#!/bin/bash

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
NAT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
ROOT_DIR="$(cd "$NAT_DIR/../.." && pwd)"
DERIVE_KEYS="$ROOT_DIR/testing/lib/derive_keys.py"
# Per-run, for the same reason static's and firewall's generators are: this
# directory is bind-mounted by compose and read back by the suite scripts
# AFTER the containers are up, so a shared path lets a second run's generator
# overwrite the npubs a first run is about to ping. Empty suffix renders
# today's plain path, so a bare invocation is unchanged.
OUTPUT_DIR="$NAT_DIR/generated-configs${FIPS_CI_NAME_SUFFIX:-}"
SCENARIO="${1:?usage: generate-configs.sh <cone|symmetric|lan> [mesh-name]}"
MESH_NAME="${2:-nat-lab-$(date +%s)-$$}"

case "$SCENARIO" in
    cone|symmetric|lan|nostr-publish-consume|stun-faults) ;;
    *)
        echo "Unknown scenario: $SCENARIO" >&2
        exit 1
        ;;
esac

mkdir -p "$OUTPUT_DIR/$SCENARIO"

keys_a="$(python3 "$DERIVE_KEYS" "$MESH_NAME" "a")"
keys_b="$(python3 "$DERIVE_KEYS" "$MESH_NAME" "b")"

nsec_a="$(echo "$keys_a" | awk -F= '/^nsec=/{print $2}')"
npub_a="$(echo "$keys_a" | awk -F= '/^npub=/{print $2}')"
nsec_b="$(echo "$keys_b" | awk -F= '/^nsec=/{print $2}')"
npub_b="$(echo "$keys_b" | awk -F= '/^npub=/{print $2}')"

# The two lab bridges. ci-local.sh claims a free /24 for each per run and
# exports these; unset renders the addresses the lab has always used, so a
# bare invocation and the GitHub matrix are unaffected.
wan="${NAT_WAN_PREFIX:-172.31.254}"
lan="${NAT_LAN_PREFIX:-172.31.10}"

relay_addr="ws://${wan}.30:7777"
stun_addr="stun:${wan}.40:3478"
if [ "$SCENARIO" = "lan" ] || [ "$SCENARIO" = "nostr-publish-consume" ] \
        || [ "$SCENARIO" = "stun-faults" ]; then
    relay_addr="ws://${lan}.30:7777"
    stun_addr="stun:${lan}.40:3478"
fi

peer_block_a=$(cat <<EOF
  - npub: "$npub_b"
    alias: "node-b"
    addresses:
      - transport: udp
        addr: "nat"
        priority: 1
EOF
)

peer_block_b=$(cat <<EOF
  - npub: "$npub_a"
    alias: "node-a"
    addresses:
      - transport: udp
        addr: "nat"
        priority: 1
EOF
)

if [ "$SCENARIO" = "symmetric" ]; then
    peer_block_a="$peer_block_a"$'\n'"      - transport: tcp
        addr: \"${wan}.11:8443\"
        priority: 20"
    peer_block_b="$peer_block_b"$'\n'"      - transport: tcp
        addr: \"${wan}.10:8443\"
        priority: 20"
fi

write_config() {
    local output_file="$1"
    local nsec="$2"
    local peer_block="$3"

    cat > "$output_file" <<EOF
node:
  identity:
    nsec: "$nsec"
  retry:
    max_retries: 3
    base_interval_secs: 2
    max_backoff_secs: 8
  discovery:
    nostr:
      enabled: true
      advertise: true
      app: "fips.nat.lab.v1"
      advert_relays:
        - "$relay_addr"
      dm_relays:
        - "$relay_addr"
      stun_servers:
        - "$stun_addr"
      signal_ttl_secs: 30
      attempt_timeout_secs: 6
      replay_window_secs: 60
      punch_start_delay_ms: 500
      punch_interval_ms: 100
      punch_duration_ms: 2500
      advert_ttl_secs: 60
      advert_refresh_secs: 20

tun:
  enabled: true
  name: fips0
  mtu: 1280

dns:
  enabled: true
  port: 5354

transports:
  udp:
    bind_addr: "0.0.0.0:2121"
    mtu: 1472
    advertise_on_nostr: true
    public: false
  tcp:
    bind_addr: "0.0.0.0:8443"

peers:
$peer_block
    connect_policy: auto_connect
    auto_reconnect: true
EOF
}

write_config "$OUTPUT_DIR/$SCENARIO/node-a.yaml" "$nsec_a" "$peer_block_a"
write_config "$OUTPUT_DIR/$SCENARIO/node-b.yaml" "$nsec_b" "$peer_block_b"

# stun-faults runs two real FIPS daemons:
#   stun-fault-node (key "a") — target of tc/iptables faults via the shim
#   stun-fault-peer (key "b") — fault-free peer that publishes a valid
#                               overlay advert so the fault-node's
#                               traversal actually invokes the STUN client
# Mutual peering ensures both sides advertise; without a real advert the
# fault-node would abort at "no overlay advert" and never generate STUN
# egress. The shim's netem/iptables rules can then meaningfully drop
# the STUN UDP traffic during Phase 1.
if [ "$SCENARIO" = "stun-faults" ]; then
    write_config "$OUTPUT_DIR/$SCENARIO/stun-fault-node.yaml" \
        "$nsec_a" "$peer_block_a"
    write_config "$OUTPUT_DIR/$SCENARIO/stun-fault-peer.yaml" \
        "$nsec_b" "$peer_block_b"
fi

cat > "$OUTPUT_DIR/$SCENARIO/npubs.env" <<EOF
NPUB_A=$npub_a
NPUB_B=$npub_b
MESH_NAME=$MESH_NAME
SCENARIO=$SCENARIO
EOF

echo "Generated NAT lab configs for scenario=$SCENARIO mesh=$MESH_NAME"
echo "NPUB_A=$npub_a"
echo "NPUB_B=$npub_b"