy Lime native library: " + e, Context.currentPos());
        }
    }

    private static function findAssetsMeta(metaAccess:Array<MetadataEntry>):MetadataEntry {
        if (metaAccess == null) return null;
        
        for (meta in metaAccess) {
            if (meta.name == ":Assets" || meta.name == "Assets") {
                return meta;
            }
        }
        return null;
    }
    
    private static function extractString(expr:Expr):String {
        switch (expr.expr) {
            case EConst(CString(s)): return s;
            default: Context.error("Expected string literal", expr.pos);
        }
        return null;
    }
    
    private static function getAssetType(path:String):String {
        var ext = path.split(".").pop().toLowerCase();
        return (switch (ext) {
            case "jpg", "jpeg", "png", "gif", "bmp": "image";
            case "mp3", "ogg", "wav": "sound";
            case "ttf", "otf": "font";
            case "json", "xml", "txt": "text";
            default: "binary";
        }).toUpperCase();
    }
}
#end