//! writer 模块（JSON 序列化）的集成测试。
//! Integration tests for the writer module (JSON serialization).

use focus_json::{parse, to_string, JsonValue};

fn roundtrip(input: &str) {
    let parsed = parse(input).unwrap_or_else(|e| panic!("parse failed for {:?}: {}", input, e));
    let serialized = to_string(&parsed);
    let reparsed = parse(&serialized).expect("reparse failed");
    assert_eq!(parsed, reparsed, "roundtrip mismatch for {:?}", input);
}

#[test]
fn serializes_primitives() {
    assert_eq!(to_string(&JsonValue::Null), "null");
    assert_eq!(to_string(&JsonValue::Bool(true)), "true");
    assert_eq!(to_string(&JsonValue::Bool(false)), "false");
    assert_eq!(to_string(&JsonValue::Str("hi".into())), r#""hi""#);
}

#[test]
fn serializes_integers_without_fraction() {
    assert_eq!(to_string(&JsonValue::Num(3.0)), "3");
    assert_eq!(to_string(&JsonValue::Num(-42.0)), "-42");
    assert_eq!(to_string(&JsonValue::Num(0.0)), "0");
}

#[test]
fn serializes_fractional_numbers() {
    assert_eq!(to_string(&JsonValue::Num(12.345)), "12.345");
}

#[test]
fn escapes_strings() {
    let s = JsonValue::Str("a\"b\nc".into());
    assert_eq!(to_string(&s), r#""a\"b\nc""#);
}

#[test]
fn escapes_control_chars_as_unicode() {
    let s = JsonValue::Str("\u{0001}".into());
    assert_eq!(to_string(&s), r#""\u0001""#);
}

#[test]
fn serializes_arrays_and_objects() {
    let mut o = JsonValue::obj();
    o.insert("a", JsonValue::Num(1.0)).unwrap();
    o.insert(
        "b",
        JsonValue::Arr(vec![JsonValue::Bool(true), JsonValue::Null]),
    )
    .unwrap();
    assert_eq!(to_string(&o), r#"{"a":1,"b":[true,null]}"#);
}

#[test]
fn roundtrips_various() {
    roundtrip(r#"{"name":"focus","nums":[1,2,3],"nested":{"deep":true}}"#);
    roundtrip(r#""escape: \\ \" \n \t""#);
    roundtrip("12.345159");
    roundtrip("-0");
    roundtrip("[]");
    roundtrip("{}");
}

#[test]
fn handles_unicode_in_strings() {
    let s = JsonValue::Str("中文😀".into());
    let serialized = to_string(&s);
    assert_eq!(serialized, r#""中文😀""#);
    assert_eq!(parse(&serialized).unwrap(), s);
}

#[test]
fn non_finite_becomes_null() {
    assert_eq!(to_string(&JsonValue::Num(f64::NAN)), "null");
    assert_eq!(to_string(&JsonValue::Num(f64::INFINITY)), "null");
}