package main

import (
	"database/sql"
	"fmt"
	"time"
)

// 定期更新小时雨量统计
func startHourlyRainfallUpdater() {
	// 确保小时雨量表存在
	ensureHourlyRainfallTable()
	
	// 更新历史数据
	updateHistoricalHourlyRainfall()
	
	// 启动定时更新
	go periodicHourlyRainfallUpdate()
}

// 确保小时雨量表存在
func ensureHourlyRainfallTable() {
	_, err := db.Exec(`
		CREATE TABLE IF NOT EXISTS hourly_rainfall (
			id INTEGER PRIMARY KEY AUTOINCREMENT,
			hour_start DATETIME NOT NULL,
			hour_end DATETIME NOT NULL,
			rainfall INTEGER NOT NULL,
			min_value INTEGER,
			max_value INTEGER,
			samples INTEGER,
			created_at DATETIME NOT NULL,
			UNIQUE(hour_start)
		)
	`)
	
	if err != nil {
		logger.Printf("创建小时雨量表错误: %v", err)
	}
}

// 更新历史小时雨量数据（从2025-04-21 18:00:00开始）
func updateHistoricalHourlyRainfall() {
	logger.Printf("开始更新历史小时雨量数据...")
	
	// 查询现有的小时数据
	rows, err := db.Query(`
		SELECT 
			datetime(strftime('%Y-%m-%d %H:00:00', timestamp)) as hour_start,
			datetime(strftime('%Y-%m-%d %H:59:59', timestamp)) as hour_end,
			MIN(optical_rain) as min_value,
			MAX(optical_rain) as max_value,
			COUNT(*) as samples,
			MAX(optical_rain) - MIN(optical_rain) as rainfall
		FROM sensor_data
		WHERE timestamp >= '2025-04-21 18:00:00'
		GROUP BY strftime('%Y-%m-%d %H', timestamp)
		ORDER BY hour_start
	`)
	
	if err != nil {
		logger.Printf("查询历史数据错误: %v", err)
		return
	}
	defer rows.Close()
	
	// 准备插入语句
	stmt, err := db.Prepare(`
		INSERT OR IGNORE INTO hourly_rainfall 
		(hour_start, hour_end, rainfall, min_value, max_value, samples, created_at)
		VALUES (?, ?, ?, ?, ?, ?, datetime('now'))
	`)
	
	if err != nil {
		logger.Printf("准备插入语句错误: %v", err)
		return
	}
	defer stmt.Close()
	
	// 插入数据
	count := 0
	for rows.Next() {
		var hourStart, hourEnd string
		var minValue, maxValue, samples, rainfall int
		
		err := rows.Scan(&hourStart, &hourEnd, &minValue, &maxValue, &samples, &rainfall)
		if err != nil {
			logger.Printf("读取行数据错误: %v", err)
			continue
		}
		
		_, err = stmt.Exec(hourStart, hourEnd, rainfall, minValue, maxValue, samples)
		if err != nil {
			logger.Printf("插入数据错误: %v", err)
			continue
		}
		
		count++
	}
	
	logger.Printf("历史小时雨量数据更新完成，共插入 %d 条记录", count)
}

// 定期更新小时雨量
func periodicHourlyRainfallUpdate() {
	// 计算下一个整点后5分钟的时间（给足够时间收集整点数据）
	now := time.Now()
	nextHour := time.Date(now.Year(), now.Month(), now.Day(), now.Hour()+1, 5, 0, 0, now.Location())
	delay := nextHour.Sub(now)
	
	// 首次等待到下一个整点后5分钟
	time.Sleep(delay)
	
	// 然后每小时更新一次
	ticker := time.NewTicker(time.Hour)
	for range ticker.C {
		updateLastHourRainfall()
	}
}

// 更新上一个小时的雨量数据
func updateLastHourRainfall() {
	// 计算上一个小时的时间范围
	now := time.Now()
	lastHourEnd := time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 0, 0, 0, now.Location())
	lastHourStart := lastHourEnd.Add(-time.Hour)
	
	// 查询这个小时的数据
	var minValue, maxValue, samples, rainfall sql.NullInt64
	
	err := db.QueryRow(`
		SELECT 
			MIN(optical_rain),
			MAX(optical_rain),
			COUNT(*),
			MAX(optical_rain) - MIN(optical_rain)
		FROM sensor_data
		WHERE timestamp >= ? AND timestamp < ?
	`, lastHourStart.Format("2006-01-02 15:04:05"), lastHourEnd.Format("2006-01-02 15:04:05")).Scan(
		&minValue, &maxValue, &samples, &rainfall)
	
	if err != nil {
		logger.Printf("查询上一小时数据错误: %v", err)
		return
	}
	
	// 检查是否有足够的数据
	if !samples.Valid || samples.Int64 < 2 {
		logger.Printf("上一小时 (%s) 数据样本不足，跳过更新", lastHourStart.Format("2006-01-02 15:04"))
		return
	}
	
	// 插入或更新小时雨量记录
	_, err = db.Exec(`
		INSERT OR REPLACE INTO hourly_rainfall 
		(hour_start, hour_end, rainfall, min_value, max_value, samples, created_at)
		VALUES (?, ?, ?, ?, ?, ?, datetime('now'))
	`, 
	lastHourStart.Format("2006-01-02 15:04:05"), 
	lastHourEnd.Format("2006-01-02 15:04:05"),
	rainfall.Int64,
	minValue.Int64,
	maxValue.Int64,
	samples.Int64)
	
	if err != nil {
		logger.Printf("更新小时雨量记录错误: %v", err)
		return
	}
	
	logger.Printf("已更新 %s 小时的雨量数据: %.1fmm (%d 个样本)",
		lastHourStart.Format("2006-01-02 15:04"),
		float64(rainfall.Int64)/10.0,
		samples.Int64)
}

// 获取最近24小时的降雨数据
func getRecentHourlyRainfall(hours int) ([]HourlyRainfall, error) {
	if hours <= 0 {
		hours = 24
	}
	
	rows, err := db.Query(`
		SELECT hour_start, rainfall, samples
		FROM hourly_rainfall
		ORDER BY hour_start DESC
		LIMIT ?
	`, hours)
	
	if err != nil {
		return nil, fmt.Errorf("查询小时雨量错误: %v", err)
	}
	defer rows.Close()
	
	var result []HourlyRainfall
	for rows.Next() {
		var hr HourlyRainfall
		var hourStart string
		
		err := rows.Scan(&hourStart, &hr.Rainfall, &hr.Samples)
		if err != nil {
			return nil, fmt.Errorf("读取小时雨量错误: %v", err)
		}
		
		// 解析时间
		hr.HourStart, _ = time.Parse("2006-01-02 15:04:05", hourStart)
		
		result = append(result, hr)
	}
	
	// 反转数组，使其按时间顺序排列
	for i, j := 0, len(result)-1; i < j; i, j = i+1, j-1 {
		result[i], result[j] = result[j], result[i]
	}
	
	return result, nil
}

// 小时雨量数据结构
type HourlyRainfall struct {
	HourStart time.Time
	Rainfall  int64
	Samples   int64
}