#!/bin/bash

# PostgreSQL 生产环境数据库配置脚本
# 用于初始化生产环境数据库配置、连接池、备份策略等

set -e

# 颜色定义
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# 日志函数
log() {
    echo -e "${BLUE}[$(date +'%Y-%m-%d %H:%M:%S')]${NC} $1"
}

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

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

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

# 配置变量
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
CONFIG_DIR="$PROJECT_ROOT/configs"
BACKUP_DIR="/var/backups/photography"
LOG_DIR="/var/log/photography"

# 默认配置
DB_HOST="${DB_HOST:-localhost}"
DB_PORT="${DB_PORT:-5432}"
DB_NAME="${DB_NAME:-photography}"
DB_USER="${DB_USER:-postgres}"
DB_PASSWORD="${DB_PASSWORD:-}"
DB_POOL_SIZE="${DB_POOL_SIZE:-20}"
DB_MAX_CONNECTIONS="${DB_MAX_CONNECTIONS:-100}"

# 检查依赖
check_dependencies() {
    log "检查系统依赖..."
    
    local missing_deps=()
    
    # 检查 PostgreSQL 客户端
    if ! command -v psql &> /dev/null; then
        missing_deps+=("postgresql-client")
    fi
    
    # 检查 Docker（如果使用容器部署）
    if ! command -v docker &> /dev/null; then
        warning "Docker 未安装，跳过容器相关配置"
    fi
    
    # 检查 systemctl
    if ! command -v systemctl &> /dev/null; then
        warning "systemctl 未找到，跳过服务配置"
    fi
    
    if [ ${#missing_deps[@]} -ne 0 ]; then
        error "缺少依赖: ${missing_deps[*]}"
        echo "请运行以下命令安装依赖:"
        echo "sudo apt-get update && sudo apt-get install -y ${missing_deps[*]}"
        exit 1
    fi
    
    success "依赖检查完成"
}

# 创建必要目录
create_directories() {
    log "创建必要目录..."
    
    # 创建备份目录
    sudo mkdir -p "$BACKUP_DIR"
    sudo chown -R postgres:postgres "$BACKUP_DIR"
    sudo chmod 755 "$BACKUP_DIR"
    
    # 创建日志目录
    sudo mkdir -p "$LOG_DIR"
    sudo chown -R postgres:postgres "$LOG_DIR"
    sudo chmod 755 "$LOG_DIR"
    
    # 创建配置目录
    mkdir -p "$CONFIG_DIR/postgres"
    
    success "目录创建完成"
}

# 测试数据库连接
test_connection() {
    log "测试数据库连接..."
    
    if [ -z "$DB_PASSWORD" ]; then
        error "数据库密码未设置，请设置 DB_PASSWORD 环境变量"
        exit 1
    fi
    
    export PGPASSWORD="$DB_PASSWORD"
    
    if psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" -c "SELECT version();" &> /dev/null; then
        success "数据库连接成功"
    else
        error "数据库连接失败，请检查配置"
        exit 1
    fi
}

# 创建数据库配置
create_database_config() {
    log "创建数据库配置..."
    
    # 生产环境配置文件
    cat > "$CONFIG_DIR/postgres/postgresql.conf" << EOF
# PostgreSQL 生产环境配置
# Photography Portfolio 项目

# 连接设置
listen_addresses = '*'
port = $DB_PORT
max_connections = $DB_MAX_CONNECTIONS
superuser_reserved_connections = 3

# 内存设置
shared_buffers = 256MB
effective_cache_size = 1GB
work_mem = 4MB
maintenance_work_mem = 64MB

# WAL 设置
wal_buffers = 16MB
checkpoint_completion_target = 0.9
wal_writer_delay = 200ms

# 查询规划器
random_page_cost = 1.1
effective_io_concurrency = 200
default_statistics_target = 100

# 日志设置
logging_collector = on
log_directory = '$LOG_DIR'
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
log_truncate_on_rotation = on
log_rotation_age = 1d
log_rotation_size = 100MB
log_min_duration_statement = 1000
log_checkpoints = on
log_connections = on
log_disconnections = on
log_lock_waits = on
log_temp_files = 10MB

