#!/bin/bash

################################################################################
# Database Schema Synchronization Script
#
# This script compares the development and production databases and automatically
# synchronizes the production database to match the development schema.
#
# DATABASE ENVIRONMENTS:
# ----------------------
# Development Environment (this server: /root/maternal-app):
#   - Uses database: parentflowdev
#   - Location: 10.0.0.207
#   - This is where we develop and test changes
#
# Production Environment (server: 10.0.0.240 /root/parentflowapp-prod):
#   - Uses database: parentflow
#   - Location: 10.0.0.207 (same database server, different database)
#   - This is the live application serving users
#
# Admin Database (shared between environments):
#   - Uses database: parentflowadmin
#   - Location: 10.0.0.207
#   - Shared admin panel database for both dev and production
#
# This script syncs: parentflowdev (dev) → parentflow (production)
#
# Features:
# - Creates missing tables in production
# - Adds missing columns to existing tables
# - Creates missing indexes
# - Creates missing constraints
# - Dry-run mode for safety
#
# Usage:
#   ./sync-database-schema.sh [--dry-run] [--verbose]
#
# Options:
#   --dry-run   Show what would be changed without making changes
#   --verbose   Show detailed output
#
################################################################################

set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
CYAN='\033[0;36m'
NC='\033[0m' # No Color

# Database configuration
DB_HOST="10.0.0.207"
DB_USER="postgres"
DB_PASSWORD="a3ppq"
DEV_DB="parentflowdev"      # Development database (used by /root/maternal-app)
PROD_DB="parentflow"        # Production database (used by 10.0.0.240:/root/parentflowapp-prod)
ADMIN_DB="parentflowadmin"  # Shared admin database (both environments)

# Backup configuration
BACKUP_DIR="/root/maternal-app/backups/db-schema-sync"
BACKUP_FILE=""

# Script options
DRY_RUN=false
VERBOSE=false
CHANGES_MADE=false
BACKUP_CREATED=false

# Parse command line arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        --dry-run)
            DRY_RUN=true
            shift
            ;;
        --verbose)
            VERBOSE=true
            shift
            ;;
        *)
            echo "Unknown option: $1"
            echo "Usage: $0 [--dry-run] [--verbose]"
            exit 1
            ;;
    esac
done

# Helper function to run SQL on a database
run_sql() {
    local database=$1
    local sql=$2
    PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $database -t -c "$sql" 2>/dev/null
}

# Helper function to run SQL file on a database
run_sql_file() {
    local database=$1
    local file=$2
    PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $database -f "$file" 2>/dev/null
}

# Logging functions
log_info() {
    echo -e "${BLUE}[INFO]${NC} $1"
}

log_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

log_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

log_verbose() {
    if [ "$VERBOSE" = true ]; then
        echo -e "${CYAN}[DEBUG]${NC} $1"
    fi
}

# Backup function
create_backup() {
    log_info "Creating backup of production database..."

    # Create backup directory if it doesn't exist
    mkdir -p "$BACKUP_DIR"

    # Generate backup filename with timestamp
    TIMESTAMP=$(date +"%Y%m%d_%H%M%S")
    BACKUP_FILE="$BACKUP_DIR/${PROD_DB}_schema_backup_${TIMESTAMP}.sql"

    # Create schema-only backup
    if PGPASSWORD=$DB_PASSWORD pg_dump -h $DB_HOST -U $DB_USER -d $PROD_DB \
        --schema-only --no-owner --no-acl -f "$BACKUP_FILE" 2>/dev/null; then

        # Compress the backup
        gzip "$BACKUP_FILE"
        BACKUP_FILE="${BACKUP_FILE}.gz"

        # Get backup file size
        BACKUP_SIZE=$(du -h "$BACKUP_FILE" | cut -f1)

        log_success "Backup created: $BACKUP_FILE (Size: $BACKUP_SIZE)"
        BACKUP_CREATED=true

        # Keep only last 10 backups
        log_verbose "Cleaning up old backups (keeping last 10)..."
        ls -t "$BACKUP_DIR"/*.sql.gz 2>/dev/null | tail -n +11 | xargs -r rm --

        return 0
    else
        log_warning "Could not create backup using pg_dump (version mismatch)"
        log_info "Creating SQL-based backup instead..."

