//
// Common
//

export type MetadataProps = 'id' | 'createdAt'

type Opaque<T, K, L extends string = 'opaque'> = T & { _: K; __: L }
type Id<T> = Opaque<string, T, 'id'>

//
// Users
//

export type AdministratorRole = 'admin' | 'moderator'
export type StudentRole = 'student'

export type UserRole = AdministratorRole | StudentRole

export type UserId = Id<User>

export type User = {
    id: UserId
    role: UserRole
}

export function isAdministrator(role: UserRole): role is AdministratorRole {
    return role !== 'student'
}

export function isStudent(role: UserRole): role is StudentRole {
    return role === 'student'
}

//
// Problems
//

export type ProblemId = Id<Problem>

export type Problem = {
    id: ProblemId
    content: string
    createdBy: UserId
    createdAt: string
}

//
// Solutions
//

export type SolutionStatus = 'pending' | 'correct' | 'wrong'

export type SolutionId = string

export type Solution = {
    id: SolutionId
    sentBy: UserId
    forProblem: ProblemId
    content: string
    status: SolutionStatus
}