package main

import (
	"bssapp-backend/queries"
	"context"
	"database/sql"
	"log"
	"os"
	"strconv"
	"strings"
	"sync/atomic"
	"time"
)

func startProductPerformanceScheduler(pgDB *sql.DB) {
	enabled := strings.TrimSpace(strings.ToLower(os.Getenv("PRODUCT_PERFORMANCE_ENABLED")))
	if enabled == "0" || enabled == "false" || enabled == "off" {
		log.Println("Product performance scheduler disabled")
		return
	}
	if pgDB == nil {
		return
	}

	deltaDays := productPerformanceEnvInt("PRODUCT_PERFORMANCE_DELTA_DAYS", 45, 1, 365)
	deltaHHMM := productPerformanceEnvString("PRODUCT_PERFORMANCE_DELTA_HHMM", "02:00")
	deltaTimeoutHours := productPerformanceEnvInt("PRODUCT_PERFORMANCE_DELTA_TIMEOUT_HOURS", 6, 1, 24)
	runOnStartup := productPerformanceEnvBool("PRODUCT_PERFORMANCE_DELTA_RUN_ON_STARTUP", false)

	var running int32
	runDelta := func(reason string) {
		if !atomic.CompareAndSwapInt32(&running, 0, 1) {
			log.Printf("[ProductPerformanceJob] skip (%s): already running", reason)
			return
		}
		defer atomic.StoreInt32(&running, 0)

		endDate := time.Now()
		ctx, cancel := context.WithTimeout(context.Background(), time.Duration(deltaTimeoutHours)*time.Hour)
		defer cancel()

		result, err := queries.RefreshProductPerformance(ctx, pgDB, queries.ProductPerformanceRefreshRequest{
			Mode:      "delta",
			Stage:     "all",
			StartDate: endDate.AddDate(0, 0, -deltaDays),
			EndDate:   endDate,
		})
		if err != nil {
			log.Printf("[ProductPerformanceJob] error (%s): %v", reason, err)
			return
		}
		log.Printf("[ProductPerformanceJob] ok (%s): mode=%s stage=%s start=%s end=%s sales=%d stock=%d kpi=%d duration_ms=%d",
			reason, result.Mode, result.Stage, result.StartDate, result.EndDate, result.SalesRows, result.StockRows, result.KpiRows, result.DurationMS)
	}

	log.Printf("[ProductPerformanceJob] scheduled daily_delta=%s lookback_days=%d run_delta_on_startup=%t",
		deltaHHMM, deltaDays, runOnStartup)

	go func() {
		if runOnStartup {
			time.Sleep(20 * time.Second)
			runDelta("startup-delta")
		}

		for {
			next := productPerformanceNextDaily(time.Now(), deltaHHMM)
			log.Printf("[ProductPerformanceJob] daily delta next_at=%s in=%s", next.Format(time.RFC3339), time.Until(next).Round(time.Second))
			time.Sleep(time.Until(next))
			runDelta("daily-delta")
		}
	}()
}

func productPerformanceNextDaily(now time.Time, hhmm string) time.Time {
	hour, minute := productPerformanceParseHHMM(hhmm, 2, 0)
	next := time.Date(now.Year(), now.Month(), now.Day(), hour, minute, 0, 0, now.Location())
	if !next.After(now) {
		next = next.AddDate(0, 0, 1)
	}
	return next
}

func productPerformanceParseHHMM(raw string, fallbackHour, fallbackMinute int) (int, int) {
	parts := strings.Split(strings.TrimSpace(raw), ":")
	if len(parts) != 2 {
		return fallbackHour, fallbackMinute
	}
	h, herr := strconv.Atoi(parts[0])
	m, merr := strconv.Atoi(parts[1])
	if herr != nil || merr != nil || h < 0 || h > 23 || m < 0 || m > 59 {
		return fallbackHour, fallbackMinute
	}
	return h, m
}

func productPerformanceEnvString(name, fallback string) string {
	raw := strings.TrimSpace(os.Getenv(name))
	if raw == "" {
		return fallback
	}
	return raw
}

func productPerformanceEnvInt(name string, fallback, min, max int) int {
	raw := strings.TrimSpace(os.Getenv(name))
	if raw == "" {
		return fallback
	}
	n, err := strconv.Atoi(raw)
	if err != nil || n < min || n > max {
		return fallback
	}
	return n
}

func productPerformanceEnvBool(name string, fallback bool) bool {
	raw := strings.TrimSpace(strings.ToLower(os.Getenv(name)))
	if raw == "" {
		return fallback
	}
	return raw == "1" || raw == "true" || raw == "on" || raw == "yes"
}