# 性能监控
shared_preload_libraries = 'pg_stat_statements'
track_activities = on
track_counts = on
track_io_timing = on
track_functions = all

# 自动清理
autovacuum = on
autovacuum_max_workers = 3
autovacuum_naptime = 1min
autovacuum_vacuum_threshold = 50
autovacuum_analyze_threshold = 50

# 时区设置
timezone = 'Asia/Shanghai'
log_timezone = 'Asia/Shanghai'

# 字符集设置
default_text_search_config = 'pg_catalog.simple'
EOF

    # 创建 pg_hba.conf 配置
    cat > "$CONFIG_DIR/postgres/pg_hba.conf" << EOF
# PostgreSQL Client Authentication Configuration File
# Photography Portfolio 项目

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# 本地连接
local   all             postgres                                peer
local   all             all                                     md5

# IPv4 本地连接
host    all             all             127.0.0.1/32            md5
host    all             all             ::1/128                 md5

# 应用连接
host    $DB_NAME        $DB_USER        0.0.0.0/0               md5

# 复制连接
host    replication     postgres        127.0.0.1/32            md5
host    replication     postgres        ::1/128                 md5
EOF

    success "数据库配置创建完成"
}

# 配置连接池
setup_connection_pool() {
    log "配置数据库连接池..."
    
    # 使用 PgBouncer 作为连接池
    if command -v pgbouncer &> /dev/null; then
        cat > "$CONFIG_DIR/postgres/pgbouncer.ini" << EOF
[databases]
$DB_NAME = host=$DB_HOST port=$DB_PORT dbname=$DB_NAME

[pgbouncer]
listen_port = 6432
listen_addr = 127.0.0.1
auth_type = md5
auth_file = $CONFIG_DIR/postgres/userlist.txt
logfile = $LOG_DIR/pgbouncer.log
pidfile = /var/run/pgbouncer/pgbouncer.pid
admin_users = postgres
stats_users = postgres

# 连接池配置
pool_mode = transaction
max_client_conn = 100
default_pool_size = $DB_POOL_SIZE
min_pool_size = 5
reserve_pool_size = 5
reserve_pool_timeout = 5
server_lifetime = 3600
server_idle_timeout = 600

# 性能调优
server_connect_timeout = 15
server_login_retry = 15
query_timeout = 0
query_wait_timeout = 120
client_idle_timeout = 0
client_login_timeout = 60
autodb_idle_timeout = 3600

# 日志设置
log_connections = 1
log_disconnections = 1
log_pooler_errors = 1
EOF

        # 创建用户认证文件
        echo "\"$DB_USER\" \"$DB_PASSWORD\"" > "$CONFIG_DIR/postgres/userlist.txt"
        chmod 600 "$CONFIG_DIR/postgres/userlist.txt"
        
        success "PgBouncer 连接池配置完成"
    else
        warning "PgBouncer 未安装，跳过连接池配置"
        echo "安装 PgBouncer: sudo apt-get install pgbouncer"
    fi
}

# 配置自动备份
setup_backup_strategy() {
    log "配置自动备份策略..."
    
    # 创建备份脚本
    cat > "$BACKUP_DIR/backup.sh" << 'EOF'
#!/bin/bash

# PostgreSQL 自动备份脚本
# Photography Portfolio 项目

set -e

# 配置
DB_HOST="${DB_HOST:-localhost}"
DB_PORT="${DB_PORT:-5432}"
DB_NAME="${DB_NAME:-photography}"
DB_USER="${DB_USER:-postgres}"
BACKUP_DIR="/var/backups/photography"
LOG_FILE="$BACKUP_DIR/backup.log"
RETENTION_DAYS=30

# 日志函数
log() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

# 执行备份
backup_database() {
    local backup_date=$(date +'%Y%m%d_%H%M%S')
    local backup_file="$BACKUP_DIR/${DB_NAME}_${backup_date}.sql"
    local compressed_file="${backup_file}.gz"
    
    log "开始备份数据库: $DB_NAME"
    
