Dirty implementation of createVotes

internal/models/elections.go

@@ -20,8 +20,8 @@ type Election struct {
 	Tokens         int
 	AreVotersKnown bool
 	MaxVoters      int
-	CreatedAt      string
-	ExpiresAt      string
+	CreatedAt      time.Time
+	ExpiresAt      time.Time
 	Choices        []string
 }
 

internal/models/voters.go

@@ -2,10 +2,13 @@ package models
 
 import (
 	"database/sql"
+	"errors"
 )
 
 type VoterModelInterface interface {
 	Insert(identity string, electionID int) (int, error)
+	CountByElection(electionID int) (int, error)
+	Exists(voterIdentity string, electionID int) (bool, error)
 }
 
 type VoterModel struct {
@@ -34,3 +37,53 @@ func (v *VoterModel) Insert(identity string, electionID int) (int, error) {
 	voterId, err := result.LastInsertId()
 	return int(voterId), nil
 }
+
+func (v *VoterModel) CountByElection(electionID int) (int, error) {
+	// use a transaction to prevent race conditions
+	tx, err := v.DB.Begin()
+	if err != nil {
+		return 0, err
+	}
+	defer tx.Rollback()
+
+	query := `
+		SELECT COUNT(identity)
+		FROM voters
+		WHERE election_id = ?
+		GROUP BY election_id;
+	`
+
+	row := tx.QueryRow(query, electionID)
+
+	var voterCount int
+
+	err = row.Scan(&voterCount)
+	if err != nil {
+		return 0, err
+	}
+
+	tx.Commit()
+
+	return voterCount, nil
+}
+
+func (v *VoterModel) Exists(voterIdentity string, electionID int) (bool, error) {
+	query := `
+		SELECT EXISTS (
+			SELECT 1
+			FROM voters
+			WHERE identity = ? AND election_id = ?
+		)
+	`
+
+	var exists bool
+
+	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
+}

internal/models/votes.go

@@ -0,0 +1,57 @@
+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
+}