//! Phase 15: link-health diagnostics + TOC/links/orphans queries.

use std::path::PathBuf;

use nuwiki_core::syntax::vimwiki::VimwikiSyntax;
use nuwiki_core::syntax::SyntaxPlugin;
use nuwiki_lsp::commands::ops;
use nuwiki_lsp::config::LinkSeverity;
use nuwiki_lsp::diagnostics::{self, BrokenLinkKind};
use nuwiki_lsp::index::WorkspaceIndex;
use tower_lsp::lsp_types::{DiagnosticSeverity, Url};

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

fn build_index(root: &str, pages: &[(&str, &str)]) -> WorkspaceIndex {
    let mut idx = WorkspaceIndex::new(Some(PathBuf::from(root)));
    for (name, src) in pages {
        let ast = parse(src);
        let path = format!("{root}/{name}.wiki");
        let uri = Url::from_file_path(&path).unwrap();
        idx.upsert(uri, &ast);
    }
    idx
}

fn home_uri(root: &str) -> Url {
    Url::from_file_path(format!("{root}/Home.wiki")).unwrap()
}

// ===== severity_to_lsp =====

#[test]
fn severity_off_returns_none() {
    assert!(diagnostics::severity_to_lsp(LinkSeverity::Off).is_none());
}

#[test]
fn severity_levels_round_trip() {
    assert_eq!(
        diagnostics::severity_to_lsp(LinkSeverity::Hint),
        Some(DiagnosticSeverity::HINT)
    );
    assert_eq!(
        diagnostics::severity_to_lsp(LinkSeverity::Warning),
        Some(DiagnosticSeverity::WARNING)
    );
    assert_eq!(
        diagnostics::severity_to_lsp(LinkSeverity::Error),
        Some(DiagnosticSeverity::ERROR)
    );
}

// ===== link_health: wiki targets =====

#[test]
fn link_to_missing_page_warns() {
    let root = "/tmp/lh1";
    let idx = build_index(root, &[("Home", "[[GhostPage]]\n")]);
    let src = "[[GhostPage]]\n";
    let ast = parse(src);
    let uri = home_uri(root);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&uri),
        &idx,
        "Home",
        LinkSeverity::Warning,
        true,
    );
    assert_eq!(diags.len(), 1);
    assert!(diags[0].message.contains("GhostPage"));
    assert_eq!(diags[0].severity, Some(DiagnosticSeverity::WARNING));
}

#[test]
fn link_to_existing_page_silent() {
    let root = "/tmp/lh2";
    let idx = build_index(root, &[("Home", "[[Other]]\n"), ("Other", "= Other =\n")]);
    let src = "[[Other]]\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Warning,
        true,
    );
    assert!(diags.is_empty(), "got: {:?}", diags);
}

#[test]
fn link_with_valid_anchor_silent() {
    let root = "/tmp/lh3";
    let idx = build_index(
        root,
        &[
            ("Home", "[[Target#section-one]]\n"),
            ("Target", "= Target =\n== Section One ==\n"),
        ],
    );
    let src = "[[Target#section-one]]\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Warning,
        true,
    );
    assert!(diags.is_empty(), "got: {:?}", diags);
}

#[test]
fn link_with_missing_anchor_warns() {
    let root = "/tmp/lh4";
    let idx = build_index(
        root,
        &[
            ("Home", "[[Target#ghost-anchor]]\n"),
            ("Target", "= Target =\n"),
        ],
    );
    let src = "[[Target#ghost-anchor]]\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Warning,
        true,
    );
    assert_eq!(diags.len(), 1);
    assert!(diags[0].message.to_lowercase().contains("anchor"));
}

#[test]
fn anchor_only_link_resolves_against_current_page() {
    let root = "/tmp/lh5";
    let idx = build_index(root, &[("Home", "= Home =\n== Intro ==\n[[#intro]]\n")]);
    let src = "= Home =\n== Intro ==\n[[#intro]]\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Warning,
        true,
    );
    assert!(diags.is_empty(), "got: {:?}", diags);
}

#[test]
fn anchor_only_link_to_missing_anchor_warns() {
    let root = "/tmp/lh6";
    let idx = build_index(root, &[("Home", "[[#nowhere]]\n")]);
    let src = "[[#nowhere]]\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Warning,
        true,
    );
    assert_eq!(diags.len(), 1);
    assert!(diags[0].message.contains("nowhere"));
}

#[test]
fn link_severity_off_emits_nothing() {
    let root = "/tmp/lh7";
    let idx = build_index(root, &[("Home", "[[GhostPage]]\n")]);
    let src = "[[GhostPage]]\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Off,
        true,
    );
    assert!(diags.is_empty());
}