    # 执行 pg_dump
    export PGPASSWORD="$DB_PASSWORD"
    if pg_dump -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" \
              -f "$backup_file" \
              --verbose --clean --no-owner --no-privileges \
              "$DB_NAME" 2>> "$LOG_FILE"; then
        
        # 压缩备份文件
        gzip "$backup_file"
        
        # 验证备份文件
        if [ -f "$compressed_file" ] && [ -s "$compressed_file" ]; then
            log "备份成功: $compressed_file"
            log "备份大小: $(du -h "$compressed_file" | cut -f1)"
        else
            log "ERROR: 备份文件创建失败"
            exit 1
        fi
    else
        log "ERROR: 数据库备份失败"
        exit 1
    fi
}

# 清理旧备份
cleanup_old_backups() {
    log "清理 $RETENTION_DAYS 天前的备份文件"
    
    find "$BACKUP_DIR" -name "${DB_NAME}_*.sql.gz" -mtime +$RETENTION_DAYS -delete
    
    log "旧备份清理完成"
}

# 主函数
main() {
    log "=== PostgreSQL 自动备份开始 ==="
    
    backup_database
    cleanup_old_backups
    
    log "=== PostgreSQL 自动备份完成 ==="
}

# 执行主函数
main "$@"
EOF

    # 设置执行权限
    chmod +x "$BACKUP_DIR/backup.sh"
    
    # 创建 crontab 条目
    cat > "$CONFIG_DIR/postgres/backup.crontab" << EOF
# Photography Portfolio 数据库备份计划任务
# 每天凌晨 2 点执行备份

0 2 * * * $BACKUP_DIR/backup.sh >> $LOG_DIR/cron.log 2>&1

# 每周日凌晨 3 点执行完整备份
0 3 * * 0 $BACKUP_DIR/backup.sh full >> $LOG_DIR/cron.log 2>&1
EOF

    success "自动备份策略配置完成"
    echo "要启用自动备份，请运行: sudo crontab $CONFIG_DIR/postgres/backup.crontab"
}

# 配置监控
setup_monitoring() {
    log "配置数据库监控..."
    
    # 创建监控脚本
    cat > "$CONFIG_DIR/postgres/monitor.sh" << 'EOF'
#!/bin/bash

# PostgreSQL 监控脚本
# Photography Portfolio 项目

set -e

# 配置
DB_HOST="${DB_HOST:-localhost}"
DB_PORT="${DB_PORT:-5432}"
DB_NAME="${DB_NAME:-photography}"
DB_USER="${DB_USER:-postgres}"
ALERT_EMAIL="${ALERT_EMAIL:-admin@photography.com}"

# 检查数据库连接
check_connection() {
    export PGPASSWORD="$DB_PASSWORD"
    
    if ! psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" \
             -c "SELECT 1;" &> /dev/null; then
        echo "CRITICAL: 数据库连接失败"
        return 1
    fi
    
    echo "OK: 数据库连接正常"
    return 0
}

# 检查数据库大小
check_database_size() {
    local size_mb=$(psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" \
                        -t -c "SELECT pg_size_pretty(pg_database_size('$DB_NAME'));" | tr -d ' ')
    
    echo "INFO: 数据库大小: $size_mb"
}

# 检查慢查询
check_slow_queries() {
    local slow_count=$(psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" \
                           -t -c "SELECT count(*) FROM pg_stat_statements WHERE mean_time > 1000;" | tr -d ' ')
    
    if [ "$slow_count" -gt 10 ]; then
        echo "WARNING: 发现 $slow_count 个慢查询"
    else
        echo "OK: 慢查询数量正常 ($slow_count)"
    fi
}

# 检查连接数
check_connections() {
    local conn_count=$(psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" \
                           -t -c "SELECT count(*) FROM pg_stat_activity;" | tr -d ' ')
    local max_conn=$(psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" \
                         -t -c "SHOW max_connections;" | tr -d ' ')
    
    local usage_percent=$((conn_count * 100 / max_conn))
    
    if [ $usage_percent -gt 80 ]; then
        echo "WARNING: 连接数使用率过高: $conn_count/$max_conn ($usage_percent%)"
    else
        echo "OK: 连接数正常: $conn_count/$max_conn ($usage_percent%)"
    fi
}

