/*******************************************
* Section : 15
* Machine No. : N
* Roll No. : 18CS100XY
* Name : Soumyajit Dey, Aritra Hazra
* Assignment No : 7
* Description : Restaurent Order and Service
********************************************/

#include <stdio.h>
#include <string.h>

#define MAX_CUSTOMER 50
#define MAX_ITEM 5
#define MAX_NAME 11
#define PRECISION 0.000001

struct order{
    char name[MAX_NAME];
    int item[MAX_ITEM];
};

int main()
{
    char choice = ' ', delReq, deleteCustName[MAX_NAME];
    int custID = 0, i, j, k, deleteCustID, itemReq;
    struct order custOrder[MAX_CUSTOMER], tempCustOrder;
    double itemRevenue[MAX_ITEM], orderRevenue[MAX_CUSTOMER], targetAvgRevenue, tempOrderRevenue;
    
    printf("\n===== Welcome to PDS Restaurant! =====\n");
    printf("-- There are FIVE Items in MENU: Item-1, Item-2, Item-3, Item-4 and Item-5\n");
    printf("-- Enter Per-Plate Revenue (Profit) for these Five Items: ");
    for(i=0; i<MAX_ITEM; i++){
        scanf("%lf", &itemRevenue[i]);
    }
    printf("-- Enter Minimum Target Average Revenue (Profit) for Consecutive Three Orders: ");
    scanf("%lf", &targetAvgRevenue);
    
    while(choice != 'e'){
        printf("\n===== Hello! How Can We Help You? =====\n");
        printf("-- Customer Options:\n(a) Create New Order,\n(b) Delete Existing Order,\n(c) Serve Order,\n(d) Display Item Statistics,\n(e) Exit\n");
        printf("-- Enter a Choice: ");
        scanf(" %c", &choice);
        
        switch(choice){
            case 'a': /* Creating Order */
            case 'A':
                printf("*** Creating Order for Customer [ID: %d] ***\n", custID);
                printf("-- Enter the Name of Customer: ");
                scanf("%s", custOrder[custID].name);
                printf("-- Enter Quantity of Five Items: ");
                
                /* Calculate Revenue for Each Order */
                orderRevenue[custID] = 0;
                for(i=0; i<MAX_ITEM; i++){
                    scanf("%d", &(custOrder[custID].item[i]));
                    orderRevenue[custID] = orderRevenue[custID] + itemRevenue[i]*(custOrder[custID].item[i]);
                }
                /* Find Suitable Position for the Pending Order to meet Target Average Revenue */
                if( (custID > 1) && ( (targetAvgRevenue - (orderRevenue[custID]+orderRevenue[custID-1]+orderRevenue[custID-2])/3) > PRECISION ) ){
                    j = custID - 3;
                    while(j>=0){
                        if(j > 1){
                            if( (targetAvgRevenue - (orderRevenue[custID]+orderRevenue[j-1]+orderRevenue[j-2])/3) > PRECISION ){
                                j = j-3;
                            }
                            else if( (targetAvgRevenue - (orderRevenue[custID]+orderRevenue[j]+orderRevenue[j-1])/3) > PRECISION ){
                                j = j-2;
                            }
                            else if( (targetAvgRevenue - (orderRevenue[custID]+orderRevenue[j]+orderRevenue[j+1])/3) > PRECISION ){
                                j = j-1;
                            }
                            else{
                                break;
                            }
                        }
                        else if(j == 1){
                            if( (targetAvgRevenue - (orderRevenue[custID]+orderRevenue[j]+orderRevenue[j-1])/3) > PRECISION ){
                                j = j-2;
                            }
                            else if( (targetAvgRevenue - (orderRevenue[custID]+orderRevenue[j]+orderRevenue[j+1])/3) > PRECISION ){
                                j = j-1;
                            }
                            else{
                                break;
                            }
                        }
                        else if(j == 0){
                            if( (targetAvgRevenue - (orderRevenue[custID]+orderRevenue[j]+orderRevenue[j+1])/3) > PRECISION ){
                                j = j-1;
                            }
                            else{
                                break;
                            }
                        }
                    }
                    /* Inserting the Order in Proper Loaction keeping Target Average Revenue */
                    if(j>=0){
                        tempCustOrder = custOrder[custID];
                        tempOrderRevenue = orderRevenue[custID];
                        for(k=custID-1; k>=j; k--){
                            custOrder[k+1] = custOrder[k];
                            orderRevenue[k+1] = orderRevenue[k];
                        }
                        custOrder[j] = tempCustOrder;
                        orderRevenue[j] = tempOrderRevenue;
                        custID++;
                    }
                    else{ //customer order not considered
                        printf("*** Target Revenue NOT Met ... Order Cancelled! ***\n");;
                    }
                }
                else{ // first two customer request always entered
                    custID++;
                }
                printf("+++ Pending Order List +++\n");
                for(j=0; j<custID; j++){
                    printf("-- Customer ID: %d, Name: %s\n", j, custOrder[j].name);
                    for(i=0; i<MAX_ITEM; i++){
                        if(custOrder[j].item[i] > 0)
                            printf("\tItem %d --> Quantity = %d\n", i+1, custOrder[j].item[i]);
                        else
                            printf("\tItem %d --> NOT Ordered\n", i+1);
                    }
                }
                break;
            
