// gumlet/gumlet_url_builder.go
package gumlet

import (
    "fmt"
    "net/url"
    "strings"
)

type GumletURLBuilder struct {
    scheme      string
    host        string
    port        int
    path        string
    queryParams map[string]string
}

func NewGumletURLBuilder() *GumletURLBuilder {
    return &GumletURLBuilder{
        port:        -1,
        queryParams: make(map[string]string),
    }
}

func (b *GumletURLBuilder) SetScheme(scheme string) *GumletURLBuilder {
    b.scheme = scheme
    return b
}

func (b *GumletURLBuilder) SetHost(host string) *GumletURLBuilder {
    b.host = host
    return b
}

func (b *GumletURLBuilder) SetPort(port int) *GumletURLBuilder {
    b.port = port
    return b
}

func (b *GumletURLBuilder) SetPath(path string) *GumletURLBuilder {
    b.path = path
    return b
}

func (b *GumletURLBuilder) AddQueryParameter(name, value string) *GumletURLBuilder {
    b.queryParams[name] = value
    return b
}

func (b *GumletURLBuilder) Build() (string, error) {
    u := url.URL{}
    if b.scheme != "" {
        u.Scheme = b.scheme
    }
    if b.host != "" {
        u.Host = b.host
    }
    if b.port != -1 {
        u.Host = fmt.Sprintf("%s:%d", b.host, b.port)
    }
    if b.path != "" {
        if !strings.HasPrefix(b.path, "/") {
            b.path = "/" + b.path
        }
        u.Path = b.path
    }

    query := url.Values{}
    for k, v := range b.queryParams {
        query.Set(k, v)
    }
    u.RawQuery = query.Encode()

    return u.String(), nil
}

A sample code:

// main.go
package main

import (
    "fmt"
    "gumlet"
)


func main() {
    builder := NewGumletURLBuilder().
        SetScheme("https").
        SetHost("demo.gumlet.io").
        SetPath("/flower.jpeg").
        AddQueryParameter("width", "250").
        AddQueryParameter("dpr", "2.0").
			  AddQueryParameter("overlay", "https://demo.gumlet.io/logo.png")

    url, err := builder.Build()
    if err != nil {
        fmt.Println("Error building URL:", err)
    } else {
        fmt.Println("Built URL:", url) //output - Built URL: https://demo.gumlet.io/flower.jpeg?overlay=https%3A%2F%2Fdemo.gumlet.io%2Flogo.png&dpr=2.0&width=250
    }
}