#!/usr/bin/env bash
# shellcheck disable=SC2086

# Downloads and installs the latest Nightly version from
# https://github.com/ClementTsang/bottom/releases
#
# Supported platforms:
#   macOS    : Apple Silicon (arm64), Intel (x86_64)
#   Linux    : x86_64, aarch64(RPi4/5), armv7(RPi2/3 32bit), armv6(RPi Zero/1), i686
#   FreeBSD  : x86_64
#   Windows  : Git Bash / MSYS2 / Cygwin (.zip install)
#              (Native PowerShell/CMD not supported → use WSL)

set -euo pipefail

# ────────────────────────────────────────────
# 상수 정의
# ────────────────────────────────────────────
REPO="ClementTsang/bottom"
API_URL="https://api.github.com/repos/${REPO}/releases"
INSTALL_DIR="${HOME}/.local/bin"

# ────────────────────────────────────────────
# 유틸리티 함수 (모두 stderr 출력)
# ────────────────────────────────────────────
info()    { echo "[INFO]  $*" >&2; }
warn()    { echo "[WARN]  $*" >&2; }
error()   { echo "[ERROR] $*" >&2; exit 1; }
success() { echo "[OK]    $*" >&2; }

# ────────────────────────────────────────────
# 필수 명령어 확인
# ────────────────────────────────────────────
for cmd in curl uname; do
    command -v "$cmd" &>/dev/null || error "'$cmd' 명령어가 필요합니다."
done

# Fallback: use python3 if jq is not available
if command -v jq &>/dev/null; then
    _json_nightly_tag() {
        jq -r '[.[] | select(.prerelease==true and (.tag_name | startswith("nightly-")))] | .[0].tag_name'
    }
else
    command -v python3 &>/dev/null || error "'jq' or 'python3' is required."
    _json_nightly_tag() {
        python3 -c "
import sys, json
data = json.load(sys.stdin)
for r in data:
    if r.get('prerelease') and r.get('tag_name','').startswith('nightly-'):
        print(r['tag_name'])
        break
"
    }
fi

# ────────────────────────────────────────────
# OS / 아키텍처 감지
# ────────────────────────────────────────────
# 반환값 형식: "<플랫폼 트리플>:<압축포맷>"
#   압축포맷 = tar.gz | zip
detect_platform() {
    local os arch

    os="$(uname -s)"
    arch="$(uname -m)"

    case "$os" in
        # ── macOS ──────────────────────────────────────────────
        Darwin)
            case "$arch" in
                arm64)  echo "aarch64-apple-darwin:tar.gz" ;;
                x86_64) echo "x86_64-apple-darwin:tar.gz" ;;
                *)      error "지원하지 않는 macOS 아키텍처: $arch" ;;
            esac
            ;;

        # ── Linux (라즈베리파이 전 모델 포함) ──────────────────
        Linux)
            case "$arch" in
                x86_64|amd64)
                    echo "x86_64-unknown-linux-musl:tar.gz" ;;
                aarch64|arm64)
                    # RPi 4/5, 64bit OS
                    echo "aarch64-unknown-linux-musl:tar.gz" ;;
                armv7l)
                    # RPi 2/3, 32bit OS (ARMv7)
                    echo "armv7-unknown-linux-musleabihf:tar.gz" ;;
                armv6l)
                    # RPi Zero / 1 (ARMv6)
                    # No pre-built binaries available for ARMv6.
                    # (armv7 musl/gnu binaries don't work on ARMv6)
                    error "No pre-built binaries for ARMv6 (RPi Zero/1). Build from source: 'cargo install bottom'" ;;
                i686|i386)
                    echo "i686-unknown-linux-musl:tar.gz" ;;
                *)
                    error "지원하지 않는 Linux 아키텍처: $arch" ;;
            esac
            ;;

        # ── FreeBSD ────────────────────────────────────────────
        FreeBSD)
            case "$arch" in
                amd64|x86_64) echo "x86_64-unknown-freebsd:tar.gz" ;;
                *)            error "FreeBSD는 x86_64만 지원합니다 (현재: $arch)" ;;
            esac
            ;;

