#!/bin/env python

# Ported from https://github.com/wofsauge/IsaacSavegameReader/blob/main/Program.cs#L228

import sys

REP_ITEMSTART = 0x00000AB6 + 4
REP_NBITEMS = 732

EID_FILE = "eid_savegames.lua"

DGH_FILE1 = "saveX.dat"

def loadFromFile(filename, itemstart, nbitems):
    table = []
    try:
        file = open(filename, "rb")
    except FileNotFoundError:
        print(f"File not found: {filename}", file=sys.stderr)
        for i in range(nbitems):
            table.append(0)
        return table
    data = file.read(1)
    i = 0
    while data:
        if (i > itemstart) and i - itemstart <= nbitems:
            table.append(int.from_bytes(data, byteorder='big'))
            # Should be 1 (for already seen), or 0
        data = file.read(1)
        i += 1
    file.close()

    return table


def eidfile(t1, saveid):
    content = "-- Auto generated from a python script\n"
    content += "if EID then\n"
    content += "\tEID.SaveGame = {}\n"
    content += "\tEID.SaveGame.Platform = \"Steam\"\n"
    content += "\tEID.SaveGame.UserID = \"0\"\n"
    content += "\tEID.SaveGame.UserName = \"username\"\n"

    for savefileindex in range(3):

        content += f"\tEID.SaveGame[{savefileindex+1}] = {{\n"
        content += "\t\tItemCollection = {\n\t\t\t"
        for i, v in enumerate(table):
            if savefileindex + 1 == saveid:
                content += f"[{i+1}]={'true' if v==1 else 'false'}, "
            else:
                content += f"[{i+1}]=false, "
        content += "\n\t\t},\n"
        content += "\t\tItemNeedsPickup = {\n\t\t\t"
        for i, v in enumerate(table):
            if savefileindex + 1 == saveid:
                content += f"[{i+1}]={'true' if v==0 else 'false'}, "
            else:
                content += f"[{i+1}]=true, "
        content += "\n\t\t}\n\t}\n"

    content += "end"

    return content


def dghfile(table):
    content = '{'
    content += '"settings":{"visual":true,"eid":true,"showonmodded":true,"showonblind":false},'
    content += '"seen":['
    for i, v in enumerate(table):
        if table[i] == 1:
            content += "true"
        else:
            content += "false"
        if i < len(table) - 1:
            content += ", "
    content += "],"
    content += ' "seenmodded":{}}'
    return content


def isHelp(args):
    return ("--help" in args) or ("-h" in args)


if __name__ == "__main__":
    args = sys.argv

    if len(args) < 3 or isHelp(args):
        print(f"USAGE: python {args[0]} path/to/persistengamedata.dat slotnumber")
        if len(args)==2:
            print("ERROR: It seems like you forgot to specify the slot number you're importing from.")
        print("This will generate the following files:")
        print("\t- eid_savegames.lua , used by External Items Description (to be placed in EID's script folder)")
        print("\t- saveX.dat , used by Dead God Helper (to be placed in Dead God Helper data folder)")
    else:
        saveid = 1
        error = False
        try:
            saveid = int(args[2])
            if not (saveid <= 3 and saveid >= 1):
                error = True
        except ValueError:
            error = True

        if error:
            print(f"Invalid save ID: '{args[2]}'")
            print("Please retry with a number between 1 and 3!")
            exit(1)

        table = loadFromFile(args[1], REP_ITEMSTART, REP_NBITEMS)
        with open(EID_FILE, "w") as f:
            f.write(eidfile(table, saveid))
        with open(DGH_FILE1.replace("X", str(saveid)), "w") as f:
            f.write(dghfile(table))