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

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
DIST_DIR="${DIST_DIR:-"$ROOT_DIR/dist/field"}"
TARGETS="${TARGETS:-}"
APPS="${APPS:-"edge node"}"
CGO_ENABLED="${CGO_ENABLED:-0}"
GOFLAGS="${GOFLAGS:-"-trimpath"}"

if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
  cat <<'USAGE'
Build field-deployable IOP edge/node binaries.

Usage:
  bin/build/field-binaries.sh

Environment:
  APPS="edge node"                 apps to build
  TARGETS="linux/amd64 linux/arm64" GOOS/GOARCH target list
  DIST_DIR=dist/field              output directory
  VERSION=<value>                  release version label
  COMMIT=<value>                   commit label
  BUILD_DATE=<value>               build date label
  CGO_ENABLED=0                    Go CGO setting
  GOFLAGS="-trimpath"              extra go build flags
  LDFLAGS="-s -w"                  linker flags
USAGE
  exit 0
fi

VERSION="${VERSION:-"$(git -C "$ROOT_DIR" describe --tags --always --dirty 2>/dev/null || echo dev)"}"
COMMIT="${COMMIT:-"$(git -C "$ROOT_DIR" rev-parse --short=12 HEAD 2>/dev/null || echo unknown)"}"
BUILD_DATE="${BUILD_DATE:-"$(date -u +%Y%m%dT%H%M%SZ)"}"
LDFLAGS="${LDFLAGS:-"-s -w"}"

if [[ -z "$TARGETS" ]]; then
  TARGETS="$(go env GOOS)/$(go env GOARCH)"
fi

checksum() {
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$@"
    return
  fi
  shasum -a 256 "$@"
}

build_one() {
  local app="$1"
  local goos="$2"
  local goarch="$3"
  local output_dir="$DIST_DIR/$VERSION/$goos-$goarch"
  local output="$output_dir/iop-$app"

  mkdir -p "$output_dir"
  echo "building $app for $goos/$goarch -> $output"
  (
    cd "$ROOT_DIR"
    GOOS="$goos" GOARCH="$goarch" CGO_ENABLED="$CGO_ENABLED" \
      go build $GOFLAGS -ldflags "$LDFLAGS" -o "$output" "./apps/$app/cmd/$app"
  )
  checksum "$output" > "$output.sha256"
}

for target in $TARGETS; do
  IFS=/ read -r goos goarch extra <<< "$target"
  if [[ -z "${goos:-}" || -z "${goarch:-}" || -n "${extra:-}" ]]; then
    echo "invalid target '$target'; expected GOOS/GOARCH" >&2
    exit 1
  fi

  for app in $APPS; do
    case "$app" in
      edge|node) build_one "$app" "$goos" "$goarch" ;;
      *)
        echo "unsupported app '$app'; expected edge or node" >&2
        exit 1
        ;;
    esac
  done

  output_dir="$DIST_DIR/$VERSION/$goos-$goarch"
  {
    echo "version=$VERSION"
    echo "commit=$COMMIT"
    echo "build_date=$BUILD_DATE"
    echo "target=$goos/$goarch"
    echo "apps=$APPS"
  } > "$output_dir/manifest.env"
  (
    cd "$output_dir"
    checksum iop-* | grep -v '\.sha256$' > SHA256SUMS
  )
done

echo "field binaries written to $DIST_DIR/$VERSION"