using Xunit;
using System.Reflection;

namespace NozCli.Tests;

// Tests the private ReplaceReferences + PatchTopicIfNeeded methods via reflection
// so we don't expose them publicly just for testing.
public class NoteRenamerTests
{
    private static string ReplaceReferences(string md, string oldSlug, string newSlug)
    {
        var method = typeof(NozCli.Core.Client.NoteRenamer)
            .GetMethod("ReplaceReferences", BindingFlags.NonPublic | BindingFlags.Static)!;
        return (string)method.Invoke(null, [md, oldSlug, newSlug])!;
    }

    private static string PatchTopicIfNeeded(string md, string oldSlug, string newSlug)
    {
        var method = typeof(NozCli.Core.Client.NoteRenamer)
            .GetMethod("PatchTopicIfNeeded", BindingFlags.NonPublic | BindingFlags.Static)!;
        return (string)method.Invoke(null, [md, oldSlug, newSlug])!;
    }

    // ── Wikilink replacement ─────────────────────────────────────────────────

    [Fact]
    public void ReplaceReferences_BareWikilink_IsReplaced()
    {
        var md     = "Siehe [[psychologie/flow]] für Details.";
        var result = ReplaceReferences(md, "psychologie/flow", "psychologie/new-flow");
        Assert.Equal("Siehe [[psychologie/new-flow]] für Details.", result);
    }

    [Fact]
    public void ReplaceReferences_WikilinkWithDisplay_PreservesDisplay()
    {
        var md     = "Lies [[psychologie/flow|Flow-Zustand]] weiter.";
        var result = ReplaceReferences(md, "psychologie/flow", "psychologie/new-flow");
        Assert.Equal("Lies [[psychologie/new-flow|Flow-Zustand]] weiter.", result);
    }

    [Fact]
    public void ReplaceReferences_MarkdownLink_IsReplaced()
    {
        var md     = "Siehe [Flow](/noosphere/psychologie/flow) hier.";
        var result = ReplaceReferences(md, "psychologie/flow", "psychologie/new-flow");
        Assert.Equal("Siehe [Flow](/noosphere/psychologie/new-flow) hier.", result);
    }

    [Fact]
    public void ReplaceReferences_MarkdownLinkWithAnchor_PreservesAnchor()
    {
        var md     = "[Abschnitt](/noosphere/psychologie/flow#abschnitt-2)";
        var result = ReplaceReferences(md, "psychologie/flow", "psychologie/new-flow");
        Assert.Equal("[Abschnitt](/noosphere/psychologie/new-flow#abschnitt-2)", result);
    }

    [Fact]
    public void ReplaceReferences_UnrelatedLinks_AreUntouched()
    {
        var md     = "[[other/note]] und [Ext](https://example.com/psychologie/flow)";
        var result = ReplaceReferences(md, "psychologie/flow", "psychologie/new-flow");
        Assert.Equal(md, result);
    }

    [Fact]
    public void ReplaceReferences_MultipleOccurrences_AllReplaced()
    {
        var md     = "[[psychologie/flow]] und nochmal [[psychologie/flow|Flow]].";
        var result = ReplaceReferences(md, "psychologie/flow", "psychologie/new-flow");
        Assert.DoesNotContain("psychologie/flow]]", result);
        Assert.Equal(2, result.Split("psychologie/new-flow").Length - 1);
    }

    // ── Topic frontmatter patch ───────────────────────────────────────────────

    [Fact]
    public void PatchTopic_SameTopic_NoChange()
    {
        var md = "---\ntitle: Flow\ntopic: psychologie\n---\nInhalt";
        var result = PatchTopicIfNeeded(md, "psychologie/flow", "psychologie/new-flow");
        Assert.Equal(md, result);
    }

    [Fact]
    public void PatchTopic_DifferentTopic_UpdatesFrontmatter()
    {
        var md = "---\ntitle: Flow\ntopic: psychologie\n---\nInhalt";
        var result = PatchTopicIfNeeded(md, "psychologie/flow", "biosysteme/flow");
        Assert.Contains("topic: biosysteme", result);
        Assert.DoesNotContain("topic: psychologie", result);
        Assert.Contains("Inhalt", result);  // body untouched
    }

    [Fact]
    public void PatchTopic_NoFrontmatter_NoChange()
    {
        var md = "# Kein Frontmatter\nNur Inhalt";
        var result = PatchTopicIfNeeded(md, "psychologie/flow", "biosysteme/flow");
        Assert.Equal(md, result);
    }
}