#!/usr/bin/env bash
set -e

# Add hash files for packages with custom versions for
# BR2_DOWNLOAD_FORCE_CHECK_HASHES=y
#
# Run in a configured Buildroot directory, E.G.
# make foo_defconfig; ./utils/add-custom-hashes

# print BR-style message
# message <info message>
message() {
    tput smso 2>/dev/null
    echo "$*"
    tput rmso 2>/dev/null
}

# print error message and exit
# die <error message>
die() {
    echo "Error: $*" >&2
    exit 1
}

# get package(s) for download file, if any
# get_pkgs <json> <file>
get_pkgs() {
    jq --arg file "$2" -r \
       'to_entries[] | select(.value.downloads[0].source == $file) | .key | strings' "$1"
}

# get download dir for package
# get_pkg_dl_dir <json> <package>
get_pkg_dl_dir() {
    jq --arg pkg "$2" -r '.[$pkg].dl_dir | strings' "$1"
}

# generate hash file for download file
# gen_hash <dir> <file>
gen_hash() {
    (
        cd "$1" && printf '# Locally calculated\nsha256  ' && sha256sum "$2"
    )
}

command -v jq >/dev/null || die 'Script needs jq'

[ -e .config ] || \
  die "No .config found, please run this in a configured Buildroot (O=) directory"

message Collecting data

eval "$(make -s VARS='TOPDIR DL_DIR BR_NO_CHECK_HASH_FOR BR2_GLOBAL_PATCH_DIR' QUOTED_VARS=YES printvars)"
# global patch dir may already have quotes
BR2_GLOBAL_PATCH_DIR=$(echo "$BR2_GLOBAL_PATCH_DIR" | tr -d '"')

[ -n "$BR2_GLOBAL_PATCH_DIR" ] || die "No BR2_GLOBAL_PATCH_DIR defined, nothing to do"
[ -n "$BR_NO_CHECK_HASH_FOR" ] || die "No packages without hashes found, nothing to do"

[ -d "$TOPDIR" ] || die "TOPDIR ($TOPDIR) does not look correct"
[ -d "$DL_DIR" ] || die "DL_DIR ($DL_DIR) does not look correct"

# patch dir may contain multiple dirs, use the last one
# shellcheck disable=SC2086 # we need the word splitting
set -- $BR2_GLOBAL_PATCH_DIR
if [ $# -gt 1 ]; then
    BR2_GLOBAL_PATCH_DIR="${!#}";
    message BR2_GLOBAL_PATCH_DIR contains multiple directories, using "$BR2_GLOBAL_PATCH_DIR"
fi

# patch dir may be relative to TOPDIR
case "$BR2_GLOBAL_PATCH_DIR" in
    /*) ;;
    *) BR2_GLOBAL_PATCH_DIR="$TOPDIR/$BR2_GLOBAL_PATCH_DIR"
       ;;
esac

[ -d "$BR2_GLOBAL_PATCH_DIR" ] \
  || die "BR2_GLOBAL_PATCH_DIR ($BR2_GLOBAL_PATCH_DIR) does not look correct"

trap 'rm -f "$JSON"' EXIT
JSON=$(mktemp)
make show-info > "$JSON"

# ensure files have been downloaded, but without checking
make BR2_DOWNLOAD_FORCE_CHECK_HASHES= source

message Updating hashes

for file in $BR_NO_CHECK_HASH_FOR; do
    for pkg in $(get_pkgs "$JSON" "$file"); do
        HASHFILE="$BR2_GLOBAL_PATCH_DIR/$pkg/$pkg.hash"
        PKG_DL_DIR=$(get_pkg_dl_dir "$JSON" "$pkg")
        message "Adding hash for $file to $HASHFILE"
        mkdir -p "${HASHFILE%/*}"
        gen_hash "$DL_DIR/$PKG_DL_DIR" "$file" > "$HASHFILE"
    done
done

# Symlink linux-headers to linux if identical
linux_hash="$BR2_GLOBAL_PATCH_DIR/linux/linux.hash"
linux_headers_hash="$BR2_GLOBAL_PATCH_DIR/linux-headers/linux-headers.hash"
if [ -e "$linux_hash" ] && [ -e "$linux_headers_hash" ] \
    && cmp -s "$linux_hash" "$linux_headers_hash"; then
    ln -sf ../linux/linux.hash "$linux_headers_hash"
fi

message Verifying hashes

make clean
make BR2_DOWNLOAD_FORCE_CHECK_HASHES=y source