{ config, lib, pkgs, ... }:

with lib;
let
  options.services.joinmarket = {
    enable = mkEnableOption "JoinMarket, a Bitcoin CoinJoin implementation";
    payjoinAddress = mkOption {
      type = types.str;
      default = "127.0.0.1";
      description = mdDoc ''
        The address where payjoin onion connections are forwarded to.
        This address is never used directly, it only serves as the internal endpoint
        for the payjoin onion service.
        The onion service is automatically setup by joinmarket and accepts
        connections at port 80.
      '';
    };
    payjoinPort = mkOption {
      type = types.port;
      default = 64180; # A random private port
      description = mdDoc "The port corresponding to option {option}`payjoinAddress`.";
    };
    messagingAddress = mkOption {
      type = types.str;
      default = "127.0.0.1";
      description = mdDoc ''
        The address where messaging onion connections are forwarded to.
        This address is never used directly, it only serves as the internal endpoint
        for the messaging onion service.
        The onion service is automatically setup by joinmarket.
      '';
    };
    messagingPort = mkOption {
      type = types.port;
      default = 64181; # payjoinPort + 1
      description = mdDoc "The port corresponding to option {option}`messagingAddress`.";
    };
    dataDir = mkOption {
      type = types.path;
      default = "/var/lib/joinmarket";
      description = mdDoc "The data directory for JoinMarket.";
    };
    rpcWalletFile = mkOption {
      type = types.nullOr types.str;
      default = "jm_wallet";
      description = mdDoc ''
        Name of the watch-only bitcoind wallet the JoinMarket addresses are imported to.
      '';
    };
    user = mkOption {
      type = types.str;
      default = "joinmarket";
      description = mdDoc "The user as which to run JoinMarket.";
    };
    group = mkOption {
      type = types.str;
      default = cfg.user;
      description = mdDoc "The group as which to run JoinMarket.";
    };
    cli = mkOption {
      default = cli;
      defaultText = "(See source)";
    };
    # Used by ./joinmarket-ob-watcher.nix
    messagingConfig = mkOption {
      readOnly = true;
      default = messagingConfig;
      defaultText = "(See source)";
    };
    # This option is only used by netns-isolation.
    # Tor is always enabled.
    tor.enforce = nbLib.tor.enforce;
    inherit (nbLib) cliExec;

    yieldgenerator = {
      enable = mkEnableOption "JoinMarket yield generator bot";
      ordertype = mkOption {
        type = types.enum [ "reloffer" "absoffer" ];
        default = "reloffer";
        description = mdDoc ''
          Which fee type to actually use.
        '';
      };
      cjfee_a = mkOption {
        type = types.ints.unsigned;
        default = 500;
        description = mdDoc ''
          Absolute offer fee you wish to receive for coinjoins (cj) in Satoshis.
        '';
      };
      cjfee_r = mkOption {
        type = types.float;
        default = 0.00002;
        description = mdDoc ''
          Relative offer fee you wish to receive based on a cj's amount.
        '';
      };
      cjfee_factor = mkOption {
        type = types.float;
        default = 0.1;
        description = mdDoc ''
          Variance around the average cj fee.
        '';
      };
      txfee = mkOption {
        type = types.ints.unsigned;
        default = 100;
        description = mdDoc ''
          The average transaction fee you're adding to coinjoin transactions.
        '';
      };
      txfee_contribution_factor = mkOption {
        type = types.float;
        default = 0.3;
        description = mdDoc ''
          Variance around the average tx fee.
        '';
      };
      minsize = mkOption {
        type = types.ints.unsigned;
        default = 100000;
        description = mdDoc ''
          Minimum size of your cj offer in Satoshis. Lower cj amounts will be disregarded.
        '';
      };
      size_factor = mkOption {
        type = types.float;
        default = 0.1;
        description = mdDoc ''
          Variance around all offer sizes.
        '';
      };
    };
  };

  cfg = config.services.joinmarket;
  nbLib = config.nix-bitcoin.lib;
  nbPkgs = config.nix-bitcoin.pkgs;
  secretsDir = config.nix-bitcoin.secretsDir;
  runAsUser = config.nix-bitcoin.runAsUserCmd;

  inherit (config.services) bitcoind;

  torAddress = config.services.tor.client.socksListenAddress;
  socks5Settings = ''
    socks5 = true
    socks5_host = ${torAddress.addr}
    socks5_port = ${toString torAddress.port}
  '';

  messagingConfig = ''
    [MESSAGING:onion]
    type = onion
    ${socks5Settings}
    tor_control_host = unix:/run/tor/control
    # required option, but ignored for unix socket host
    tor_control_port = 9051
    onion_serving_host = ${cfg.messagingAddress}
    onion_serving_port = ${toString cfg.messagingPort}
    hidden_service_dir =
    directory_nodes = g3hv4uynnmynqqq2mchf3fcm3yd46kfzmcdogejuckgwknwyq5ya6iad.onion:5222,3kxw6lf5vf6y26emzwgibzhrzhmhqiw6ekrek3nqfjjmhwznb2moonad.onion:5222,bqlpq6ak24mwvuixixitift4yu42nxchlilrcqwk2ugn45tdclg42qid.onion:5222