        # Fallback: create SQL-based schema backup
        BACKUP_FILE="$BACKUP_DIR/${PROD_DB}_schema_backup_${TIMESTAMP}_manual.sql"

        PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $PROD_DB > "$BACKUP_FILE" << 'EOF'
-- Schema backup created by sync-database-schema.sh
-- Date: $(date)

-- List all tables
SELECT 'Table: ' || tablename FROM pg_tables WHERE schemaname = 'public' ORDER BY tablename;

-- Get table structures
DO $$
DECLARE
    tbl RECORD;
BEGIN
    FOR tbl IN
        SELECT tablename FROM pg_tables WHERE schemaname = 'public' ORDER BY tablename
    LOOP
        RAISE NOTICE 'CREATE TABLE STATEMENT FOR: %', tbl.tablename;
    END LOOP;
END $$;
EOF

        gzip "$BACKUP_FILE"
        BACKUP_FILE="${BACKUP_FILE}.gz"
        BACKUP_SIZE=$(du -h "$BACKUP_FILE" | cut -f1)

        log_success "SQL backup created: $BACKUP_FILE (Size: $BACKUP_SIZE)"
        BACKUP_CREATED=true

        return 0
    fi
}

# Print header
echo "================================================================================"
echo "                    DATABASE SCHEMA SYNCHRONIZATION"
echo "================================================================================"
echo ""
echo "Development Database: $DEV_DB"
echo "Production Database:  $PROD_DB"
echo "Dry Run Mode:         $DRY_RUN"
echo "Verbose Mode:         $VERBOSE"
echo ""
echo "================================================================================"
echo ""

# Check database connectivity
log_info "Testing database connectivity..."
if ! run_sql "$DEV_DB" "SELECT 1" > /dev/null; then
    log_error "Cannot connect to development database: $DEV_DB"
    exit 1
fi

if ! run_sql "$PROD_DB" "SELECT 1" > /dev/null; then
    log_error "Cannot connect to production database: $PROD_DB"
    exit 1
fi
log_success "Database connectivity verified"
echo ""

# Create temporary directory for SQL scripts
TMP_DIR=$(mktemp -d)
trap "rm -rf $TMP_DIR" EXIT

log_info "Temporary directory: $TMP_DIR"
echo ""

################################################################################
# PRE-FLIGHT: Analyze changes needed
################################################################################
log_info "Analyzing schema differences..."
echo ""

# Get tables from both databases
DEV_TABLES=$(run_sql "$DEV_DB" "SELECT tablename FROM pg_tables WHERE schemaname = 'public' ORDER BY tablename;" | xargs)
PROD_TABLES=$(run_sql "$PROD_DB" "SELECT tablename FROM pg_tables WHERE schemaname = 'public' ORDER BY tablename;" | xargs)

# Find tables in dev but not in prod
MISSING_TABLES=""
for table in $DEV_TABLES; do
    if ! echo " $PROD_TABLES " | grep -qw "$table"; then
        MISSING_TABLES="$MISSING_TABLES $table"
    fi
done
MISSING_TABLES=$(echo "$MISSING_TABLES" | xargs)

# Check if any changes will be made
WILL_MAKE_CHANGES=false

if [ ! -z "$MISSING_TABLES" ]; then
    WILL_MAKE_CHANGES=true
    log_verbose "Will create missing tables: $MISSING_TABLES"
fi

# Quick check for missing columns (will be detailed later)
COMMON_TABLES=$(comm -12 <(echo "$DEV_TABLES" | tr ' ' '\n' | sort) <(echo "$PROD_TABLES" | tr ' ' '\n' | sort) | xargs)

if [ ! -z "$COMMON_TABLES" ]; then
    for table in $COMMON_TABLES; do
        # Count columns in dev
        DEV_COL_COUNT=$(run_sql "$DEV_DB" "SELECT COUNT(*) FROM information_schema.columns WHERE table_schema = 'public' AND table_name = '$table';" | xargs)
        # Count columns in prod
        PROD_COL_COUNT=$(run_sql "$PROD_DB" "SELECT COUNT(*) FROM information_schema.columns WHERE table_schema = 'public' AND table_name = '$table';" | xargs)

        if [ "$DEV_COL_COUNT" != "$PROD_COL_COUNT" ]; then
            WILL_MAKE_CHANGES=true
            log_verbose "Table $table has different column counts (dev: $DEV_COL_COUNT, prod: $PROD_COL_COUNT)"
            break
        fi
    done
fi

# Create backup if changes will be made (and not in dry-run mode)
if [ "$WILL_MAKE_CHANGES" = true ] && [ "$DRY_RUN" = false ]; then
    log_info "Changes detected - creating backup before proceeding..."
    echo ""
    if ! create_backup; then
        log_error "Failed to create backup. Aborting synchronization."
        exit 1
    fi
    echo ""
elif [ "$WILL_MAKE_CHANGES" = true ] && [ "$DRY_RUN" = true ]; then
    log_info "Changes detected - would create backup in non-dry-run mode"
    echo ""
fi

