#!/usr/bin/env bash
set -euo pipefail

# Installer for bgit: curl -fsSL https://raw.githubusercontent.com/rootCircle/bgit/main/scripts/install.sh | bash

REPO="rootCircle/bgit"
BIN_NAME="bgit"
INSTALL_DIR_DEFAULT="$HOME/.local/bin"
SUDO_BIN="sudo"

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

detect_os() {
  case "$(uname -s)" in
    Linux) echo linux;;
    Darwin) echo macos;;
    *) echo unsupported;;
  esac
}

detect_arch() {
  local arch
  arch=$(uname -m)
  case "$arch" in
    x86_64|amd64) echo x86_64;;
    arm64) echo arm64;;
    aarch64) echo aarch64;;
    *) echo "$arch";;
  esac
}

usage() {
  cat <<EOF
Usage: install.sh [install|update|uninstall|purge] [--tag vX.Y.Z] [--to DIR] [--no-sudo]

Options:
  --tag       Install specific tag (default: latest)
  --to DIR    Install directory (default: $INSTALL_DIR_DEFAULT or /usr/local/bin)
  --no-sudo   Do not use sudo when writing to system directories
Commands:
  install     Install bgit (default)
  update      Update bgit to latest or specified --tag
  uninstall   Remove the bgit binary from common install locations
  purge       Complete uninstall: uninstall + remove ~/.ssh/bgit_ssh_agent.sock, and global config at ~/.config/bgit (or $XDG_CONFIG_HOME/bgit)
EOF
}

CMD="install"
TAG=""
INSTALL_DIR=""
USE_SUDO=1
while [ "$#" -gt 0 ]; do
  case "$1" in
    install|update|uninstall|purge)
      CMD="$1"; shift;;
    --tag) TAG="$2"; shift 2;;
    --to) INSTALL_DIR="$2"; shift 2;;
    --no-sudo) USE_SUDO=0; shift;;
    -h|--help) usage; exit 0;;
    *) echo "Unknown arg: $1" >&2; usage; exit 2;;
  esac
done

OS=$(detect_os)
ARCH=$(detect_arch)
if [ "$OS" = unsupported ]; then
  echo "Unsupported OS: $(uname -s)" >&2
  exit 1
fi

if [ -z "$INSTALL_DIR" ]; then
  if [ -w "/usr/local/bin" ]; then
    INSTALL_DIR="/usr/local/bin"
  else
    INSTALL_DIR="$INSTALL_DIR_DEFAULT"
  fi
fi

[ "$CMD" != "uninstall" ] && [ "$CMD" != "purge" ] && mkdir -p "$INSTALL_DIR"

if ! command_exists curl && ! command_exists wget; then
  echo "Need curl or wget to download assets" >&2
  exit 1
fi

gh_api() {
  local url=$1
  if command_exists curl; then
    curl -fsSL "$url"
  else
    wget -qO- "$url"
  fi
}

get_latest_tag() {
  gh_api "https://api.github.com/repos/$REPO/releases/latest" | sed -n 's/^[[:space:]]*"tag_name":[[:space:]]*"\(v[^"\n]*\)".*/\1/p'
}

do_resolve_tag() {
  TAG=${TAG:-$(get_latest_tag)}
  if [ -z "$TAG" ]; then
    echo "Could not determine latest release tag" >&2
    exit 1
  fi
}

# Map matrix.os to artifact OS label
case "$OS" in
  linux) ART_OS="ubuntu-latest";;
  macos) ART_OS="macos-latest";;
esac

# Try common arch labels. We'll determine candidates and pick the first asset that exists.
PREFER_MUSL=${PREFER_MUSL:-${MUSL:-0}}
case "$ARCH" in
  x86_64) BASE_ARCH="x86_64" ;;
  aarch64) BASE_ARCH="aarch64" ;;
  arm64) BASE_ARCH=$([ "$OS" = macos ] && echo arm64 || echo aarch64) ;;
  *) BASE_ARCH="$ARCH" ;;
esac

# Build candidate suffixes in order of preference for this OS/arch
build_suffix_candidates() {
  local os="$1" arch="$2" prefer_musl="$3"
  local -a c=()
  if [ "$os" = linux ]; then
    case "$arch" in
      x86_64)
        if [ "$prefer_musl" != 0 ]; then c+=("x86_64-musl" "x86_64"); else c+=("x86_64" "x86_64-musl"); fi ;;
      aarch64)
        # Linux aarch64 builds are not published; no candidates
        ;;
      *)
        c+=("$arch") ;;
    esac
  elif [ "$os" = macos ]; then
    case "$arch" in
  aarch64|arm64) c+=("arm64" "aarch64") ;;
      x86_64) c+=("x86_64" "aarch64") ;; # allow Rosetta fallback
      *) c+=("$arch") ;;
    esac
  else
    c+=("$arch")
  fi
  printf '%s\n' "${c[@]}"
}

do_install() {
  do_resolve_tag
  REL_JSON=$(gh_api "https://api.github.com/repos/$REPO/releases/tags/$TAG")

