#!/usr/bin/env python3

import json
import os
import subprocess
import sys

"""Dict of dicts associating a second person to an amount"""
balance = {}
store_path = "."

name2num = {}
num2name = {}

registration_path = "reg.json"

group_id = "GELD!!!"

send_cmd = "signal-cli -u irgendwer send -g irgendwem"

def send(msg):
    subprocess.run(send_cmd.split(' '), input=msg.encode())

def create_summary(user):
    summary = ""
    total = 0
    p_balances = balance[user] # failes if user is not in balance
    for person in p_balances:
        amount = p_balances[person]
        if amount == 0:
            continue
        total -= amount
        summary += "\t" + ("<-" if amount < 0 else "->")
        summary += " " + person + " " + str(abs(amount)) + "\n"
    if summary == "":
        summary = "\tAll fine :)\n"
    else:
        summary += "\tBalance: " + str(total)
    summary = user + ":\n" + summary
    return summary

def create_total_summary():
    summary = "Summary:"

    for person in balance:
        summary += '\n'
        summary += "* " + create_summary(person)

    return summary

def create_members():
    r = ""
    for m in name2num:
        r += m + ": " + name2num[m] + "\n"
    return r

def create_help():
    return """
Usage: send a message starting with '!' followed by a command
Commands:
ls | list                - print all registered members
help                     - print this help message
reg name                 - register the sender with the name: name
sum [name]               - print a summary
schieb amount recipient  - give money to recipient
zieh amount donor        - get money from donor
	
Happy Geldschieben!
"""

def handle_input(inp):
    messages = inp.split("\n\n")
    for message in messages:
        lines = message.split('\n')

        # A message with Body must have at least 4 lines
        if len(lines) < 4:
            continue

        w = lines[0].split(' ')

        # Broken message
        if len(w) < 4:
            print("Broken msg:")
            print(message)
            continue

        # TODO support linked devices
        sender_number = w[-3]

        body_found = False
        body = ""

        # message is not in the group with group_id 
        not_in_group = True

        for idx, line in enumerate(lines[1:]):
            if line[0:6] == "Body: ":
                body = line[6:]
                body_found = True
            # Only one line bodies are supported
            elif body_found:
                not_in_group = lines[idx+1].strip() == "Id: " + group_id
                break

        if not_in_group:
            continue

        # strip of '\n'
        w = body.split(' ')

        # supported commands are:
        # "!reg"        register a name for this number
        # "!sum"        send a summary to the group
        # "!schieb"     give money to somebody
        # "!zieh"       add debt of somebody
        # "!list" "!ls" list members
        # "!help"       print all commands
        if w[0] == "!reg":
            if len(w) != 2:
                send('ERROR: not in form "!reg name"')
            else:
                w[1] = w[1].lower()
                if w[1] in name2num:
                    send("ERROR: name already registered")
                elif sender_number in num2name:
                    send("ERROR: you are already registered")
                else:
                    num2name[sender_number] = w[1]
                    name2num[w[1]] = sender_number

                    # add to balance
                    nm = {}
                    for m in balance:
                        balance[m][w[1]] = 0
                        nm[m] = 0
                    balance[w[1]] = nm

        elif w[0] == "!sum":
            if len(w) == 1:
                send(create_total_summary())
            elif len(w) == 2:
                w[1] = w[1].lower()
                if w[1] in name2num:
                    send("Summary:\n" + create_summary(w[1]))
                else:
                    send("ERROR: name not registered")
            else:
                send('ERROR: not in form "!sum [name]"')

        elif w[0] == "!schieb" or w[0] == "!zieh":
            if len(w) != 3:
                send('ERROR: not in form "!schieb amount recipient"')
            else:
                w[2] = w[2].lower()
                if not sender_number in num2name:
                    send('ERROR: you must register first')
                elif not w[2] in name2num:
                    send('ERROR: recipient not known')
                else:
                    sender = num2name[sender_number]
                    try:
                        amount = float(w[1])
                    except:
                        send("ERROR: amount musst be a number")
                        continue

                    if amount < 0:
                        send("ERROR: amount must be positiv")
                        continue

                    if w[0] == "!zieh":
                        amount *= -1

                    balance[sender][w[2]] -= amount
                    balance[w[2]][sender] += amount

                    p_balance = balance[sender][w[2]]

                    send("New Balance: {0} {1} {2} {3}\n".format(sender, ("->" if p_balance > 0 else "<-"), abs(p_balance), w[2]))
                
        elif w[0] == "!list" or w[0] == "!ls":
            send(create_members())

        elif w[0] == "!help":
            send(create_help())

def main():
    global group_id
    group_id = os.environ["GSB_GROUP_ID"]

    global balance
    store_path = os.environ["GSB_STORE_PATH"]
    balance_path = store_path + "/balance.json"
    registration_path = store_path + "/registration.json"

    global name2num
    global num2name

    global send_cmd
    send_cmd = os.environ["GSB_SEND_CMD"]

    if os.path.isfile(balance_path):
            balance = json.load(open(balance_path, "r"))

    if os.path.isfile(registration_path):
            name2num = json.load(open(registration_path, "r"))
            for name in name2num:
                num2name[name2num[name]] = name

    handle_input(sys.stdin.read())

    with open(balance_path, "w") as f:
        json.dump(balance, f)

    with open(registration_path, "w") as f:
        json.dump(name2num, f)

if __name__ == "__main__":
    main()