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

# ── build-apk.sh ──────────────────────────────────────────────────────────────
# Builds the Meal Tracker Android APK from the android/ directory.
#
# Usage:
#   ./build-apk.sh              # Build debug APK (default)
#   ./build-apk.sh release      # Build release APK (unsigned)
#
# Prerequisites (auto-installed if missing):
#   - Java 17+ (OpenJDK)
#   - Android SDK command-line tools
#   - Gradle (via wrapper)
# ──────────────────────────────────────────────────────────────────────────────

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ANDROID_DIR="$SCRIPT_DIR/android"
OUTPUT_DIR="$ANDROID_DIR/app/build/outputs/apk"
SDK_ROOT="${ANDROID_SDK_ROOT:-$HOME/android-sdk}"
CMDLINE_URL="https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip"
BUILD_TOOLS_VER="34.0.0"
PLATFORM_VER="34"
GRADLE_VER="8.7"
GRADLE_URL="https://services.gradle.org/distributions/gradle-${GRADLE_VER}-bin.zip"

BUILD_TYPE="${1:-debug}"

# ── Colors ──
RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; NC='\033[0m'
info()  { echo -e "${GREEN}[INFO]${NC}  $*"; }
warn()  { echo -e "${YELLOW}[WARN]${NC}  $*"; }
err()   { echo -e "${RED}[ERR]${NC}   $*"; }

# ── Detect package manager ──
if command -v apt-get &>/dev/null; then
    PM="apt"
elif command -v yum &>/dev/null; then
    PM="yum"
elif command -v dnf &>/dev/null; then
    PM="dnf"
else
    PM=""
fi

# ── Install Java if needed ──
install_java() {
    info "Installing Java 17..."
    case "$PM" in
        apt)
            apt-get update -qq && apt-get install -y -qq openjdk-21-jdk-headless ;;
        yum)
            yum install -y java-17-openjdk-headless ;;
        dnf)
            dnf install -y java-17-openjdk-headless ;;
        *)
            err "Cannot install Java automatically. Please install Java 17+ manually."
            exit 1
            ;;
    esac
}

if ! command -v java &>/dev/null; then
    if [ "$PM" != "" ]; then
        install_java
    else
        err "Java is required but not found. Install Java 17+ (OpenJDK)."
        exit 1
    fi
fi

JAVA_VER=$(java -version 2>&1 | head -1 | grep -oP '\d+' | head -1 || echo "0")
if [ "$JAVA_VER" -lt 17 ] 2>/dev/null; then
    warn "Java $JAVA_VER detected. Java 17+ is recommended."
fi
info "Java: $(java -version 2>&1 | head -1)"

# ── Install Android SDK if needed ──
install_sdk() {
    info "Installing Android SDK command-line tools to $SDK_ROOT..."
    mkdir -p "$SDK_ROOT"
    tmp_zip="/tmp/cmdline-tools.zip"
    tmp_dir="/tmp/cmdline-tools-tmp"

    if command -v wget &>/dev/null; then
        wget -q --show-progress "$CMDLINE_URL" -O "$tmp_zip"
    elif command -v curl &>/dev/null; then
        curl -L --progress-bar "$CMDLINE_URL" -o "$tmp_zip"
    else
        err "Need wget or curl to download Android SDK."
        exit 1
    fi

    rm -rf "$tmp_dir"
    mkdir -p "$tmp_dir"
    unzip -qo "$tmp_zip" -d "$tmp_dir"
    mkdir -p "$SDK_ROOT/cmdline-tools"
    rm -rf "$SDK_ROOT/cmdline-tools/latest"
    mv "$tmp_dir/cmdline-tools" "$SDK_ROOT/cmdline-tools/latest"
    rm -f "$tmp_zip"
    rm -rf "$tmp_dir"
    info "Android SDK command-line tools installed."
}

if [ ! -f "$SDK_ROOT/cmdline-tools/latest/bin/sdkmanager" ]; then
    install_sdk
fi

export ANDROID_SDK_ROOT="$SDK_ROOT"

# Accept SDK licenses (avoid SIGPIPE under -o pipefail)
{ yes 2>/dev/null || true; } | "$SDK_ROOT/cmdline-tools/latest/bin/sdkmanager" --licenses > /dev/null 2>&1 || true

# ── Install required SDK packages ──
info "Checking Android SDK packages..."
"$SDK_ROOT/cmdline-tools/latest/bin/sdkmanager" \
    "platform-tools" \
    "build-tools;${BUILD_TOOLS_VER}" \
    "platforms;android-${PLATFORM_VER}" \
    > /dev/null 2>&1 || true

# Create local.properties
cat > "$ANDROID_DIR/local.properties" <<EOF
sdk.dir=$SDK_ROOT
EOF

# ── Download Gradle if needed ──
GRADLE_DIR="$ANDROID_DIR/.gradle-home"
GRADLE_BIN="$GRADLE_DIR/gradle-${GRADLE_VER}/bin/gradle"
if [ ! -f "$GRADLE_BIN" ]; then
    info "Downloading Gradle ${GRADLE_VER}..."
    gradle_zip="/tmp/gradle-${GRADLE_VER}.zip"
    if command -v wget &>/dev/null; then
        wget -q --show-progress "$GRADLE_URL" -O "$gradle_zip"
    else
        curl -L --progress-bar "$GRADLE_URL" -o "$gradle_zip"
    fi
    rm -rf "$GRADLE_DIR"
    mkdir -p "$GRADLE_DIR"
    unzip -qo "$gradle_zip" -d "$GRADLE_DIR"
    rm -f "$gradle_zip"
    info "Gradle ${GRADLE_VER} ready."
fi

# Generate wrapper in the android dir so gradlew works
if [ ! -f "$ANDROID_DIR/gradlew" ]; then
    info "Generating Gradle wrapper..."
    cd "$ANDROID_DIR"
    "$GRADLE_BIN" wrapper --gradle-version "$GRADLE_VER" --no-daemon 2>&1 | tail -3
    cd "$SCRIPT_DIR"
fi

# ── Build ──
info "Building $BUILD_TYPE APK..."
cd "$ANDROID_DIR"
./gradlew "assemble${BUILD_TYPE^}" --no-daemon --warning-mode=all

# ── Report ──
APK_FILE=$(find "$OUTPUT_DIR" -name "*.apk" -type f | head -1)
if [ -f "$APK_FILE" ]; then
    cp "$APK_FILE" "$SCRIPT_DIR/meal-tracker.apk"
    APK_SIZE=$(du -h "$APK_FILE" | cut -f1)
    echo ""
    echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
    echo -e "  ${GREEN}✓ BUILD SUCCESSFUL${NC}"
    echo "  APK: $SCRIPT_DIR/meal-tracker.apk"
    echo "  Size: $APK_SIZE"
    echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
else
    err "APK not found in $OUTPUT_DIR"
    exit 1
fi