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

# Installs dua (Disk Usage Analyzer) — https://github.com/byron/dua-cli
#
# Supported platforms:
#   macOS    : Apple Silicon (arm64), Intel (x86_64) — via Homebrew
#   Linux    : x86_64, aarch64 — via package manager or direct download
#
# Prerequisites:
#   - macOS: Homebrew (brew) — auto-installed if missing
#   - Linux: curl — for direct download fallback

set -euo pipefail

# ────────────────────────────────────────────
# Constants
# ────────────────────────────────────────────
REPO="Byron/dua-cli"
API_URL="https://api.github.com/repos/${REPO}/releases"
INSTALL_DIR="${HOME}/.local/bin"

# ────────────────────────────────────────────
# Utility functions (all stderr output)
# ────────────────────────────────────────────
info() { echo "[INFO]  $*" >&2; }
warn() { echo "[WARN]  $*" >&2; }
error() {
	echo "[ERROR] $*" >&2
	exit 1
}
success() { echo "[OK]    $*" >&2; }

# ────────────────────────────────────────────
# Ensure Homebrew is available on macOS
# ────────────────────────────────────────────
ensure_brew() {
	if command -v brew &>/dev/null; then
		return 0
	fi
	info "Homebrew is not installed. Installing Homebrew..."
	/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
	if [ -d /opt/homebrew/bin ]; then
		export PATH="/opt/homebrew/bin:$PATH"
	fi
	if [ -d /usr/local/bin ]; then
		export PATH="/usr/local/bin:$PATH"
	fi
	command -v brew &>/dev/null || error "Homebrew installation failed. Install it manually: https://brew.sh/"
	success "Homebrew installed"
}

# ────────────────────────────────────────────
# Detect OS / Architecture
# ────────────────────────────────────────────
OS="$(uname -s)"
ARCH="$(uname -m)"

case "$OS" in
Darwin | Linux) ;;
*)
	error "Unsupported OS: $OS. This script only supports macOS and Linux."
	;;
esac

# ────────────────────────────────────────────
# Check required commands
# ────────────────────────────────────────────
for cmd in curl; do
	command -v "$cmd" &>/dev/null || error "'$cmd' command is required."
done

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

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

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

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

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

# ────────────────────────────────────────────
# Step 1: Install dua
# ────────────────────────────────────────────
info "Installing dua (Disk Usage Analyzer)..."

if command -v dua &>/dev/null; then
	CURRENT_VER="$(dua --version 2>/dev/null || echo 'unknown')"
	info "dua is already installed ($CURRENT_VER). Skipping installation."
else
	case "$OS" in
	Darwin)
		ensure_brew
		brew install dua-cli
		success "dua installed via Homebrew"
		;;
	Linux)
		# Try package managers first
		DUA_INSTALLED=false

		if command -v apt-get &>/dev/null; then
			info "Trying apt-get..."
			sudo apt-get update -y 2>/dev/null || true
			if sudo apt-get install -y dua-cli 2>/dev/null; then
				DUA_INSTALLED=true
				success "dua installed via apt-get"
			fi
		fi

		if [ "$DUA_INSTALLED" = "false" ] && command -v dnf &>/dev/null; then
			info "Trying dnf..."
			if sudo dnf install -y dua-cli 2>/dev/null; then
				DUA_INSTALLED=true
				success "dua installed via dnf"
			fi
		fi

		if [ "$DUA_INSTALLED" = "false" ] && command -v pacman &>/dev/null; then
			info "Trying pacman..."
			if sudo pacman -S --noconfirm dua-cli 2>/dev/null; then
				DUA_INSTALLED=true
				success "dua installed via pacman"
			fi
		fi

		if [ "$DUA_INSTALLED" = "false" ] && command -v zypper &>/dev/null; then
			info "Trying zypper..."
			if sudo zypper -n install dua-cli 2>/dev/null; then
				DUA_INSTALLED=true
				success "dua installed via zypper"
			fi
		fi

		# Fallback: download binary from GitHub releases
		if [ "$DUA_INSTALLED" = "false" ]; then
			info "No package manager had dua-cli. Downloading from GitHub releases..."

			# Determine target
			case "$ARCH" in
			x86_64 | amd64) TARGET="x86_64-unknown-linux-musl" ;;
			aarch64 | arm64) TARGET="aarch64-unknown-linux-musl" ;;
			*) error "Unsupported Linux architecture: $ARCH" ;;
			esac

			TAG="$(get_latest_tag)"
			FILENAME="dua-${TAG}-${TARGET}.tar.gz"
			DOWNLOAD_URL="https://github.com/${REPO}/releases/download/${TAG}/${FILENAME}"

			info "Downloading: $DOWNLOAD_URL"
			TMPDIR="$(mktemp -d)"
			trap '[[ -d "${TMPDIR:-}" ]] && rm -rf "$TMPDIR"' EXIT

			curl -fsSL --progress-bar -o "${TMPDIR}/${FILENAME}" "$DOWNLOAD_URL" ||
				error "Download failed: $DOWNLOAD_URL"

			info "Extracting..."
			tar -xzf "${TMPDIR}/${FILENAME}" -C "$TMPDIR"

			# Find the dua binary
			DUA_BIN="$(find "$TMPDIR" -maxdepth 3 -type f -name "dua" | head -1)"
			[[ -z "$DUA_BIN" ]] && error "Cannot find 'dua' binary in the archive."

			mkdir -p "$INSTALL_DIR"
			cp "$DUA_BIN" "${INSTALL_DIR}/dua"
			chmod +x "${INSTALL_DIR}/dua"
			success "dua installed to ${INSTALL_DIR}/dua"

			# 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
		fi
		;;
	esac
fi

# Verify dua is available
if command -v dua &>/dev/null; then
	success "dua is available: $(command -v dua)"
else
	warn "dua was not found in PATH after installation. You may need to open a new terminal."
fi

# ────────────────────────────────────────────
# Step 2: Post-install notes
# ────────────────────────────────────────────
info ""
info "=================================================="
success "dua installation complete!"
info "=================================================="
info ""
info "Getting started:"
info "  dua                     - Show disk usage of current directory"
info "  dua /path/to/dir        - Show disk usage of specific directory"
info "  dua i                   - Interactive mode (explore & delete)"
info "  dua --help              - Show help"
info ""
info "Interactive mode shortcuts:"
info "  Arrow keys / h/j/k/l   - Navigate"
info "  ?                       - Show help"
info "  d                       - Delete selected entry"
info "  q / Esc                 - Quit"