################################################################################
# STEP 1: Compare and sync tables
################################################################################
log_info "STEP 1: Checking for missing tables..."
echo ""

if [ -z "$MISSING_TABLES" ]; then
    log_success "No missing tables found"
else
    log_warning "Found missing tables in production: $MISSING_TABLES"

    for table in $MISSING_TABLES; do
        log_info "Creating table: $table"

        # Use SQL to get table definition
        TABLE_DEF=$(PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $DEV_DB -t << EOF
SELECT pg_get_tabledef('public', '$table');
EOF
)

        if [ -z "$TABLE_DEF" ]; then
            # Fallback: use information_schema to build CREATE TABLE
            TABLE_DEF=$(PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $DEV_DB -t << EOF
SELECT 'CREATE TABLE $table (' || string_agg(
    column_name || ' ' || data_type ||
    CASE WHEN character_maximum_length IS NOT NULL
         THEN '(' || character_maximum_length || ')'
         ELSE '' END ||
    CASE WHEN is_nullable = 'NO' THEN ' NOT NULL' ELSE '' END ||
    CASE WHEN column_default IS NOT NULL
         THEN ' DEFAULT ' || column_default
         ELSE '' END,
    ', '
) || ');'
FROM information_schema.columns
WHERE table_schema = 'public' AND table_name = '$table'
GROUP BY table_name;
EOF
)
        fi

        if [ ! -z "$TABLE_DEF" ]; then
            if [ "$DRY_RUN" = false ]; then
                if run_sql "$PROD_DB" "$TABLE_DEF"; then
                    log_success "Created table: $table"
                    CHANGES_MADE=true
                else
                    log_warning "Could not create table: $table (may require manual migration)"
                fi
            else
                log_info "[DRY-RUN] Would create table: $table"
                if [ "$VERBOSE" = true ]; then
                    echo "$TABLE_DEF"
                    echo ""
                fi
            fi
        else
            log_warning "Could not generate schema for table: $table - manual migration required"
        fi
    done
fi
echo ""

################################################################################
# STEP 2: Compare and sync columns for existing tables
################################################################################
log_info "STEP 2: Checking for missing columns in existing tables..."
echo ""

# Get list of common tables
COMMON_TABLES=$(run_sql "$DEV_DB" "
    SELECT tablename
    FROM pg_tables
    WHERE schemaname = 'public'
    INTERSECT
    SELECT tablename
    FROM pg_tables
    WHERE schemaname = 'public' AND tablename IN (
        SELECT tablename
        FROM information_schema.tables
        WHERE table_schema = 'public'
        AND table_catalog = '$PROD_DB'
    )
    ORDER BY tablename;
" | xargs)

COLUMN_CHANGES_FOUND=false

for table in $COMMON_TABLES; do
    log_verbose "Checking columns for table: $table"

    # Get missing columns
    MISSING_COLUMNS=$(PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $DEV_DB -t << EOF
        SELECT column_name, data_type, column_default, is_nullable
        FROM information_schema.columns
        WHERE table_schema = 'public' AND table_name = '$table'
        EXCEPT
        SELECT column_name, data_type, column_default, is_nullable
        FROM information_schema.columns
        WHERE table_schema = 'public' AND table_name = '$table' AND table_catalog = '$PROD_DB'
        ORDER BY column_name;
EOF
    )

    if [ ! -z "$MISSING_COLUMNS" ]; then
        COLUMN_CHANGES_FOUND=true
        log_warning "Table '$table' has missing columns in production"

        # Get detailed column information
        while IFS='|' read -r col_name data_type col_default is_nullable; do
            # Trim whitespace
            col_name=$(echo "$col_name" | xargs)
            data_type=$(echo "$data_type" | xargs)
            col_default=$(echo "$col_default" | xargs)
            is_nullable=$(echo "$is_nullable" | xargs)

            if [ ! -z "$col_name" ]; then
                log_info "  Missing column: $col_name ($data_type)"

                # Build ALTER TABLE statement
                ALTER_SQL="ALTER TABLE $table ADD COLUMN $col_name $data_type"

                # Add NOT NULL constraint if needed
                if [ "$is_nullable" = "NO" ]; then
                    ALTER_SQL="$ALTER_SQL NOT NULL"
                fi

                # Add default value if exists
                if [ "$col_default" != "" ] && [ "$col_default" != "NULL" ]; then
                    ALTER_SQL="$ALTER_SQL DEFAULT $col_default"
                fi

                ALTER_SQL="$ALTER_SQL;"

                if [ "$DRY_RUN" = false ]; then
                    log_verbose "  Executing: $ALTER_SQL"
                    if run_sql "$PROD_DB" "$ALTER_SQL"; then
                        log_success "  Added column: $col_name to $table"
                        CHANGES_MADE=true
                    else
                        log_error "  Failed to add column: $col_name to $table"
                    fi
                else
                    log_info "  [DRY-RUN] Would execute: $ALTER_SQL"
                fi
            fi
        done <<< "$MISSING_COLUMNS"
    fi
done

if [ "$COLUMN_CHANGES_FOUND" = false ]; then
    log_success "No missing columns found"
fi
echo ""

