//! Integration tests for the `cstr_ffi` module.
//!
//! These exercise the public API only. The thread-local cache is reset at the start of every test
//! to keep cases independent. Tests that hand raw pointers back into the parse functions do so
//! immediately, within the scope where the backing storage is guaranteed to live.

use sarasacw_omrf::cstr_ffi;

fn cptr_of(bytes: &[u8]) -> cstr_ffi::CStrPtr {
    bytes.as_ptr() as cstr_ffi::CStrPtr
}

/// Coverage: single NUL-terminated string push -> parse round trip.
#[test]
fn push_single_string_round_trip() {
    cstr_ffi::clear_ffi_strings();
    let ptr = cstr_ffi::push_ffi_string("hello").unwrap();
    assert!(!ptr.is_null());
    assert_eq!(cstr_ffi::parse_ffi_string(ptr).unwrap(), "hello");
}

/// Coverage: pointers returned by earlier `push_ffi_string` calls stay valid after the internal
/// storage reallocates from many later pushes (move-stability of the cached `CString` buffers).
#[test]
fn pushed_strings_remain_valid_after_more_pushes() {
    cstr_ffi::clear_ffi_strings();
    let p1 = cstr_ffi::push_ffi_string("first").unwrap();
    // Force the internal Vec to reallocate by pushing many entries.
    let later: Vec<_> = (0..64)
        .map(|_| cstr_ffi::push_ffi_string("filler").unwrap())
        .collect();
    let p2 = cstr_ffi::push_ffi_string("second").unwrap();
    let p3 = cstr_ffi::push_ffi_string("third").unwrap();
    assert_eq!(cstr_ffi::parse_ffi_string(p1).unwrap(), "first");
    assert_eq!(cstr_ffi::parse_ffi_string(p2).unwrap(), "second");
    assert_eq!(cstr_ffi::parse_ffi_string(p3).unwrap(), "third");
    assert_eq!(cstr_ffi::parse_ffi_string(later[40]).unwrap(), "filler");
}

/// Coverage: `push_ffi_string` rejects a string containing an interior NUL byte.
#[test]
fn push_ffi_string_rejects_interior_nul() {
    cstr_ffi::clear_ffi_strings();
    assert!(cstr_ffi::push_ffi_string("a\x00b").is_err());
}

/// Coverage: `parse_ffi_string` rejects a null pointer.
#[test]
fn parse_ffi_string_null_ptr_errors() {
    assert!(cstr_ffi::parse_ffi_string(std::ptr::null()).is_err());
}

/// Coverage: `parse_ffi_string` rejects a NUL-terminated buffer whose content is not valid UTF-8.
#[test]
fn parse_ffi_string_invalid_utf8_errors() {
    let mut buf: Vec<u8> = vec![b'h', b'i', 0xFF];
    buf.push(0);
    let ptr = cptr_of(&buf);
    assert!(cstr_ffi::parse_ffi_string(ptr).is_err());
}

/// Coverage: nullptr-terminated string vector push -> parse round trip.
#[test]
fn push_string_vec_nullptr_terminated_round_trip() {
    cstr_ffi::clear_ffi_strings();
    let head = cstr_ffi::push_ffi_string_vec(&["a", "bb", "ccc"]).unwrap();
    let collected = cstr_ffi::parse_ffi_string_vec(head).unwrap();
    assert_eq!(collected, vec!["a", "bb", "ccc"]);
}

/// Coverage: an empty input to `push_ffi_string_vec` yields a valid empty list (only the trailing
/// null), which parses back to an empty vector.
#[test]
fn push_string_vec_empty_is_valid_empty_list() {
    cstr_ffi::clear_ffi_strings();
    let head = cstr_ffi::push_ffi_string_vec(&[]).unwrap();
    let collected = cstr_ffi::parse_ffi_string_vec(head).unwrap();
    assert!(collected.is_empty());
}

/// Coverage: `push_ffi_string_vec` rejects an entry containing an interior NUL byte.
#[test]
fn push_string_vec_rejects_interior_nul() {
    cstr_ffi::clear_ffi_strings();
    assert!(cstr_ffi::push_ffi_string_vec(&["ok", "ba\x00d"]).is_err());
}

