package postgres

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

	"github.com/jackc/pgx/v5/pgxpool"

	"cryptoHermes/internal/entity"
)

type FundingRepo struct {
	pool pgxPool
}

func NewFundingRepo(pool *pgxpool.Pool) *FundingRepo {
	return &FundingRepo{pool: pool}
}

const fundingUpsertSQL = `
INSERT INTO funding_rates (source, symbol, funding_time, funding_rate, mark_price)
VALUES ($1, $2, $3, $4, NULLIF($5, '')::NUMERIC)
ON CONFLICT (source, symbol, funding_time) DO UPDATE SET
  funding_rate = EXCLUDED.funding_rate,
  mark_price = EXCLUDED.mark_price
`

func (r *FundingRepo) UpsertMany(ctx context.Context, items []entity.FundingRate) error {
	if len(items) == 0 {
		return nil
	}
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback(ctx)

	for _, f := range items {
		if f.FundingRate == "" || f.FundingTime == 0 {
			continue
		}
		if _, err := tx.Exec(ctx, fundingUpsertSQL,
			f.Source, f.Symbol, f.FundingTime, f.FundingRate, f.MarkPrice,
		); err != nil {
			return fmt.Errorf("upsert funding %s@%d: %w", f.Symbol, f.FundingTime, err)
		}
	}
	return tx.Commit(ctx)
}

const fundingFindSQL = `
SELECT source, symbol, funding_time, funding_rate::text, COALESCE(mark_price::text, '')
FROM funding_rates
WHERE symbol = $1
ORDER BY funding_time DESC
LIMIT $2
`

func (r *FundingRepo) FindRecent(ctx context.Context, symbol string, limit int) ([]entity.FundingRate, error) {
	if limit <= 0 {
		limit = 100
	}
	rows, err := r.pool.Query(ctx, fundingFindSQL, symbol, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	out := make([]entity.FundingRate, 0, limit)
	for rows.Next() {
		var f entity.FundingRate
		var mark sql.NullString
		if err := rows.Scan(&f.Source, &f.Symbol, &f.FundingTime, &f.FundingRate, &mark); err != nil {
			return nil, err
		}
		if mark.Valid {
			f.MarkPrice = mark.String
		}
		out = append(out, f)
	}
	for i, j := 0, len(out)-1; i < j; i, j = i+1, j-1 {
		out[i], out[j] = out[j], out[i]
	}
	return out, rows.Err()
}