#!/bin/sh

# shellcheck disable=SC3043         # local is not POSIX, but every shell has it
# shellcheck disable=SC3013,SC3045  # ditto for test {-nt,-t}

GITHUB_REPO='node-cache'
SUBDIR='node_modules'

V="${V-0}" # default to friendly messages

set -eu
cd "${0%/*}/.."
# shellcheck source-path=SCRIPTDIR/..
. test/common/git-utils.sh

cmd_remove() {
    # if we did this for ourselves the rm is enough, but it might be the case
    # that someone actually used git-submodule to fetch this, so clean up after
    # that as well.  NB: deinit nicely recreates the empty directory for us.
    message REMOVE node_modules
    rm -rf node_modules
    git submodule deinit node_modules
    rm -rf -- "$(git rev-parse --absolute-git-dir)/modules/node_modules"
}

cmd_checkout() {
    # we default to check out the node_modules corresponding to the gitlink in the index
    local force=""
    if [ "${1-}" = "--force" ]; then
        force="1"
        shift
    fi

    local sha="${1-$(get_index_gitlink node_modules)}"

    # fetch by sha to prevent us from downloading something we don't want
    fetch_sha_to_cache "${sha}"

    # verify that our package.json is equal to the one the cached node_modules
    # was created with, unless --force is given
    if [ -z "$force" ]; then
        if ! cmp_from_cache "${sha}" '.package.json' 'package.json'; then
            cat >&2 <<EOF

*** node_modules ${sha} doesn't match our package.json
*** refusing to automatically check out node_modules

Options:

    - tools/node-modules checkout --force     # disable this check

    - tools/node-modules install              # npm install with our package.json

$0: *** aborting

EOF
            exit 1
        fi
    fi

    # we're actually going to do this; let's remove the old one
    cmd_remove

    # and check out the new one
    # we need to use the tag name here, unfortunately
    clone_from_cache "${sha}"
}

cmd_install() {
    test -e bots || test/common/make-bots

    # We first read the result directly into the cache, then we unpack it.
    tree="$(bots/npm download < package.json | tar_to_cache)"
    commit="$(sha256sum package.json | git_cache commit-tree "${tree}")"
    git_cache tag "sha-${commit}" "${commit}"
    cmd_checkout "${commit}"

    cat <<EOF
Next steps:

  - git add node_modules && git commit
  - tools/node-modules push

EOF
}

cmd_push() {
    # push via the cache: the shared history with the remote helps to thin out the pack we send
    tag="sha-$(git -C node_modules rev-parse HEAD)"
    message PUSH "${GITHUB_REPO} ${tag}"
    git_cache push "${SSH_REMOTE}" "${tag}"
}

cmd_verify() {
    test -e bots || test/common/make-bots

    # Verifies that the package.json and node_modules of the given commit match.
    commit="$(git rev-parse "$1:node_modules")"
    fetch_sha_to_cache "${commit}"

    committed_tree="$(git_cache rev-parse "${commit}^{tree}")"
    expected_tree="$(git cat-file blob "$1:package.json" | bots/npm download | tar_to_cache)"

    if [ "${committed_tree}" != "${expected_tree}" ]; then
        exec >&2
        printf "\nCommit %s package.json and node_modules aren't in sync!\n\n" "$1"
        git --no-pager show --stat "$1"

        printf "\nThe above commit refers to the following node_modules commit:\n\n"
        git_cache --no-pager show --no-patch "${commit}"

        printf "\nOur attempt to recreate that commit differs as follows:\n\n"
        git_cache --no-pager diff --stat "${commit}" "${expected_tree}" --
        git_cache --no-pager diff "${commit}" "${expected_tree}" -- .package-lock.json
        exit 1
    fi
}

# called from Makefile.am
cmd_make_package_lock_json() {
    # Run from make to ensure package-lock.json is up to date

    # package-lock.json is used as the stamp file for all things that use
    # node_modules, so this is the main bit of glue that drives the entire process

    # We try our best not to touch package-lock.json unless it actually changes

    # This isn't going to work for a tarball, but as long as
    # package-lock.json is already there, and newer than package.json,
    # we're OK
    if [ ! -e .git ]; then
        if [ package-lock.json -nt package.json ]; then
            exit 0
        fi

        echo "*** Can't update node modules unless running from git" >&2
        exit 1
    fi

    # Otherwise, our main goal is to ensure that the node_modules from
    # the index is the one that we actually have.
    local sha
    sha="$(get_index_gitlink node_modules)"
    if [ ! -e node_modules/.git ]; then
        # nothing there yet...
        cmd_checkout
    elif [ "$(git -C node_modules rev-parse HEAD)" != "${sha}" ]; then
        # wrong thing there...
        cmd_checkout
    fi

    # This check is more about catching local changes to package.json than
    # about validating something we just checked out:
    if ! cmp -s node_modules/.package.json package.json; then
        cat 2>&1 <<EOF
*** package.json is out of sync with node_modules
*** If you modified package.json, please run:
***
***    tools/node-modules install
***
*** and add the result to the index.
EOF
        exit 1
    fi

    # Only copy the package-lock.json if it differs from the one we have
    if ! cmp -s node_modules/.package-lock.json package-lock.json; then
        message COPY package-lock.json
        cp node_modules/.package-lock.json package-lock.json
    fi

    # We're now in a situation where:
    #  - the checked out node_modules is equal to the gitlink in the index
    #  - the package.json in the tree is equal to the one in node_modules
    #  - ditto package-lock.json
    exit 0
}

main() {
    if [ $# = 0 ]; then
        # don't list the "private" ones
        echo 'This command requires a subcommand: remove checkout install push verify'
        exit 1
    fi

    local fname
    fname="$(printf 'cmd_%s' "$1" | tr '-' '_')"
    if ! type -t "${fname}" | grep -q function; then
        echo "Unknown subcommand '$1'"
        exit 1
    fi

    shift
    [ -n "${quiet}" ] || set -x
    "${fname}" "$@"
}

main "$@"