#[test]
fn raw_url_never_emits_diagnostic() {
    let root = "/tmp/lh8";
    let idx = build_index(root, &[("Home", "https://example.com\n")]);
    let src = "https://example.com\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Error,
        true,
    );
    assert!(diags.is_empty());
}

#[test]
fn tag_as_anchor_resolves() {
    let root = "/tmp/lh9";
    let idx = build_index(
        root,
        &[
            ("Home", "[[Notes#release]]\n"),
            ("Notes", "= Notes =\n:release:\n"),
        ],
    );
    let src = "[[Notes#release]]\n";
    let ast = parse(src);
    let diags = diagnostics::link_health(
        &ast,
        src,
        Some(&home_uri(root)),
        &idx,
        "Home",
        LinkSeverity::Warning,
        true,
    );
    assert!(diags.is_empty(), "got: {:?}", diags);
}

// ===== BrokenLinkKind classification =====

#[test]
fn classify_missing_page() {
    let kind = BrokenLinkKind::MissingPage("X".into());
    assert_eq!(kind.tag(), "missing-page");
    assert!(kind.message().contains("X"));
}

#[test]
fn classify_missing_anchor() {
    let kind = BrokenLinkKind::MissingAnchor {
        page: "P".into(),
        anchor: "a".into(),
    };
    assert_eq!(kind.tag(), "missing-anchor");
    assert!(kind.message().contains("a"));
    assert!(kind.message().contains("P"));
}

#[test]
fn classify_missing_file() {
    let kind = BrokenLinkKind::MissingFile(PathBuf::from("/tmp/nope.txt"));
    assert_eq!(kind.tag(), "missing-file");
    assert!(kind.message().contains("nope.txt"));
}

// ===== heading_text =====

#[test]
fn heading_text_strips_formatting() {
    let src = "= *Bold* heading =\n";
    let ast = parse(src);
    let h = match &ast.children[0] {
        nuwiki_core::ast::BlockNode::Heading(h) => h,
        _ => panic!("expected heading"),
    };
    let t = diagnostics::heading_text(&h.children);
    assert!(t.contains("Bold"));
    assert!(t.contains("heading"));
}

// ===== TOC text generation =====

#[test]
fn build_toc_text_nests_by_level() {
    let items = vec![
        (1u8, "Top".into(), "top".into()),
        (2u8, "Sub".into(), "sub".into()),
        (1u8, "Other".into(), "other".into()),
    ];
    let out = ops::build_toc_text(&items, "Contents");
    assert!(out.starts_with("= Contents =\n"));
    let lines: Vec<&str> = out.lines().collect();
    assert_eq!(lines[0], "= Contents =");
    assert_eq!(lines[1], "- [[#top|Top]]");
    assert_eq!(lines[2], "  - [[#sub|Sub]]");
    assert_eq!(lines[3], "- [[#other|Other]]");
}

#[test]
fn build_toc_text_with_no_headings_is_just_the_heading() {
    let out = ops::build_toc_text(&[], "Contents");
    assert_eq!(out, "= Contents =\n");
}

// ===== Links text generation =====

#[test]
fn build_links_text_excludes_current_page() {
    let pages = vec!["A".to_string(), "Home".to_string(), "B".to_string()];
    let out = ops::build_links_text(&pages, "Generated Links", Some("Home"));
    let lines: Vec<&str> = out.lines().collect();
    assert_eq!(lines[0], "= Generated Links =");
    assert!(lines.contains(&"- [[A]]"));
    assert!(lines.contains(&"- [[B]]"));
    assert!(!lines.iter().any(|l| l.contains("Home")));
}

#[test]
fn build_links_text_no_excludes_includes_all() {
    let pages = vec!["A".to_string(), "B".to_string()];
    let out = ops::build_links_text(&pages, "Generated Links", None);
    assert!(out.contains("[[A]]"));
    assert!(out.contains("[[B]]"));
}

// ===== find_section_range =====

#[test]
fn find_section_range_matches_case_insensitive() {
    let src = "= contents =\n- [[A]]\n- [[B]]\n";
    let ast = parse(src);
    let (_, _) = ops::find_section_range(&ast, "Contents").expect("found");
}

#[test]
fn find_section_range_misses_when_absent() {
    let src = "= Welcome =\n";
    let ast = parse(src);
    assert!(ops::find_section_range(&ast, "Contents").is_none());
}

#[test]
fn find_section_range_matches_any_heading_level() {
    // Section replacement accepts any heading level so
    // VimwikiGenerateTagLinks stays idempotent when tag sections live
    // under non-h1 headings (e.g. `== Tag: foo ==`).
    let src = "== Contents ==\n- [[A]]\n";
    let ast = parse(src);
    assert!(ops::find_section_range(&ast, "Contents").is_some());
}

