//! Heading level rewriter — `nuwiki.heading.addLevel` /
//! `nuwiki.heading.removeLevel`.

use nuwiki_core::syntax::vimwiki::VimwikiSyntax;
use nuwiki_core::syntax::SyntaxPlugin;
use nuwiki_lsp::commands::ops;
use tower_lsp::lsp_types::Url;

fn parse(src: &str) -> nuwiki_core::ast::DocumentNode {
    VimwikiSyntax::new().parse(src)
}

fn dummy_uri() -> Url {
    Url::parse("file:///tmp/note.wiki").unwrap()
}

fn one_text_edit(edit: tower_lsp::lsp_types::WorkspaceEdit) -> tower_lsp::lsp_types::TextEdit {
    let changes = edit.changes.expect("expected changes map");
    let (_, edits) = changes.into_iter().next().expect("at least one uri");
    assert_eq!(edits.len(), 1, "expected exactly one text edit");
    edits.into_iter().next().unwrap()
}

#[test]
fn add_heading_level_promotes_h2_to_h3() {
    let src = "== Sub ==\n";
    let doc = parse(src);
    let edit =
        ops::heading_change_level(src, &doc, &dummy_uri(), 0, 0, true, 1).expect("add_level edit");
    let te = one_text_edit(edit);
    assert_eq!(te.new_text, "=== Sub ===");
}

#[test]
fn add_heading_level_caps_at_6() {
    let src = "====== Deep ======\n";
    let doc = parse(src);
    let edit = ops::heading_change_level(src, &doc, &dummy_uri(), 0, 0, true, 1);
    // No-op because level 6 is the cap; clamp matched current level.
    assert!(edit.is_none());
}

#[test]
fn remove_heading_level_demotes() {
    let src = "=== Mid ===\n";
    let doc = parse(src);
    let edit = ops::heading_change_level(src, &doc, &dummy_uri(), 0, 0, true, -1)
        .expect("remove_level edit");
    let te = one_text_edit(edit);
    assert_eq!(te.new_text, "== Mid ==");
}

#[test]
fn remove_heading_level_at_h1_is_noop() {
    let src = "= Top =\n";
    let doc = parse(src);
    let edit = ops::heading_change_level(src, &doc, &dummy_uri(), 0, 0, true, -1);
    assert!(edit.is_none());
}

#[test]
fn heading_change_returns_none_when_cursor_not_on_heading() {
    let src = "paragraph\n";
    let doc = parse(src);
    let edit = ops::heading_change_level(src, &doc, &dummy_uri(), 0, 0, true, 1);
    assert!(edit.is_none());
}

#[test]
fn rewrite_heading_with_level_keeps_leading_whitespace_outside_span() {
    // The lexer's heading span starts at the first `=`, not the line's
    // start, so the leading whitespace that marks a "centered" heading
    // lives outside the edit range — preserved automatically. The
    // rewriter's output is just the `=...=` portion.
    let src = "  = Title =\n";
    let doc = parse(src);
    let h = match &doc.children[0] {
        nuwiki_core::ast::BlockNode::Heading(h) => h,
        _ => panic!("expected heading"),
    };
    let new = ops::rewrite_heading_with_level(src, h.span, 2).unwrap();
    assert_eq!(new, "== Title ==");
}