#!/usr/bin/env bash

# Modules integration test runner.
# The tests (defined in ./tests.nix) use the NixOS testing framework and are executed in a VM.
#
# Usage:
#   Run all tests
#   ./run-tests.sh
#
#   Test specific scenario
#   ./run-tests.sh --scenario|-s <scenario>
#
#   - When <scenario> contains a space, <scenario> is treated as nix code defining
#     a scenario. It is evaluated in the same context as other scenarios in ./tests.nix
#
#     Example:
#     ./run-tests.sh -s "{ nix-bitcoin.nodeinfo.enable = true; }" container --run c nodeinfo
#
#   - When <scenario> does not name a scenario, the test is run with an adhoc scenario
#     where services.<scenario> is enabled.
#
#     Example:
#     ./run-tests.sh -s electrs
#
#   Run test(s) and link results to avoid garbage collection
#   ./run-tests.sh [--scenario <scenario>] --out-link-prefix /tmp/nix-bitcoin-test
#
#   Pass extra args to nix-build
#   ./run-tests.sh build --builders 'ssh://mybuildhost - - 15'
#
#   Run interactive test debugging
#   ./run-tests.sh [--scenario <scenario>] debug
#
#     This starts the testing VM and drops you into a Python REPL where you can
#     manually execute the tests from ./tests.py
#
#   Run a test scenario in a container
#   sudo ./run-tests.sh [--scenario <scenario>] container
#
#     This is useful for quick experiments; containers start much faster than VMs.
#     Running the Python test suite in containers is not yet supported.
#     For now, creating NixOS containers requires root permissions.
#     See ./lib/make-container.sh for a complete documentation.
#
#   Run a test scenario in a regular NixOS VM.
#   No tests are executed, the machine's serial console is attached to your terminal.
#   ./run-tests.sh [--scenario <scenario>] vm
#
#     This is useful for directly exploring a test configuration without the
#     intermediate Python REPL layer.
#     Run command 'q' inside the machine for instant poweroff.
#
#   Run tests from a snapshot copy of the source files
#   ./run-tests.sh --copy-src|-c ...
#
#     This allows you to continue editing the nix-bitcoin sources while tests are running
#     and reading source files.
#     Files are copied to /tmp, a caching scheme helps minimizing copies.
#
#   To add custom scenarios, set the environment variable `scenarioOverridesFile`.

set -eo pipefail

scriptDir=$(cd "${BASH_SOURCE[0]%/*}" && pwd)

args=("$@")
scenario=
outLinkPrefix=
ciBuild=
while :; do
    case $1 in
        --scenario|-s)
            if [[ $2 ]]; then
                scenario=$2
                shift
                shift
            else
                >&2 echo "Error: $1 requires an argument."
                exit 1
            fi
            ;;
        --out-link-prefix|-o)
            if [[ $2 ]]; then
                outLinkPrefix=$2
                shift
                shift
            else
                >&2 echo "Error: $1 requires an argument."
                exit 1
            fi
            ;;
        --ci)
            shift
            ciBuild=1
            ;;
        --copy-src|-c)
            shift
            if [[ ! $_nixBitcoinInCopiedSrc ]]; then
                . "$scriptDir/lib/copy-src.sh"
                exit
            fi
            ;;
        *)
            break
    esac
done

numCPUs=${numCPUs:-$(nproc)}
# Min. 800 MiB needed to avoid 'out of memory' errors
memoryMiB=${memoryMiB:-2048}

NIX_PATH=nixpkgs=$(nix eval --raw -f "$scriptDir/../pkgs/nixpkgs-pinned.nix" nixpkgs):nix-bitcoin=$(realpath "$scriptDir/..")
export NIX_PATH

runAtExit=
trap 'eval "$runAtExit"' EXIT

# Support explicit scenario definitions
if [[ $scenario = *' '* ]]; then
    scenarioOverridesFile=$(mktemp "${XDG_RUNTIME_DIR:-/tmp}/nb-scenario.XXX")
    export scenarioOverridesFile