        # ── Windows (Git Bash / MSYS2 / Cygwin) ───────────────
        # Native PowerShell/CMD don't have bash, so this script won't run
        # WSL is detected as Linux, not Windows
        MINGW*|MSYS*|CYGWIN*)
            warn "Windows environment (Git Bash/MSYS2/Cygwin) detected."
            warn "WSL (Windows Subsystem for Linux) is recommended."
            # Windows에는 tar.exe(Windows 10 1803+)가 있어 .zip 처리 가능
            case "$arch" in
                x86_64) echo "x86_64-pc-windows-msvc:zip" ;;
                aarch64) echo "aarch64-pc-windows-msvc:zip" ;;
                i686)    echo "i686-pc-windows-msvc:zip" ;;
                *)       error "지원하지 않는 Windows 아키텍처: $arch" ;;
            esac
            ;;

        *)
            error "지원하지 않는 OS: $os  (uname -a: $(uname -a))"
            ;;
    esac
}

# ────────────────────────────────────────────
# Get latest Nightly release tag
# ────────────────────────────────────────────
get_latest_nightly_tag() {
    info "Fetching latest Nightly release from GitHub API..."

    local releases
    releases="$(curl -fsSL "${API_URL}")" || error "Failed to call GitHub API."

    local tag
    tag="$(echo "$releases" | _json_nightly_tag)"

    [[ -z "$tag" || "$tag" == "null" ]] && error "Could not find Nightly release tag."
    echo "$tag"
}

# ────────────────────────────────────────────
# Build download URL
# ────────────────────────────────────────────
build_download_url() {
    local tag="$1"
    local triple="$2"   # Platform triple (e.g. x86_64-apple-darwin)
    local ext="$3"      # tar.gz | zip
    local filename="bottom_${triple}.${ext}"
    echo "https://github.com/${REPO}/releases/download/${tag}/${filename}"
}

# ────────────────────────────────────────────
# Download, extract & install
# ────────────────────────────────────────────
download_and_install() {
    local url="$1"
    local ext="$2"      # tar.gz | zip
    local is_windows="${3:-false}"

    local tmpdir
    tmpdir="$(mktemp -d)"
    trap '[[ -d "${tmpdir:-}" ]] && rm -rf "$tmpdir"' EXIT

    local filename
    filename="${url##*/}"

    info "Downloading: $url"
    curl -fsSL --progress-bar -o "${tmpdir}/${filename}" "$url" \
        || error "Download failed: $url"

    info "Extracting..."
    case "$ext" in
        tar.gz)
            command -v tar &>/dev/null || error "'tar' command is required."
            tar -xzf "${tmpdir}/${filename}" -C "$tmpdir"
            ;;
        zip)
            if command -v unzip &>/dev/null; then
                unzip -q "${tmpdir}/${filename}" -d "$tmpdir"
            elif command -v tar &>/dev/null; then
                # Windows 10+ tar.exe supports zip
                tar -xf "${tmpdir}/${filename}" -C "$tmpdir"
            else
                error "'unzip' or 'tar' (Windows 10+) is required."
            fi
            ;;
        *)
            error "Unknown archive format: $ext"
            ;;
    esac

    # Windows uses btm.exe, others use btm
    local bin_name="btm"
    [[ "$is_windows" == "true" ]] && bin_name="btm.exe"

    local bin_src
    bin_src="$(find "$tmpdir" -maxdepth 3 -type f -name "$bin_name" | head -1)"
    [[ -z "$bin_src" ]] && error "Cannot find '$bin_name' in the archive."

    # Create install directory
    mkdir -p "$INSTALL_DIR"

    local install_path="${INSTALL_DIR}/${bin_name}"
    info "Installing: ${install_path}"
    cp "$bin_src" "$install_path"
    chmod +x "$install_path"

    success "Installation complete!"
    info "Version check:"
    "$install_path" --version || true

    # PATH instructions
    if ! echo ":${PATH}:" | grep -q ":${INSTALL_DIR}:"; then
        warn "'${INSTALL_DIR}' is not in your PATH."
        warn "Add this line to your ~/.bashrc or ~/.zshrc:"
        warn "  export PATH=\"\$HOME/.local/bin:\$PATH\""
    fi
}

# ────────────────────────────────────────────
# Main
# ────────────────────────────────────────────
main() {
    local platform_info triple ext is_windows tag url

    platform_info="$(detect_platform)"
    triple="${platform_info%%:*}"   # Before ':'
    ext="${platform_info##*:}"      # After ':'

    info "Detected platform: $triple  (format: $ext)"

    # Check if Windows
    is_windows="false"
    [[ "$triple" == *"windows"* ]] && is_windows="true"

    tag="$(get_latest_nightly_tag)"
    info "Latest Nightly tag: $tag"

    url="$(build_download_url "$tag" "$triple" "$ext")"
    download_and_install "$url" "$ext" "$is_windows"
}

main "$@"