    # irc.darkscience.net
    [MESSAGING:server1]
    host = darkirc6tqgpnwd3blln3yfv5ckl47eg7llfxkmtovrv7c7iwohhb6ad.onion
    channel = joinmarket-pit
    port = 6697
    usessl = true
    ${socks5Settings}

    # ilita
    [MESSAGING:server2]
    host = ilitafrzzgxymv6umx2ux7kbz3imyeko6cnqkvy4nisjjj4qpqkrptid.onion
    channel = joinmarket-pit
    port = 6667
    usessl = false
    ${socks5Settings}

    # irc.hackint.org
    [MESSAGING:server3]
    host = ncwkrwxpq2ikcngxq3dy2xctuheniggtqeibvgofixpzvrwpa77tozqd.onion
    channel = joinmarket-pit
    port = 6667
    usessl = false
    ${socks5Settings}
  '';

  # Based on https://github.com/JoinMarket-Org/joinmarket-clientserver/blob/master/jmclient/jmclient/configure.py
  yg = cfg.yieldgenerator;
  configFile = builtins.toFile "config" ''
    [DAEMON]
    no_daemon = 0
    daemon_port = 27183
    daemon_host = 127.0.0.1
    use_ssl = false

    [BLOCKCHAIN]
    blockchain_source = ${bitcoind.makeNetworkName "bitcoin-rpc" "regtest"}
    network = ${bitcoind.makeNetworkName "mainnet" "testnet"}
    rpc_host = ${nbLib.address bitcoind.rpc.address}
    rpc_port = ${toString bitcoind.rpc.port}
    rpc_user = ${bitcoind.rpc.users.privileged.name}
    ${optionalString (cfg.rpcWalletFile != null) "rpc_wallet_file = ${cfg.rpcWalletFile}"}

    ${messagingConfig}

    [LOGGING]
    console_log_level = INFO
    color = false

    [POLICY]
    segwit = true
    native = true
    merge_algorithm = default
    gaplimit = 6
    tx_fees = 3
    tx_fees_factor = 0.2
    absurd_fee_per_kb = 350000
    max_sweep_fee_change = 0.8
    tx_broadcast = self
    minimum_makers = 4
    max_sats_freeze_reuse = -1
    interest_rate = 0.015
    bondless_makers_allowance = 0.125
    bond_value_exponent = 1.3
    taker_utxo_retries = 3
    taker_utxo_age = 5
    taker_utxo_amtpercent = 20
    accept_commitment_broadcasts = 1
    commit_file_location = cmtdata/commitments.json
    commitment_list_location = cmtdata/commitmentlist

    [PAYJOIN]
    payjoin_version = 1
    disable_output_substitution = 0
    max_additional_fee_contribution = default
    min_fee_rate = 1.1
    onion_socks5_host = ${torAddress.addr}
    onion_socks5_port = ${toString torAddress.port}
    tor_control_host = unix:/run/tor/control
    # Required option, but unused because `tor_control_host` is a Unix socket
    tor_control_port = 9051
    onion_serving_host = ${cfg.payjoinAddress}
    onion_serving_port = ${toString cfg.payjoinPort}
    hidden_service_ssl = false

    [YIELDGENERATOR]
    ordertype = ${yg.ordertype}
    cjfee_a = ${toString yg.cjfee_a}
    cjfee_r = ${toString yg.cjfee_r}
    cjfee_factor = ${toString yg.cjfee_factor}
    txfee_contribution = 0
    txfee_contribution_factor = ${toString yg.txfee_contribution_factor}
    minsize = ${toString yg.minsize}
    size_factor = ${toString yg.size_factor}

    [SNICKER]
    enabled = false
    lowest_net_gain = 0
    servers = cn5lfwvrswicuxn3gjsxoved6l2gu5hdvwy5l3ev7kg6j7lbji2k7hqd.onion,
    polling_interval_minutes = 60
  '';

   # The jm scripts create a 'logs' dir in the working dir,
   # so run them inside dataDir.
   cli = pkgs.runCommand "joinmarket-cli" {} ''
     mkdir -p "$out/bin"
     jm=${nbPkgs.joinmarket}/bin
     cd "$jm"
     for bin in jm-*; do
       {
         echo "#!${pkgs.bash}/bin/bash";
         echo "cd '${cfg.dataDir}' && ${cfg.cliExec} ${runAsUser} ${cfg.user} "$jm/$bin" --datadir='${cfg.dataDir}' \"\$@\"";
       } > "$out/bin/$bin"
     done
     chmod -R +x "$out/bin"
   '';
in {
  inherit options;

  config = mkIf cfg.enable (mkMerge [{
    services.bitcoind = {
      enable = true;
      disablewallet = false;
    };