    # shellcheck disable=SC2016
    runAtExit+='rm -f "$scenarioOverridesFile";'
    echo "{ scenarios, pkgs, lib }: with lib; { tmp = $scenario; }" > "$scenarioOverridesFile"
    scenario=tmp
fi

# Run the test. No temporary files are left on the host system.
run() {
    # TMPDIR is also used by the test driver for VM tmp files
    TMPDIR=$(mktemp -d /tmp/nix-bitcoin-test.XXX)
    export TMPDIR
    runAtExit+="rm -rf ${TMPDIR};"

    nix-build --out-link "$TMPDIR/driver" -E "((import \"$scriptDir/tests.nix\" {}).getTest \"$scenario\").vm" -A driver

    # Variable 'tests' contains the Python code that is executed by the driver on startup
    if [[ $1 == --interactive ]]; then
        echo "Running interactive testing environment"
        tests=$(
            echo 'is_interactive = True'
            echo 'exec(open(os.environ["testScript"]).read())'
            # Start VM
            echo 'if "machine" in vars(): machine.start()'
            # Start REPL.
            # Use `code.interact` for the REPL instead of the builtin test driver REPL
            # because it supports low featured terminals like Emacs' shell-mode.
            echo 'import code'
            echo 'code.interact(local=globals())'
        )
    else
        tests='exec(open(os.environ["testScript"]).read())'
    fi

    echo "VM stats: CPUs: $numCPUs, memory: $memoryMiB MiB"
    [[ $NB_TEST_ENABLE_NETWORK ]] || QEMU_NET_OPTS='restrict=on'
    cd "$TMPDIR" # The VM creates a VDE control socket in $PWD
    env -i \
        NIX_PATH="$NIX_PATH" \
        TMPDIR="$TMPDIR" \
        USE_TMPDIR=1 \
        QEMU_OPTS="-smp $numCPUs -m $memoryMiB -nographic $QEMU_OPTS"  \
        QEMU_NET_OPTS="$QEMU_NET_OPTS" \
        "$TMPDIR/driver/bin/nixos-test-driver" <(echo "$tests")
}

debug() {
    run --interactive
}

evalTest() {
    nix-instantiate --eval -E "($(vmTestNixExpr)).outPath"
}

instantiate() {
    nix-instantiate -E "$(vmTestNixExpr)" "$@"
}

container() {
    export scriptDir scenario
    "$scriptDir/lib/make-container.sh" "$@"
}

# Run a regular NixOS VM
vm() {
    TMPDIR=$(mktemp -d /tmp/nix-bitcoin-vm.XXX)
    export TMPDIR
    runAtExit+="rm -rf $TMPDIR;"

    nix-build --out-link "$TMPDIR/vm" -E "((import \"$scriptDir/tests.nix\" {}).getTest \"$scenario\").vmWithoutTests"

    echo "VM stats: CPUs: $numCPUs, memory: $memoryMiB MiB"
    [[ $NB_TEST_ENABLE_NETWORK ]] || export QEMU_NET_OPTS="restrict=on,$QEMU_NET_OPTS"

    # shellcheck disable=SC2211
    USE_TMPDIR=1 \
    NIX_DISK_IMAGE=$TMPDIR/img.qcow2 \
    QEMU_OPTS="-smp $numCPUs -m $memoryMiB -nographic $QEMU_OPTS"  \
      "$TMPDIR"/vm/bin/run-*-vm
}

doBuild() {
    name=$1
    shift
    if [[ $ciBuild ]]; then
        "$scriptDir/ci/build-to-cachix.sh" "$@"
    else
        if [[ $outLinkPrefix ]]; then
            outLink="--out-link $outLinkPrefix-$name"
        else
            outLink=--no-out-link
        fi
        nix-build $outLink "$@"
    fi
}