// ===== toc_edit =====

#[test]
fn toc_edit_inserts_at_top_when_no_existing_toc() {
    let src = "= One =\n== Two ==\n";
    let ast = parse(src);
    let uri = Url::parse("file:///tmp/page.wiki").unwrap();
    let edit = ops::toc_edit(src, &ast, &uri, true).expect("got an edit");
    let changes = edit.changes.expect("changes map");
    let edits = &changes[&uri];
    assert_eq!(edits.len(), 1);
    let te = &edits[0];
    // Insertion at position 0,0 → zero-width range.
    assert_eq!(te.range.start, te.range.end);
    assert!(te.new_text.starts_with("= Contents =\n"));
    assert!(te.new_text.contains("[[#one|One]]"));
}

#[test]
fn toc_edit_replaces_existing_toc() {
    let src = "= Contents =\n- [[#stale|Stale]]\n\n= Real =\n";
    let ast = parse(src);
    let uri = Url::parse("file:///tmp/page.wiki").unwrap();
    let edit = ops::toc_edit(src, &ast, &uri, true).expect("got an edit");
    let changes = edit.changes.expect("changes map");
    let edits = &changes[&uri];
    let te = &edits[0];
    assert!(te.new_text.contains("[[#real|Real]]"));
    assert!(!te.new_text.contains("Stale"));
    // The replacement range must start at line 0.
    assert_eq!(te.range.start.line, 0);
}

#[test]
fn toc_edit_returns_none_for_empty_doc() {
    let src = "";
    let ast = parse(src);
    let uri = Url::parse("file:///tmp/empty.wiki").unwrap();
    assert!(ops::toc_edit(src, &ast, &uri, true).is_none());
}

// ===== links_edit =====

#[test]
fn links_edit_inserts_when_section_absent() {
    let src = "Hello\n";
    let ast = parse(src);
    let uri = Url::parse("file:///tmp/page.wiki").unwrap();
    let pages = vec!["A".into(), "B".into(), "Home".into()];
    let edit = ops::links_edit(src, &ast, &uri, "Home", &pages, true).expect("edit");
    let te = &edit.changes.unwrap()[&uri][0];
    assert!(te.new_text.contains("[[A]]"));
    assert!(te.new_text.contains("[[B]]"));
    assert!(!te.new_text.contains("[[Home]]"));
}

#[test]
fn links_edit_replaces_when_section_present() {
    let src = "= Generated Links =\n- [[Stale]]\n\n= Real =\n";
    let ast = parse(src);
    let uri = Url::parse("file:///tmp/page.wiki").unwrap();
    let pages = vec!["Fresh".into()];
    let edit = ops::links_edit(src, &ast, &uri, "Home", &pages, true).expect("edit");
    let te = &edit.changes.unwrap()[&uri][0];
    assert!(te.new_text.contains("[[Fresh]]"));
    assert!(!te.new_text.contains("Stale"));
    assert_eq!(te.range.start.line, 0);
}

#[test]
fn links_edit_returns_none_for_empty_page_list() {
    let src = "Hi\n";
    let ast = parse(src);
    let uri = Url::parse("file:///tmp/page.wiki").unwrap();
    assert!(ops::links_edit(src, &ast, &uri, "Home", &[], true).is_none());
}

// ===== find_orphans =====

#[test]
fn find_orphans_lists_pages_with_no_backlinks() {
    let root = "/tmp/orph";
    let idx = build_index(
        root,
        &[
            ("Home", "[[A]]\n"),
            ("A", "= A =\n"),
            ("B", "= B =\n"), // not linked from anywhere
        ],
    );
    let orphans = ops::find_orphans(&idx);
    let names: Vec<&str> = orphans.iter().map(|o| o.name.as_str()).collect();
    // Home + B have no backlinks. A is linked from Home.
    assert!(names.contains(&"Home"));
    assert!(names.contains(&"B"));
    assert!(!names.contains(&"A"));
}

// ===== collect_wiki_links (AST walker) =====

#[test]
fn collect_wiki_links_finds_nested() {
    let src = "= [[A]] =\n*[[B]]* and [[C|desc]]\n- [[D]]\n";
    let ast = parse(src);
    let links = nuwiki_lsp::diagnostics::collect_wiki_links(&ast);
    let paths: Vec<&str> = links
        .iter()
        .filter_map(|l| l.target.path.as_deref())
        .collect();
    for expected in ["A", "B", "C", "D"] {
        assert!(paths.contains(&expected), "missing {expected}");
    }
}

// ===== COMMANDS completeness =====

#[test]
fn commands_list_includes_phase15_entries() {
    let names: Vec<&str> = nuwiki_lsp::commands::COMMANDS.to_vec();
    for name in [
        "nuwiki.toc.generate",
        "nuwiki.links.generate",
        "nuwiki.workspace.checkLinks",
        "nuwiki.workspace.findOrphans",
    ] {
        assert!(names.contains(&name), "missing: {name}");
    }
}