// XIR reader tests
//
//  Copyright (C) 2014-2021 Ryan Specialty Group, LLC.
//
//  This file is part of TAME.
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.

use std::borrow::Cow;

use super::*;
use crate::sym::GlobalSymbolIntern;
use crate::{
    convert::ExpectInto,
    span::DUMMY_SPAN,
    xir::{Error, Token},
};

/// These tests use [`quick_xml`] directly,
///   rather than mocking it,
///   because parsing XML isn't a simple matter and we want to be sure that
///     our assumptions of how `quick_xml` performs its parsing is accurate.
/// Consequently,
///   these act more like integration tests than unit tests.
///
/// This means that `quick_xml` breakages will break these tests,
///   and that is (unlike with unit tests) exactly what we want to happen
///   here;
///     we _complement_ the behavior of quick-xml,
///       both by reimplementing certain functionality
///         (like namespace management)
///         and by relying on certain parsing behavior to eliminate
///           redundant checks.

type Sut<'a, B, S> = XmlXirReader<'a, B, S>;

#[derive(Debug, Default)]
struct MockEscaper {}

// Simply adds ":UNESC" as a suffix to the provided byte slice.
impl Escaper for MockEscaper {
    fn escape_bytes(_: &[u8]) -> Cow<[u8]> {
        unreachable!("Reader should not be escaping!")
    }

    fn unescape_bytes(value: &[u8]) -> result::Result<Cow<[u8]>, Error> {
        let mut unesc = value.to_owned();
        unesc.extend_from_slice(b":UNESC");

        Ok(Cow::Owned(unesc))
    }
}

/// A byte that will be invalid provided that there is either no following
///   UTF-8 byte,
///     or if it's followed by another byte that is invalid in that
///     position.
const INVALID_UTF8_BYTE: u8 = 0b11000000u8;

// SAFETY: We want an invalid UTF-8 str for tests.
//   (We can use raw bytes and avoid `unsafe`,
//     but this is more convenient.)
const INVALID_STR: &str =
    unsafe { std::str::from_utf8_unchecked(&[INVALID_UTF8_BYTE]) };

macro_rules! new_sut {
    ($sut:ident = $data:expr) => {
        new_sut!(b $sut = $data.as_bytes())
    };

    (b $sut:ident = $data:expr) => {
        let escaper = MockEscaper::default();
        let $sut = Sut::new($data, &escaper);
    };
}

#[test]
fn empty_node_without_prefix_or_attributes() {
    new_sut!(sut = "<empty-node />");

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("empty-node".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
        ],
    );
}

// Resolving namespaces is not the concern of XIR.
#[test]
fn does_not_resolve_xmlns() {
    new_sut!(sut = r#"<no-ns xmlns="noresolve" />"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("no-ns".unwrap_into(), DUMMY_SPAN),
            // Since we didn't parse @xmlns, it's still an attribute.
            Token::AttrName("xmlns".unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("noresolve:UNESC".intern(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
        ],
    );
}

// Resolving namespaces is not the concern of XIR.
#[test]
fn empty_node_with_prefix_without_attributes_unresolved() {
    new_sut!(sut = r#"<x:empty-node xmlns:x="noresolve" />"#);

    let result = sut.collect::<Result<Vec<_>>>();

    // Should be the QName, _unresolved_.
    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open(("x", "empty-node").unwrap_into(), DUMMY_SPAN),
            Token::AttrName(("xmlns", "x").unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("noresolve:UNESC".intern(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
        ],
    );
}

// TODO: Enough information for error recovery and reporting.
#[test]
fn prefix_with_empty_local_name_invalid_qname() {
    // No local name (trailing colon).
    new_sut!(sut = r#"<x: xmlns:x="testns" />"#);

    let result = sut.collect::<Result<Vec<_>>>();

    match result {
        Ok(_) => panic!("expected failure"),
        Err(given) => {
            assert_eq!(Error::InvalidQName("x:".into()), given);
        }
    }
}

// The order of attributes must be retained.
#[test]
fn multiple_attrs_ordered() {
    new_sut!(sut = r#"<ele foo="a" bar="b" b:baz="c" />"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("ele".unwrap_into(), DUMMY_SPAN),
            Token::AttrName("foo".unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("a:UNESC".intern(), DUMMY_SPAN),
            Token::AttrName("bar".unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("b:UNESC".intern(), DUMMY_SPAN),
            Token::AttrName(("b", "baz").unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("c:UNESC".intern(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
        ],
    );
}

// Contrary to the specification, but this is the responsibility of XIRT; we
// need to allow it to support e.g. recovery, code formatting, and LSPs.
#[test]
fn permits_duplicate_attrs() {
    new_sut!(sut = r#"<dup attr="a" attr="b" />"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("dup".unwrap_into(), DUMMY_SPAN),
            Token::AttrName("attr".unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("a:UNESC".intern(), DUMMY_SPAN),
            Token::AttrName("attr".unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("b:UNESC".intern(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
        ],
    );
}

#[test]
fn child_node_self_closing() {
    new_sut!(sut = r#"<root><child /></root>"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("root".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Open("child".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
            Token::Close(Some("root".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

