package dbi

import (
	"context"
	"database/sql"
	"math/rand"
	"testing"

	_ "modernc.org/sqlite"
)

func testDB(t *testing.T) *sql.DB {
	t.Helper()
	db, err := sql.Open("sqlite", ":memory:")
	if err != nil {
		t.Fatalf("open in-memory db: %v", err)
	}
	if _, err := db.Exec(ActivityReportSchema); err != nil {
		t.Fatalf("apply schema: %v", err)
	}
	t.Cleanup(func() { db.Close() })
	return db
}

func testConn(t *testing.T, db *sql.DB) *sql.Conn {
	t.Helper()
	conn, err := db.Conn(context.Background())
	if err != nil {
		t.Fatalf("get conn: %v", err)
	}
	t.Cleanup(func() { conn.Close() })
	return conn
}

func randString(n int) string {
	const letters = "abcdefghijklmnopqrstuvwxyz"
	b := make([]byte, n)
	for i := range b {
		b[i] = letters[rand.Intn(len(letters))]
	}
	return string(b)
}

func genUser() User {
	return User{
		APIKey:    randString(16),
		FirstName: randString(8),
		LastName:  randString(8),
		Password:  randString(20),
		Status:    "faculty",
		Username:  randString(10),
	}
}

func TestCreateUser(t *testing.T) {
	conn := testConn(t, testDB(t))
	u := genUser()

	if err := CreateUser(conn, &u); err != nil {
		t.Fatalf("CreateUser: %v", err)
	}

	got, err := GetUser(conn, u.Username)
	if err != nil {
		t.Fatalf("GetUser after create: %v", err)
	}
	if got != u {
		t.Errorf("got %+v, want %+v", got, u)
	}
}

func TestCreateUserDuplicateUsername(t *testing.T) {
	conn := testConn(t, testDB(t))
	u := genUser()

	if err := CreateUser(conn, &u); err != nil {
		t.Fatalf("first CreateUser: %v", err)
	}
	if err := CreateUser(conn, &u); err == nil {
		t.Error("expected error on duplicate username, got nil")
	}
}

func TestGetUser(t *testing.T) {
	conn := testConn(t, testDB(t))
	u := genUser()

	if err := CreateUser(conn, &u); err != nil {
		t.Fatalf("CreateUser: %v", err)
	}

	got, err := GetUser(conn, u.Username)
	if err != nil {
		t.Fatalf("GetUser: %v", err)
	}
	if got != u {
		t.Errorf("got %+v, want %+v", got, u)
	}
}

func TestGetUserNotFound(t *testing.T) {
	conn := testConn(t, testDB(t))

	_, err := GetUser(conn, randString(10))
	if err == nil {
		t.Error("expected error for missing user, got nil")
	}
}

func TestUpdateUser(t *testing.T) {
	conn := testConn(t, testDB(t))
	u := genUser()

	if err := CreateUser(conn, &u); err != nil {
		t.Fatalf("CreateUser: %v", err)
	}

	u.FirstName = randString(8)
	u.LastName = randString(8)
	u.APIKey = randString(16)
	u.Status = "admin"

	if err := UpdateUser(conn, &u); err != nil {
		t.Fatalf("UpdateUser: %v", err)
	}

	got, err := GetUser(conn, u.Username)
	if err != nil {
		t.Fatalf("GetUser after update: %v", err)
	}
	if got != u {
		t.Errorf("got %+v, want %+v", got, u)
	}
}

func TestDeleteUser(t *testing.T) {
	conn := testConn(t, testDB(t))
	u := genUser()

	if err := CreateUser(conn, &u); err != nil {
		t.Fatalf("CreateUser: %v", err)
	}

	if err := DeleteUser(conn, u.Username); err != nil {
		t.Fatalf("DeleteUser: %v", err)
	}

	_, err := GetUser(conn, u.Username)
	if err == nil {
		t.Error("expected error after delete, got nil")
	}
}