feat: add markdown renderer for review documents

src/lib.rs

@@ -2,6 +2,7 @@ pub mod cli;
 pub mod error;
 pub mod model;
 pub mod output;
+pub mod render;
 
 pub fn run() -> anyhow::Result<()> {
     Ok(())

src/render/markdown.rs

@@ -0,0 +1,109 @@
+use crate::model::{CommentThread, PrReviewDocument};
+
+fn backtick_fence(body: &str) -> String {
+    let mut max_run = 0usize;
+    let mut current_run = 0usize;
+
+    for ch in body.chars() {
+        if ch == '`' {
+            current_run += 1;
+            max_run = max_run.max(current_run);
+        } else {
+            current_run = 0;
+        }
+    }
+
+    let fence_len = std::cmp::max(3, max_run + 1);
+    "`".repeat(fence_len)
+}
+
+fn render_body(body: &str) -> String {
+    let fence = backtick_fence(body);
+    format!("{fence}md\n{body}\n{fence}\n")
+}
+
+fn render_thread(thread_index: usize, thread: &CommentThread) -> String {
+    let mut out = String::new();
+    out.push_str(&format!("### Comment {}.1\n", thread_index));
+    if let Some(file_path) = &thread.file_path {
+        if let Some(line) = thread.line {
+            out.push_str(&format!("{file_path}:{line}\n"));
+        } else {
+            out.push_str(&format!("{file_path}\n"));
+        }
+    }
+    out.push_str(&format!("{}:\n", thread.root_comment.user));
+    out.push_str(&render_body(&thread.root_comment.body));
+
+    for (reply_index, reply) in thread.replies.iter().enumerate() {
+        let reply_number = format!("{thread_index}.1.{}", reply_index + 1);
+        out.push_str(&format!("\n### Reply {reply_number}\n"));
+        out.push_str(&format!("{}:\n", reply.user));
+        out.push_str(&render_body(&reply.body));
+    }
+
+    out
+}
+
+pub fn render_markdown(doc: &PrReviewDocument) -> String {
+    let mut out = String::new();
+
+    out.push_str(&format!(
+        "# {} `#{}` {}\n\n",
+        doc.meta.repo, doc.meta.pr_index, doc.meta.title
+    ));
+
+    out.push_str("## Metadata\n\n");
+    out.push_str(&format!("- state: {}\n", doc.meta.state));
+    out.push_str(&format!("- author: {}\n", doc.meta.author));
+    out.push_str(&format!("- base branch: {}\n", doc.meta.base_branch));
+    out.push_str(&format!("- head branch: {}\n", doc.meta.head_branch));
+    out.push_str(&format!("- created at: {}\n", doc.meta.created_at));
+    out.push_str(&format!("- updated at: {}\n", doc.meta.updated_at));
+    out.push_str(&format!(
+        "- merged at: {}\n",
+        doc.meta.merged_at.as_deref().unwrap_or("null")
+    ));
+    out.push_str("\n");
+
+    out.push_str("## Commits\n\n");
+    for commit in &doc.commits {
+        out.push_str(&format!(
+            "- {} {} ({}, {})\n",
+            commit.short_sha, commit.title, commit.author, commit.date
+        ));
+    }
+    out.push_str("\n");
+
+    out.push_str("## Diff Stat\n\n");
+    out.push_str(&format!(
+        "- files changed: {}\n- additions: {}\n- deletions: {}\n",
+        doc.diff_stat.files_changed, doc.diff_stat.additions, doc.diff_stat.deletions
+    ));
+    for file in &doc.diff_stat.files {
+        out.push_str(&format!(
+            "- {}: +{}, -{}\n",
+            file.path, file.additions, file.deletions
+        ));
+    }
+    out.push_str("\n");
+
+    for (review_index, review) in doc.reviews.iter().enumerate() {
+        out.push_str(&format!(
+            "## Review {} ({})\n\n",
+            review_index + 1,
+            review.state
+        ));
+        out.push_str(&format!("> {}\n\n", review.reviewer));
+        if let Some(submitted_at) = &review.submitted_at {
+            out.push_str(&format!("- submitted at: {}\n\n", submitted_at));
+        }
+    }
+
+    for (thread_index, thread) in doc.threads.iter().enumerate() {
+        out.push_str(&render_thread(thread_index + 1, thread));
+        out.push('\n');
+    }
+
+    out.trim_end().to_string()
+}

