#!/bin/sh
set -eu

ROOT=$(CDPATH='' cd -- "$(dirname -- "$0")/.." && pwd)
ASSETS="$ROOT/android/store-assets"
LISTINGS="$ROOT/android/play-store"

if ! command -v identify >/dev/null 2>&1; then
  echo "ImageMagick identify is required to validate Play Store assets." >&2
  exit 1
fi

validate_image() {
  path=$1
  expected_width=$2
  expected_height=$3
  max_bytes=$4
  alpha_policy=$5

  if [ ! -s "$path" ]; then
    echo "Missing or empty Play Store asset: $path" >&2
    exit 1
  fi

  dimensions=$(identify -format '%wx%h' "$path")
  if [ "$dimensions" != "${expected_width}x${expected_height}" ]; then
    echo "Unexpected dimensions for $path: $dimensions" >&2
    exit 1
  fi

  bytes=$(stat -c '%s' "$path")
  if [ "$bytes" -gt "$max_bytes" ]; then
    echo "Play Store asset exceeds its size limit: $path ($bytes bytes)" >&2
    exit 1
  fi

  channels=$(identify -format '%[channels]' "$path")
  case "$alpha_policy:$channels" in
    required:*a*) ;;
    forbidden:*a*)
      echo "Play Store asset must not contain an alpha channel: $path" >&2
      exit 1
      ;;
    forbidden:*) ;;
    required:*)
      echo "Play Store asset must contain an alpha channel: $path" >&2
      exit 1
      ;;
  esac
}

extract_section() {
  file=$1
  heading=$2

  awk -v heading="$heading" '
    $0 == heading {in_section = 1; next}
    in_section && /^## / {exit}
    in_section {
      if (seen || $0 != "") {
        print
        seen = 1
      }
    }
  ' "$file" |
    sed -e '/^[[:space:]]*$/d' -e '${/^$/d;}'
}

validate_image "$ASSETS/icon-512.png" 512 512 1048576 required
validate_image \
  "$ASSETS/feature-graphic-1024x500.png" \
  1024 500 15728640 forbidden

screenshot_count=0
for screenshot in "$ASSETS"/screenshots/phone/*.png; do
  validate_image "$screenshot" 1080 1920 8388608 forbidden
  screenshot_count=$((screenshot_count + 1))
done

if [ "$screenshot_count" -lt 4 ]; then
  echo "At least four approved phone screenshots are required." >&2
  exit 1
fi

for listing in "$LISTINGS"/store-listing-*.md; do
  app_name=$(extract_section "$listing" "## App name")
  short_description=$(extract_section "$listing" "## Short description")
  full_description=$(extract_section "$listing" "## Full description")

  app_name_length=$(printf '%s' "$app_name" | wc -m)
  short_length=$(printf '%s' "$short_description" | wc -m)
  full_length=$(printf '%s' "$full_description" | wc -m)

  if [ "$app_name_length" -gt 30 ]; then
    echo "App name exceeds 30 characters in $listing." >&2
    exit 1
  fi

  if [ "$short_length" -gt 80 ]; then
    echo "Short description exceeds 80 characters in $listing." >&2
    exit 1
  fi

  if [ "$full_length" -gt 4000 ]; then
    echo "Full description exceeds 4000 characters in $listing." >&2
    exit 1
  fi
done

echo "Play Store assets and listing lengths are valid."