#!/usr/bin/env sh
set -eu

VERSION="0.1.2"
TARGET="aarch64-apple-darwin"
PKG="egret-${VERSION}-${TARGET}"
DEFAULT_URL="https://github.com/egret-lang/release/releases/download/pre-release/${PKG}.zip"
DEFAULT_INSTALL_DIR="${HOME}/.local/bin"

INSTALL_DIR="${EGRET_INSTALL_DIR:-$DEFAULT_INSTALL_DIR}"
DOWNLOAD_URL="${EGRET_INSTALL_URL:-$DEFAULT_URL}"
ASSUME_YES=0
INSTALL_DEPS=1
CREATE_LINKS=1

init_colors() {
    color_enabled=0
    if [ "${NO_COLOR:-}" != "" ]; then
        color_enabled=0
    elif [ "${EGRET_INSTALL_COLOR:-}" = "always" ]; then
        color_enabled=1
    elif [ -t 1 ] || [ -t 2 ]; then
        color_enabled=1
    fi

    if [ "$color_enabled" -eq 1 ]; then
        C_RESET="$(printf '\033[0m')"
        C_BOLD="$(printf '\033[1m')"
        C_DIM="$(printf '\033[2m')"
        C_RED="$(printf '\033[31m')"
        C_GREEN="$(printf '\033[32m')"
        C_YELLOW="$(printf '\033[33m')"
        C_BLUE="$(printf '\033[34m')"
        C_MAGENTA="$(printf '\033[35m')"
        C_CYAN="$(printf '\033[36m')"
        C_WHITE="$(printf '\033[37m')"
        C_BG_BLUE="$(printf '\033[44m')"
    else
        C_RESET=""
        C_BOLD=""
        C_DIM=""
        C_RED=""
        C_GREEN=""
        C_YELLOW=""
        C_BLUE=""
        C_MAGENTA=""
        C_CYAN=""
        C_WHITE=""
        C_BG_BLUE=""
    fi
}

show_logo() {
    size="$(terminal_size)"
    cols="${size% *}"
    rows="${size#* }"
    full_logo_width=88
    full_logo_min_rows=14
    logo_margin=4

    banner_blank "$cols"
    if [ "$cols" -ge $((full_logo_width + logo_margin)) ] && [ "$rows" -ge "$full_logo_min_rows" ]; then
        banner_center_width "$cols" "$C_WHITE" 88 '███████╗ ██████╗ ██████╗ ███████╗████████╗      ██╗      █████╗ ███╗   ██╗ ██████╗ '
        banner_center_width "$cols" "$C_WHITE" 88 '██╔════╝██╔════╝ ██╔══██╗██╔════╝╚══██╔══╝      ██║     ██╔══██╗████╗  ██║██╔════╝ '
        banner_center_width "$cols" "$C_WHITE" 88 '█████╗  ██║  ███╗██████╔╝█████╗     ██║   █████╗██║     ███████║██╔██╗ ██║██║  ███╗'
        banner_center_width "$cols" "$C_WHITE" 88 '██╔══╝  ██║   ██║██╔══██╗██╔══╝     ██║   ╚════╝██║     ██╔══██║██║╚██╗██║██║   ██║'
        banner_center_width "$cols" "$C_WHITE" 88 '███████╗╚██████╔╝██║  ██║███████╗   ██║         ███████╗██║  ██║██║ ╚████║╚██████╔╝'
        banner_center_width "$cols" "$C_WHITE" 88 '╚══════╝ ╚═════╝ ╚═╝  ╚═╝╚══════╝   ╚═╝         ╚══════╝╚═╝  ╚═╝╚═╝  ╚═══╝ ╚═════╝ '
    elif [ "$rows" -ge 8 ]; then
        banner_center_width "$cols" "$C_WHITE" 10 "EGRET-LANG"
    else
        banner_center_width "$cols" "$C_WHITE" 5 "EGRET"
    fi
    banner_blank "$cols"
    banner_center "$cols" "$C_WHITE" "EGRET-LANG INSTALLER ${VERSION}"
    banner_blank "$cols"
}

is_uint() {
    case "${1:-}" in
        ''|*[!0-9]*) return 1 ;;
        *) return 0 ;;
    esac
}

terminal_size() {
    cols="${COLUMNS:-}"
    rows="${LINES:-}"
    if ! is_uint "$cols"; then
        cols=""
    fi
    if ! is_uint "$rows"; then
        rows=""
    fi

