package infra

import (
	"database/sql"
	"os"
	"path/filepath"
	"testing"

	_ "github.com/mattn/go-sqlite3"
)

func openMigrationTestDB(t *testing.T) *sql.DB {
	t.Helper()
	db, err := sql.Open("sqlite3", ":memory:")
	if err != nil {
		t.Fatalf("cannot open test DB: %v", err)
	}
	t.Cleanup(func() { db.Close() })
	return db
}

func writeMigrationFile(t *testing.T, dir, filename, content string) {
	t.Helper()
	if err := os.WriteFile(filepath.Join(dir, filename), []byte(content), 0o644); err != nil {
		t.Fatalf("cannot write migration file %s: %v", filename, err)
	}
}

func TestMigrationUp(t *testing.T) {
	t.Run("base de datos vacia aplica todas las migraciones", func(t *testing.T) {
		db := openMigrationTestDB(t)
		dir := t.TempDir()

		writeMigrationFile(t, dir, "001_create_users.sql",
			"-- +up\nCREATE TABLE users (id TEXT PRIMARY KEY, name TEXT NOT NULL);\n-- +down\nDROP TABLE IF EXISTS users;\n")
		writeMigrationFile(t, dir, "002_create_roles.sql",
			"-- +up\nCREATE TABLE roles (id TEXT PRIMARY KEY);\n-- +down\nDROP TABLE IF EXISTS roles;\n")

		applied, err := MigrationUp(db, dir)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if len(applied) != 2 {
			t.Errorf("applied count: got %d, want 2", len(applied))
		}
		if applied[0].Version != 1 || applied[1].Version != 2 {
			t.Errorf("applied versions: got %v", []int{applied[0].Version, applied[1].Version})
		}

		// Verify tables were created
		var count int
		if err := db.QueryRow("SELECT COUNT(*) FROM users").Scan(&count); err != nil {
			t.Errorf("users table not created: %v", err)
		}
		if err := db.QueryRow("SELECT COUNT(*) FROM roles").Scan(&count); err != nil {
			t.Errorf("roles table not created: %v", err)
		}
	})

	t.Run("migraciones ya aplicadas se omiten", func(t *testing.T) {
		db := openMigrationTestDB(t)
		dir := t.TempDir()

		writeMigrationFile(t, dir, "001_create_users.sql",
			"-- +up\nCREATE TABLE users (id TEXT PRIMARY KEY);\n-- +down\nDROP TABLE IF EXISTS users;\n")
		writeMigrationFile(t, dir, "002_create_roles.sql",
			"-- +up\nCREATE TABLE roles (id TEXT PRIMARY KEY);\n-- +down\nDROP TABLE IF EXISTS roles;\n")

		// Apply all
		_, err := MigrationUp(db, dir)
		if err != nil {
			t.Fatalf("first up failed: %v", err)
		}

		// Apply again — should apply nothing
		applied, err := MigrationUp(db, dir)
		if err != nil {
			t.Fatalf("second up failed: %v", err)
		}
		if len(applied) != 0 {
			t.Errorf("expected 0 applied on second run, got %d", len(applied))
		}
	})

	t.Run("migracion con SQL invalido retorna error y deja las anteriores aplicadas", func(t *testing.T) {
		db := openMigrationTestDB(t)
		dir := t.TempDir()

		writeMigrationFile(t, dir, "001_create_users.sql",
			"-- +up\nCREATE TABLE users (id TEXT PRIMARY KEY);\n-- +down\nDROP TABLE IF EXISTS users;\n")
		writeMigrationFile(t, dir, "002_bad_sql.sql",
			"-- +up\nTHIS IS NOT VALID SQL!!!;\n-- +down\n\n")

		applied, err := MigrationUp(db, dir)
		if err == nil {
			t.Fatal("expected error for invalid SQL, got nil")
		}
		// Version 1 should be applied
		if len(applied) != 1 || applied[0].Version != 1 {
			t.Errorf("expected [1] applied before failure, got versions: %v", applied)
		}

		// users table should still exist (migration 1 committed)
		var count int
		if err2 := db.QueryRow("SELECT COUNT(*) FROM users").Scan(&count); err2 != nil {
			t.Errorf("users table not present after partial apply: %v", err2)
		}
	})

	t.Run("directorio sin archivos sql no aplica nada", func(t *testing.T) {
		db := openMigrationTestDB(t)
		dir := t.TempDir()

		applied, err := MigrationUp(db, dir)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if len(applied) != 0 {
			t.Errorf("expected 0 applied for empty dir, got %d", len(applied))
		}
	})
}