feat(admin): add routed task evidence details

admin/internal/server/task_detail.go

@@ -0,0 +1,84 @@
+package server
+
+import (
+	"errors"
+	"mime"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+
+	"cmbuyer/admin/internal/taskdetail"
+	"cmbuyer/admin/internal/transport/webui"
+
+	"github.com/gin-gonic/gin"
+)
+
+const detailViewHeader = "X-CMBuyer-View"
+const detailVaryHeader = "X-CMBuyer-View, Accept, Sec-Fetch-Site"
+
+func taskDetailPage(options Options) gin.HandlerFunc {
+	return func(context *gin.Context) {
+		context.Header("Vary", detailVaryHeader)
+		if !options.Sessions.IsAuthenticated(context.Request) {
+			context.Redirect(http.StatusSeeOther, "/login?return_to="+url.QueryEscape(context.Request.URL.RequestURI()))
+			return
+		}
+		view := context.GetHeader(detailViewHeader)
+		if view != "" && view != "drawer" {
+			context.Status(http.StatusBadRequest)
+			return
+		}
+		if view == "drawer" {
+			if context.GetHeader("Sec-Fetch-Site") != "same-origin" {
+				context.Status(http.StatusForbidden)
+				return
+			}
+			if !acceptsHTML(context.GetHeader("Accept")) {
+				context.Status(http.StatusNotAcceptable)
+				return
+			}
+		}
+		detail, err := options.TaskDetails.Get(context.Request.Context(), context.Param("id"))
+		if errors.Is(err, taskdetail.ErrNotFound) {
+			context.Status(http.StatusNotFound)
+			return
+		}
+		if err != nil {
+			context.Status(http.StatusInternalServerError)
+			return
+		}
+		context.Header("Content-Type", "text/html; charset=utf-8")
+		context.Status(http.StatusOK)
+		data := webui.TaskDetailData{Detail: detail}
+		if view == "drawer" {
+			if err := webui.RenderTaskDetailFragment(context.Writer, data); err != nil {
+				_ = context.Error(err)
+			}
+			return
+		}
+		if err := webui.RenderTaskDetailPage(context.Writer, data); err != nil {
+			_ = context.Error(err)
+		}
+	}
+}
+
+func acceptsHTML(header string) bool {
+	for _, value := range strings.Split(header, ",") {
+		mediaType, parameters, err := mime.ParseMediaType(strings.TrimSpace(value))
+		if err != nil || !strings.EqualFold(mediaType, "text/html") {
+			continue
+		}
+		quality := 1.0
+		if rawQuality, exists := parameters["q"]; exists {
+			quality, err = strconv.ParseFloat(rawQuality, 64)
+			if err != nil || quality < 0 || quality > 1 {
+				continue
+			}
+		}
+		if quality > 0 {
+			return true
+		}
+	}
+	return false
+}