package queries

import (
	"context"
	"database/sql"
	"fmt"
	"strings"
	"time"

	"github.com/lib/pq"
)

// EnqueuePriceRecalc enqueues product codes for delta FX publish.
// It is safe to call repeatedly; duplicates in pending/processing are ignored.
func EnqueuePriceRecalc(ctx context.Context, tx *sql.Tx, productCodes []string, reason string) (int, error) {
	if len(productCodes) == 0 {
		return 0, nil
	}
	reason = strings.TrimSpace(reason)
	if reason == "" {
		reason = "manual"
	}

	seen := map[string]struct{}{}
	inserted := 0
	for _, raw := range productCodes {
		code := strings.TrimSpace(raw)
		if code == "" {
			continue
		}
		if _, ok := seen[code]; ok {
			continue
		}
		seen[code] = struct{}{}

		_, err := tx.ExecContext(ctx, `
INSERT INTO mk_price_recalc_queue (
  product_code, pricing_parameter_id, reason, status, attempts,
  available_at, queued_at, processed_at, last_error,
  created_at, updated_at
)
VALUES ($1, NULL, $2, 'pending', 0, now(), now(), NULL, '', now(), now())
`, code, reason)
		if err != nil {
			if pe, ok := err.(*pq.Error); ok && pe != nil && string(pe.Code) == "23505" {
				// Duplicate in pending/processing (partial unique index).
				continue
			}
			return inserted, err
		}
		inserted++
	}
	return inserted, nil
}

type PriceRecalcQueueItem struct {
	ID          int64
	ProductCode string
	Attempts    int
}

// ClaimPriceRecalcQueue claims up to limit pending items for processing (SKIP LOCKED).
func ClaimPriceRecalcQueue(ctx context.Context, tx *sql.Tx, limit int) ([]PriceRecalcQueueItem, error) {
	if limit <= 0 {
		limit = 100
	}
	rows, err := tx.QueryContext(ctx, `
WITH picked AS (
  SELECT id
  FROM mk_price_recalc_queue
  WHERE status = 'pending'
    AND available_at <= now()
  ORDER BY queued_at
  LIMIT $1
  FOR UPDATE SKIP LOCKED
)
UPDATE mk_price_recalc_queue q
SET status = 'processing', updated_at = now()
FROM picked
WHERE q.id = picked.id
RETURNING q.id, q.product_code, q.attempts;
`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	out := make([]PriceRecalcQueueItem, 0, limit)
	for rows.Next() {
		var it PriceRecalcQueueItem
		if err := rows.Scan(&it.ID, &it.ProductCode, &it.Attempts); err != nil {
			return nil, err
		}
		it.ProductCode = strings.TrimSpace(it.ProductCode)
		out = append(out, it)
	}
	return out, rows.Err()
}

func MarkPriceRecalcQueueDone(ctx context.Context, tx *sql.Tx, id int64) error {
	_, err := tx.ExecContext(ctx, `
UPDATE mk_price_recalc_queue
SET status='done',
    processed_at = now(),
    updated_at = now(),
    last_error=''
WHERE id=$1;
`, id)
	return err
}

func MarkPriceRecalcQueueFailed(ctx context.Context, tx *sql.Tx, id int64, attempts int, errText string) error {
	errText = strings.TrimSpace(errText)
	if len(errText) > 900 {
		errText = errText[:900]
	}
	// Exponential-ish backoff: 5m, 15m, 60m.
	delay := 5 * time.Minute
	if attempts >= 1 {
		delay = 15 * time.Minute
	}
	if attempts >= 2 {
		delay = 60 * time.Minute
	}
	_, err := tx.ExecContext(ctx, `
UPDATE mk_price_recalc_queue
SET status='failed',
    attempts = attempts + 1,
    processed_at = now(),
    updated_at = now(),
    last_error=$2,
    available_at = now() + $3::interval
WHERE id=$1;
`, id, errText, fmt.Sprintf("%d seconds", int(delay.Seconds())))
	return err
}

// MarkPriceRecalcQueueDoneByProductCodes marks pending/processing rows as done for given product codes.
// This is useful when an immediate publish path completes successfully and we want to avoid a second run.
func MarkPriceRecalcQueueDoneByProductCodes(ctx context.Context, tx *sql.Tx, productCodes []string) (int64, error) {
	if len(productCodes) == 0 {
		return 0, nil
	}
	clean := make([]string, 0, len(productCodes))
	seen := map[string]struct{}{}
	for _, raw := range productCodes {
		code := strings.TrimSpace(raw)
		if code == "" {
			continue
		}
		if _, ok := seen[code]; ok {
			continue
		}
		seen[code] = struct{}{}
		clean = append(clean, code)
	}
	if len(clean) == 0 {
		return 0, nil
	}
	res, err := tx.ExecContext(ctx, `
UPDATE mk_price_recalc_queue
SET status='done',
    processed_at = now(),
    updated_at = now(),
    last_error=''
WHERE product_code = ANY($1)
  AND status IN ('pending','processing');
`, pq.Array(clean))
	if err != nil {
		return 0, err
	}
	ra, _ := res.RowsAffected()
	return ra, nil
}