Merge pull request #21 from ystv/semesterisation

Semesterisation

services/campus/period.go

@@ -0,0 +1,114 @@
+package campus
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"time"
+)
+
+type (
+	// AcademicYear represents the academic year and the teaching cycle
+	AcademicYear struct {
+		Year          int              `db:"year" json:"year"`
+		TeachingCycle []TeachingPeriod `json:"teachingCycle"`
+	}
+
+	// TeachingPeriod represents an academic time period either a term or semester
+	TeachingPeriod struct {
+		TeachingPeriodID int       `db:"teaching_period_id" json:"teachingPeriodID"`
+		Year             int       `db:"year" json:"year"`
+		Name             string    `db:"name" json:"name"` // autumn / spring / summer
+		Start            time.Time `db:"start" json:"start"`
+		Finish           time.Time `db:"finish" json:"finish"`
+	}
+
+	// Week is a normal week plus the number since
+	// the start of teaching period
+	Week struct {
+		TeachingPeriod TeachingPeriod `json:"teachingPeriod"`
+		WeekNo         int            `json:"weekNo"`
+	}
+)
+
+var (
+	ErrNoAcademicYearFound   = errors.New("no academic year found")
+	ErrNoTeachingPeriodFound = errors.New("no teaching period found")
+	ErrNoWeekFound           = errors.New("no week found")
+)
+
+// GetAcademicYear retrieves an academic year for a given time
+func (c *Campuser) GetAcademicYear(ctx context.Context, t time.Time) (AcademicYear, error) {
+	ay := AcademicYear{}
+	ay.Year = t.Year()
+
+	err := c.db.SelectContext(ctx, &ay.TeachingCycle, `
+	SELECT teaching_period_id, period.year, name, start finish
+	FROM misc.teaching_periods period
+	INNER JOIN (
+		SELECT year
+		FROM misc.teaching_periods
+		GROUP BY year
+		HAVING $1 BETWEEN min(start) AND max(finish)
+	) selected_year ON selected_year.year = period.year
+	ORDER BY start;`)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return AcademicYear{}, ErrNoAcademicYearFound
+		}
+		return AcademicYear{}, err
+	}
+	return ay, nil
+}
+
+// GetTeachingPeriod retrives an academic term for a given time
+func (c *Campuser) GetTeachingPeriod(ctx context.Context, t time.Time) (TeachingPeriod, error) {
+	tp := TeachingPeriod{}
+	err := c.db.GetContext(ctx, &tp, `
+		  SELECT teaching_period_id, year, name, start, finish
+		  FROM misc.teaching_periods
+		  WHERE $1 BETWEEN start AND finish;`, t)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return TeachingPeriod{}, ErrNoTeachingPeriodFound
+		}
+		return TeachingPeriod{}, err
+	}
+	return tp, nil
+}
+
+// GetWeek retrives the week and it's term
+func (c *Campuser) GetWeek(ctx context.Context, t time.Time) (Week, error) {
+	w := Week{}
+	var err error
+	w.TeachingPeriod, err = c.GetTeachingPeriod(ctx, t)
+	if err != nil {
+		if errors.Is(err, ErrNoTeachingPeriodFound) {
+			return Week{}, ErrNoWeekFound
+		}
+		return Week{}, fmt.Errorf("failed to get teaching period: %w", err)
+	}
+
+	// TODO: Need to convert time from what's given to
+	// that times Monday and return a better week no.
+	w.WeekNo = (int(t.Sub(w.TeachingPeriod.Start).Hours()) / 24 / 7) + 1
+
+	return w, nil
+}
+
+// GetCurrentAcademicYear returns the academic year as of the current time
+func (c *Campuser) GetCurrentAcademicYear(ctx context.Context) (AcademicYear, error) {
+	return c.GetAcademicYear(ctx, time.Now())
+}
+
+// GetCurrentTeachingPeriod returns the teaching period as of the current time
+func (c *Campuser) GetCurrentTeachingPeriod(ctx context.Context) (TeachingPeriod, error) {
+	return c.GetTeachingPeriod(ctx, time.Now())
+}
+
+// GetCurrentWeek returns the week of the current time
+func (c *Campuser) GetCurrentWeek(ctx context.Context) (Week, error) {
+	return c.GetWeek(ctx, time.Now())
+}