From 7e2704ce7d36f2c929676c36f803f5a83e2a7448 Mon Sep 17 00:00:00 2001
From: sneak <sneak@sneak.berlin>
Date: Tue, 24 Mar 2020 18:32:40 -0700
Subject: [PATCH] writer half almost working

---
 hn/db.go      | 15 ++++++++-
 hn/fetcher.go | 89 +++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 101 insertions(+), 3 deletions(-)

diff --git a/hn/db.go b/hn/db.go
index df78766..c6f8438 100644
--- a/hn/db.go
+++ b/hn/db.go
@@ -6,13 +6,26 @@ import (
 	"github.com/jinzhu/gorm"
 )
 
+// this schema is quite redundant, i know
+
+type HNFrontPage struct {
+	gorm.Model
+	InternalID  uint64 `gorm:"primary_key;auto_increment:true`
+	HNID        uint   // HN integer id
+	Appeared    time.Time
+	Disappeared time.Time
+	HighestRank uint   // frontpage index
+	Rank        uint   // frontpage index
+	Title       string // submission title
+	URL         string // duh
+}
+
 type HNStoryRank struct {
 	gorm.Model
 	InternalStoryID uint64    `gorm:"primary_key;auto_increment:true`
 	HNID            uint      // HN integer id
 	Title           string    // submission title
 	URL             string    // duh
-	FetchID         uint      // integer identifying fetch batch
 	Rank            uint      // frontpage index
 	FetchedAt       time.Time // identical within fetchid
 }
diff --git a/hn/fetcher.go b/hn/fetcher.go
index 8d37570..379bee4 100644
--- a/hn/fetcher.go
+++ b/hn/fetcher.go
@@ -1,6 +1,7 @@
 package hn
 
 import (
+	"fmt"
 	"net/http"
 	"time"
 
@@ -54,7 +55,10 @@ func (f *Fetcher) run() {
 func (f *Fetcher) StoreFrontPage() error {
 
 	// FIXME set fetchid
-	r := f.db.Select("max(FetchID)").Find(&HNStoryRank)
+	//r, err := f.db.Table("hn_story_rank").Select("MAX(FetchID)").Rows()
+
+	//pp.Print(r)
+	//Select("max(FetchID)").Find(&HNStoryRank)
 
 	ids, err := f.hn.TopStories()
 	t := time.Now()
@@ -62,6 +66,7 @@ func (f *Fetcher) StoreFrontPage() error {
 		return err
 	}
 
+	// 30 items on HN frontpage.
 	for i, id := range ids[:30] {
 
 		item, err := f.hn.Item(id)
@@ -70,7 +75,6 @@ func (f *Fetcher) StoreFrontPage() error {
 		}
 		s := HNStoryRank{
 			HNID:      uint(id),
-			FetchID:   uint(0),
 			Rank:      uint(i + 1),
 			URL:       item.URL,
 			Title:     item.Title,
@@ -78,6 +82,87 @@ func (f *Fetcher) StoreFrontPage() error {
 		}
 		f.log.Info().Msgf("storing story with rank %d in db", (i + 1))
 		f.db.Create(&s)
+
+		// check to see if the item was on the frontpage already or not
+		var c int
+		f.db.Model(&HNFrontPage{}).Where("HNID = ? and Disappeared is NULL", id).Count(&c)
+		if c == 0 {
+			// first appearance on frontpage
+			r := HNFrontPage{
+				HNID:        uint(id),
+				Appeared:    t,
+				HighestRank: uint(i + 1),
+				Title:       item.Title,
+				URL:         item.URL,
+			}
+			f.db.Create(&r)
+			f.log.Info().
+				Uint("hnid", uint(id)).
+				Uint("rank", uint(i+1)).
+				Str("title", item.Title).
+				Str("url", item.URL).
+				Msg("HN new story on frontpage")
+		} else {
+			// it's still here, compare its ranking
+			var old HNFrontPage
+			f.db.Model(&HNFrontPage{}).Where("HNID = ? and Disappeared is NULL", id).First(&old)
+			// FIXME update highestrank if new is lower
+			needSave := false
+			if old.Rank != uint(i+1) {
+				f.log.Info().
+					Uint("hnid", uint(id)).
+					Uint("oldrank", old.Rank).
+					Uint("newrank", uint(i+1)).
+					Str("title", item.Title).
+					Str("url", item.URL).
+					Msg("HN story rank changed, recording new rank")
+				old.Rank = uint(i + 1)
+				needSave = true
+			}
+
+			if old.HighestRank > uint(i+1) {
+				old.HighestRank = uint(i + 1)
+				f.log.Info().
+					Uint("hnid", uint(id)).
+					Uint("oldrank", old.Rank).
+					Uint("newrank", uint(i+1)).
+					Msg("recording new record high rank for story")
+				needSave = true
+			}
+			if needSave {
+				f.db.Save(&old)
+			}
+		}
+
+	}
+
+	// FIXME iterate over frontpage items still active in DB and note any
+	// that are no longer on the scrape
+	fpitems, err := f.db.Model(&HNFrontPage{}).Where("Disappeared is NULL").Rows()
+	defer fpitems.Close()
+	for fpitems.Next() {
+		var item HNFrontPage
+		f.db.ScanRows(fpitems, &item)
+		fmt.Println(item)
+		exitedFrontPage := true
+		for _, xd := range ids[:30] {
+			if item.HNID == uint(xd) {
+				exitedFrontPage = false
+			}
+		}
+		if exitedFrontPage {
+			item.Disappeared = t
+			dur := item.Disappeared.Sub(item.Appeared)
+			f.db.Save(&item)
+			f.log.Info().
+				Uint("hnid", item.HNID).
+				Uint("HighestRank", item.HighestRank).
+				Str("title", item.Title).
+				Dur("fpduration", dur).
+				Str("url", item.URL).
+				Msg("HN story exited frontpage")
+
+		}
 	}
 	return nil
 }