    if { [ "$cols" = "" ] || [ "$rows" = "" ]; } && command -v stty >/dev/null 2>&1; then
        stty_size="$(stty size < /dev/tty 2>/dev/null || stty size 2>/dev/null || printf '')"
        set -- $stty_size
        if [ "$#" -ge 2 ]; then
            if [ "$rows" = "" ] && is_uint "$1"; then
                rows="$1"
            fi
            if [ "$cols" = "" ] && is_uint "$2"; then
                cols="$2"
            fi
        fi
    fi

    if [ "$cols" = "" ] && command -v tput >/dev/null 2>&1; then
        cols="$(tput cols 2>/dev/null || printf '')"
        if ! is_uint "$cols"; then
            cols=""
        fi
    fi
    if [ "$rows" = "" ] && command -v tput >/dev/null 2>&1; then
        rows="$(tput lines 2>/dev/null || printf '')"
        if ! is_uint "$rows"; then
            rows=""
        fi
    fi

    if [ "$cols" = "" ]; then
        cols=80
    fi
    if [ "$rows" = "" ]; then
        rows=24
    fi
    if [ "$cols" -lt 20 ]; then
        cols=20
    fi
    if [ "$rows" -lt 6 ]; then
        rows=6
    fi
    printf '%s %s\n' "$cols" "$rows"
}

repeat_spaces() {
    n="$1"
    while [ "$n" -gt 0 ]; do
        printf ' '
        n=$((n - 1))
    done
}

banner_blank() {
    cols="$1"
    if banner_clear_line; then
        printf '%s\n' "$C_RESET"
        return 0
    fi
    printf '%s%s' "$C_BG_BLUE" "$C_BOLD"
    repeat_spaces "$cols"
    printf '%s\n' "$C_RESET"
}

banner_clear_line() {
    if [ "$C_BG_BLUE" = "" ]; then
        return 1
    fi
    printf '\r%s%s\033[2K' "$C_BG_BLUE" "$C_BOLD"
}

banner_text() {
    cols="$1"
    color="$2"
    text="$3"
    if banner_clear_line; then
        printf '%s%s%s%s\n' "$C_BG_BLUE" "$color" "$text" "$C_RESET"
        return 0
    fi
    len=${#text}
    if [ "$len" -ge "$cols" ]; then
        printf '%s%s%s%s%s\n' "$C_BG_BLUE" "$color" "$C_BOLD" "$text" "$C_RESET"
        return 0
    fi
    pad=$((cols - len))
    printf '%s%s%s%s' "$C_BG_BLUE" "$color" "$C_BOLD" "$text"
    repeat_spaces "$pad"
    printf '%s\n' "$C_RESET"
}

banner_center() {
    cols="$1"
    color="$2"
    text="$3"
    len=${#text}
    if banner_clear_line; then
        if [ "$len" -ge "$cols" ]; then
            printf '%s%s%s%s\n' "$C_BG_BLUE" "$color" "$text" "$C_RESET"
            return 0
        fi
        left=$(((cols - len) / 2))
        printf '%s%s%s' "$C_BG_BLUE" "$color" "$C_BOLD"
        repeat_spaces "$left"
        printf '%s%s\n' "$text" "$C_RESET"
        return 0
    fi
    if [ "$len" -ge "$cols" ]; then
        banner_text "$cols" "$color" "$text"
        return 0
    fi
    left=$(((cols - len) / 2))
    right=$((cols - len - left))
    printf '%s%s%s' "$C_BG_BLUE" "$color" "$C_BOLD"
    repeat_spaces "$left"
    printf '%s' "$text"
    repeat_spaces "$right"
    printf '%s\n' "$C_RESET"
}

banner_center_width() {
    cols="$1"
    color="$2"
    width="$3"
    text="$4"
    if banner_clear_line; then
        if [ "$width" -ge "$cols" ]; then
            printf '%s%s%s%s\n' "$C_BG_BLUE" "$color" "$text" "$C_RESET"
            return 0
        fi
        left=$(((cols - width) / 2))
        printf '%s%s%s' "$C_BG_BLUE" "$color" "$C_BOLD"
        repeat_spaces "$left"
        printf '%s%s\n' "$text" "$C_RESET"
        return 0
    fi
    if [ "$width" -ge "$cols" ]; then
        printf '%s%s%s%s%s\n' "$C_BG_BLUE" "$color" "$C_BOLD" "$text" "$C_RESET"
        return 0
    fi
    left=$(((cols - width) / 2))
    right=$((cols - width - left))
    printf '%s%s%s' "$C_BG_BLUE" "$color" "$C_BOLD"
    repeat_spaces "$left"
    printf '%s' "$text"
    repeat_spaces "$right"
    printf '%s\n' "$C_RESET"
}

paint() {
    printf '%s%s%s' "$1" "$2" "$C_RESET"
}

path_text() {
    paint "$C_GREEN" "$1"
}

url_text() {
    paint "$C_BLUE" "$1"
}

pkg_text() {
    paint "$C_MAGENTA" "$1"
}

usage() {
    cat <<EOF
Usage:
    sh install.sh [options]

