Rewrite `LetterRating` to match protobuf def

Also changes DB schema to accept strings instead of integers.

3 files changed, 61 insertions, 71 deletions

diff --git a/backend/db/migrations/000002_create_data_tables.up.sql b/backend/db/migrations/000002_create_data_tables.up.sql
index 116c424..f279aa3 100644
--- a/backend/db/migrations/000002_create_data_tables.up.sql
+++ b/backend/db/migrations/000002_create_data_tables.up.sql
@@ -55,9 +55,9 @@ CREATE TABLE IF NOT EXISTS ratings
     composite      SMALLINT,                                        -- The composite rating (0-99)
     eps            SMALLINT,                                        -- The EPS rating (0-99)
     rel_str        SMALLINT,                                        -- The relative strength rating (0-99)
-    group_rel_str  SMALLINT,                                        -- The group relative strength rating (E-A+) E=0, A+=13
-    smr            SMALLINT,                                        -- The SMR rating (E-A+)
-    acc_dis        SMALLINT,                                        -- The acc/dis rating (E-A+)
+    group_rel_str  CHAR(2),                                         -- The group relative strength rating (E-A+) E=0, A+=13
+    smr            CHAR(2),                                         -- The SMR rating (E-A+)
+    acc_dis        CHAR(2),                                         -- The acc/dis rating (E-A+)
     chart_analysis UUID REFERENCES chart_analysis (id),             -- The ID of the chart analysis for the stock
     price          MONEY,                                           -- The price of the stock at the time of the rating
 
diff --git a/backend/internal/database/stocks.go b/backend/internal/database/stocks.go
index 865aec4..0627a72 100644
--- a/backend/internal/database/stocks.go
+++ b/backend/internal/database/stocks.go
@@ -3,9 +3,10 @@ package database
 import (
 	"context"
 	"database/sql"
+	"database/sql/driver"
 	"errors"
-	"fmt"
 
+	pb "github.com/ansg191/ibd-trader-backend/api/gen/idb/stock/v1"
 	"github.com/ansg191/ibd-trader-backend/internal/analyzer"
 	"github.com/ansg191/ibd-trader-backend/internal/utils"
 
@@ -193,93 +194,94 @@ type Ratings struct {
 	AccDis      LetterRating
 }
 
-type LetterRating uint8
-
-const (
-	LetterRatingE LetterRating = iota
-	LetterRatingEPlus
-	LetterRatingDMinus
-	LetterRatingD
-	LetterRatingDPlus
-	LetterRatingCMinus
-	LetterRatingC
-	LetterRatingCPlus
-	LetterRatingBMinus
-	LetterRatingB
-	LetterRatingBPlus
-	LetterRatingAMinus
-	LetterRatingA
-	LetterRatingAPlus
-)
+type LetterRating pb.LetterGrade
 
 func (r LetterRating) String() string {
-	switch r {
-	case LetterRatingE:
+	switch pb.LetterGrade(r) {
+	case pb.LetterGrade_LETTER_GRADE_E:
 		return "E"
-	case LetterRatingEPlus:
+	case pb.LetterGrade_LETTER_GRADE_E_PLUS:
 		return "E+"
-	case LetterRatingDMinus:
+	case pb.LetterGrade_LETTER_GRADE_D_MINUS:
 		return "D-"
-	case LetterRatingD:
+	case pb.LetterGrade_LETTER_GRADE_D:
 		return "D"
-	case LetterRatingDPlus:
+	case pb.LetterGrade_LETTER_GRADE_D_PLUS:
 		return "D+"
-	case LetterRatingCMinus:
+	case pb.LetterGrade_LETTER_GRADE_C_MINUS:
 		return "C-"
-	case LetterRatingC:
+	case pb.LetterGrade_LETTER_GRADE_C:
 		return "C"
-	case LetterRatingCPlus:
+	case pb.LetterGrade_LETTER_GRADE_C_PLUS:
 		return "C+"
-	case LetterRatingBMinus:
+	case pb.LetterGrade_LETTER_GRADE_B_MINUS:
 		return "B-"
-	case LetterRatingB:
+	case pb.LetterGrade_LETTER_GRADE_B:
 		return "B"
-	case LetterRatingBPlus:
+	case pb.LetterGrade_LETTER_GRADE_B_PLUS:
 		return "B+"
-	case LetterRatingAMinus:
+	case pb.LetterGrade_LETTER_GRADE_A_MINUS:
 		return "A-"
-	case LetterRatingA:
+	case pb.LetterGrade_LETTER_GRADE_A:
 		return "A"
-	case LetterRatingAPlus:
+	case pb.LetterGrade_LETTER_GRADE_A_PLUS:
 		return "A+"
 	default:
-		return "Unknown"
+		return "NA"
 	}
 }
 
