#!/usr/bin/python3
import os
import sys

#
# Constants
#

ASSETS_DIR="assets"
RESOURCES_FILE="src/resources/Resources.g.h"

RESOURCES_FILE_HEADER=("// WARNING: This file is auto generated by the build/prepareAssets.py script.\n"
                       "#ifndef STORAGE_RESOURCES_G_H_\n"
                       "#define STORAGE_RESOURCES_G_H_\n"
                       "\n"
                       "#include <resources/ResourceInfo.h>\n"
                       "\n"
                       "namespace farmlands {\n"
                       "namespace resources {\n"
                       "\n")

RESOURCES_FILE_FOOTER=("\n"
                       "}\n"
                       "}\n"
                       "#endif /* STORAGE_RESOURCES_G_H_ */\n")

R_HEADER=("    /**\n"
          "     * This namespace contains all the resource IDs, used by the resource manager.\n"
          "     * The IDs are generated at build time by the 'prepareAssets.py' script.\n"
          "     */\n"
          "    namespace R {\n")

R_FOOTER="    }\n"

RINFO_HEADER=("    /**\n"
              "     * This array contains the names of all the files, and the corresponding file type.\n"
              "     */\n"
              "    const ResourceInfo RInfo[] = {\n")

RINFO_FOOTER="    };\n"


#
# File types
#
FILE_TYPES = [
    ([".png", ".bmp"], "Texture"),
    ([".level"], "Level"),
    ([".csv"], "LevelLayer"),
    ([".ttf"], "Font"),    
]


#
# Capitalizes the given string by converting the first character to uppercase.
# It does not convert the other characters to lowercase.
#
def capitalize(s):
    if len(s) == 0:
        return s
    
    return s[0].upper() + s[1:]

#
# Obtains the file type using FILE_TYPES constant
#
def getFileType(fileName):
    ext = os.path.splitext(fileName)[1]

    for (extensions, type) in FILE_TYPES:
        if ext in extensions:
            return type
        
    return "None"


#
# Main routine
#
if __name__ == '__main__':
    r = ""
    rInfo = ""
    rInfoBegin = ""
    
    assetId = 0
    
    print ("Preparing assets...")
    
    # Build R and RInfo
    for assetDir in os.listdir(ASSETS_DIR):
        assetDirPath=os.path.join(ASSETS_DIR, assetDir)
        
        # Warning for non-directories
        if not os.path.isdir(assetDirPath):
            sys.stderr.writeline("Warning: file {0} is in the root 'assets' folder, and it will not be imported.".format(assetDir))
            continue
        
        # Create R enum
        assetIdBegin = assetId
        rInfoBegin += "    const int RInfo_{0}_Begin = {1};\n".format(capitalize(assetDir), assetIdBegin)
        r += ("        enum " + capitalize(assetDir) + "\n"
              "        {\n")
                
        # Get items in directory
        for (dir, dirs, files) in os.walk(assetDirPath):
            
            # R prefix - remove assetDirPath from path, replace path separators with _
            RdirPrefix = os.path.relpath(dir, assetDirPath)
            RdirPrefix = RdirPrefix.replace("/", "_").replace("\\", "_")
            if (RdirPrefix == "."):
                RdirPrefix = ""
            else:
                RdirPrefix += "_"
            
            for f in files:
                # Append to R
                fResName = RdirPrefix + capitalize(os.path.splitext(f)[0])
                r += "            {0} = {1},\n".format(fResName, assetId)
                assetId += 1
                
                # RInfo path should be relative to assets directory
                fPath = os.path.join(dir, f)
                fPath = os.path.relpath(fPath, ASSETS_DIR)
                fType = getFileType(f)
                
                rInfo += "        {{ \"{0}\", ResourceType::{1} }},\n".format(fPath, fType) # TODO: obtain resource type
        
        # Finish R enum
        r += "        };\n"
        
    # Build resource header file
    resFile = RESOURCES_FILE_HEADER
    resFile += R_HEADER + r + R_FOOTER
    resFile += "\n" + rInfoBegin + "\n"
    resFile += RINFO_HEADER + rInfo + RINFO_FOOTER
    resFile += RESOURCES_FILE_FOOTER
    
    # Write resource file
    f = open(RESOURCES_FILE, "w")
    f.write(resFile)
    f.close()