/// Coverage: `parse_ffi_string_vec` (nullptr-terminated) rejects a null pointer.
#[test]
fn parse_ffi_string_vec_null_ptr_errors() {
    assert!(cstr_ffi::parse_ffi_string_vec(std::ptr::null()).is_err());
}

/// Coverage: count-terminated string vector push -> parse round trip, with the returned count.
#[test]
fn push_string_vec_with_len_round_trip() {
    cstr_ffi::clear_ffi_strings();
    let (head, count) = cstr_ffi::push_ffi_string_vec_with_len(&["x", "yy", "zzz"]).unwrap();
    assert_eq!(count, 3);
    let collected = cstr_ffi::parse_ffi_string_vec_with_len(head, count).unwrap();
    assert_eq!(collected, vec!["x", "yy", "zzz"]);
}

/// Coverage: empty input to `push_ffi_string_vec_with_len` yields count 0 and parses to an empty
/// vector.
#[test]
fn push_string_vec_with_len_empty() {
    cstr_ffi::clear_ffi_strings();
    let (head, count) = cstr_ffi::push_ffi_string_vec_with_len(&[]).unwrap();
    assert_eq!(count, 0);
    let collected = cstr_ffi::parse_ffi_string_vec_with_len(head, count).unwrap();
    assert!(collected.is_empty());
}

/// Coverage: `parse_ffi_string_vec_with_len` with count 0 accepts a null pointer and returns an
/// empty vector.
#[test]
fn parse_ffi_string_vec_with_len_null_zero_len_is_empty() {
    assert!(cstr_ffi::parse_ffi_string_vec_with_len(std::ptr::null(), 0)
        .unwrap()
        .is_empty());
}

/// Coverage: `parse_ffi_string_vec_with_len` with count > 0 rejects a null pointer.
#[test]
fn parse_ffi_string_vec_with_len_null_nonzero_errors() {
    assert!(cstr_ffi::parse_ffi_string_vec_with_len(std::ptr::null(), 1).is_err());
}

/// Coverage: independent single-string, count-terminated, and nullptr-terminated slots produced in
/// one call cycle all coexist and read back correctly.
#[test]
fn multiple_string_vec_slots_coexist() {
    cstr_ffi::clear_ffi_strings();
    let single = cstr_ffi::push_ffi_string("solo").unwrap();
    let (h1, c1) = cstr_ffi::push_ffi_string_vec_with_len(&["l1a", "l1b"]).unwrap();
    let h2 = cstr_ffi::push_ffi_string_vec(&["l2a", "l2b", "l2c"]).unwrap();
    assert_eq!(cstr_ffi::parse_ffi_string(single).unwrap(), "solo");
    assert_eq!(
        cstr_ffi::parse_ffi_string_vec_with_len(h1, c1).unwrap(),
        vec!["l1a", "l1b"]
    );
    assert_eq!(
        cstr_ffi::parse_ffi_string_vec(h2).unwrap(),
        vec!["l2a", "l2b", "l2c"]
    );
}

/// Coverage: `push_ffi_string_view` re-exposes the source string in place (no copy) -- the pointer
/// aliases the source buffer and the length matches.
#[test]
fn push_ffi_string_view_points_into_source() {
    cstr_ffi::clear_ffi_strings();
    let owned = String::from("a long string that we keep alive");
    let (ptr, len) = cstr_ffi::push_ffi_string_view(&owned);
    assert_eq!(len, owned.len());
    assert_eq!(ptr as *const u8, owned.as_ptr());
    let parsed = cstr_ffi::parse_ffi_string_view(ptr, len).unwrap();
    assert_eq!(parsed, owned);
}

/// Coverage: a string view may contain interior NUL bytes (length-delimited, not NUL-terminated).
#[test]
fn string_view_allows_interior_nul() {
    let src: &str = "ab\x00cd";
    let (ptr, len) = cstr_ffi::push_ffi_string_view(src);
    assert_eq!(len, 5);
    let parsed = cstr_ffi::parse_ffi_string_view(ptr, len).unwrap();
    assert_eq!(parsed.as_bytes(), src.as_bytes());
}

