fix(timezones): move from utc offsets to timezones

This fixed various issues related to calculating streaks, etc. Now we
appropriately handle time as it was, vs as it is relative to an offset.

database/manager.go

@@ -3,15 +3,17 @@ package database
 import (
 	"context"
 	"database/sql"
+	"database/sql/driver"
 	"embed"
 	_ "embed"
+	"errors"
 	"fmt"
 	"path/filepath"
 	"time"
 
 	"github.com/pressly/goose/v3"
 	log "github.com/sirupsen/logrus"
-	_ "modernc.org/sqlite"
+	sqlite "modernc.org/sqlite"
 	"reichard.io/antholume/config"
 	_ "reichard.io/antholume/database/migrations"
 )
@@ -26,9 +28,21 @@ type DBManager struct {
 //go:embed schema.sql
 var ddl string
 
+//go:embed views.sql
+var views string
+
 //go:embed migrations/*
 var migrations embed.FS
 
+// Register scalar sqlite function on init
+func init() {
+	sqlite.MustRegisterFunction("LOCAL_TIME", &sqlite.FunctionImpl{
+		NArgs:         2,
+		Deterministic: true,
+		Scalar:        localTime,
+	})
+}
+
 // Returns an initialized manager
 func NewMgr(c *config.Config) *DBManager {
 	// Create Manager
@@ -90,6 +104,12 @@ func (dbm *DBManager) init() error {
 		return err
 	}
 
+	// Execute views
+	if _, err := dbm.DB.Exec(views, nil); err != nil {
+		log.Panicf("Error executing views: %v", err)
+		return err
+	}
+
 	// Update settings
 	err = dbm.updateSettings()
 	if err != nil {
@@ -182,6 +202,7 @@ func (dbm *DBManager) performMigrations(isNew bool) error {
 	return goose.UpContext(ctx, dbm.DB, "migrations")
 }
 
+// Determines whether the database is empty
 func isEmpty(db *sql.DB) (bool, error) {
 	var tableCount int
 	err := db.QueryRow("SELECT COUNT(*) FROM sqlite_master WHERE type='table';").Scan(&tableCount)
@@ -190,3 +211,28 @@ func isEmpty(db *sql.DB) (bool, error) {
 	}
 	return tableCount == 0, nil
 }
+
+// LOCAL_TIME custom SQL function
+func localTime(ctx *sqlite.FunctionContext, args []driver.Value) (driver.Value, error) {
+	timeStr, ok := args[0].(string)
+	if !ok {
+		return nil, errors.New("both arguments to TZTime must be strings")
+	}
+
+	timeZoneStr, ok := args[1].(string)
+	if !ok {
+		return nil, errors.New("both arguments to TZTime must be strings")
+	}
+
+	timeZone, err := time.LoadLocation(timeZoneStr)
+	if err != nil {
+		return nil, errors.New("unable to parse timezone")
+	}
+
+	formattedTime, err := time.ParseInLocation(time.RFC3339, timeStr, time.UTC)
+	if err != nil {
+		return nil, errors.New("unable to parse time")
+	}
+
+	return formattedTime.In(timeZone).Format("2006-01-02 15:04:05.000"), nil
+}