# Run the test by building the test derivation
buildTest() {
    vmTestNixExpr | doBuild $scenario "$@" -
}

vmTestNixExpr() {
    extraQEMUOpts=

    if [[ $ciBuild ]]; then
        # On continuous integration nodes there are few other processes running alongside the
        # test, so use more memory here for maximum performance.
        memoryMiB=4096
        memTotalKiB=$(awk '/MemTotal/ { print $2 }' /proc/meminfo)
        memAvailableKiB=$(awk '/MemAvailable/ { print $2 }' /proc/meminfo)
        # Round down to nearest multiple of 50 MiB for improved test build caching
        # shellcheck disable=SC2017
        ((memAvailableMiB = memAvailableKiB / (1024 * 50) * 50))
        ((memAvailableMiB < memoryMiB)) && memoryMiB=$memAvailableMiB
        >&2 echo "VM stats: CPUs: $numCPUs, memory: $memoryMiB MiB"
        >&2 echo "Host memory total: $((memTotalKiB / 1024)) MiB, available: $memAvailableMiB MiB"

        # VMX is usually not available on CI nodes due to recursive virtualisation.
        # Explicitly disable VMX, otherwise QEMU 4.20 fails with message
        # "error: failed to set MSR 0x48b to 0x159ff00000000"
        extraQEMUOpts="-cpu host,-vmx"
    fi

    cat <<EOF
    ((import "$scriptDir/tests.nix" {}).getTest "$scenario").vm.overrideAttrs (old: rec {
      buildCommand = ''
        export QEMU_OPTS="-smp $numCPUs -m $memoryMiB $extraQEMUOpts"
        echo "VM stats: CPUs: $numCPUs, memory: $memoryMiB MiB"
      '' + old.buildCommand;
    })
EOF
}

checkFlakeSupport() {
    testName=$1
    if [[ ! -v hasFlakes ]]; then
        if [[ $(nix flake 2>&1) == *"requires a sub-command"* ]]; then
            hasFlakes=1
        else
            hasFlakes=
        fi
    fi
    if [[ ! $hasFlakes ]]; then
        echo "Skipping test '$testName'. Nix flake support is not enabled."
        return 1
    fi
}

flake() {
    if ! checkFlakeSupport "flake"; then return; fi

    nix flake check "$scriptDir/.."
}

# Test generating module documentation for search.nixos.org
nixosSearch() {
    if ! checkFlakeSupport "nixosSearch"; then return; fi

    if [[ $_nixBitcoinInCopiedSrc ]]; then
      # flake-info requires that its target flake is under version control
      . "$scriptDir/lib/create-git-repo.sh"
    fi

    if [[ $outLinkPrefix ]]; then
        # Add gcroots for flake-info
        nix build "$scriptDir/nixos-search#flake-info" -o "$outLinkPrefix-flake-info"
    fi
    echo "Running flake-info (nixos-search)"
    nix run "$scriptDir/nixos-search#flake-info" -- flake "$scriptDir/.."
}

# A basic subset of tests to keep the total runtime within
# manageable bounds (<4 min on desktop systems).
# These are also run on the CI server.
basic() {
    scenario=default buildTest "$@"
    scenario=netns buildTest "$@"
    scenario=netnsRegtest buildTest "$@"
}

# All tests that only consist of building a nix derivation.
# Their output is cached in /nix/store.
buildable() {
    basic "$@"
    scenario=full buildTest "$@"
    scenario=regtest buildTest "$@"
    scenario=hardened buildTest "$@"
    scenario=clightningReplication buildTest "$@"
}

examples() {
    script="
      set -e
      ./deploy-container.sh
      ./deploy-container-minimal.sh
      ./deploy-qemu-vm.sh
      ./deploy-krops.sh
    "
    (cd "$scriptDir/../examples" && nix-shell --run "$script")
}

shellcheck() {
    if ! checkFlakeSupport "shellcheck"; then return; fi
    "$scriptDir/shellcheck.sh"
}

all() {
    buildable "$@"
    shellcheck
    examples
    flake
    nixosSearch
}

# An alias for buildTest
build() {
    buildTest "$@"
}

if [[ $# -gt 0 && $1 != -* ]]; then
    # An explicit command was provided
    command=$1
    shift
    if [[ $command == eval ]]; then
        command=evalTest
    fi
    : ${scenario:=default}
elif [[ $scenario ]]; then
    command=buildTest
else
    command=basic
fi
$command "$@"