import os
from re import split
import subprocess

def getCfFileId(std: str):
    return "08" if std == "08" else "93" ## Weird behaviour from GHDL, but all vhdl versions besides 08 have [...]93.cf

def ghdlEnvExists(std, lib):
    ## Check if work exists
    try:
        os.lstat("work")
    except:
        return False
    ## Check that work is writable
    if not os.access("work", os.W_OK):
        print("work is write-protected, please acquire correct permissions")
        return False
    cfFileExists = False
    filesInWork = os.listdir("work")
    cfFileId = getCfFileId(std)
    for file in filesInWork:
        if ".cf" in file and lib in file and cfFileId in file:
            cfFileExists = True
    if not cfFileExists:
        return False
    ## Nothing bad, continue
    return True

def createBuildEnv(std: str, lib: str):
    if ghdlEnvExists(std=std, lib=lib):
        print("Build environment already exists, exiting...")
        return -1
    ## Create build env
    print("Initializing GHDL project in current directory...")
    os.makedirs("work",exist_ok=True)
    addAllVHDLFiles(std=std, lib=lib, init=True)
    return 0

def addAllVHDLFiles(std: str, lib: str, init=False):
    ## Ensure everything is ready for adding files 
    ## (init exception to avoid one if-case in ghdlEnvExists)
    if not ghdlEnvExists(std=std, lib=lib) and not init:
       return -1
    vhdlFiles = []
    currentlyAdded = []
    cfFileId = getCfFileId(std)
    ## Find already present files
    if not init:
        cfFileName = list(filter(lambda x: ".cf" in x and lib in x and cfFileId in x, os.listdir("work")))[0]
        cfFilePath = os.path.join("work",cfFileName)
        currentlyAdded = getCurrentlyAddedFiles(cfFilePath)
    ## Add files not added
    for file in os.listdir():
        if ".vhd" in file and file not in currentlyAdded:
            vhdlFiles.append(file)
    if len(vhdlFiles) > 0:
        print(f"Detected new files. Adding {vhdlFiles}")
        command = ["ghdl", "-i", "--workdir=work", f"--work={lib}", f"--std={std}"] + vhdlFiles
        subprocess.run(command)
    return 0

def getCurrentlyAddedFiles(cfFilePath:str):
    f = open(cfFilePath,"r")
    lines = f.readlines()
    f.close()
    fileLines = filter(lambda x: "file" in x, lines) 
    files = map(lambda x: split("\" \"",x)[1], fileLines)
    return list(files)