# 主监控函数
main() {
    echo "=== PostgreSQL 监控报告 $(date) ==="
    
    if ! check_connection; then
        echo "数据库连接失败，停止监控"
        exit 1
    fi
    
    check_database_size
    check_slow_queries
    check_connections
    
    echo "=== 监控完成 ==="
}

# 执行监控
main "$@"
EOF

    chmod +x "$CONFIG_DIR/postgres/monitor.sh"
    
    success "数据库监控配置完成"
}

# 配置性能优化
setup_performance_tuning() {
    log "配置性能优化..."
    
    # 创建性能调优脚本
    cat > "$CONFIG_DIR/postgres/tune.sql" << EOF
-- PostgreSQL 性能调优脚本
-- Photography Portfolio 项目

-- 创建性能监控扩展
CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
CREATE EXTENSION IF NOT EXISTS pg_buffercache;

-- 创建索引优化函数
CREATE OR REPLACE FUNCTION analyze_missing_indexes()
RETURNS TABLE (
    schemaname text,
    tablename text,
    seq_scan bigint,
    seq_tup_read bigint,
    idx_scan bigint,
    idx_tup_fetch bigint,
    missing_index_suggestion text
) AS \$\$
BEGIN
    RETURN QUERY
    SELECT 
        s.schemaname,
        s.tablename,
        s.seq_scan,
        s.seq_tup_read,
        s.idx_scan,
        s.idx_tup_fetch,
        CASE 
            WHEN s.seq_scan > s.idx_scan AND s.seq_tup_read > 10000 
            THEN '建议添加索引'
            ELSE '索引使用正常'
        END as missing_index_suggestion
    FROM pg_stat_user_tables s
    WHERE s.schemaname = 'public'
    ORDER BY s.seq_scan DESC, s.seq_tup_read DESC;
END;
\$\$ LANGUAGE plpgsql;

-- 创建慢查询分析函数
CREATE OR REPLACE FUNCTION analyze_slow_queries()
RETURNS TABLE (
    query text,
    calls bigint,
    total_time double precision,
    mean_time double precision,
    rows bigint
) AS \$\$
BEGIN
    RETURN QUERY
    SELECT 
        left(s.query, 100) as query,
        s.calls,
        s.total_time,
        s.mean_time,
        s.rows
    FROM pg_stat_statements s
    WHERE s.mean_time > 100
    ORDER BY s.mean_time DESC
    LIMIT 20;
END;
\$\$ LANGUAGE plpgsql;

-- 创建表空间使用分析函数
CREATE OR REPLACE FUNCTION analyze_table_sizes()
RETURNS TABLE (
    schemaname text,
    tablename text,
    size_pretty text,
    size_bytes bigint
) AS \$\$
BEGIN
    RETURN QUERY
    SELECT 
        s.schemaname,
        s.tablename,
        pg_size_pretty(pg_total_relation_size(s.schemaname||'.'||s.tablename)),
        pg_total_relation_size(s.schemaname||'.'||s.tablename)
    FROM pg_tables s
    WHERE s.schemaname = 'public'
    ORDER BY pg_total_relation_size(s.schemaname||'.'||s.tablename) DESC;
END;
\$\$ LANGUAGE plpgsql;

-- 更新表统计信息
ANALYZE;

-- 重建索引（如需要）
-- REINDEX DATABASE $DB_NAME;
EOF

    success "性能优化配置完成"
}

# 创建启动脚本
create_startup_script() {
    log "创建服务启动脚本..."
    
    cat > "$CONFIG_DIR/postgres/photography-db.service" << EOF
[Unit]
Description=Photography Portfolio Database Service
After=postgresql.service
Requires=postgresql.service

[Service]
Type=oneshot
RemainAfterExit=yes
User=postgres
Group=postgres

# 环境变量
Environment=DB_HOST=$DB_HOST
Environment=DB_PORT=$DB_PORT
Environment=DB_NAME=$DB_NAME
Environment=DB_USER=$DB_USER

