package main

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

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

	intervalHours := 24
	if raw := strings.TrimSpace(os.Getenv("PRODUCT_PRICING_CALC_INTERVAL_HOURS")); raw != "" {
		if parsed, err := strconv.Atoi(raw); err == nil && parsed >= 1 {
			intervalHours = parsed
		}
	}

	codeBatch := 1000
	if raw := strings.TrimSpace(os.Getenv("PRODUCT_PRICING_CALC_PUBLISH_CODE_BATCH")); raw != "" {
		if parsed, err := strconv.Atoi(raw); err == nil && parsed >= 100 && parsed <= 5000 {
			codeBatch = parsed
		}
	}

	runOnStartup := true
	if raw := strings.TrimSpace(strings.ToLower(os.Getenv("PRODUCT_PRICING_CALC_RUN_ON_STARTUP"))); raw == "0" || raw == "false" || raw == "off" {
		runOnStartup = false
	}
	// Snapshot calculation should not update sdprc by default. sdprc is updated by
	// the weekly full FX publisher and by the delta queue after manual price edits.
	publishEnabled := false
	if raw := strings.TrimSpace(strings.ToLower(os.Getenv("PRODUCT_PRICING_CALC_PUBLISH_ENABLED"))); raw == "1" || raw == "true" || raw == "on" || raw == "yes" {
		publishEnabled = true
	}
	forceFxRefresh := true
	if raw := strings.TrimSpace(strings.ToLower(os.Getenv("PRODUCT_PRICING_CALC_FORCE_FX_REFRESH"))); raw == "0" || raw == "false" || raw == "off" {
		forceFxRefresh = false
	}

	var running int32

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

		ctx, cancel := context.WithTimeout(context.Background(), 4*time.Hour)
		defer cancel()

		started := time.Now()
		result, err := queries.CalculateProductPricingSnapshots(ctx, pgDB, queries.ProductPricingSnapshotCalcRequest{
			ForceFxRefresh: forceFxRefresh,
		})
		if err != nil {
			log.Printf("[ProductPricingCalcJob] calculate_error (%s): err=%v duration=%s", reason, err, time.Since(started).Round(time.Second))
			return
		}

		totalWritten := 0
		totalSkipped := 0
		totalProducts := 0
		if publishEnabled {
			written, skipped, products, err := publishAllProductPricingSnapshots(ctx, pgDB, codeBatch, forceFxRefresh)
			if err != nil {
				log.Printf("[ProductPricingCalcJob] publish_error (%s): calculated=%d err=%v duration=%s", reason, result.Calculated, err, time.Since(started).Round(time.Second))
				return
			}
			totalWritten = written
			totalSkipped = skipped
			totalProducts = products
		}

		log.Printf("[ProductPricingCalcJob] ok (%s): requested=%d calculated=%d skipped=%d fx_date=%s snapshot_publish=%t products=%d sdprc_written=%d publish_skipped=%d interval_hours=%d duration=%s",
			reason,
			result.Requested,
			result.Calculated,
			result.Skipped,
			result.RateDate,
			publishEnabled,
			totalProducts,
			totalWritten,
			totalSkipped,
			intervalHours,
			time.Since(started).Round(time.Second),
		)
	}

	go func() {
		if runOnStartup {
			time.Sleep(5 * time.Second)
			runOnce("startup")
		}

		ticker := time.NewTicker(time.Duration(intervalHours) * time.Hour)
		defer ticker.Stop()
		for range ticker.C {
			runOnce("scheduled")
		}
	}()
}

func publishAllProductPricingSnapshots(ctx context.Context, pgDB *sql.DB, codeBatch int, forceFxRefresh bool) (int, int, int, error) {
	totalWritten := 0
	totalSkipped := 0
	totalProducts := 0
	lastCode := ""
	for {
		rows, err := pgDB.QueryContext(ctx, `
SELECT product_code
FROM mk_price_snapshot
WHERE COALESCE(NULLIF(BTRIM(product_code), ''), '') <> ''
  AND product_code > $1
GROUP BY product_code
ORDER BY product_code
LIMIT $2
`, lastCode, codeBatch)
		if err != nil {
			return totalWritten, totalSkipped, totalProducts, err
		}

		codes := make([]string, 0, codeBatch)
		for rows.Next() {
			var code string
			if err := rows.Scan(&code); err != nil {
				_ = rows.Close()
				return totalWritten, totalSkipped, totalProducts, err
			}
			code = strings.TrimSpace(code)
			if code != "" {
				codes = append(codes, code)
			}
		}
		if err := rows.Err(); err != nil {
			_ = rows.Close()
			return totalWritten, totalSkipped, totalProducts, err
		}
		_ = rows.Close()

		if len(codes) == 0 {
			break
		}
		lastCode = codes[len(codes)-1]

		written, skipped, err := queries.PublishDerivedPricesFromAnchor(ctx, pgDB, codes, "", forceFxRefresh)
		if err != nil {
			return totalWritten, totalSkipped, totalProducts, err
		}
		totalWritten += written
		totalSkipped += skipped
		totalProducts += len(codes)
	}
	return totalWritten, totalSkipped, totalProducts, nil
}