package models

import (
	"database/sql"
	"errors"
)

type VoteModelInterface interface {
	Insert(voterIdentity string, electionId int, choiceText string, tokens int) (int, error)
	Exists(voterIdentity string, electionID int) (bool, error)
}

type VoteModel struct {
	DB *sql.DB
}

func (v *VoteModel) Insert(voterIdentity string, electionId int, choiceText string, tokens int) (int, error) {
	tx, err := v.DB.Begin()
	if err != nil {
		return 0, err
	}
	defer tx.Rollback()

	result, err := tx.Exec(`
        INSERT INTO votes (voter_identity, election_id, choice_text, tokens)
        VALUES (?, ?, ?, ?)`,
		voterIdentity, electionId, choiceText, tokens)
	if err != nil {
		return 0, err
	}

	if err = tx.Commit(); err != nil {
		return 0, err
	}

	voteId, err := result.LastInsertId()
	return int(voteId), nil
}

func (v *VoteModel) Exists(voterIdentity string, electionID int) (bool, error) {
	var exists bool
	query := `
		SELECT EXISTS (
			SELECT 1
			FROM votes
			WHERE voter_identity = ? AND election_id = ?
		)
	`
	err := v.DB.QueryRow(query, voterIdentity, electionID).Scan(&exists)
	if err != nil {
		if errors.Is(sql.ErrNoRows, err) {
			return false, nil
		}
		return false, err
	}
	return exists, nil
}