1 files changed, 146 insertions, 0 deletions
diff --git a/internal/unsorted/http_handle_repo_commit.go b/internal/unsorted/http_handle_repo_commit.go
new file mode 100644
index 0000000..44f8f54
--- /dev/null
+++ b/internal/unsorted/http_handle_repo_commit.go
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package unsorted
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/plumbing/filemode"
+	"github.com/go-git/go-git/v5/plumbing/format/diff"
+	"github.com/go-git/go-git/v5/plumbing/object"
+	"go.lindenii.runxiyu.org/forge/internal/misc"
+	"go.lindenii.runxiyu.org/forge/internal/oldgit"
+	"go.lindenii.runxiyu.org/forge/internal/web"
+)
+
+// usableFilePatch is a [diff.FilePatch] that is structured in a way more
+// friendly for use in HTML templates.
+type usableFilePatch struct {
+	From   diff.File
+	To     diff.File
+	Chunks []usableChunk
+}
+
+// usableChunk is a [diff.Chunk] that is structured in a way more friendly for
+// use in HTML templates.
+type usableChunk struct {
+	Operation diff.Operation
+	Content   string
+}
+
+func (s *Server) httpHandleRepoCommit(writer http.ResponseWriter, request *http.Request, params map[string]any) {
+	var repo *git.Repository
+	var commitIDStrSpec, commitIDStrSpecNoSuffix string
+	var commitID plumbing.Hash
+	var parentCommitHash plumbing.Hash
+	var commitObj *object.Commit
+	var commitIDStr string
+	var err error
+	var patch *object.Patch
+
+	repo, commitIDStrSpec = params["repo"].(*git.Repository), params["commit_id"].(string)
+
+	commitIDStrSpecNoSuffix = strings.TrimSuffix(commitIDStrSpec, ".patch")
+	commitID = plumbing.NewHash(commitIDStrSpecNoSuffix)
+	if commitObj, err = repo.CommitObject(commitID); err != nil {
+		web.ErrorPage500(s.templates, writer, params, "Error getting commit object: "+err.Error())
+		return
+	}
+	if commitIDStrSpecNoSuffix != commitIDStrSpec {
+		var patchStr string
+		if patchStr, err = oldgit.FmtCommitPatch(commitObj); err != nil {
+			web.ErrorPage500(s.templates, writer, params, "Error formatting patch: "+err.Error())
+			return
+		}
+		fmt.Fprintln(writer, patchStr)
+		return
+	}
+	commitIDStr = commitObj.Hash.String()
+
+	if commitIDStr != commitIDStrSpec {
+		http.Redirect(writer, request, commitIDStr, http.StatusSeeOther)
+		return
+	}
+
+	params["commit_object"] = commitObj
+	params["commit_id"] = commitIDStr
+
+	parentCommitHash, patch, err = oldgit.CommitToPatch(commitObj)
+	if err != nil {
+		web.ErrorPage500(s.templates, writer, params, "Error getting patch from commit: "+err.Error())
+		return
+	}
+	params["parent_commit_hash"] = parentCommitHash.String()
+	params["patch"] = patch
+
+	params["file_patches"] = makeUsableFilePatches(patch)
+
+	s.renderTemplate(writer, "repo_commit", params)
+}
+
+type fakeDiffFile struct {
+	hash plumbing.Hash
+	mode filemode.FileMode
+	path string
+}
+
+func (f fakeDiffFile) Hash() plumbing.Hash {
+	return f.hash
+}
+
+func (f fakeDiffFile) Mode() filemode.FileMode {
+	return f.mode
+}
+
+func (f fakeDiffFile) Path() string {
+	return f.path
+}
+
+var nullFakeDiffFile = fakeDiffFile{ //nolint:gochecknoglobals
+	hash: plumbing.NewHash("0000000000000000000000000000000000000000"),
+	mode: misc.FirstOrPanic(filemode.New("100644")),
+	path: "",
+}
+
+func makeUsableFilePatches(patch diff.Patch) (usableFilePatches []usableFilePatch) {
+	// TODO: Remove unnecessary context
+	// TODO: Prepend "+"/"-"/" " instead of solely distinguishing based on color
+
+	for _, filePatch := range patch.FilePatches() {
+		var fromFile, toFile diff.File
+		var ufp usableFilePatch
+		chunks := []usableChunk{}
+
+		fromFile, toFile = filePatch.Files()
+		if fromFile == nil {
+			fromFile = nullFakeDiffFile
+		}
+		if toFile == nil {
+			toFile = nullFakeDiffFile
+		}
+		for _, chunk := range filePatch.Chunks() {
+			var content string
+
+			content = chunk.Content()
+			if len(content) > 0 && content[0] == '\n' {
+				content = "\n" + content
+			} // Horrible hack to fix how browsers newlines that immediately proceed <pre>
+			chunks = append(chunks, usableChunk{
+				Operation: chunk.Type(),
+				Content:   content,
+			})
+		}
+		ufp = usableFilePatch{
+			Chunks: chunks,
+			From:   fromFile,
+			To:     toFile,
+		}
+		usableFilePatches = append(usableFilePatches, ufp)
+	}
+	return
+}