Options:
    --dir PATH       Installation directory (default: ${DEFAULT_INSTALL_DIR})
    --url URL        Package URL (default: ${DEFAULT_URL})
    --yes, -y        Use defaults without prompts
    --no-deps        Do not try to install missing system dependencies
    --no-links       Do not create command symlinks in the installation directory
    -h, --help       Show this help

Environment:
    EGRET_INSTALL_DIR    Same as --dir
    EGRET_INSTALL_URL    Same as --url
EOF
}

log() {
    printf '%s\n' "$*"
}

step() {
    printf '%s %s\n' "$(paint "$C_CYAN" "==>")" "$*"
}

ok() {
    printf '%s %s\n' "$(paint "$C_GREEN" "✓")" "$*"
}

die() {
    printf '%s %s\n' "$(paint "$C_RED" "error:")" "$*" >&2
    exit 1
}

need_value() {
    if [ "${2:-}" = "" ]; then
        die "$1 requires a value"
    fi
}

init_colors

while [ "$#" -gt 0 ]; do
    case "$1" in
        --dir)
            need_value "$1" "${2:-}"
            INSTALL_DIR="$2"
            shift 2
            ;;
        --url)
            need_value "$1" "${2:-}"
            DOWNLOAD_URL="$2"
            shift 2
            ;;
        --yes|-y)
            ASSUME_YES=1
            shift
            ;;
        --no-deps)
            INSTALL_DEPS=0
            shift
            ;;
        --no-links)
            CREATE_LINKS=0
            shift
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        *)
            die "unknown option: $1"
            ;;
    esac
done

expand_path() {
    case "$1" in
        "~") printf '%s\n' "$HOME" ;;
        "~/"*) printf '%s/%s\n' "$HOME" "${1#~/}" ;;
        *) printf '%s\n' "$1" ;;
    esac
}

read_tty_answer() {
    if answer="$({ IFS= read -r line < /dev/tty && printf '%s' "$line"; } 2>/dev/null)"; then
        return 0
    fi
    die "interactive input is unavailable. Re-run from a terminal or use: sh install.sh --yes"
}

prompt() {
    question="$1"
    default="$2"
    if [ "$ASSUME_YES" -eq 1 ]; then
        printf '%s\n' "$default"
        return 0
    fi
    printf '%s %s [%s]: ' "$(paint "$C_CYAN" "?")" "$(paint "$C_BOLD" "$question")" "$(paint "$C_YELLOW" "$default")" >&2
    read_tty_answer
    if [ "$answer" = "" ]; then
        printf '%s\n' "$default"
    else
        printf '%s\n' "$answer"
    fi
}

prompt_yes_no() {
    question="$1"
    default="$2"
    if [ "$ASSUME_YES" -eq 1 ]; then
        [ "$default" = "y" ] || [ "$default" = "Y" ]
        return $?
    fi
    printf '%s %s [%s]: ' "$(paint "$C_CYAN" "?")" "$(paint "$C_BOLD" "$question")" "$(paint "$C_YELLOW" "$default")" >&2
    read_tty_answer
    if [ "$answer" = "" ]; then
        answer="$default"
    fi
    case "$answer" in
        y|Y|yes|YES|Yes) return 0 ;;
        *) return 1 ;;
    esac
}

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

detect_platform() {
    os="$(uname -s 2>/dev/null || printf unknown)"
    arch="$(uname -m 2>/dev/null || printf unknown)"

    case "$os" in
        Darwin) ;;
        *)
            die "this installer currently supports macOS only; detected OS: $os"
            ;;
    esac

    case "$arch" in
        arm64|aarch64) ;;
        *)
            die "this package is for ${TARGET}; detected CPU: $arch"
            ;;
    esac

    ok "Detected platform: $(paint "$C_BOLD" "macOS") $(paint "$C_YELLOW" "$arch")"
}

install_xcode_tools() {
    if [ "$INSTALL_DEPS" -ne 1 ]; then
        return 1
    fi
    if ! have_cmd xcode-select; then
        return 1
    fi
    step "Installing Apple Command Line Tools. Follow the macOS prompt if it appears."
    xcode-select --install >/dev/null 2>&1 || true
    log "$(paint "$C_YELLOW" "After Command Line Tools finish installing, run this installer again.")"
    exit 1
}

ensure_tool() {
    tool="$1"
    hint="$2"
    if have_cmd "$tool"; then
        return 0
    fi
    die "missing required tool: ${tool}. ${hint}"
}

