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

# Downloads and installs the latest stable lazygit from
# https://github.com/jesseduffield/lazygit/releases
#
# Supported platforms:
#   macOS    : Apple Silicon (arm64), Intel (x86_64)
#   Linux    : x86_64, aarch64/arm64, armv6
#   FreeBSD  : x86_64
#   Windows  : Git Bash / MSYS2 / Cygwin (.zip install)

set -euo pipefail

# ────────────────────────────────────────────
# Constants
# ────────────────────────────────────────────
REPO="jesseduffield/lazygit"
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; }

# ────────────────────────────────────────────
# Check for git (required by lazygit)
# ────────────────────────────────────────────
if ! command -v git &>/dev/null; then
	info "git is not installed. Installing git..."
	case "$(uname -s)" in
	Darwin)
		if command -v brew &>/dev/null; then
			brew install -y git
			success "git installed via Homebrew"
		else
			error "Homebrew (brew) is required to install git on macOS. Install it from https://brew.sh/"
		fi
		;;
	Linux)
		if command -v apt-get &>/dev/null; then
			sudo apt-get update -y && sudo apt-get install -y git
			success "git installed via apt-get"
		elif command -v dnf &>/dev/null; then
			sudo dnf install -y git
			success "git installed via dnf"
		elif command -v yum &>/dev/null; then
			sudo yum install -y git
			success "git installed via yum"
		elif command -v zypper &>/dev/null; then
			sudo zypper -n install git
			success "git installed via zypper"
		elif command -v pacman &>/dev/null; then
			sudo pacman -S --noconfirm git
			success "git installed via pacman"
		else
			error "No supported package manager found. Install git manually."
		fi
		;;
	*)
		error "Cannot auto-install git on this OS. Please install git manually."
		;;
	esac

	# Verify git is now available
	if ! command -v git &>/dev/null; then
		error "git installation failed. Please install git manually and re-run this script."
	fi
fi

info "git is available: $(command -v git)"

# ────────────────────────────────────────────
# Check required commands
# ────────────────────────────────────────────
for cmd in curl uname; 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

# ────────────────────────────────────────────
# OS / Architecture detection
# ────────────────────────────────────────────
# Returns: "<asset_name>:<archive_format>"
#   asset_name = lazygit_X.XX.X_PLATFORM
#   archive_format = tar.gz | zip
detect_platform() {
	local os arch

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

	case "$os" in
	# ── macOS ──────────────────────────────────────────────
	Darwin)
		case "$arch" in
		arm64) echo "darwin_arm64:tar.gz" ;;
		x86_64) echo "darwin_x86_64:tar.gz" ;;
		*) error "Unsupported macOS architecture: $arch" ;;
		esac
		;;

	# ── Linux (including Raspberry Pi) ──────────────────
	Linux)
		case "$arch" in
		x86_64 | amd64)
			echo "linux_x86_64:tar.gz"
			;;
		aarch64 | arm64)
			# RPi 4/5, 64bit OS
			echo "linux_arm64:tar.gz"
			;;
		armv7l)
			# RPi 2/3, 32bit OS - use armv6 as fallback
			echo "linux_armv6:tar.gz"
			;;
		armv6l)
			# RPi Zero / 1
			echo "linux_armv6:tar.gz"
			;;
		i686 | i386)
			echo "linux_32-bit:tar.gz"
			;;
		*)
			error "Unsupported Linux architecture: $arch"
			;;
		esac
		;;

	# ── FreeBSD ────────────────────────────────────────────
	FreeBSD)
		case "$arch" in
		amd64 | x86_64) echo "freebsd_x86_64:tar.gz" ;;
		*) error "FreeBSD x86_64 is only supported (current: $arch)" ;;
		esac
		;;

	# ── Windows (Git Bash / MSYS2 / Cygwin) ───────────────
	MINGW* | MSYS* | CYGWIN*)
		warn "Windows environment (Git Bash/MSYS2/Cygwin) detected."
		warn "Native .exe will be installed."
		case "$arch" in
		x86_64) echo "windows_x86_64:zip" ;;
		aarch64) echo "windows_arm64:zip" ;;
		i686) echo "windows_32-bit:zip" ;;
		*) error "Unsupported Windows architecture: $arch" ;;
		esac
		;;

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

# ────────────────────────────────────────────
# 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"
}

# ────────────────────────────────────────────
# Build download URL
# ────────────────────────────────────────────
build_download_url() {
	local tag="$1"
	local platform="$2"      # e.g. darwin_arm64, linux_x86_64
	local ext="$3"           # tar.gz | zip
	local version="${tag#v}" # Remove 'v' prefix
	local filename="lazygit_${version}_${platform}.${ext}"
	echo "https://github.com/${REPO}/releases/download/${tag}/${filename}"
}

# ────────────────────────────────────────────
# Download, extract & install
# ────────────────────────────────────────────
download_and_install() {
	local url="$1"
	local ext="$2"
	local is_windows="${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 "$tmpdir"
		elif command -v tar &>/dev/null; then
			tar -xf "${tmpdir}/${filename}" -C "$tmpdir"
		else
			error "'unzip' or 'tar' (Windows 10+) is required."
		fi
		;;
	*)
		error "Unknown archive format: $ext"
		;;
	esac

	# Binary name
	local bin_name="lazygit"
	[[ "$is_windows" == "true" ]] && bin_name="lazygit.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 platform ext is_windows tag url

	platform_info="$(detect_platform)"
	platform="${platform_info%%:*}"
	ext="${platform_info##*:}"

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

	is_windows="false"
	[[ "$platform" == "windows"* ]] && is_windows="true"

	tag="$(get_latest_tag)"
	info "Latest release: $tag"

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

main "$@"