#[test]
fn sibling_nodes() {
    new_sut!(sut = r#"<root><child /><child /></root>"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("root".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Open("child".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
            Token::Open("child".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
            Token::Close(Some("root".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

#[test]
fn child_node_with_attrs() {
    new_sut!(sut = r#"<root><child foo="bar" /></root>"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("root".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Open("child".unwrap_into(), DUMMY_SPAN),
            Token::AttrName("foo".unwrap_into(), DUMMY_SPAN),
            Token::AttrValue("bar:UNESC".intern(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
            Token::Close(Some("root".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

#[test]
fn child_text() {
    new_sut!(sut = r#"<text>foo bar</text>"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("text".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Text("foo bar:UNESC".into(), DUMMY_SPAN),
            Token::Close(Some("text".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

#[test]
fn mixed_child_content() {
    new_sut!(sut = r#"<text>foo<em>bar</em></text>"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("text".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Text("foo:UNESC".into(), DUMMY_SPAN),
            Token::Open("em".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Text("bar:UNESC".into(), DUMMY_SPAN),
            Token::Close(Some("em".unwrap_into()), DUMMY_SPAN),
            Token::Close(Some("text".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

// This is how XML is typically written; people don't perceive it as mixed,
// even though it is.  This intentionally adds newlines before and after the
// opening and closing tags of the root node.
#[test]
fn mixed_child_content_with_newlines() {
    new_sut!(
        sut = r#"
<root>
  <child />
</root>
"#
    );

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Text("\n:UNESC".into(), DUMMY_SPAN),
            Token::Open("root".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Text("\n  :UNESC".into(), DUMMY_SPAN),
            Token::Open("child".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
            Token::Text("\n:UNESC".into(), DUMMY_SPAN),
            Token::Close(Some("root".unwrap_into()), DUMMY_SPAN),
            Token::Text("\n:UNESC".into(), DUMMY_SPAN),
        ],
    );
}

#[test]
fn comment() {
    new_sut!(sut = r#"<!--root--><root><!--<child>--></root>"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Comment("root".into(), DUMMY_SPAN),
            Token::Open("root".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Comment("<child>".into(), DUMMY_SPAN),
            Token::Close(Some("root".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

#[test]
fn comment_multiline() {
    new_sut!(
        sut = r#"<mult><!--comment
on multiple
lines-->
</mult>"#
    );

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("mult".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Comment("comment\non multiple\nlines".into(), DUMMY_SPAN),
            Token::Text("\n:UNESC".into(), DUMMY_SPAN),
            Token::Close(Some("mult".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

// XIRT handles mismatch errors; XIR must explicitly support them.
#[test]
fn permits_mismatched_tags() {
    new_sut!(sut = r#"<root><child /></mismatch>"#);

    let result = sut.collect::<Result<Vec<_>>>();

    assert_eq!(
        result.expect("parsing failed"),
        vec![
            Token::Open("root".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Open("child".unwrap_into(), DUMMY_SPAN),
            Token::AttrEnd(DUMMY_SPAN),
            Token::Close(None, DUMMY_SPAN),
            Token::Close(Some("mismatch".unwrap_into()), DUMMY_SPAN),
        ],
    );
}

// TODO: Enough information for error recovery and reporting.
#[test]
fn node_name_invalid_utf8() {
    let bytes: &[u8] = &[b'<', INVALID_UTF8_BYTE, b'/', b'>'];
    new_sut!(b sut = bytes);

    let result = sut.collect::<Result<Vec<_>>>();

    match result {
        Ok(_) => panic!("expected failure"),
        Err(Error::InvalidUtf8(_, bytes)) => {
            assert_eq!(bytes, &[INVALID_UTF8_BYTE]);
        }
        _ => panic!("unexpected failure"),
    }
}

// TODO: Enough information for error recovery and reporting.
#[test]
fn attr_name_invalid_utf8() {
    let mut s = String::from("<a ");
    s.push_str(INVALID_STR);
    s.push_str(r#"="value"/>"#);

    new_sut!(sut = s);

    let result = sut.collect::<Result<Vec<_>>>();

    match result {
        Ok(_) => panic!("expected failure"),
        Err(Error::InvalidUtf8(_, bytes)) => {
            assert_eq!(bytes, &[INVALID_UTF8_BYTE]);
        }
        _ => panic!("unexpected failure"),
    }
}

// TODO: Enough information for error recovery and reporting.
#[test]
fn attr_value_invalid_utf8() {
    let mut s = String::from(r#"<a attr="bad"#);
    s.push_str(INVALID_STR);
    s.push_str(r#""/>"#);

    new_sut!(sut = s);

    let result = sut.collect::<Result<Vec<_>>>();

    match result {
        Ok(_) => panic!("expected failure"),
        Err(Error::InvalidUtf8(_, bytes)) => {
            // Doesn't make it to the Escaper.
            assert_eq!(bytes, &[b'b', b'a', b'd', INVALID_UTF8_BYTE]);
        }
        _ => panic!("unexpected failure"),
    }
}