package models

import (
	"database/sql"
	"errors"
	"time"
)

type VoteModelInterface interface {
	Insert(voterIdentity string, electionId int, choiceText string, tokens int) (int, error)
	Exists(voterIdentity string, electionID int) (bool, error)
	GetByElection(electionID int) (*[]Vote, error)
}

type VoteModel struct {
	DB *sql.DB
}

type Vote struct {
	VoterIdentity string
	ElectionID    int
	ChoiceText    string
	Tokens        int
	CreatedAt     time.Time
}

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
}

func (v *VoteModel) GetByElection(electionID int) (*[]Vote, error) {
	query := `
		SELECT voter_identity, election_id, choice_text, tokens, created_at
		FROM votes
		WHERE election_id = ?
	`

	rows, err := v.DB.Query(query, electionID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var votes []Vote
	for rows.Next() {
		var vote Vote
		err := rows.Scan(
			&vote.VoterIdentity,
			&vote.ElectionID,
			&vote.ChoiceText,
			&vote.Tokens,
			&vote.CreatedAt,
		)
		if err != nil {
			return nil, err
		}
		votes = append(votes, vote)
	}

	if err = rows.Err(); err != nil {
		return nil, err
	}

	if len(votes) == 0 {
		return nil, sql.ErrNoRows
	}

	return &votes, nil
}