ensure_compiler() {
    if have_cmd cc || have_cmd gcc || have_cmd clang; then
        return 0
    fi
    install_xcode_tools
    die "missing C compiler. Install Apple Command Line Tools with: xcode-select --install"
}

ensure_dependencies() {
    downloader=""
    if have_cmd curl; then
        downloader="curl"
    elif have_cmd wget; then
        downloader="wget"
    else
        die "missing downloader: install curl or wget"
    fi

    ensure_tool unzip "Install unzip or Apple Command Line Tools."
    ensure_tool mktemp "Install Apple Command Line Tools."
    ensure_tool chmod "Install core system utilities."
    ensure_compiler

    ok "Dependency check ok: downloader=$(paint "$C_YELLOW" "$downloader"), unzip, compiler"
}

download_file() {
    url="$1"
    out="$2"
    if have_cmd curl; then
        curl -fL --retry 3 --connect-timeout 20 -o "$out" "$url"
    elif have_cmd wget; then
        wget -O "$out" "$url"
    else
        die "missing downloader: curl or wget"
    fi
}

abs_dir() {
    path="$1"
    parent="$(dirname "$path")"
    base="$(basename "$path")"
    mkdir -p "$parent"
    parent_abs="$(cd "$parent" && pwd -P)"
    printf '%s/%s\n' "$parent_abs" "$base"
}

install_package() {
    install_dir="$(expand_path "$INSTALL_DIR")"
    install_dir="$(abs_dir "$install_dir")"
    dest="${install_dir}/${PKG}"

    tmp="$(mktemp -d "${TMPDIR:-/tmp}/egret-install.XXXXXX")"
    trap 'rm -rf "$tmp"' EXIT INT HUP TERM
    zip_path="${tmp}/${PKG}.zip"

    step "Downloading package"
    log "  $(url_text "$DOWNLOAD_URL")"
    download_file "$DOWNLOAD_URL" "$zip_path"

    step "Extracting package"
    unzip -q "$zip_path" -d "$tmp"
    [ -d "${tmp}/${PKG}" ] || die "archive does not contain expected directory: ${PKG}"
    [ -x "${tmp}/${PKG}/bin/egret" ] || die "archive does not contain executable: ${PKG}/bin/egret"

    mkdir -p "$install_dir"
    if [ -e "$dest" ]; then
        if prompt_yes_no "Replace existing ${dest}?" "y"; then
            rm -rf "$dest"
        else
            die "installation cancelled"
        fi
    fi

    mv "${tmp}/${PKG}" "$dest"

    if [ "$CREATE_LINKS" -eq 1 ]; then
        for name in egret eg egretc egret4c egretdoc egrettest egretperf; do
            if [ "$name" = "eg" ]; then
                target="${dest}/bin/egret"
            else
                target="${dest}/bin/${name}"
            fi
            if [ -x "$target" ]; then
                ln -sf "$target" "${install_dir}/${name}"
            fi
        done
    fi

    ok "Installed $(pkg_text "Egret ${VERSION}")"
    log "  $(path_text "$dest")"

    if [ "$CREATE_LINKS" -eq 1 ]; then
        step "Command links"
        log "  $(path_text "${install_dir}/egret")"
        log "  $(path_text "${install_dir}/egretc")"
    fi

    case ":${PATH}:" in
        *":${install_dir}:"*) ;;
        *)
            log ""
            log "$(paint "$C_YELLOW" "Add this directory to PATH if needed:")"
            log "  export PATH=\"$(path_text "$install_dir"):\$PATH\""
            ;;
    esac

    if "${install_dir}/egret" version >/dev/null 2>&1; then
        log ""
        step "Verification"
        "${install_dir}/egret" version || true
    else
        log ""
        log "$(paint "$C_YELLOW" "Verification: installed, but '${install_dir}/egret version' did not run successfully.")"
    fi
}

show_logo

detect_platform
ensure_dependencies

INSTALL_DIR="$(prompt "Installation directory" "$INSTALL_DIR")"
INSTALL_DIR="$(expand_path "$INSTALL_DIR")"

if [ "$ASSUME_YES" -ne 1 ]; then
    log ""
    step "Install configuration"
    log "  package: $(pkg_text "$PKG")"
    log "  url: $(url_text "$DOWNLOAD_URL")"
    log "  install_dir: $(path_text "$INSTALL_DIR")"
    if [ "$CREATE_LINKS" -eq 1 ]; then
        log "  command_links: $(paint "$C_GREEN" "yes")"
    else
        log "  command_links: $(paint "$C_YELLOW" "no")"
    fi
    if ! prompt_yes_no "Continue installation?" "y"; then
        die "installation cancelled"
    fi
fi

install_package