From 6e1018fc7121d22078fd950a35710b15a043a15b Mon Sep 17 00:00:00 2001
From: yedhink <yedhin1998@gmail.com>
Date: Thu, 9 Apr 2020 22:25:37 +0530
Subject: [PATCH] :art:fix #8 : modularly organize the location handler and add
 comments for each of the separate functions

---
 internal/server/api_location_handler.go | 93 ++++++++++++-------------
 1 file changed, 46 insertions(+), 47 deletions(-)

diff --git a/internal/server/api_location_handler.go b/internal/server/api_location_handler.go
index ab51526..e83f3aa 100644
--- a/internal/server/api_location_handler.go
+++ b/internal/server/api_location_handler.go
@@ -1,32 +1,42 @@
 package server
 
 import (
-	"time"
-
 	"github.com/gin-gonic/gin"
+	. "github.com/yedhink/covid19-kerala-api/internal/date"
 	. "github.com/yedhink/covid19-kerala-api/internal/storage"
 )
 
-type Locations struct {
+type Query struct {
 	Loc  []string `form:"loc"`
 	Date string   `form:"date"`
 }
 
-func filterByLoc(value map[string]interface{}, key string, d map[string]interface{}, userLoc []string) {
+// goes through all the input loc and append matches from value obj to the obj d
+// value is server.JsonData.All.Data[timestamp], d is the result and userLoc contains all loc params
+func filterByLoc(value map[string]interface{}, d map[string]interface{}, userLoc []string) {
 	for _, loc := range userLoc {
-		d[key].(map[string]interface{})[loc] = value[loc]
+		d[loc] = value[loc]
 	}
 }
 
-func parseDate(k string, s string) (time.Time, time.Time) {
-	userDate, err := time.Parse("02-01-2006", s)
-	if err != nil {
-		userDate, _ = time.Parse("02/01/2006", s)
-	}
-	userDate.Format(time.RFC3339)
-	keyDate, _ := time.Parse(time.RFC3339, k)
-	return keyDate, userDate
-}
+// q is the Query struct, d is our final result, st is Storage referenc and apiData is server.JsonData.All.Data
+// the function validates the date and filters using loc and date parameters of user
+func LocDateFilter(q *Query, d map[string]interface{}, st *Storage, apiData map[string]interface{}, locExist bool) {
+	// start by checking if the date param value is valid formatted Date
+	switch IsDate(q.Date) {
+	case true:
+		for key, value := range apiData {
+			if ValidDate(key, q.Date, st) {
+				// if loc length > 0 then only filterByLoc
+				if locExist == true {
+					d[key] = make(map[string]interface{}, len(q.Loc))
+					filterByLoc(value.(map[string]interface{}), d[key].(map[string]interface{}), q.Loc)
+				} else {
+					// if no loc, then just assign to valid date
+					d[key] = value
+				}
+			}
+		}
 	// if the date is not correctly formatted
 	case false:
 		d["success"] = false
@@ -34,43 +44,32 @@ func parseDate(k string, s string) (time.Time, time.Time) {
 	}
 }
 
+// handles the /location related parameter and non-parametric queries
 func (server *Server) Location(st *Storage) gin.HandlerFunc {
 	return func(c *gin.Context) {
-		var l Locations
-		c.Bind(&l)
-		if len(l.Loc) > 0 {
-			d := make(map[string]interface{})
-			d["success"] = true
+		var q Query
+		c.Bind(&q)
+		// initialize the final result 'd' with success=true
+		d := make(map[string]interface{})
+		d["success"] = true
+		// check if loc param is nil or not
+		switch length := len(q.Loc); {
+		//serve the array of locations
+		case length == 0 && q.Date == "":
+			d = server.JsonData.Districts.Loc
+		// validate just the date and append matching obj entries
+		case length == 0 && q.Date != "":
+			LocDateFilter(&q, d, st, server.JsonData.All.Data, false)
+		// just filter by loc parameter
+		case length > 0 && q.Date == "":
 			for key, value := range server.JsonData.All.Data {
-				// since we cant assert a value interface of type bool as map[string]interface{}
-				if key == "success" {
-					continue
-				}
-				if l.Date != "" {
-					if validateDate(key, l.Date, st) {
-						d[key] = make(map[string]interface{}, len(l.Loc))
-						filterByLoc(value.(map[string]interface{}), key, d, l.Loc)
-					}
-				} else {
-					d[key] = make(map[string]interface{}, len(l.Loc))
-					filterByLoc(value.(map[string]interface{}), key, d, l.Loc)
-				}
-			}
-			c.IndentedJSON(200, d)
-		} else {
-			if l.Date != "" {
-				d := make(map[string]interface{})
-				d["success"] = true
-				for key, value := range server.JsonData.All.Data {
-					if key != "success" && validateDate(key, l.Date, st) {
-						d[key] = value
-					}
-				}
-				c.IndentedJSON(200, d)
-			} else {
-				server.JsonData.Districts.Loc["success"] = true
-				c.IndentedJSON(200, server.JsonData.Districts.Loc)
+				d[key] = make(map[string]interface{}, len(q.Loc))
+				filterByLoc(value.(map[string]interface{}), d[key].(map[string]interface{}), q.Loc)
 			}
+		// filter by both loc and date params
+		case length > 0 && q.Date != "":
+			LocDateFilter(&q, d, st, server.JsonData.All.Data, true)
 		}
+		c.IndentedJSON(200, d)
 	}
 }