Code Challenge | Software Engineer

README.md

@@ -1,52 +1,17 @@
-#Degrees of Separation
+# Go Project
 
-With cinema going global these days, every one of the [A-Z]ollywoods are now connected. Use the wealth of data available at [Moviebuff](http://www.moviebuff.com) to see how. 
+## Overview
 
-Write a Go program that behaves the following way:
+This project processes a queue system and requires multiple Go files to run. The command below ensures all necessary files are included in execution.
 
-```
-$ degrees amitabh-bachchan robert-de-niro
+## Prerequisites
 
-Degrees of Separation: 3
+- Install [Go](https://go.dev/dl/) (if not already installed).
+- Ensure all required `.go` files are present in the same directory.
 
-1. Movie: The Great Gatsby
-Supporting Actor: Amitabh Bachchan
-Actor: Leonardo DiCaprio
+## Running the Project
 
-2. Movie: The Wolf of Wall Street
-Actor: Leonardo DiCaprio
-Director: Martin Scorsese
+To execute the project, run the following command:
 
-3. Movie: Taxi Driver
-Director: Martin Scorsese
-Actor: Robert De Niro
-```
-
-Your solution should use the Moviebuff data available to figure out the smallest degree of separation between the two people. 
-All the inputs should be Moviebuff URLs for their respective people: For Amitabh Bachchan, his page is on http://www.moviebuff.com/amitabh-bachchan and his Moviebuff URL is `amitabh-bachchan`.
-
-Please do not attempt to scrape the Moviebuff website - All the data is available on an S3 bucket in an easy to parse JSON format here: `https://data.moviebuff.com/{moviebuff_url}`
-
-To solve the example above, your solution would fetch at least the following:
-
-http://data.moviebuff.com/amitabh-bachchan
-
-http://data.moviebuff.com/the-great-gatsby
-
-http://data.moviebuff.com/leonardo-dicaprio
-
-http://data.moviebuff.com/the-wolf-of-wall-street
-
-http://data.moviebuff.com/martin-scorsese
-
-http://data.moviebuff.com/taxi-driver
-
-##Notes
-* If you receive HTTP errors when trying to fetch the data, that might be the CDN throttling you. Luckily, Go has some very elegant idioms for rate limiting :)
-* There may be a discrepancy in some cases where a movie appears on an actor's list but not vice versa. This usually happens when we edit data while exporting it, so feel free to either ignore these mismatches or handle them in some way.
-
-Write a program in any language you want (If you're here from Gophercon, use Go :D) that does this. Feel free to make your own input and output format / command line tool / GUI / Webservice / whatever you want. Feel free to hold the dataset in whatever structure you want, but try not to use external databases - as far as possible stick to your langauage without bringing in MySQL/Postgres/MongoDB/Redis/Etc.
-
-To submit a solution, fork this repo and send a Pull Request on Github.
-
-For any questions or clarifications, raise an issue on this repo and we'll answer your questions as fast as we can.
+```sh
+go run main.go queue.go amitabh-bachchan akshay-kumar

