package postgres

import (
	"context"
	"fmt"

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

	"cryptoHermes/internal/entity"
)

type OpenInterestRepo struct {
	pool *pgxpool.Pool
}

func NewOpenInterestRepo(pool *pgxpool.Pool) *OpenInterestRepo {
	return &OpenInterestRepo{pool: pool}
}

const oiUpsertSQL = `
INSERT INTO open_interest (source, symbol, period, timestamp, open_interest, open_interest_value)
VALUES ($1, $2, $3, $4, $5, NULLIF($6, '')::NUMERIC)
ON CONFLICT (source, symbol, period, timestamp) DO UPDATE SET
  open_interest = EXCLUDED.open_interest,
  open_interest_value = EXCLUDED.open_interest_value
`

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

	for _, o := range items {
		if o.OpenInterest == "" || o.Timestamp == 0 {
			continue
		}
		if _, err := tx.Exec(ctx, oiUpsertSQL,
			o.Source, o.Symbol, o.Period, o.Timestamp, o.OpenInterest, o.OpenInterestValue,
		); err != nil {
			return fmt.Errorf("upsert oi %s/%s@%d: %w", o.Symbol, o.Period, o.Timestamp, err)
		}
	}
	return tx.Commit(ctx)
}

const oiFindSQL = `
SELECT source, symbol, period, timestamp,
       open_interest::text, COALESCE(open_interest_value::text, '')
FROM open_interest
WHERE symbol = $1 AND period = $2
ORDER BY timestamp DESC
LIMIT $3
`

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

	out := make([]entity.OpenInterest, 0, limit)
	for rows.Next() {
		var o entity.OpenInterest
		if err := rows.Scan(&o.Source, &o.Symbol, &o.Period, &o.Timestamp, &o.OpenInterest, &o.OpenInterestValue); err != nil {
			return nil, err
		}
		out = append(out, o)
	}
	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()
}