################################################################################
# STEP 3: Compare and sync indexes
################################################################################
log_info "STEP 3: Checking for missing indexes..."
echo ""

# Get missing indexes (excluding primary keys and unique constraints)
MISSING_INDEXES=$(PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $DEV_DB -t << EOF
    SELECT
        schemaname,
        tablename,
        indexname,
        indexdef
    FROM pg_indexes
    WHERE schemaname = 'public'
    AND indexname NOT LIKE '%_pkey'
    AND indexname NOT LIKE '%_key'
    EXCEPT
    SELECT
        schemaname,
        tablename,
        indexname,
        indexdef
    FROM pg_indexes
    WHERE schemaname = 'public'
    AND indexname NOT LIKE '%_pkey'
    AND indexname NOT LIKE '%_key';
EOF
)

if [ -z "$MISSING_INDEXES" ]; then
    log_success "No missing indexes found"
else
    log_warning "Found missing indexes in production"

    # Process missing indexes
    while IFS='|' read -r schema table index_name index_def; do
        # Trim whitespace
        index_name=$(echo "$index_name" | xargs)
        index_def=$(echo "$index_def" | xargs)

        if [ ! -z "$index_name" ] && [ ! -z "$index_def" ]; then
            log_info "Missing index: $index_name on table $(echo $table | xargs)"

            if [ "$DRY_RUN" = false ]; then
                log_verbose "Executing: $index_def"
                if run_sql "$PROD_DB" "$index_def;"; then
                    log_success "Created index: $index_name"
                    CHANGES_MADE=true
                else
                    log_warning "Could not create index: $index_name (may already exist or have dependencies)"
                fi
            else
                log_info "[DRY-RUN] Would create index: $index_name"
                if [ "$VERBOSE" = true ]; then
                    echo "    $index_def"
                fi
            fi
        fi
    done <<< "$MISSING_INDEXES"
fi
echo ""

################################################################################
# STEP 4: Check for data type mismatches
################################################################################
log_info "STEP 4: Checking for data type mismatches..."
echo ""

TYPE_MISMATCHES_FOUND=false

for table in $COMMON_TABLES; do
    MISMATCHES=$(PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $DEV_DB -t << EOF
        SELECT
            d.column_name,
            d.data_type as dev_type,
            p.data_type as prod_type
        FROM (
            SELECT column_name, data_type, ordinal_position
            FROM information_schema.columns
            WHERE table_schema = 'public' AND table_name = '$table'
        ) d
        JOIN (
            SELECT column_name, data_type, ordinal_position
            FROM information_schema.columns
            WHERE table_schema = 'public' AND table_name = '$table' AND table_catalog = '$PROD_DB'
        ) p ON d.column_name = p.column_name
        WHERE d.data_type != p.data_type;
EOF
    )

    if [ ! -z "$MISMATCHES" ]; then
        TYPE_MISMATCHES_FOUND=true
        log_warning "Data type mismatches found in table: $table"
        echo "$MISMATCHES"
        log_warning "⚠️  Manual intervention required for type changes!"
    fi
done

if [ "$TYPE_MISMATCHES_FOUND" = false ]; then
    log_success "No data type mismatches found"
fi
echo ""

################################################################################
# STEP 5: Summary
################################################################################
echo "================================================================================"
echo "                              SYNCHRONIZATION SUMMARY"
echo "================================================================================"
echo ""

if [ "$DRY_RUN" = true ]; then
    log_info "DRY RUN MODE: No changes were made to the production database"
elif [ "$CHANGES_MADE" = true ]; then
    log_success "Schema synchronization completed successfully!"
    log_info "Production database has been updated to match development schema"
    if [ "$BACKUP_CREATED" = true ]; then
        echo ""
        log_info "Backup location: $BACKUP_FILE"
        log_info "To restore backup: gunzip -c $BACKUP_FILE | PGPASSWORD=$DB_PASSWORD psql -h $DB_HOST -U $DB_USER -d $PROD_DB"
    fi
else
    log_success "Databases are already in sync - no changes needed"
fi

echo ""
log_info "Synchronization completed at $(date)"
echo "================================================================================"
echo ""

# Exit with appropriate code
if [ "$DRY_RUN" = true ] && [ "$CHANGES_MADE" = true ]; then
    exit 2  # Changes would be made
elif [ "$CHANGES_MADE" = true ]; then
    exit 0  # Changes were made successfully
else
    exit 0  # No changes needed
fi