main.go

@@ -0,0 +1,254 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"time"
+)
+
+
+
+
+type cast struct {
+	Name string `json:"name"`
+	Role string `json:"role"`
+	URL  string `json:"url"`
+}
+
+type movie struct {
+	Name string `json:"name"`
+	URL  string `json:"url"`
+	Role string `json:"role"`
+}
+
+type data struct {
+	URL    string  `json:"url"`
+	Type   string  `json:"type"`
+	Name   string  `json:"name"`
+	Movies []movie `json:"movies"`
+	Casts  []cast  `json:"cast"`
+	Crew   []cast  `json:"crew"`
+}
+
+type out struct {
+	r   *relationship
+	err error
+}
+
+type skippable struct {
+	reason string
+}
+
+func (s skippable) Error() string {
+	return s.reason
+}
+
+type relationship struct {
+	cast1 cast
+	cast2 cast
+	movie string
+	path  []relationship
+}
+
+type response struct {
+	d   data
+	err error
+}
+
+func validateInputs() bool {
+	res := make(chan response)
+	throttle := time.Tick(time.Second / 800)
+
+	go getdata(os.Args[1], res, throttle)
+
+	r := <-res
+	if r.err != nil {
+		return false
+	}
+
+	go getdata(os.Args[2], res, throttle)
+
+	r = <-res
+	if r.err != nil {
+		return false
+	}
+
+	return true
+}
+
+func main() {
+	if len(os.Args) < 3 {
+		fmt.Print("Usage: degrees <actor-name> <actor-name>")
+	}
+
+	ok := validateInputs()
+	if !ok {
+		fmt.Print("Invalid ")
+	}
+
+	out := make(chan out)
+	q := NewQueue()
+	q.enqueue(workRequest{actor: os.Args[1]})
+
+	go getrelationship(q, out)
+
+	for {
+		o := <-out
+		if o.err != nil {
+			if _, ok := o.err.(skippable); ok {
+				continue
+			}
+			panic(o.err)
+		}
+
+		if o.r == nil {
+			continue
+		}
+
+		if o.r.cast2.URL == os.Args[2] {
+			var result []relationship
+			result = o.r.path
+			result = append(result, *o.r)
+
+			fmt.Println("Degrees of seperation:", len(result))
+			fmt.Println()
+
+			for i, r := range result {
+				fmt.Printf("%d. Movie: %s\n", i+1, r.movie)
+				fmt.Println(r.cast1.Role+":", r.cast1.Name)
+				fmt.Println(r.cast2.Role+":", r.cast2.Name)
+				fmt.Println()
+			}
+			return
+		}
+
+		path := make([]relationship, len(o.r.path))
+		copy(path, o.r.path)
+		path = append(path, *o.r)
+
+		q.enqueue(workRequest{actor: o.r.cast2.URL, path: path})
+	}
+}
+
+func getdata(id string, res chan<- response, throttle <-chan time.Time) {
+	fmt.Println("fetching", id)
+	<-throttle
+	resp, err := http.Get("http://data.moviebuff.com/" + id)
+
+	if resp != nil {
+		defer resp.Body.Close()
+	}
+
+	if err != nil {
+		res <- response{d: data{}, err: err}
+		return
+	}
+
+	if resp.StatusCode == http.StatusForbidden {
+		res <- response{d: data{}, err: skippable{reason: "forbidden"}}
+		return
+	}
+
+	jsonBlob, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		res <- response{d: data{}, err: err}
+		return
+	}
+
+	var data data
+	err = json.Unmarshal(jsonBlob, &data)
+	res <- response{d: data, err: err}
+	return
+}
+
+func getrelationship(q *queue, output chan<- out) {
+	visited := map[string]bool{}
+	throttle := time.Tick(time.Second / 800)
+
+	for {
+		if q.empty() {
+			continue
+		}
+
+		i := q.dequeue()
+		if visited[i.actor] {
+			output <- out{}
+		}
+
+		res := make(chan response)
+		go getdata(i.actor, res, throttle)
+
+		actorProfile := <-res
+		if actorProfile.err != nil {
+			if _, ok := actorProfile.err.(skippable); ok {
+				output <- out{}
+				continue
+			}
+			output <- out{err: actorProfile.err}
+			continue
+		}
+
+		visited[i.actor] = true
+
+		var count int
+		urlVsMovie := map[string]movie{}
+		for _, movie := range actorProfile.d.Movies {
+			if visited[movie.URL] {
+				continue
+			}
+
+			go getdata(movie.URL, res, throttle)
+
+			urlVsMovie[movie.URL] = movie
+			visited[movie.URL] = true
+			count++
+		}
+
+		for k := 0; k < count; k++ {
+			resp := <-res
+			if resp.err != nil {
+				if _, ok := resp.err.(skippable); ok {
+					continue
+				}
+				output <- out{err: resp.err}
+				return
+			}
+
+			for _, c := range resp.d.Casts {
+				if c.URL == i.actor || visited[c.URL] {
+					continue
+				}
+
+				visited[c.URL] = true
+
+				output <- out{
+					r: &relationship{
+						cast1: cast{Name: actorProfile.d.Name, URL: actorProfile.d.URL, Role: urlVsMovie[resp.d.URL].Role},
+						cast2: c,
+						movie: urlVsMovie[resp.d.URL].Name,
+						path:  i.path,
+					},
+				}
+			}
+
+			for _, c := range resp.d.Crew {
+				if c.URL == i.actor || visited[c.URL] {
+					continue
+				}
+
+				visited[c.URL] = true
+				output <- out{
+					r: &relationship{
+						cast1: cast{Name: actorProfile.d.Name, URL: actorProfile.d.URL, Role: urlVsMovie[resp.d.URL].Role},
+						cast2: c,
+						movie: urlVsMovie[resp.d.URL].Name,
+						path:  i.path,
+					},
+				}
+			}
+		}
+	}
+}

queue.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"sync"
+)
+
+type workRequest struct {
+	actor string
+	path  []relationship
+}
+
+type queue struct {
+	works []workRequest
+	sync.Mutex
+}
+
+func (q *queue) enqueue(w ...workRequest) {
+	q.Lock()
+	defer q.Unlock()
+	q.works = append(q.works, w...)
+}
+
+
+func (q *queue) dequeue() workRequest {
+	q.Lock()
+	defer q.Unlock()
+	rel := q.works[0]
+	q.works = q.works[1:]
+	return rel
+}
+
+func (q *queue) empty() bool {
+	q.Lock()
+	defer q.Unlock()
+	return len(q.works) == 0
+}
+
+func NewQueue() *queue {
+	return &queue{}
+}