# 启动前检查
ExecStartPre=/bin/bash -c 'until pg_isready -h $DB_HOST -p $DB_PORT; do sleep 1; done'

# 启动命令
ExecStart=/bin/bash $CONFIG_DIR/postgres/monitor.sh

# 停止命令
ExecStop=/bin/true

[Install]
WantedBy=multi-user.target
EOF

    success "服务启动脚本创建完成"
    echo "要启用服务，请运行:"
    echo "sudo cp $CONFIG_DIR/postgres/photography-db.service /etc/systemd/system/"
    echo "sudo systemctl enable photography-db.service"
    echo "sudo systemctl start photography-db.service"
}

# 生成配置摘要
generate_summary() {
    log "生成配置摘要..."
    
    cat > "$CONFIG_DIR/postgres/SETUP_SUMMARY.md" << EOF
# PostgreSQL 生产环境配置摘要

## 配置文件位置
- PostgreSQL 配置: \`$CONFIG_DIR/postgres/postgresql.conf\`
- 认证配置: \`$CONFIG_DIR/postgres/pg_hba.conf\`
- PgBouncer 配置: \`$CONFIG_DIR/postgres/pgbouncer.ini\`
- 备份脚本: \`$BACKUP_DIR/backup.sh\`
- 监控脚本: \`$CONFIG_DIR/postgres/monitor.sh\`

## 数据库信息
- 主机: $DB_HOST
- 端口: $DB_PORT
- 数据库: $DB_NAME
- 用户: $DB_USER
- 最大连接数: $DB_MAX_CONNECTIONS
- 连接池大小: $DB_POOL_SIZE

## 目录结构
- 备份目录: $BACKUP_DIR
- 日志目录: $LOG_DIR
- 配置目录: $CONFIG_DIR/postgres

## 自动化任务
- 每日备份: 凌晨 2:00
- 每周完整备份: 周日凌晨 3:00
- 备份保留期: 30 天

## 监控指标
- 数据库连接状态
- 数据库大小
- 慢查询统计
- 连接数使用率

## 性能优化
- 已启用 pg_stat_statements 扩展
- 已创建性能分析函数
- 已配置合理的内存参数
- 已优化 WAL 和检查点设置

## 下一步操作
1. 复制配置文件到 PostgreSQL 目录
2. 重启 PostgreSQL 服务
3. 启用自动备份 crontab
4. 配置监控服务
5. 运行性能调优脚本

## 维护命令
\`\`\`bash
# 手动备份
$BACKUP_DIR/backup.sh

# 监控检查
$CONFIG_DIR/postgres/monitor.sh

# 性能分析
psql -d $DB_NAME -f $CONFIG_DIR/postgres/tune.sql

# 查看慢查询
psql -d $DB_NAME -c "SELECT * FROM analyze_slow_queries();"

# 查看表大小
psql -d $DB_NAME -c "SELECT * FROM analyze_table_sizes();"
\`\`\`

配置完成时间: $(date)
EOF

    success "配置摘要生成完成: $CONFIG_DIR/postgres/SETUP_SUMMARY.md"
}

# 主函数
main() {
    log "开始 PostgreSQL 生产环境配置..."
    
    check_dependencies
    create_directories
    test_connection
    create_database_config
    setup_connection_pool
    setup_backup_strategy
    setup_monitoring
    setup_performance_tuning
    create_startup_script
    generate_summary
    
    success "PostgreSQL 生产环境配置完成!"
    echo ""
    echo "配置文件位置: $CONFIG_DIR/postgres/"
    echo "查看配置摘要: cat $CONFIG_DIR/postgres/SETUP_SUMMARY.md"
    echo ""
    echo "要应用配置，请参考配置摘要中的'下一步操作'部分"
}

# 处理命令行参数
case "${1:-}" in
    "test")
        test_connection
        ;;
    "backup")
        setup_backup_strategy
        ;;
    "monitor")
        setup_monitoring
        ;;
    "tune")
        setup_performance_tuning
        ;;
    *)
        main
        ;;
esac