#!/bin/sh

set -eu

DEFAULT_RELEASE_URL="https://cheesedanish.nickmeslovich.com"
if [ -f "$0" ]; then
    SOURCE_DIR=$(cd "$(dirname "$0")" 2>/dev/null && pwd)
    if [ -s "$SOURCE_DIR/lib/release-url" ]; then
        IFS= read -r DEFAULT_RELEASE_URL < "$SOURCE_DIR/lib/release-url"
    fi
fi

RELEASE_URL=${CHEESEDANISH_RELEASE_URL:-$DEFAULT_RELEASE_URL}
RELEASE_URL=${RELEASE_URL%/}
CURL_BIN=${CHEESEDANISH_CURL:-curl}
if [ -z "${PREFIX:-}" ]; then
    PREFIX=${HOME:?HOME is not set}/.local
fi
BIN_DIR="$PREFIX/bin"
LIB_DIR="$PREFIX/lib/cheesedanish"
TEMP_BASE=${TMPDIR:-/tmp}
TEMP_DIR=$(mktemp -d "$TEMP_BASE/cheesedanish-install.XXXXXX") || exit 1

cleanup() {
    rm -rf "$TEMP_DIR"
}
trap cleanup EXIT
trap 'exit 129' HUP
trap 'exit 130' INT
trap 'exit 143' TERM

case "$RELEASE_URL" in
    http://*|https://*) ;;
    *) printf 'cheesedanish installer: release URL must start with http:// or https://\n' >&2; exit 1 ;;
esac

command -v "$CURL_BIN" >/dev/null 2>&1 || {
    printf 'cheesedanish installer: curl is required\n' >&2
    exit 1
}
if command -v sha256sum >/dev/null 2>&1; then
    SHA256_TOOL=sha256sum
elif command -v shasum >/dev/null 2>&1; then
    SHA256_TOOL=shasum
elif command -v sha256 >/dev/null 2>&1; then
    SHA256_TOOL=sha256
else
    printf 'cheesedanish installer: sha256sum, shasum, or sha256 is required\n' >&2
    exit 1
fi

verify_checksums() {
    case "$SHA256_TOOL" in
        sha256sum) sha256sum -c SHA256SUMS ;;
        shasum) shasum -a 256 -c SHA256SUMS ;;
        sha256)
            failed=0
            while IFS= read -r line || [ -n "$line" ]; do
                case "$line" in
                    ''|'#'*) continue ;;
                esac
                hash=${line%% *}
                file=${line#"$hash"}
                while [ "$file" != "${file# }" ]; do
                    file=${file# }
                done
                case "$file" in
                    \*) file=${file#?} ;;
                esac
                actual=$(sha256 -q "$file")
                if [ "$actual" = "$hash" ]; then
                    printf '%s: OK\n' "$file"
                else
                    printf '%s: FAILED\n' "$file" >&2
                    failed=1
                fi
            done < SHA256SUMS
            [ "$failed" -eq 0 ]
            ;;
    esac
}

download() {
    destination=$1
    path=$2
    "$CURL_BIN" --fail --silent --show-error --location \
        --connect-timeout 30 --max-time 300 \
        --output "$destination" "$RELEASE_URL/$path"
}

mkdir -p "$TEMP_DIR/lib"
download "$TEMP_DIR/SHA256SUMS" latest/SHA256SUMS
download "$TEMP_DIR/cheesedanish" latest/cheesedanish
download "$TEMP_DIR/lib/json.awk" latest/lib/json.awk
download "$TEMP_DIR/lib/quote-bytes.awk" latest/lib/quote-bytes.awk
download "$TEMP_DIR/lib/replace.awk" latest/lib/replace.awk
download "$TEMP_DIR/lib/sse.awk" latest/lib/sse.awk
download "$TEMP_DIR/release-url" latest/release-url

(
    cd "$TEMP_DIR"
    verify_checksums
) || {
    printf 'cheesedanish installer: release checksum verification failed\n' >&2
    exit 1
}

mkdir -p "$BIN_DIR" "$LIB_DIR"
cp "$TEMP_DIR/cheesedanish" "$BIN_DIR/cheesedanish"
cp "$TEMP_DIR/lib/json.awk" "$LIB_DIR/json.awk"
cp "$TEMP_DIR/lib/quote-bytes.awk" "$LIB_DIR/quote-bytes.awk"
cp "$TEMP_DIR/lib/replace.awk" "$LIB_DIR/replace.awk"
cp "$TEMP_DIR/lib/sse.awk" "$LIB_DIR/sse.awk"
cp "$TEMP_DIR/release-url" "$LIB_DIR/release-url"
chmod 755 "$BIN_DIR/cheesedanish"
chmod 644 "$LIB_DIR/json.awk" "$LIB_DIR/quote-bytes.awk" "$LIB_DIR/replace.awk" "$LIB_DIR/sse.awk" "$LIB_DIR/release-url"

version=$(sed -n 's/^CHEESEDANISH_VERSION="\([^"]*\)"/\1/p' "$TEMP_DIR/cheesedanish")
printf 'Installed cheesedanish %s in %s\n' "${version:-unknown}" "$BIN_DIR"
case ":${PATH:-}:" in
    *":$BIN_DIR:"*) ;;
    *) printf 'Add %s to PATH. For example:\n  export PATH="%s:$PATH"\n' "$BIN_DIR" "$BIN_DIR" ;;
esac