#!/usr/bin/env bash

# Inspired on official babashka install script https://github.com/babashka/babashka/blob/master/install

set -euo pipefail

version=""
checksum=""
default_install_dir="/usr/local/bin"
install_dir="$default_install_dir"
download_dir=""

print_help() {
    echo "Installs latest (or specific) version of eca. Installation directory defaults to $default_install_dir."
    echo -e
    echo "Usage:"
    echo "install [--dir <dir>] [--download-dir <download-dir>] [--version <version> or \"nightly\"] [--checksum <checksum>]"
    echo -e
    echo "Defaults:"
    echo " * Installation directory: ${default_install_dir}"
    echo " * Download directory: temporary"
    if [[ -z "$checksum" ]]; then
        echo " * Checksum: no"
    else
        echo " * Checksum: ${checksum}"
    fi
    echo " * Version: <Latest release on github>"
    echo -e
    echo "Requires curl and unzip (plus sha256sum or shasum when using --checksum)."
    exit 1
}

# Prints an error (and an optional hint) to stderr and exits.
error() {
    >&2 echo "Error: $1"
    if [[ -n "${2:-}" ]]; then
        >&2 echo "$2"
    fi
    exit 1
}

has() {
    command -v "$1" >/dev/null 2>&1
}

file_sha256() {
    if has shasum; then
        shasum -a 256 < "$1" | cut -d' ' -f1
    else
        sha256sum < "$1" | cut -d' ' -f1
    fi
}

while [[ $# -gt 0 ]]
do
    key="$1"
    case "$key" in
        --dir)
            install_dir="$2"
            shift
            shift
            ;;
        --download-dir)
            download_dir="$2"
            shift
            shift
            ;;
        --version)
            version="$2"
            shift
            shift
            ;;
        --checksum)
            checksum="$2"
            shift
            shift
            ;;
        --static)
            # Retro compatible, always static if available for that arch.
            shift
            ;;
        *)  # unknown option
            print_help
            ;;
    esac
done

if [[ -z "$download_dir" ]]; then
    download_dir="$(mktemp -d)"
    trap 'rm -rf "$download_dir"' EXIT
fi

if [[ "$checksum" != "" ]] && [[ "$version" == "" ]]; then
    error "options --checksum and --version should be provided together!"
fi

# Check required commands upfront, otherwise `set -e` would make the script
# exit halfway through without saying why when one of them is missing.
missing=""
for cmd in curl unzip; do
    has "$cmd" || missing="$missing $cmd"
done
if [[ -n "$checksum" ]] && ! has shasum && ! has sha256sum; then
    missing="$missing sha256sum"
fi
if [[ -n "$missing" ]]; then
    error "required command(s) not found:$missing" \
          "Please install the missing command(s) using your system package manager and run this script again."
fi

case "$(uname -s)" in
    Linux*)  platform=linux;;
    Darwin*) platform=macos;;
    *)       error "unsupported OS: $(uname -s)" \
                   "Please download eca manually from https://github.com/editor-code-assistant/eca/releases";;
esac

case "$(uname -m)" in
    aarch64) arch=aarch64;;
    arm64)   arch=aarch64;;
    *)       arch=amd64;;
esac

if [[ "$version" == "" ]]; then
    version_url="https://raw.githubusercontent.com/editor-code-assistant/eca/master/resources/ECA_VERSION"
    if ! version="$(curl -fsSL "$version_url")" || [[ -z "$version" ]]; then
        error "failed to fetch the latest eca version from $version_url" \
              "Check your internet connection or pass a specific version with --version."
    fi
fi

ext="zip"

case "$platform-$arch" in
    linux-amd64)   filename="eca-native-static-$platform-$arch."$ext
                   ;;
    *)             filename="eca-native-$platform-$arch."$ext
                   ;;
esac

if [[ "$version" == "nightly" ]]; then
    download_url="https://github.com/editor-code-assistant/eca-dev-builds/releases/latest/download/$filename"
else
    download_url="https://github.com/editor-code-assistant/eca/releases/download/$version/$filename"
fi

# No subshell here on purpose: bash 3.2 (macOS default) doesn't stop on a failing
# subshell even with `set -e`, which would let the script continue after an error.
mkdir -p "$download_dir"
archive="$download_dir/$filename"
echo -e "Downloading $download_url to $download_dir"

if ! curl -fsSL -o "$archive" "$download_url"; then
    rm -f "$archive"
    error "failed to download $download_url" \
          "Check your internet connection and that eca version '$version' is available for $platform-$arch."
fi
if [[ -n "$checksum" ]]; then
    actual_checksum="$(file_sha256 "$archive")"
    expected_checksum="$(echo "$checksum" | tr '[:upper:]' '[:lower:]')"
    if [[ "$actual_checksum" != "$expected_checksum" ]]; then
        >&2 echo "Error: failed checksum on $filename"
        >&2 echo "Got: $actual_checksum"
        >&2 echo "Expected: $expected_checksum"
        exit 1
    fi
fi
unzip -qqo "$archive" -d "$download_dir"
rm -f "$archive"

if [[ "$download_dir" != "$install_dir" ]]
then
    mkdir -p "$install_dir"
    if [ -f "$install_dir/eca" ]; then
        echo "Moving $install_dir/eca to $install_dir/eca.old"
        mv -f "$install_dir/eca" "$install_dir/eca.old"
    fi
    mv -f "$download_dir/eca" "$install_dir/eca"
fi

if [[ "$version" == "nightly" ]]; then
    chmod +x "$install_dir/eca"
fi

echo "Successfully installed eca in $install_dir"