            case 'b': /* Deleting Order */
            case 'B':
                printf("*** Deleting Order for Customer ***\n");
                if(custID > 0){
                    printf("-- Enter Customer ID (enter any negative number, if forgotten): ");
                    scanf("%d", &deleteCustID);
                    if(deleteCustID < 0){
                        printf("-- Enter Customer Name: ");
                        scanf("%s", deleteCustName);
                        for(j=0; j<MAX_CUSTOMER; j++){
                            if(!strcmp(custOrder[j].name,deleteCustName)){
                                deleteCustID = j;
                                break;
                            }
                        }
                    }
                    printf("+++ Selected Order Details +++\n");
                    printf("-- Customer ID: %d, Name: %s\n", j, custOrder[deleteCustID].name);
                    for(i=0; i<MAX_ITEM; i++){
                        if(custOrder[deleteCustID].item[i] > 0)
                            printf("\tItem %d --> Quantity = %d\n", i+1, custOrder[deleteCustID].item[i]);
                        else
                            printf("\tItem %d --> NOT Ordered\n", i+1);
                    }
                    printf("-- Want to delete for sure (press Y/N)? ");
                    scanf(" %c", &delReq);
                    if(delReq == 'Y' || delReq == 'y'){
                        for(j=deleteCustID; j<custID-1; j++)
                            custOrder[j] = custOrder[j+1];
                        custID--;
                    }
                    printf("+++ Pending Order List +++\n");
                    for(j=0; j<custID; j++){
                        printf("-- Customer ID: %d, Name: %s\n", j, custOrder[j].name);
                        for(i=0; i<MAX_ITEM; i++){
                            if(custOrder[j].item[i] > 0)
                                printf("\tItem %d --> Quantity = %d\n", i+1, custOrder[j].item[i]);
                            else
                                printf("\tItem %d --> NOT Ordered\n", i+1);
                        }
                    }
                }
                else{
                    printf("*** NO Pending Order Exists! ***\n");
                }
                break;
            
            case 'c': /* Serve Order */
            case 'C':
                printf("*** Served Order Details ***\n");
                if(custID > 0){
                    printf("-- Customer Name: %s\n", custOrder[0].name);
                    for(i=0; i<MAX_ITEM; i++){
                        if(custOrder[0].item[i] > 0)
                            printf("\tItem %d --> Quantity = %d\n", i+1, custOrder[0].item[i]);
                        else
                            printf("\tItem %d --> NOT Ordered\n", i+1);
                    }
                    for(j=0; j<custID-1; j++)
                        custOrder[j] = custOrder[j+1];
                    custID--;
                    printf("+++ Pending Order List +++\n");
                    for(j=0; j<custID; j++){
                        printf("-- Customer ID: %d, Name: %s\n", j, custOrder[j].name);
                        for(i=0; i<MAX_ITEM; i++){
                            if(custOrder[j].item[i] > 0)
                                printf("\tItem %d --> Quantity = %d\n", i+1, custOrder[j].item[i]);
                            else
                                    printf("\tItem %d --> NOT Ordered\n", i+1);
                        }
                    }
                }
                else{
                    printf("*** NO Order Remains to Serve! ***\n");
                }
                break;
            
            case 'd': /* Display Statistics */
            case 'D':
                printf("*** Item Requirement Statistics ***\n");
                for(i=0; i<MAX_ITEM; i++){
                    itemReq = 0;
                    for(j=0; j<custID; j++){
                        itemReq = itemReq + custOrder[j].item[i];
                    }
                    printf("\tItem %d --> Requirement = %d\n", i+1, itemReq);
                }
                break;
            
            case 'e': /* Exit or Terminate */
            case 'E':
                printf("\n===== Good-Bye! Have a Nice Day! =====\n");
                break;
            
            default: /* Wrong Choice */
                printf("*** Wrong Choice Entered! ***\n");
                break;
        }
    }

    return 0;
}