use std::env;
use std::fs::File;
use std::io::Write;

use pathfinder2::graph;
use pathfinder2::io;
use pathfinder2::types::Address;
use pathfinder2::types::U256;

const HUB_ADDRESS: &str = "0x29b9a7fBb8995b2423a71cC17cf9810798F6C543";
const TRANSFER_THROUGH_SIG: &str = "transferThrough(address[],address[],address[],uint256[])";
const RPC_URL: &str = "https://rpc.gnosischain.com";

fn main() {
    let (dotfile, args) = if env::args().len() >= 2 && env::args().nth_back(1).unwrap() == "--dot" {
        (
            Some(env::args().last().unwrap()),
            env::args().rev().skip(2).rev().collect::<Vec<_>>(),
        )
    } else {
        (None, env::args().collect::<Vec<_>>())
    };

    if args.len() < 4 {
        println!("Usage: cli <from> <to> <edges.dat> [--dot <dotfile>]");
        println!("Usage: cli <from> <to> <edges.dat> <max_hops>  [--dot <dotfile>]");
        println!("Usage: cli <from> <to> <edges.dat> <max_hops> <max_flow> [--dot <dotfile>]");
        return;
    }
    let mut max_hops = None;
    let mut max_flow = U256::MAX;
    let (from_str, to_str, edges_file) = (&args[1], &args[2], &args[3]);
    if args.len() >= 5 {
        max_hops = Some(
            args[4]
                .parse()
                .unwrap_or_else(|_| panic!("Expected number of hops, but got: {}", args[4])),
        );
        if args.len() >= 6 {
            max_flow = args[5].as_str().into();
        }
    }

    println!("Computing flow {from_str} -> {to_str} using {edges_file}");
    let edges = io::read_edges_binary(edges_file)
        .unwrap_or_else(|_| panic!("Error loading edges from file \"{edges_file}\"."));
    println!("Read {} edges", edges.len());
    let (flow, transfers) = graph::compute_flow(
        &Address::from(from_str.as_str()),
        &Address::from(to_str.as_str()),
        &edges,
        max_flow,
        max_hops,
    );
    println!("Found flow: {flow}");
    println!("{:?}", transfers);

    let token_owners = transfers
        .iter()
        .map(|e| e.token.to_string())
        .collect::<Vec<String>>()
        .join(",");
    let froms = transfers
        .iter()
        .map(|e| e.from.to_string())
        .collect::<Vec<String>>()
        .join(",");
    let tos = transfers
        .iter()
        .map(|e| e.to.to_string())
        .collect::<Vec<String>>()
        .join(",");
    let amounts = transfers
        .iter()
        .map(|e| e.capacity.to_decimal())
        .collect::<Vec<String>>()
        .join(",");
    println!("To check, run the following command (requires foundry):");
    println!("cast call '{HUB_ADDRESS}' '{TRANSFER_THROUGH_SIG}' '[{token_owners}]' '[{froms}]' '[{tos}]' '[{amounts}]' --rpc-url {RPC_URL} --from {}", &transfers[0].from.to_string());
    if let Some(dotfile) = dotfile {
        File::create(&dotfile)
            .unwrap()
            .write_all(graph::transfers_to_dot(&transfers).as_bytes())
            .unwrap();
        println!("Wrote dotfile {dotfile}.");
    }
}