src/render/mod.rs

@@ -0,0 +1 @@
+pub mod markdown;

tests/render_markdown_tests.rs

@@ -0,0 +1,118 @@
+use gitea_pr_review::model::{
+    CommentItem, CommentThread, CommitItem, DiffStat, FileStat, PrMeta, PrReviewDocument,
+    ReviewItem,
+};
+use gitea_pr_review::render::markdown::render_markdown;
+
+#[test]
+fn render_markdown_includes_expected_sections_and_preserves_comment_markdown() {
+    let doc = PrReviewDocument {
+        meta: PrMeta {
+            repo: "org/repo".into(),
+            pr_index: 7,
+            title: "Fix parser".into(),
+            state: "open".into(),
+            author: "alice".into(),
+            base_branch: "main".into(),
+            head_branch: "feat/a".into(),
+            created_at: "2026-04-08T10:00:00Z".into(),
+            updated_at: "2026-04-08T11:00:00Z".into(),
+            merged_at: None,
+        },
+        commits: vec![CommitItem {
+            sha: "abcdef0123456789".into(),
+            short_sha: "abcdef0".into(),
+            title: "fix: parser".into(),
+            author: "alice".into(),
+            date: "2026-04-08T10:10:00Z".into(),
+        }],
+        diff_stat: DiffStat {
+            files_changed: 1,
+            additions: 3,
+            deletions: 1,
+            files: vec![FileStat {
+                path: "src/main.rs".into(),
+                additions: 3,
+                deletions: 1,
+            }],
+        },
+        reviews: vec![ReviewItem {
+            id: 1,
+            state: "COMMENT".into(),
+            reviewer: "bob".into(),
+            submitted_at: Some("2026-04-08T11:00:00Z".into()),
+        }],
+        threads: vec![CommentThread {
+            thread_id: "t1".into(),
+            file_path: Some("src/main.rs".into()),
+            line: Some(9),
+            root_comment: CommentItem {
+                id: 11,
+                user: "bob".into(),
+                created_at: "2026-04-08T11:01:00Z".into(),
+                body: "```rs\nlet x = 1;\n```".into(),
+            },
+            replies: vec![CommentItem {
+                id: 12,
+                user: "alice".into(),
+                created_at: "2026-04-08T11:02:00Z".into(),
+                body: "looks good".into(),
+            }],
+        }],
+    };
+
+    let md = render_markdown(&doc);
+
+    assert!(md.contains("# org/repo `#7` Fix parser"));
+    assert!(md.contains("## Metadata"));
+    assert!(md.contains("## Commits"));
+    assert!(md.contains("## Diff Stat"));
+    assert!(md.contains("## Review 1 (COMMENT)"));
+    assert!(md.contains("### Comment 1.1"));
+    assert!(md.contains("### Reply 1.1"));
+    assert!(md.contains("````md"));
+    assert!(md.contains("```rs\nlet x = 1;\n```"));
+    assert!(md.contains("looks good"));
+}
+
+#[test]
+fn render_markdown_uses_minimal_fence_for_plain_text() {
+    let body = "plain text";
+    let doc = PrReviewDocument {
+        meta: PrMeta {
+            repo: "org/repo".into(),
+            pr_index: 1,
+            title: "T".into(),
+            state: "open".into(),
+            author: "alice".into(),
+            base_branch: "main".into(),
+            head_branch: "feat".into(),
+            created_at: "2026-04-08T10:00:00Z".into(),
+            updated_at: "2026-04-08T10:00:00Z".into(),
+            merged_at: None,
+        },
+        commits: vec![],
+        diff_stat: DiffStat {
+            files_changed: 0,
+            additions: 0,
+            deletions: 0,
+            files: vec![],
+        },
+        reviews: vec![],
+        threads: vec![CommentThread {
+            thread_id: "t1".into(),
+            file_path: None,
+            line: None,
+            root_comment: CommentItem {
+                id: 1,
+                user: "bob".into(),
+                created_at: "2026-04-08T11:00:00Z".into(),
+                body: body.into(),
+            },
+            replies: vec![],
+        }],
+    };
+
+    let md = render_markdown(&doc);
+    assert!(md.contains("```md\nplain text\n```"));
+}