feat: Add calculated prayer times provider

pkg/diyanetprovider/provider.go

@@ -0,0 +1,81 @@
+package diyanetprovider
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"prayertimes/pkg/prayer"
+)
+
+type APIProvider interface {
+	Get(ctx context.Context, locationID string) ([]prayer.Times, error)
+	GetByCoords(ctx context.Context, coords prayer.Coordinates) ([]prayer.Times, error)
+	SearchLocations(ctx context.Context, query string) ([]prayer.Location, error)
+}
+
+type FallbackProvider interface {
+	GetByCoords(ctx context.Context, coords prayer.Coordinates) ([]prayer.Times, error)
+}
+
+type Provider struct {
+	api      APIProvider
+	fallback FallbackProvider
+	timeout  time.Duration
+}
+
+func New(api APIProvider, fallback FallbackProvider) Provider {
+	return Provider{
+		api:      api,
+		fallback: fallback,
+		timeout:  time.Second,
+	}
+}
+
+func (p Provider) SearchLocations(ctx context.Context, query string) ([]prayer.Location, error) {
+	locations, err := p.api.SearchLocations(ctx, query)
+	if err != nil {
+		return nil, fmt.Errorf("failed to search locations from api provider: %w", err)
+	}
+
+	return locations, nil
+}
+
+func (p Provider) Get(ctx context.Context, locationID string) ([]prayer.Times, error) {
+	ctxWithTimeout, cancel := context.WithTimeout(ctx, p.timeout)
+	defer cancel()
+
+	times, err := p.api.Get(ctxWithTimeout, locationID)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get prayer times from api provider: %w", err)
+	}
+	if len(times) == 0 {
+		return nil, fmt.Errorf("failed to get prayer times from api provider: %w", errors.New("empty prayer times result"))
+	}
+
+	return times, nil
+}
+
+func (p Provider) GetByCoords(ctx context.Context, coords prayer.Coordinates) ([]prayer.Times, error) {
+	ctxWithTimeout, cancel := context.WithTimeout(ctx, p.timeout)
+	defer cancel()
+
+	times, err := p.api.GetByCoords(ctxWithTimeout, coords)
+	if err == nil && len(times) > 0 {
+		return times, nil
+	}
+
+	fallbackTimes, fallbackErr := p.fallback.GetByCoords(ctx, coords)
+	if fallbackErr != nil {
+		if err != nil {
+			return nil, fmt.Errorf("failed to get prayer times from fallback provider: %w", errors.Join(err, fallbackErr))
+		}
+		return nil, fmt.Errorf("failed to get prayer times from fallback provider: %w", fallbackErr)
+	}
+	if len(fallbackTimes) == 0 {
+		return nil, fmt.Errorf("failed to get prayer times from fallback provider: %w", errors.New("empty prayer times result"))
+	}
+
+	return fallbackTimes, nil
+}