From a49fd2d0d769c60e4eb7c71f6a89835119db29a6 Mon Sep 17 00:00:00 2001
From: Kylesoda <249518290+kylesoda@users.noreply.github.com>
Date: Sun, 29 Mar 2026 22:18:24 -0500
Subject: [PATCH] feat: implement task respository

---
 internal/db/postgres/task.go | 150 +++++++++++++++++++++++++++++++++++
 internal/models/task.go      |  15 ++--
 internal/repository/task.go  |  21 +++++
 3 files changed, 181 insertions(+), 5 deletions(-)
 create mode 100644 internal/db/postgres/task.go
 create mode 100644 internal/repository/task.go

diff --git a/internal/db/postgres/task.go b/internal/db/postgres/task.go
new file mode 100644
index 0000000..4145eb1
--- /dev/null
+++ b/internal/db/postgres/task.go
@@ -0,0 +1,150 @@
+package postgres
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"git.ksdemosapps.com/kylesoda/pgx-learning/internal/models"
+	"git.ksdemosapps.com/kylesoda/pgx-learning/internal/repository"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+type pgxRepository struct {
+	db *pgxpool.Pool
+}
+
+func NewTaskRepository(pool *pgxpool.Pool) repository.TaskRepository {
+	return &pgxRepository{
+		db: pool,
+	}
+}
+
+func (r *pgxRepository) Save(ctx context.Context, task *models.Task) error {
+	sql := `
+INSERT INTO public.tasks (text, completed)
+VALUES ($1, $2)
+RETURNING id, created_at, updated_at
+`
+
+	return r.db.QueryRow(ctx, sql, task.Text, task.Completed).Scan(&task.Id, &task.CreatedAt, &task.UpdatedAt)
+}
+
+func (r *pgxRepository) GetById(ctx context.Context, id int) (*models.Task, error) {
+	sql := `
+SELECT id, text, completed, created_at, updated_at
+FROM public.tasks
+WHERE id = $1
+`
+
+	var task models.Task
+	err := r.db.QueryRow(ctx, sql, id).Scan(
+		&task.Id,
+		&task.Text,
+		&task.Completed,
+		&task.CreatedAt,
+		&task.UpdatedAt,
+	)
+
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, nil
+		}
+
+		return nil, fmt.Errorf("Unexpected error when retrieving task: %w", err)
+	}
+
+	return &task, nil
+}
+
+func (r *pgxRepository) GetAll(ctx context.Context, filters repository.GetAllTaskFilters) ([]models.Task, error) {
+	sql := `SELECT id, text, completed, created_at, updated_at FROM public.tasks WHERE 1 = 1`
+	args := []any{}
+
+	if filters.Completed != nil {
+		args = append(args, *filters.Completed)
+		sql += fmt.Sprintf(" AND completed = $%d", len(args))
+	}
+
+	limit := 1000
+	if filters.Limit > 0 {
+		limit = filters.Limit
+	}
+	args = append(args, limit)
+	sql += fmt.Sprintf(" LIMIT $%d", len(args))
+
+	if filters.Offset > 0 {
+		args = append(args, filters.Offset)
+		sql += fmt.Sprintf(" OFFSET $%d", len(args))
+	}
+
+	rows, err := r.db.Query(ctx, sql, args...)
+	if err != nil {
+		return nil, fmt.Errorf("Unexpected error when querying tasks: %w", err)
+	}
+
+	defer rows.Close()
+
+	tasks, err := pgx.CollectRows(rows, pgx.RowToStructByName[models.Task])
+	if err != nil {
+		return nil, fmt.Errorf("Unexpected error when collecting tasks: %w", err)
+	}
+
+	return tasks, nil
+}
+
+func (r *pgxRepository) Update(ctx context.Context, id int, input *models.UpdateTaskInput) (*models.Task, error) {
+	sql := "UPDATE public.tasks SET updated_at = CURRENT_TIMESTAMP"
+	args := []any{}
+
+	if input.Text != nil {
+		args = append(args, input.Text)
+		sql += fmt.Sprintf(", text = $%d", len(args))
+	}
+
+	if input.Completed != nil {
+		args = append(args, input.Completed)
+		sql += fmt.Sprintf(", completed = $%d", len(args))
+	}
+
+	if len(args) == 0 {
+		return r.GetById(ctx, id)
+	}
+
+	args = append(args, id)
+	sql += fmt.Sprintf(" WHERE id = $%d RETURNING id, text, completed, created_at, updated_at", len(args))
+
+	var task models.Task
+	err := r.db.QueryRow(ctx, sql, args...).Scan(
+		&task.Id,
+		&task.Text,
+		&task.Completed,
+		&task.CreatedAt,
+		&task.UpdatedAt,
+	)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, fmt.Errorf("task not found")
+		}
+
+		return nil, fmt.Errorf("updating task: %w", err)
+	}
+
+	return &task, nil
+}
+
+func (r *pgxRepository) Delete(ctx context.Context, id int) error {
+	sql := "DELETE FROM public.tasks WHERE id = $1"
+
+	commandTag, err := r.db.Exec(ctx, sql, id)
+	if err != nil {
+		return fmt.Errorf("Unexpected error when deleting task: %w", err)
+	}
+
+	if commandTag.RowsAffected() == 0 {
+		return fmt.Errorf("No task found with id %d", id)
+	}
+
+	return nil
+}
diff --git a/internal/models/task.go b/internal/models/task.go
index 3662cb3..957df9e 100644
--- a/internal/models/task.go
+++ b/internal/models/task.go
@@ -6,10 +6,15 @@ import (
 )
 
 type Task struct {
-	Id        int        `json:"id"`
-	Text      string     `json:"text"`
-	Completed bool       `json:"completed"`
-	CreatedAt time.Time  `json:"created_at"`
-	UpdatedAt *time.Time `json:"updated_at"`
+	Id        int        `db:"id" json:"id"`
+	Text      string     `db:"text" json:"text"`
+	Completed bool       `db:"completed" json:"completed"`
+	CreatedAt time.Time  `db:"created_at" json:"created_at"`
+	UpdatedAt *time.Time `db:"updated_at" json:"updated_at"`
 	// UpdatedAt pgtype.Timestamptz `json:"updated_at"` /* evaluar la posibilidad de utilizarlo */
 }
+
+type UpdateTaskInput struct {
+	Text      *string `json:"text"`
+	Completed *bool   `json:"completed"`
+}
diff --git a/internal/repository/task.go b/internal/repository/task.go
new file mode 100644
index 0000000..a074ca1
--- /dev/null
+++ b/internal/repository/task.go
@@ -0,0 +1,21 @@
+package repository
+
+import (
+	"context"
+
+	"git.ksdemosapps.com/kylesoda/pgx-learning/internal/models"
+)
+
+type GetAllTaskFilters struct {
+	Limit     int
+	Offset    int
+	Completed *bool
+}
+
+type TaskRepository interface {
+	Save(ctx context.Context, task *models.Task) error
+	GetById(ctx context.Context, id int) (*models.Task, error)
+	GetAll(ctx context.Context, filters GetAllTaskFilters) ([]models.Task, error)
+	Update(ctx context.Context, id int, input *models.UpdateTaskInput) (*models.Task, error)
+	Delete(ctx context.Context, id int) error
+}