  # Try candidates until we find a matching asset
  URL_TAR=""; URL_SHA=""; ASSET_TAR=""; ASSET_SHA=""
  while IFS= read -r suf; do
    local try_tar="${BIN_NAME}-${TAG}-${ART_OS}-${suf}.tar.gz"
    local try_sha="${try_tar}.sha256"
    local u_tar=$(printf "%s" "$REL_JSON" | sed -n "s@^[[:space:]]*\"browser_download_url\":[[:space:]]*\"\(.*${try_tar}\)\".*@\1@p")
    if [ -n "$u_tar" ]; then
      URL_TAR="$u_tar"; ASSET_TAR="$try_tar"; ASSET_SHA="$try_sha"
      URL_SHA=$(printf "%s" "$REL_JSON" | sed -n "s@^[[:space:]]*\"browser_download_url\":[[:space:]]*\"\(.*${try_sha}\)\".*@\1@p")
      break
    fi
  done < <(build_suffix_candidates "$OS" "$BASE_ARCH" "$PREFER_MUSL")

  if [ -z "$URL_TAR" ]; then
    if [ "$OS" = linux ] && [ "$BASE_ARCH" = aarch64 ]; then
      echo "No Linux aarch64 prebuilt binaries are available at this time." >&2
      echo "Please build from source or install on x86_64." >&2
    else
      echo "Could not find a suitable asset for OS=$OS arch=$ARCH (candidates tried: $(build_suffix_candidates "$OS" "$BASE_ARCH" "$PREFER_MUSL" | tr '\n' ' '))" >&2
      echo "Available assets:" >&2
      printf "%s\n" "$REL_JSON" | sed -n 's/^[[:space:]]*"name":[[:space:]]*"\([^"]*\.tar\.gz\)".*/\1/p' >&2 || true
    fi
    exit 1
  fi

  TMP_DIR=$(mktemp -d)
  cleanup() { rm -rf "$TMP_DIR"; }
  trap cleanup EXIT

  DL() {
    if command_exists curl; then
      curl -fL --retry 3 -o "$1" "$2"
    else
      wget -O "$1" "$2"
    fi
  }

  echo "Downloading: $ASSET_TAR"
  DL "$TMP_DIR/$ASSET_TAR" "$URL_TAR"
  if [ -n "$URL_SHA" ]; then
    echo "Downloading checksum: $ASSET_SHA"
    DL "$TMP_DIR/$ASSET_SHA" "$URL_SHA" || true
  fi

  echo "Verifying checksum (if available)"
  if [ -f "$TMP_DIR/$ASSET_SHA" ]; then
    (cd "$TMP_DIR" && sha256sum -c "$ASSET_SHA" 2>/dev/null) || (cd "$TMP_DIR" && shasum -a 256 -c "$ASSET_SHA")
  fi

  echo "Extracting"
  tar -C "$TMP_DIR" -xzf "$TMP_DIR/$ASSET_TAR"
  if [ ! -x "$TMP_DIR/$BIN_NAME" ]; then
    echo "Binary not found in archive" >&2
    exit 1
  fi

  TARGET="$INSTALL_DIR/$BIN_NAME"
  if [ "$USE_SUDO" = 1 ] && [ ! -w "$INSTALL_DIR" ]; then
    if command_exists sudo; then SUDO=$SUDO_BIN; else SUDO=""; fi
  else
    SUDO=""
  fi

  echo "Installing to $TARGET"
  ${SUDO:+$SUDO }install -m 0755 "$TMP_DIR/$BIN_NAME" "$TARGET"

  case :$PATH: in
    *:"$INSTALL_DIR":*) ;;
    *) echo "Note: $INSTALL_DIR is not on PATH. Consider adding it." ;;
  esac

  echo "Installed $BIN_NAME $TAG to $TARGET"
}

do_uninstall() {
  # Try to find installed binary
  TARGET="${INSTALL_DIR%/}/$BIN_NAME"
  FOUND=""
  if [ -x "$TARGET" ]; then
    FOUND="$TARGET"
  else
    FOUND=$(command -v "$BIN_NAME" || true)
  fi

  if [ -z "$FOUND" ]; then
    # Try common locations
    for d in "/usr/local/bin" "$HOME/.local/bin"; do
      if [ -x "$d/$BIN_NAME" ]; then FOUND="$d/$BIN_NAME"; break; fi
    done
  fi

  if [ -z "$FOUND" ]; then
    echo "$BIN_NAME not found; nothing to uninstall"; return 0
  fi

  DIR=$(dirname "$FOUND")
  if [ -w "$DIR" ]; then
    rm -f "$FOUND"
  else
    if command_exists sudo; then
      $SUDO_BIN rm -f "$FOUND"
    else
      echo "Insufficient permissions to remove $FOUND and sudo not available" >&2
      exit 1
    fi
  fi
  echo "Removed $FOUND"
}

do_purge() {
  do_uninstall || true
  # Remove data dirs
  AGENT_SOCK="$HOME/.ssh/bgit_ssh_agent.sock"
  # Global config dirs
  GLOBAL_CFG_DEFAULT="$HOME/.config/bgit"
  GLOBAL_CFG_XDG="${XDG_CONFIG_HOME:-}/bgit"
  [ -S "$AGENT_SOCK" ] || [ -f "$AGENT_SOCK" ] && rm -f "$AGENT_SOCK" && echo "Removed $AGENT_SOCK" || true
  if [ -n "${XDG_CONFIG_HOME:-}" ] && [ -d "$GLOBAL_CFG_XDG" ]; then
    rm -rf "$GLOBAL_CFG_XDG" && echo "Removed $GLOBAL_CFG_XDG" || true
  fi
  if [ -d "$GLOBAL_CFG_DEFAULT" ]; then
    rm -rf "$GLOBAL_CFG_DEFAULT" && echo "Removed $GLOBAL_CFG_DEFAULT" || true
  fi
}

case "$CMD" in
  install|update) do_install ;;
  uninstall) do_uninstall ;;
  purge) do_purge ;;
esac