appview: add repo_languages table

and db helpers to set and get.

Signed-off-by: oppiliappan <[e-mail]>

appview/db/db.go

···
 				on delete cascade
 		);
 
+		create table if not exists repo_languages (
+			-- identifiers
+			id integer primary key autoincrement,
+
+			-- repo identifiers
+			repo_at text not null,
+			ref text not null,
+
+			-- language breakdown
+			language text not null,
+			bytes integer not null check (bytes >= 0),
+
+			unique(repo_at, ref, language)
+		);
+
 		create table if not exists migrations (
 			id integer primary key autoincrement,
 			name text unique

appview/db/language.go

···
+package db
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/bluesky-social/indigo/atproto/syntax"
+)
+
+type RepoLanguage struct {
+	Id       int64
+	RepoAt   syntax.ATURI
+	Ref      string
+	Language string
+	Bytes    int64
+}
+
+func GetRepoLanguages(e Execer, filters ...filter) ([]RepoLanguage, error) {
+	var conditions []string
+	var args []any
+	for _, filter := range filters {
+		conditions = append(conditions, filter.Condition())
+		args = append(args, filter.Arg()...)
+	}
+
+	whereClause := ""
+	if conditions != nil {
+		whereClause = " where " + strings.Join(conditions, " and ")
+	}
+
+	query := fmt.Sprintf(
+		`select id, repo_at, ref, language, bytes from repo_languages %s`,
+		whereClause,
+	)
+	rows, err := e.Query(query, args...)
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to execute query: %w ", err)
+	}
+
+	var langs []RepoLanguage
+	for rows.Next() {
+		var rl RepoLanguage
+
+		err := rows.Scan(
+			&rl.Id,
+			&rl.RepoAt,
+			&rl.Ref,
+			&rl.Language,
+			&rl.Bytes,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("failed to scan: %w ", err)
+		}
+
+		langs = append(langs, rl)
+	}
+	if err = rows.Err(); err != nil {
+		return nil, fmt.Errorf("failed to scan rows: %w ", err)
+	}
+
+	return langs, nil
+}
+
+func InsertRepoLanguages(e Execer, langs []RepoLanguage) error {
+	stmt, err := e.Prepare(
+		"insert or replace into repo_languages (repo_at, ref, language, bytes) values (?, ?, ?, ?)",
+	)
+	if err != nil {
+		return err
+	}
+
+	for _, l := range langs {
+		_, err := stmt.Exec(l.RepoAt, l.Ref, l.Language, l.Bytes)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}