#!/usr/bin/env bash
# Installs the Astro CLI.
#
#   curl -sSL install.astronomer.io | bash -s -- [tag]        # into ~/.local/bin
#   curl -sSL install.astronomer.io | sudo bash -s -- [tag]   # into /usr/local/bin
#
# Without root it installs into $XDG_BIN_HOME, or ~/.local/bin when that is unset.
# ASTRO_INSTALL_DIR overrides the directory either way. sudo drops your
# environment, so set it on the sudo side of the pipe:
#
#   curl -sSL install.astronomer.io | sudo ASTRO_INSTALL_DIR=/opt/bin bash -s
#
# Everything runs from main, called on the last line, so a download cut short
# runs nothing.

set -euo pipefail

DOWNLOADER="https://raw.githubusercontent.com/astronomer/astro-cli/main/godownloader.sh"

fail() {
    echo "Error: $*" >&2
    exit 1
}

# Prints $1 as an absolute path with symlinks resolved, or nothing if it is not
# a directory.
physical() {
    if [[ -n "$1" && -d "$1" ]]; then
        (CDPATH="" cd -P -- "$1" 2>/dev/null && pwd) || true
    fi
}

# Succeeds when directory $1 is on PATH, however PATH spells it.
on_path() {
    local want entry entries found=1
    want=$(physical "$1")
    # read splits on the colons without the glob expansion an unquoted $PATH
    # would get, so an entry with a * in it stays one entry.
    IFS=: read -r -a entries <<<"$PATH"
    for entry in ${entries[@]+"${entries[@]}"}; do
        if [[ -n "$entry" && "$(physical "$entry")" == "$want" ]]; then
            found=0
            break
        fi
    done
    return "$found"
}

# Prints how to put $1 on PATH for the user's shell. It never edits a profile.
path_hint() {
    echo
    echo "$1 is not on your PATH."
    case "$(basename "${SHELL:-}")" in
        zsh) echo "Add this line to ~/.zshrc, then open a new terminal:" ;;
        bash) echo "Add this line to ~/.bashrc (~/.bash_profile on macOS), then open a new terminal:" ;;
        fish)
            echo "Run this once in fish:"
            echo "  fish_add_path \"$1\""
            return
            ;;
        *) echo "Add this line to your shell's profile (e.g. ~/.profile), then open a new terminal:" ;;
    esac
    echo "  export PATH=\"$1:\$PATH\""
}

main() {
    TAG=${1:-}
    local args=${TAG:+ -- $TAG}

    local dir=${ASTRO_INSTALL_DIR:-}
    if [[ -z "$dir" ]]; then
        if (( EUID == 0 )); then
            dir=/usr/local/bin
        elif [[ -n "${XDG_BIN_HOME:-}" ]]; then
            dir=$XDG_BIN_HOME
        elif [[ -n "${HOME:-}" ]]; then
            dir=$HOME/.local/bin
        else
            fail "HOME is not set, so there is no ~/.local/bin to install into.
Set ASTRO_INSTALL_DIR:  curl -sSL install.astronomer.io | ASTRO_INSTALL_DIR=/path/to/bin bash -s$args"
        fi
    fi

    # The directory, or the nearest ancestor that exists, must be writable.
    # A dangling symlink on the way would make mkdir fail after the download.
    local existing=$dir
    while [[ ! -e "$existing" ]]; do
        if [[ -L "$existing" ]]; then
            fail "$existing is a symlink to $(readlink "$existing"), which doesn't exist.
Create the target, or set ASTRO_INSTALL_DIR:  curl -sSL install.astronomer.io | ASTRO_INSTALL_DIR=/path/to/bin bash -s$args"
        fi
        existing=$(dirname "$existing")
    done
    if [[ ! -d "$existing" || ! -w "$existing" ]]; then
        if (( EUID == 0 )); then
            fail "cannot write to $dir. Set ASTRO_INSTALL_DIR to a directory that can be written to."
        fi
        fail "cannot write to $dir.
Re-run with sudo to install system-wide:  curl -sSL install.astronomer.io | sudo bash -s$args
or set ASTRO_INSTALL_DIR to a directory you can write to."
    fi

    local downloader
    downloader=$(curl -fsSL "$DOWNLOADER") || fail "could not download $DOWNLOADER"

    mkdir -p "$dir"
    if ! bash -s -- -b "$dir" "$TAG" <<<"$downloader"; then
        # Take back the empty directories this script created, and nothing else.
        local d=$dir
        while [[ "$d" != "$existing" ]] && rmdir "$d" 2>/dev/null; do d=$(dirname "$d"); done
        exit 1
    fi
    # Root's PATH, and sudo's above all, is not the one the user types astro
    # into, so the PATH hint and the shadow check are for non-root installs.
    (( EUID != 0 )) || return 0
    dir=$(CDPATH="" cd -- "$dir" && pwd)

    # godownloader installs astro.exe on Windows (Git Bash, MSYS, Cygwin).
    local bin="$dir/astro" found
    [[ ! -e "$bin" && -e "$bin.exe" ]] && bin="$bin.exe"
    found=$(command -v astro || true)
    if on_path "$dir"; then
        if [[ -n "$found" && ! "$found" -ef "$bin" ]]; then
            {
                echo
                echo "Warning: another astro comes first on your PATH and shadows the one just installed:"
                echo "  runs:      $found"
                echo "  installed: $bin"
                echo "Remove $found, or put $dir ahead of it in PATH."
            } >&2
        fi
    else
        path_hint "$dir"
        if [[ -n "$found" ]]; then
            echo
            echo "Until then, astro runs $found. Put $dir ahead of it to use the one just installed."
        fi
    fi
}

main "$@"