package main

import "fmt"

/* 实例
汤宝宝想要建造一栋属于自己的房子，于是找来了著名的建筑设计
公司——生成者模式公司（Builder Pattern Inc.）帮忙设计和建造房子。
*/

// 产品：房子
type House struct {
	Foundation string // 地基
	Structure  string // 结构
	Roof       string // 屋顶
}

// 建造者接口
type HouseBuilder interface {
	buildFoundation()
	buildStructure()
	buildRoof()
	getHouse() House
}

// 具体建造者：木屋建造者
type WoodenHouseBuilder struct {
	house House
}

func (b *WoodenHouseBuilder) buildFoundation() {
	b.house.Foundation = "木桩地基"
	fmt.Println("  建造木桩地基")
}

func (b *WoodenHouseBuilder) buildStructure() {
	b.house.Structure = "木结构"
	fmt.Println("  建造木结构")
}

func (b *WoodenHouseBuilder) buildRoof() {
	b.house.Roof = "木屋顶"
	fmt.Println("  建造木屋顶")
}

func (b *WoodenHouseBuilder) getHouse() House {
	return b.house
}

// 具体建造者：砖房建造者
type BrickHouseBuilder struct {
	house House
}

func (b *BrickHouseBuilder) buildFoundation() {
	b.house.Foundation = "混凝土地基"
	fmt.Println("  建造混凝土地基")
}

func (b *BrickHouseBuilder) buildStructure() {
	b.house.Structure = "砖结构"
	fmt.Println("  建造砖结构")
}

func (b *BrickHouseBuilder) buildRoof() {
	b.house.Roof = "瓦屋顶"
	fmt.Println("  建造瓦屋顶")
}

func (b *BrickHouseBuilder) getHouse() House {
	return b.house
}

// 指挥者
type Director struct {
	builder HouseBuilder
	house   House
}

// 重置房子
func (d *Director) reset() {
	d.house = House{}
}

func (d *Director) setBuilder(b HouseBuilder) {
	d.builder = b
}

func (d *Director) constructHouse() {
	d.reset()
	d.builder.buildFoundation()
	d.builder.buildStructure()
	d.builder.buildRoof()
	d.house = d.builder.getHouse()
}

func main() {
	var builder HouseBuilder
	var director Director
	var house House

	fmt.Println("========= 生成者模式 =========")
	// 使用木屋建造者
	builder = &WoodenHouseBuilder{}
	director.setBuilder(builder)
	fmt.Println("建造木屋：")
	director.constructHouse()
	house = director.house
	fmt.Printf("木屋建造完成：%s %s %s\n\n", house.Foundation, house.Structure, house.Roof)

	// 使用砖房建造者
	builder = &BrickHouseBuilder{}
	director.setBuilder(builder)
	fmt.Println("建造砖房：")
	director.constructHouse()
	house = director.house
	fmt.Printf("砖房建造完成：%s %s %s\n\n", house.Foundation, house.Structure, house.Roof)

	fmt.Println("======= 生成者模式结束 =======")

}