#!/bin/sh
# Installs the terrio command-line tool from its GitHub release, on Linux and macOS:
#
#     curl -LsSf https://terrio.opengeos.org/install.sh | sh
#
# Settings, from the environment:
#   TERRIO_VERSION        the release to install (0.4.0 or v0.4.0); the latest by default
#   TERRIO_INSTALL_DIR    where to put the binary; $XDG_BIN_HOME or ~/.local/bin by default
#   TERRIO_DOWNLOAD_URL   the directory the archives are downloaded from, for a mirror; the
#                         GitHub release by default
#
# On Windows, use install.ps1. Elsewhere: pip install terrio, or cargo install terrio-cli.

set -eu

REPO="opengeos/terrio"

say() {
    printf 'terrio-installer: %s\n' "$1"
}

err() {
    say "error: $1" >&2
    exit 1
}

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

# download URL FILE: FILE "-" writes to standard output.
download() {
    if has curl; then
        curl --proto-redir '=https' --tlsv1.2 -fsSL "$1" -o "$2"
    elif has wget; then
        wget -q "$1" -O "$2"
    else
        err "neither curl nor wget is installed"
    fi
}

# The Rust target triple of the release binary for this machine.
target() {
    os=$(uname -s)
    arch=$(uname -m)
    case "$arch" in
        x86_64 | amd64) arch=x86_64 ;;
        aarch64 | arm64) arch=aarch64 ;;
        *) err "no terrio binary for $arch; install it with pip install terrio or cargo install terrio-cli" ;;
    esac
    case "$os" in
        Linux) echo "$arch-unknown-linux-musl" ;;
        Darwin)
            # An x86_64 shell under Rosetta on Apple silicon: install the native binary.
            if [ "$arch" = x86_64 ] && [ "$(sysctl -n hw.optional.arm64 2> /dev/null || true)" = 1 ]; then
                arch=aarch64
            fi
            echo "$arch-apple-darwin"
            ;;
        MINGW* | MSYS* | CYGWIN*)
            err "on Windows, run in PowerShell: irm https://terrio.opengeos.org/install.ps1 | iex"
            ;;
        *) err "no terrio binary for $os; install it with pip install terrio or cargo install terrio-cli" ;;
    esac
}

# The tag of the latest release: from where github.com/$REPO/releases/latest redirects with curl
# (not rate-limited as the GitHub API is), from the API with wget.
latest() {
    if has curl; then
        url=$(curl --proto-redir '=https' --tlsv1.2 -fsSL -o /dev/null -w '%{url_effective}' "https://github.com/$REPO/releases/latest") || return 1
        tag="${url##*/}"
    else
        json=$(download "https://api.github.com/repos/$REPO/releases/latest" -) || return 1
        tag=$(printf '%s\n' "$json" | sed -n 's/.*"tag_name": *"\([^"]*\)".*/\1/p' | head -n 1)
    fi
    case "$tag" in
        v[0-9]*) echo "$tag" ;;
        *) return 1 ;;
    esac
}

sha256() {
    if has sha256sum; then
        sha256sum "$1" | cut -d ' ' -f 1
    elif has shasum; then
        shasum -a 256 "$1" | cut -d ' ' -f 1
    else
        err "neither sha256sum nor shasum is installed, to verify the download"
    fi
}

main() {
    target=$(target)

    version="${TERRIO_VERSION:-}"
    if [ -z "$version" ]; then
        version=$(latest) ||
            err "could not find the latest release of $REPO; set TERRIO_VERSION to the version to install"
    fi
    version="v${version#v}"

    install_dir="${TERRIO_INSTALL_DIR:-${XDG_BIN_HOME:-$HOME/.local/bin}}"
    base="${TERRIO_DOWNLOAD_URL:-https://github.com/$REPO/releases/download/$version}"
    name="terrio-cli-$version-$target"

    tmp=$(mktemp -d)
    trap 'rm -rf "$tmp"' EXIT

    say "downloading terrio $version for $target"
    # curl and wget print the cause (a 404 when the release has no binary for this target).
    download "$base/$name.tar.gz" "$tmp/$name.tar.gz" ||
        err "could not download terrio $version for $target; install it with pip install terrio or cargo install terrio-cli"
    download "$base/$name.tar.gz.sha256" "$tmp/$name.tar.gz.sha256" ||
        err "could not download the checksum of $name.tar.gz"
    expected=$(cut -d ' ' -f 1 < "$tmp/$name.tar.gz.sha256")
    [ "$(sha256 "$tmp/$name.tar.gz")" = "$expected" ] || err "checksum mismatch for $name.tar.gz"

    tar -xzf "$tmp/$name.tar.gz" -C "$tmp"
    mkdir -p "$install_dir"
    cp "$tmp/$name/terrio" "$install_dir/terrio.tmp"
    chmod 755 "$install_dir/terrio.tmp"
    mv -f "$install_dir/terrio.tmp" "$install_dir/terrio"

    "$install_dir/terrio" --version > /dev/null || err "the installed $install_dir/terrio does not run"
    say "installed $("$install_dir/terrio" --version) in $install_dir"

    case ":$PATH:" in
        *":$install_dir:"*) ;;
        *)
            say "$install_dir is not on your PATH; add it in your shell's startup file:"
            # $PATH is for the startup file to expand, not this script.
            # shellcheck disable=SC2016
            printf '\n    export PATH="%s:$PATH"\n\n' "$install_dir"
            ;;
    esac
}

main "$@"