From ccb341fef4f7c9abb195bbfcb8dc09c075cc63a7 Mon Sep 17 00:00:00 2001
From: Dan Anglin <daangling@gmail.com>
Date: Fri, 20 Sep 2024 10:04:13 +0100
Subject: [PATCH] checkpoint: add 50% chance to catch a pokemon

---
 main.go | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 91 insertions(+), 10 deletions(-)

diff --git a/main.go b/main.go
index fcf0dc8..6916c9f 100644
--- a/main.go
+++ b/main.go
@@ -5,11 +5,13 @@ import (
 	"errors"
 	"fmt"
 	"maps"
+	"math/rand/v2"
 	"os"
 	"slices"
 	"strings"
 	"time"
 
+	"codeflow.dananglin.me.uk/apollo/pokedex/internal/api/pokeapi"
 	"codeflow.dananglin.me.uk/apollo/pokedex/internal/pokeclient"
 )
 
@@ -18,8 +20,6 @@ type State struct {
 	Next     *string
 }
 
-var state State
-
 type command struct {
 	name        string
 	description string
@@ -28,6 +28,10 @@ type command struct {
 
 type callbackFunc func(args []string) error
 
+type pokedex map[string]pokeapi.Pokemon
+
+var dexter = make(pokedex)
+
 func main() {
 	run()
 }
@@ -38,6 +42,8 @@ func run() {
 		10*time.Second,
 	)
 
+	var state State
+
 	commandMap := map[string]command{
 		"exit": {
 			name:        "exit",
@@ -52,18 +58,23 @@ func run() {
 		"map": {
 			name:        "map",
 			description: "Displays the next 20 locations in the Pokemon world",
-			callback:    mapFunc(client),
+			callback:    mapFunc(client, &state),
 		},
 		"mapb": {
 			name:        "map back",
 			description: "Displays the previous 20 locations in the Pokemon world",
-			callback:    mapBFunc(client),
+			callback:    mapBFunc(client, &state),
 		},
 		"explore": {
 			name:        "explore",
 			description: "Lists all the pokemon in a given area",
 			callback:    exploreFunc(client),
 		},
+		"catch": {
+			name:        "catch",
+			description: "Catches a pokemon and adds them to your Pokedex",
+			callback:    catchFunc(client),
+		},
 	}
 
 	summaries := summaryMap(commandMap)
@@ -137,26 +148,26 @@ func exitFunc(_ []string) error {
 	return nil
 }
 
-func mapFunc(client *pokeclient.Client) callbackFunc {
+func mapFunc(client *pokeclient.Client, state *State) callbackFunc {
 	return func(_ []string) error {
 		url := state.Next
 		if url == nil {
 			url = new(string)
-			*url = pokeclient.LocationAreaEndpoint
+			*url = pokeclient.LocationAreaPath
 		}
 
-		return printResourceList(client, *url)
+		return printResourceList(client, *url, state)
 	}
 }
 
-func mapBFunc(client *pokeclient.Client) callbackFunc {
+func mapBFunc(client *pokeclient.Client, state *State) callbackFunc {
 	return func(_ []string) error {
 		url := state.Previous
 		if url == nil {
 			return fmt.Errorf("no previous locations available")
 		}
 
-		return printResourceList(client, *url)
+		return printResourceList(client, *url, state)
 	}
 }
 
@@ -195,7 +206,46 @@ func exploreFunc(client *pokeclient.Client) callbackFunc {
 	}
 }
 
-func printResourceList(client *pokeclient.Client, url string) error {
+func catchFunc(client *pokeclient.Client) callbackFunc {
+	return func(args []string) error {
+		if args == nil {
+			return errors.New("the name of the Pokemon has not been specified")
+		}
+
+		if len(args) != 1 {
+			return fmt.Errorf(
+				"unexpected number of Pokemon names: want 1; got %d",
+				len(args),
+			)
+		}
+
+		pokemonName := args[0]
+
+		fmt.Printf("Throwing a Pokeball at %s...\n", pokemonName)
+
+		pokemon, err := client.GetPokemon(pokemonName)
+		if err != nil {
+			return fmt.Errorf(
+				"unable to get the information on %s: %w",
+				pokemonName,
+				err,
+			)
+		}
+
+		chance := 50
+
+		if caught := catchPokemon(chance); caught {
+			dexter[pokemonName] = pokemon
+			fmt.Printf("%s was caught!\n", pokemonName)
+		} else {
+			fmt.Printf("%s escaped!\n", pokemonName)
+		}
+
+		return nil
+	}
+}
+
+func printResourceList(client *pokeclient.Client, url string, state *State) error {
 	list, err := client.GetNamedAPIResourceList(url)
 	if err != nil {
 		return fmt.Errorf("unable to get the list of resources: %w", err)
@@ -234,3 +284,34 @@ func parseArgs(input string) (string, []string) {
 
 	return split[0], split[1:]
 }
+
+func catchPokemon(chance int) bool {
+	if chance == 100 {
+		return true
+	}
+
+	if chance == 0 {
+		return false
+	}
+
+	maxInt := 100
+
+	numGenerator := rand.New(rand.NewPCG(rand.Uint64(), rand.Uint64()))
+
+	luckyNumberSet := make(map[int]struct{})
+
+	for len(luckyNumberSet) < chance {
+		num := numGenerator.IntN(maxInt)
+		if _, ok := luckyNumberSet[num]; !ok {
+			luckyNumberSet[num] = struct{}{}
+		}
+	}
+
+	roller := rand.New(rand.NewPCG(rand.Uint64(), rand.Uint64()))
+
+	got := roller.IntN(maxInt)
+
+	_, ok := luckyNumberSet[got]
+
+	return ok
+}