import json
import time

const default_time = time.parse('2025-04-16 12:00:00') or {time.now()}

type Any = string | []map[string]?Any | time.Time

struct Users {
mut:
    id         string
    created_at time.Time
}

struct EmbeddedStruct {
    v int
}

struct MyStruct {
    a       int
    opt_a   ?int
    s       string
    opt_s   ?string
    t       time.Time = default_time
    opt_v   ?EmbeddedStruct
    opt_t   ?time.Time
    opt_u64 ?u64
}

data_all := [Users{
    id:         '123'
    created_at: default_time
}, Users{
    id:         'asd'
    created_at: default_time
}]

mut result := []map[string]?Any{}
for raw in data_all {
    mut data := map[string]?Any{}
    data['id'] = raw.id
    data['time'] = raw.created_at
    result << data
}

println(result)

msg := json.encode(result)
println(msg)

x := MyStruct{
    a: 1
    s: 'hello'
    t: default_time
    // opt_t : default_time
    opt_u64: 123456
}

y := json.encode(x)
println(y)

k := json.decode(MyStruct, y)!
println(k)