rssmon3/copart/auction/auction.go

package auction

import (
	"context"
	"encoding/json"
	"errors"
	"local/sandbox/selenium/copart/copart/browser"
	"local/sandbox/selenium/copart/copart/config"
	"local/storage"
	"log"
	"strconv"
	"strings"
	"time"
)

type Auction struct {
	browser  *browser.Browser
	cars     chan *Car
	ctx      context.Context
	can      context.CancelFunc
	routines chan struct{}
}

func New(b *browser.Browser, url string) (*Auction, error) {
	if err := b.Get(url); err != nil {
		b.Close()
		return nil, err
	}

	ctx, can := context.WithTimeout(context.Background(), time.Second*10)
	defer can()

	var elem WebElement
	for err := ctx.Err(); err == nil; err = ctx.Err() {
		elem, err = b.Driver.FindElement("xpath", "//iframe")
		if err == nil {
			break
		}
		time.Sleep(time.Second)
	}
	if err := ctx.Err(); err != nil {
		b.Close()
		return nil, err
	}

	iframeURL, err := elem.GetAttribute("src")
	if err != nil {
		b.Close()
		return nil, err
	} else if iframeURL == "" {
		b.Close()
		return nil, errors.New("auction iframe has no src")
	}

	if err := b.Get(iframeURL); err != nil {
		b.Close()
		return nil, err
	}

	ctx, can = context.WithCancel(context.Background())
	return &Auction{
		browser:  b,
		cars:     make(chan *Car),
		ctx:      ctx,
		can:      can,
		routines: make(chan struct{}, 5),
	}, nil
}

func (a *Auction) Start() error {
	go a.parseCars()
	a.routines <- struct{}{}
	go a.saveCars()
	a.routines <- struct{}{}
	return nil
}

func (a *Auction) parseCars() error {
	log.Printf("[parseCars] starting")
	defer func() {
		if err := recover(); err != nil {
			log.Println("[parseCars] recover:", err)
		}
		log.Printf("[parseCars] stopping")
		close(a.cars)
		a.can()
		a.routines <- struct{}{}
	}()
	for err := a.ctx.Err(); err == nil; err = a.ctx.Err() {
		c, err := a.nextCar()
		if err != nil {
			panic(err)
		}
		log.Printf("[parseCars] found car %v", c.String())
		if !strings.Contains(c.Bid, "$") {
			continue
		}
		if b, _ := c.MarshalJSON(); strings.Contains(strings.ToLower(string(b)), ", hi") {
			continue
		} else if strings.Contains(strings.ToLower(string(b)), "guam") {
			continue
		} else if len(c.Title) < 4 {
			continue
		} else if v, err := strconv.Atoi(c.Title[:4]); err != nil {
			continue
		} else if v+5 < time.Now().Year() {
			continue
		}
		select {
		case a.cars <- c:
		case <-a.ctx.Done():
			panic(a.ctx.Err())
		}
	}
	return a.ctx.Err()
}

func (a *Auction) nextCar() (*Car, error) {
	c := NewCar()
	if err := c.Parse(a.browser.Driver); err != nil {
		if !strings.Contains(err.Error(), "stale element") {
			return nil, err
		} else {
			return a.nextCar()
		}
	}
	for err := a.ctx.Err(); err == nil; err = a.ctx.Err() {
		time.Sleep(time.Second * 2)
		d := NewCar()
		if err := d.Parse(a.browser.Driver); err != nil {
			if !strings.Contains(err.Error(), "stale element") {
				return nil, err
			}
		}
		if !c.Equals(d) {
			return c, nil
		}
		if d.Bid != "" {
			c = d
		}
	}
	return nil, a.ctx.Err()
}

func (a *Auction) saveCars() error {
	log.Printf("[saveCars] starting")
	defer func() {
		if err := recover(); err != nil {
			log.Println("[saveCars] recover:", err)
		}
		log.Printf("[saveCars] stopping")
		a.can()
		a.routines <- struct{}{}
	}()
	for err := a.ctx.Err(); err == nil; err = a.ctx.Err() {
		select {
		case <-a.ctx.Done():
			panic(a.ctx.Err())
		case c := <-a.cars:
			go func(d *Car) {
				if d == nil {
					return
				}
				log.Printf("[saveCars] saving %v", d.String())
				if err := a.saveCar(d); err != nil {
					log.Printf("[saveCars] err: %v", err)
				}
			}(c)
		}
	}
	return a.ctx.Err()
}

func (a *Auction) saveCar(c *Car) error {
	db := config.Values().DB

	b, err := c.Encode()
	if err != nil {
		return err
	}

	if err := db.Set(c.String(), b); err != nil {
		return err
	}

	var list []string
	b, err = db.Get("LIST")
	if err == storage.ErrNotFound {
		b = []byte("[]")
	} else if err != nil {
		return err
	}
	if err := json.Unmarshal(b, &list); err != nil {
		return err
	}

	list = append([]string{c.String()}, list...)
	if b, err := json.Marshal(list); err != nil {
		return err
	} else if err := db.Set("LIST", b); err != nil {
		return err
	}

	return nil
}

func (a *Auction) Stop() error {
	l := len(a.routines)
	a.can()
	ctx, can := context.WithTimeout(context.Background(), time.Second*5)
	defer can()
	for i := 0; i < 2*l; i++ {
		select {
		case <-a.routines:
		case <-ctx.Done():
		}
	}
	if len(a.routines) > 0 {
		return errors.New("not all routines exited")
	}
	return nil
}