    # Joinmarket is Tor-only
    services.tor = {
      enable = true;
      client.enable = true;
      # Needed for payjoin onion service creation
      controlSocket.enable = true;
    };

    environment.systemPackages = [
      (hiPrio cfg.cli)
    ];

    systemd.tmpfiles.rules = [
      "d '${cfg.dataDir}' 0770 ${cfg.user} ${cfg.group} - -"
    ];

    systemd.services.joinmarket = {
      wantedBy = [ "multi-user.target" ];
      requires = [ "bitcoind.service" ];
      after = [ "bitcoind.service" "nix-bitcoin-secrets.target" ];
      preStart = ''
        {
          cat ${configFile}
          echo
          echo '[BLOCKCHAIN]'
          echo "rpc_password = $(cat ${secretsDir}/bitcoin-rpcpassword-privileged)"
        } > '${cfg.dataDir}/joinmarket.cfg'
      '';
      postStart = ''
        walletname=wallet.jmdat
        wallet="${cfg.dataDir}/wallets/$walletname"
        if [[ ! -f $wallet ]]; then
          ${optionalString (cfg.rpcWalletFile != null) ''
            echo "Create watch-only wallet ${cfg.rpcWalletFile}"
            if ! output=$(${bitcoind.cli}/bin/bitcoin-cli -named createwallet \
                            wallet_name="${cfg.rpcWalletFile}" \
                            descriptors=false \
                            ${optionalString (!bitcoind.regtest) "disable_private_keys=true"} 2>&1
                         ); then
              # Ignore error if bitcoind wallet already exists
              if [[ $output != *"already exists"* ]]; then
                echo "$output"
                exit 1
              fi
            fi
          ''}

          # Restore wallet from seed if available
          seed=()
          if [[ -e jm-wallet-seed ]]; then
            seed=(--recovery-seed-file jm-wallet-seed)
          fi
          cd "${cfg.dataDir}"

          # Strip trailing newline from password file
          if ! tr -d '\n' < '${secretsDir}/jm-wallet-password' \
               | ${nbPkgs.joinmarket}/bin/jm-genwallet \
                   --datadir="${cfg.dataDir}" --wallet-password-stdin "''${seed[@]}" "$walletname" \
               | (if ((! ''${#seed[@]})); then
                    umask u=r,go=
                    grep -ohP '(?<=recovery_seed:).*' > jm-wallet-seed
                  else
                    cat > /dev/null
                  fi); then
            echo "wallet creation failed"
            rm -f "$wallet" jm-wallet-seed
            exit 1
          fi
        fi
      '';
      serviceConfig = nbLib.defaultHardening // {
        ExecStart = "${nbPkgs.joinmarket}/bin/joinmarketd";
        WorkingDirectory = cfg.dataDir; # The service creates 'commitmentlist' in the working dir
        User = cfg.user;
        Restart = "on-failure";
        RestartSec = "10s";
        ReadWritePaths = [ cfg.dataDir ];
      } // nbLib.allowedIPAddresses cfg.tor.enforce;
    };

    users.users.${cfg.user} = {
      isSystemUser = true;
      group = cfg.group;
      home = cfg.dataDir;
      # Allow access to the tor control socket, needed for payjoin onion service creation
      extraGroups = [ "tor" "bitcoin" ];
    };
    users.groups.${cfg.group} = {};
    nix-bitcoin.operator = {
      groups = [ cfg.group ];
      allowRunAsUsers = [ cfg.user ];
    };

    nix-bitcoin.secrets.jm-wallet-password.user = cfg.user;
    nix-bitcoin.generateSecretsCmds.joinmarket = ''
      makePasswordSecret jm-wallet-password
    '';
  }

  (mkIf cfg.yieldgenerator.enable {
    systemd.services.joinmarket-yieldgenerator = {
      wantedBy = [ "joinmarket.service" ];
      requires = [ "joinmarket.service" ];
      after = [ "joinmarket.service" "nix-bitcoin-secrets.target" ];
      script = ''
        tr -d "\n" <"${secretsDir}/jm-wallet-password" \
        | ${nbPkgs.joinmarket}/bin/jm-yg-privacyenhanced --datadir='${cfg.dataDir}' \
          --wallet-password-stdin wallet.jmdat
      '';
      serviceConfig = nbLib.defaultHardening // rec {
        WorkingDirectory = cfg.dataDir; # The service creates dir 'logs' in the working dir
        # Show "joinmarket-yieldgenerator" instead of "bash" in the journal.
        # The start script has to run alongside the main process
        # because it provides the wallet password via stdin to the main process
        SyslogIdentifier = "joinmarket-yieldgenerator";
        User = cfg.user;
        ReadWritePaths = [ cfg.dataDir ];
      } // nbLib.allowTor;
    };
  })
  ]);
}