#!/bin/bash

set -euo pipefail

BUILDKITE_REPO=${BUILDKITE_REPO:-}
BUILDKITE_CLEAN_CHECKOUT=${BUILDKITE_CLEAN_CHECKOUT:-}
BUILDKITE_BRANCH=${BUILDKITE_BRANCH:-}
CCACHE_DIR=${CCACHE_DIR:-}
SCCACHE_DIR=${SCCACHE_DIR:-}
ZIG_LOCAL_CACHE_DIR=${ZIG_LOCAL_CACHE_DIR:-}
ZIG_GLOBAL_CACHE_DIR=${ZIG_GLOBAL_CACHE_DIR:-}
BUN_DEPS_CACHE_DIR=${BUN_DEPS_CACHE_DIR:-}
BUN_DEPS_CACHE_DIR=${BUN_DEPS_CACHE_DIR:-}
BUILDKITE_STEP_KEY=${BUILDKITE_STEP_KEY:-}

ROOT_DIR="$(realpath "$(dirname "$0")/../../")"

# Fail if we cannot find the root directory
if [ ! -d "$ROOT_DIR" ]; then
  echo "error: Cannot find root directory: '$ROOT_DIR'" 1>&2
  exit 1
fi

function assert_os() {
  local os="$(uname -s)"
  case "$os" in
  Linux)
    echo "linux"
    ;;
  Darwin)
    echo "darwin"
    ;;
  *)
    echo "error: Unsupported operating system: $os" 1>&2
    exit 1
    ;;
  esac
}

function assert_arch() {
  local arch="$(uname -m)"
  case "$arch" in
  aarch64 | arm64)
    echo "aarch64"
    ;;
  x86_64 | amd64)
    echo "x64"
    ;;
  *)
    echo "error: Unknown architecture: $arch" 1>&2
    exit 1
    ;;
  esac
}

function assert_build() {
  if [ -z "$BUILDKITE_REPO" ]; then
    echo "error: Cannot find repository for this build"
    exit 1
  fi
  if [ -z "$BUILDKITE_COMMIT" ]; then
    echo "error: Cannot find commit for this build"
    exit 1
  fi
  if [ -z "$BUILDKITE_STEP_KEY" ]; then
    echo "error: Cannot find step key for this build"
    exit 1
  fi
  if [ -n "$BUILDKITE_GROUP_KEY" ] && [[ "$BUILDKITE_STEP_KEY" != "$BUILDKITE_GROUP_KEY"* ]]; then
    echo "error: Build step '$BUILDKITE_STEP_KEY' does not start with group key '$BUILDKITE_GROUP_KEY'"
    exit 1
  fi
  # Skip os and arch checks for Zig, since it's cross-compiled on macOS
  if [[ "$BUILDKITE_STEP_KEY" != *"zig"* ]]; then
    local os="$(assert_os)"
    if [[ "$BUILDKITE_STEP_KEY" != *"$os"* ]]; then
      echo "error: Build step '$BUILDKITE_STEP_KEY' does not match operating system '$os'"
      exit 1
    fi
    local arch="$(assert_arch)"
    if [[ "$BUILDKITE_STEP_KEY" != *"$arch"* ]]; then
      echo "error: Build step '$BUILDKITE_STEP_KEY' does not match architecture '$arch'"
      exit 1
    fi
  fi
}

function assert_buildkite_agent() {
  if (! command -v buildkite-agent &>/dev/null); then
    echo "error: Cannot find buildkite-agent, please install it:"
    echo "https://buildkite.com/docs/agent/v3/install"
    exit 1
  fi
}

function export_environment() {
  source "${ROOT_DIR}/scripts/env.sh"
  source "${ROOT_DIR}/scripts/update-submodules.sh"

  { set +x; } 2>/dev/null
  export GIT_SHA="$BUILDKITE_COMMIT"
  if [ "$BUILDKITE_CLEAN_CHECKOUT" == "true" ] || [ "$BUILDKITE_BRANCH" == "main" ]; then
    local tmpdir="$(mktemp -d 2>/dev/null || mktemp -d -t 'new')"
    export CCACHE_DIR="$tmpdir/.cache/ccache"
    export SCCACHE_DIR="$tmpdir/.cache/sccache"
    export ZIG_LOCAL_CACHE_DIR="$tmpdir/.cache/zig-cache"
    export ZIG_GLOBAL_CACHE_DIR="$tmpdir/.cache/zig-cache"
    export BUN_DEPS_CACHE_DIR="$tmpdir/.cache/bun-deps"
    export CCACHE_RECACHE="1"
  else
    export CCACHE_DIR="$HOME/.cache/ccache/$BUILDKITE_STEP_KEY"
    export SCCACHE_DIR="$HOME/.cache/sccache/$BUILDKITE_STEP_KEY"
    export ZIG_LOCAL_CACHE_DIR="$HOME/.cache/zig-cache/$BUILDKITE_STEP_KEY"
    export ZIG_GLOBAL_CACHE_DIR="$HOME/.cache/zig-cache/$BUILDKITE_STEP_KEY"
    export BUN_DEPS_CACHE_DIR="$HOME/.cache/bun-deps/$BUILDKITE_STEP_KEY"
  fi
  if [ "$(assert_os)" == "linux" ]; then
    export USE_LTO="ON"
  fi
  if [ "$(assert_arch)" == "aarch64" ]; then
    export CPU_TARGET="native"
  elif [[ "$BUILDKITE_STEP_KEY" == *"baseline"* ]]; then
    export CPU_TARGET="nehalem"
  else
    export CPU_TARGET="haswell"
  fi
  if $(buildkite-agent meta-data exists release &>/dev/null); then
    export CMAKE_BUILD_TYPE="$(buildkite-agent meta-data get release)"
  else
    export CMAKE_BUILD_TYPE="Release"
  fi
  if $(buildkite-agent meta-data exists canary &>/dev/null); then
    export CANARY="$(buildkite-agent meta-data get canary)"
  else
    export CANARY="1"
  fi
  if $(buildkite-agent meta-data exists assertions &>/dev/null); then
    export USE_DEBUG_JSC="$(buildkite-agent meta-data get assertions)"
  else
    export USE_DEBUG_JSC="OFF"
  fi
}

assert_build
assert_buildkite_agent
export_environment