/// Coverage: `parse_ffi_string_view` with a null pointer and zero length is interpreted as an
/// empty string (C++ default `std::string_view`).
#[test]
fn parse_ffi_string_view_null_zero_is_empty() {
    assert_eq!(cstr_ffi::parse_ffi_string_view(std::ptr::null(), 0).unwrap(), "");
}

/// Coverage: `parse_ffi_string_view` rejects a null pointer when the length is non-zero.
#[test]
fn parse_ffi_string_view_null_nonzero_errors() {
    assert!(cstr_ffi::parse_ffi_string_view(std::ptr::null(), 3).is_err());
}

/// Coverage: `parse_ffi_string_view` rejects a buffer whose content is not valid UTF-8.
#[test]
fn parse_ffi_string_view_invalid_utf8_errors() {
    let bad: [u8; 2] = [b'a', 0xFF];
    let ptr = cptr_of(&bad);
    assert!(cstr_ffi::parse_ffi_string_view(ptr, 2).is_err());
}

/// Coverage: string-view vector push -> parse round trip; the container is cached while the string
/// data stays caller-owned.
#[test]
fn push_string_view_vec_with_len_round_trip() {
    cstr_ffi::clear_ffi_strings();
    let a = String::from("alpha");
    let b = String::from("beta");
    let c = String::from("gamma");
    let (head, count) = cstr_ffi::push_ffi_string_view_vec_with_len(&[&a, &b, &c]);
    assert_eq!(count, 3);
    let parsed = cstr_ffi::parse_ffi_string_view_vec_with_len(head, count).unwrap();
    assert_eq!(parsed, vec!["alpha", "beta", "gamma"]);
}

/// Coverage: empty input to `push_ffi_string_view_vec_with_len` yields count 0; parsing (which
/// ignores the possibly-dangling head) returns an empty vector.
#[test]
fn push_string_view_vec_with_len_empty() {
    cstr_ffi::clear_ffi_strings();
    let (head, count) = cstr_ffi::push_ffi_string_view_vec_with_len(&[]);
    assert_eq!(count, 0);
    let collected = cstr_ffi::parse_ffi_string_view_vec_with_len(head, count).unwrap();
    assert!(collected.is_empty());
}

/// Coverage: string-view vector entries may individually contain interior NUL bytes.
#[test]
fn string_view_vec_allows_interior_nul_entries() {
    cstr_ffi::clear_ffi_strings();
    let s1: &str = "x\x00y";
    let s2: &str = "p\x00\x00q";
    let (head, count) = cstr_ffi::push_ffi_string_view_vec_with_len(&[s1, s2]);
    assert_eq!(count, 2);
    let parsed = cstr_ffi::parse_ffi_string_view_vec_with_len(head, count).unwrap();
    assert_eq!(parsed[0].as_bytes(), s1.as_bytes());
    assert_eq!(parsed[1].as_bytes(), s2.as_bytes());
}

/// Coverage: `parse_ffi_string_view_vec_with_len` with count 0 accepts a null pointer and returns
/// an empty vector.
#[test]
fn parse_ffi_string_view_vec_null_zero_len_is_empty() {
    assert!(cstr_ffi::parse_ffi_string_view_vec_with_len(std::ptr::null(), 0)
        .unwrap()
        .is_empty());
}

/// Coverage: `parse_ffi_string_view_vec_with_len` with count > 0 rejects a null pointer.
#[test]
fn parse_ffi_string_view_vec_null_nonzero_errors() {
    assert!(cstr_ffi::parse_ffi_string_view_vec_with_len(std::ptr::null(), 1).is_err());
}

/// Coverage: after `clear_ffi_strings`, the cache is reusable -- a fresh push/parse works
/// independently of any state pushed before the clear.
#[test]
fn clear_makes_cache_reusable() {
    cstr_ffi::clear_ffi_strings();
    let _first = cstr_ffi::push_ffi_string("before-clear").unwrap();
    cstr_ffi::clear_ffi_strings();
    let after = cstr_ffi::push_ffi_string("after-clear").unwrap();
    assert_eq!(cstr_ffi::parse_ffi_string(after).unwrap(), "after-clear");
}