package api

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/michaeldileo/SafelyYouCodingChallenge/internal/store"
)

func TestPostHeartbeat_UnknownDevice_404(t *testing.T) {
	s := store.New([]store.DeviceID{"known"})
	srv := NewServer(s)

	req := httptest.NewRequest(http.MethodPost, "/api/v1/devices/missing/heartbeat", strings.NewReader(`{"sent_at":"2024-01-01T12:00:00Z"}`))
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusNotFound {
		t.Fatalf("status = %d, want 404", rec.Code)
	}
	var body msgResponse
	if err := json.NewDecoder(rec.Body).Decode(&body); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if body.Msg == "" {
		t.Fatal("expected non-empty msg")
	}
}

func TestPostAndGetStats_RoundTrip(t *testing.T) {
	id := store.DeviceID("device-1")
	s := store.New([]store.DeviceID{id})
	srv := NewServer(s)
	h := srv.Handler()

	t0 := time.Date(2024, 1, 1, 12, 0, 0, 0, time.UTC)

	// two heartbeats one minute apart → uptime 200
	postJSON(t, h, http.MethodPost, "/api/v1/devices/device-1/heartbeat",
		`{"sent_at":"`+t0.Format(time.RFC3339)+`"}`, http.StatusNoContent)
	postJSON(t, h, http.MethodPost, "/api/v1/devices/device-1/heartbeat",
		`{"sent_at":"`+t0.Add(time.Minute).Format(time.RFC3339)+`"}`, http.StatusNoContent)

	// upload 197331667813 ns → "3m17.331667813s"
	postJSON(t, h, http.MethodPost, "/api/v1/devices/device-1/stats",
		`{"sent_at":"2024-01-01T12:00:00Z","upload_time":197331667813}`, http.StatusNoContent)

	req := httptest.NewRequest(http.MethodGet, "/api/v1/devices/device-1/stats", nil)
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", rec.Code)
	}
	var got getDeviceStatsResponse
	if err := json.NewDecoder(rec.Body).Decode(&got); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if got.Uptime != 200 {
		t.Fatalf("uptime = %v, want 200", got.Uptime)
	}
	if got.AvgUploadTime != "3m17.331667813s" {
		t.Fatalf("avg_upload_time = %q, want 3m17.331667813s", got.AvgUploadTime)
	}
}

func postJSON(t *testing.T, h http.Handler, method, path, body string, wantStatus int) {
	t.Helper()
	req := httptest.NewRequest(method, path, strings.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != wantStatus {
		t.Fatalf("%s %s status = %d, want %d; body=%s", method, path, rec.Code, wantStatus, rec.Body.String())
	}
}