feat: add /stats.json endpoint for JSON stats API

Returns user statistics (user, link_count, quote_count) as JSON with
pagination support via limit and offset query parameters. Limit defaults
to 50 and is capped at 1000 to prevent abuse.

Author: stahnma

cmd/tumble/main.go

@@ -223,6 +223,7 @@ func main() {
 	mux.HandleFunc("/", h.Index)
 	mux.HandleFunc("/index.cgi", h.Index)
 	mux.HandleFunc("/stats", h.Stats)
+	mux.HandleFunc("/stats.json", h.StatsJSON)
 	mux.HandleFunc("/search", h.Search)
 	mux.HandleFunc("/search.cgi", h.Search)
 	mux.HandleFunc("/link/", h.IRCLinkHandler)    // Primary endpoint for links

internal/assets/openapi.json

@@ -670,6 +670,79 @@
           }
         }
       }
+    },
+    "/stats.json": {
+      "get": {
+        "summary": "Get User Statistics as JSON",
+        "description": "Returns user statistics including link and quote counts for each user, sorted by link count descending. Supports pagination.",
+        "parameters": [
+          {
+            "name": "limit",
+            "in": "query",
+            "description": "Maximum number of results to return (default: 50, max: 1000)",
+            "schema": {
+              "type": "integer",
+              "default": 50,
+              "minimum": 1,
+              "maximum": 1000
+            }
+          },
+          {
+            "name": "offset",
+            "in": "query",
+            "description": "Number of results to skip (default: 0)",
+            "schema": {
+              "type": "integer",
+              "default": 0,
+              "minimum": 0
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "Array of user statistics",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "array",
+                  "items": {
+                    "type": "object",
+                    "properties": {
+                      "user": {
+                        "type": "string",
+                        "description": "The username"
+                      },
+                      "link_count": {
+                        "type": "integer",
+                        "description": "Number of links submitted by this user"
+                      },
+                      "quote_count": {
+                        "type": "integer",
+                        "description": "Number of quotes submitted by this user"
+                      }
+                    }
+                  },
+                  "example": [
+                    {
+                      "user": "alice",
+                      "link_count": 150,
+                      "quote_count": 42
+                    },
+                    {
+                      "user": "bob",
+                      "link_count": 120,
+                      "quote_count": 35
+                    }
+                  ]
+                }
+              }
+            }
+          },
+          "500": {
+            "description": "Server Error"
+          }
+        }
+      }
     }
   }
 }

internal/handler/handlers.go

@@ -2,6 +2,7 @@ package handler
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"html/template"
 	"log/slog"
@@ -716,3 +717,34 @@ func (h *Handler) Stats(w http.ResponseWriter, r *http.Request) {
 		slog.Error("Error rendering stats", "error", err)
 	}
 }
+
+// StatsJSON returns user statistics as JSON with pagination support
+func (h *Handler) StatsJSON(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	// Parse pagination parameters
+	limit := 50
+	if limitParam := r.URL.Query().Get("limit"); limitParam != "" {
+		if val, err := strconv.Atoi(limitParam); err == nil && val > 0 && val <= 1000 {
+			limit = val
+		}
+	}
+
+	offset := 0
+	if offsetParam := r.URL.Query().Get("offset"); offsetParam != "" {
+		if val, err := strconv.Atoi(offsetParam); err == nil && val >= 0 {
+			offset = val
+		}
+	}
+
+	stats, err := h.Store.GetUserStats(ctx, "links", limit, offset)
+	if err != nil {
+		h.ServerError(w, r, err)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(stats); err != nil {
+		slog.Error("Error encoding stats JSON", "error", err)
+	}
+}