-func LetterRatingFromString(str string) (LetterRating, error) {
+func LetterRatingFromString(str string) LetterRating {
 	switch str {
-	case "N/A":
-		fallthrough
 	case "E":
-		return LetterRatingE, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_E)
 	case "E+":
-		return LetterRatingEPlus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_E_PLUS)
 	case "D-":
-		return LetterRatingDMinus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_D_MINUS)
 	case "D":
-		return LetterRatingD, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_D)
 	case "D+":
-		return LetterRatingDPlus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_D_PLUS)
 	case "C-":
-		return LetterRatingCMinus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_C_MINUS)
 	case "C":
-		return LetterRatingC, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_C)
 	case "C+":
-		return LetterRatingCPlus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_C_PLUS)
 	case "B-":
-		return LetterRatingBMinus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_B_MINUS)
 	case "B":
-		return LetterRatingB, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_B)
 	case "B+":
-		return LetterRatingBPlus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_B_PLUS)
 	case "A-":
-		return LetterRatingAMinus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_A_MINUS)
 	case "A":
-		return LetterRatingA, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_A)
 	case "A+":
-		return LetterRatingAPlus, nil
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_A_PLUS)
+	case "NA":
+		fallthrough
 	default:
-		return 0, fmt.Errorf("unknown rating: %s", str)
+		return LetterRating(pb.LetterGrade_LETTER_GRADE_UNSPECIFIED)
 	}
 }
+
+func (r LetterRating) Value() (driver.Value, error) {
+	return r.String(), nil
+}
+
+func (r *LetterRating) Scan(src any) error {
+	var source string
+	switch v := src.(type) {
+	case string:
+		source = v
+	case []byte:
+		source = string(v)
+	default:
+		return errors.New("incompatible type for LetterRating")
+	}
+	*r = LetterRatingFromString(source)
+	return nil
+}
diff --git a/backend/internal/ibd/stockinfo.go b/backend/internal/ibd/stockinfo.go
index 9caa956..1e3b96f 100644
--- a/backend/internal/ibd/stockinfo.go
+++ b/backend/internal/ibd/stockinfo.go
@@ -207,23 +207,11 @@ func processSmartRating(node *html.Node, ratings *database.Ratings) error {
 		}
 		ratings.RelStr = uint8(ratingValue)
 	case "Group RS Rating":
-		ratingValue, err := database.LetterRatingFromString(ratingValueStr)
-		if err != nil {
-			return fmt.Errorf("failed to parse Group RS Rating: %w", err)
-		}
-		ratings.GroupRelStr = ratingValue
+		ratings.GroupRelStr = database.LetterRatingFromString(ratingValueStr)
 	case "SMR Rating":
-		ratingValue, err := database.LetterRatingFromString(ratingValueStr)
-		if err != nil {
-			return fmt.Errorf("failed to parse SMR Rating: %w", err)
-		}
-		ratings.SMR = ratingValue
+		ratings.SMR = database.LetterRatingFromString(ratingValueStr)
 	case "Acc/Dis Rating":
-		ratingValue, err := database.LetterRatingFromString(ratingValueStr)
-		if err != nil {
-			return fmt.Errorf("failed to parse Acc/Dis Rating: %w", err)
-		}
-		ratings.AccDis = ratingValue
+		ratings.AccDis = database.LetterRatingFromString(ratingValueStr)
 	default:
 		return fmt.Errorf("unknown rating name: %s", ratingName)
 	}