package httpserver

import (
	"context"
	"fmt"
	"net"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/go-chi/chi/v5"
)

// --- helpers ---

type testLogger struct{ last string }

func (l *testLogger) Info(msg string, args ...any)              { l.last = "info:" + msg }
func (l *testLogger) Error(msg string, err error, args ...any) { l.last = "error:" + msg }

func newLogger() *testLogger { return &testLogger{} }

// freePort returns a random available TCP port.
func freePort(t *testing.T) int {
	t.Helper()
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	port := ln.Addr().(*net.TCPAddr).Port
	ln.Close()
	return port
}

// --- Tests ---

func TestNew(t *testing.T) {
	srv := New(newLogger(), Config{})
	if srv == nil {
		t.Fatal("New returned nil")
	}
}

func TestNew_ImplementsLauncherComponent(t *testing.T) {
	srv := New(newLogger(), Config{})
	// Verify launcher.Component methods exist (compile-time checked in compliance_test.go)
	if err := srv.OnInit(); err != nil {
		t.Fatalf("OnInit: %v", err)
	}
}

func TestNew_WithMiddleware(t *testing.T) {
	called := false
	mw := func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			called = true
			next.ServeHTTP(w, r)
		})
	}
	srv := New(newLogger(), Config{}, WithMiddleware(mw))
	if err := srv.OnInit(); err != nil {
		t.Fatalf("OnInit: %v", err)
	}
	srv.Get("/test", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
	})
	req := httptest.NewRequest(http.MethodGet, "/test", nil)
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	if !called {
		t.Error("WithMiddleware: middleware was not called")
	}
}

func TestComponent_OnInit(t *testing.T) {
	srv := New(newLogger(), Config{})
	if err := srv.OnInit(); err != nil {
		t.Errorf("OnInit returned error: %v", err)
	}
}

func TestComponent_Routes(t *testing.T) {
	srv := New(newLogger(), Config{})
	if err := srv.OnInit(); err != nil {
		t.Fatal(err)
	}
	srv.Get("/ping", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
	})
	req := httptest.NewRequest(http.MethodGet, "/ping", nil)
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	if rec.Code != http.StatusOK {
		t.Errorf("want 200, got %d", rec.Code)
	}
}

func TestComponent_RouteGroup(t *testing.T) {
	srv := New(newLogger(), Config{})
	if err := srv.OnInit(); err != nil {
		t.Fatal(err)
	}
	srv.Route("/api", func(r chi.Router) {
		r.Get("/v1/hello", func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusOK)
		})
	})
	req := httptest.NewRequest(http.MethodGet, "/api/v1/hello", nil)
	rec := httptest.NewRecorder()
	srv.ServeHTTP(rec, req)
	if rec.Code != http.StatusOK {
		t.Errorf("want 200, got %d", rec.Code)
	}
}

func TestComponent_OnStart_OnStop(t *testing.T) {
	port := freePort(t)
	srv := New(newLogger(), Config{
		Host:         "127.0.0.1",
		Port:         port,
		ReadTimeout:  time.Second,
		WriteTimeout: time.Second,
		IdleTimeout:  time.Second,
	})
	if err := srv.OnInit(); err != nil {
		t.Fatal(err)
	}
	if err := srv.OnStart(); err != nil {
		t.Fatalf("OnStart: %v", err)
	}
	// Give the goroutine time to bind.
	time.Sleep(20 * time.Millisecond)
	if err := srv.OnStop(); err != nil {
		t.Errorf("OnStop: %v", err)
	}
}

func TestComponent_OnStop_Graceful(t *testing.T) {
	port := freePort(t)
	srv := New(newLogger(), Config{
		Host:         "127.0.0.1",
		Port:         port,
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 5 * time.Second,
		IdleTimeout:  5 * time.Second,
	})
	if err := srv.OnInit(); err != nil {
		t.Fatal(err)
	}

	// Register a slow handler.
	done := make(chan struct{})
	srv.Get("/slow", func(w http.ResponseWriter, r *http.Request) {
		<-done
		w.WriteHeader(http.StatusOK)
	})

	if err := srv.OnStart(); err != nil {
		t.Fatal(err)
	}
	time.Sleep(20 * time.Millisecond)

	// Fire a request in the background.
	result := make(chan int, 1)
	go func() {
		resp, err := http.Get("http://127.0.0.1:" + itoa(port) + "/slow")
		if err != nil {
			result <- 0
			return
		}
		result <- resp.StatusCode
	}()
	time.Sleep(20 * time.Millisecond)

	// Unblock handler, then stop the server.
	close(done)
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	h := srv.(*httpServer)
	if err := h.srv.Shutdown(ctx); err != nil {
		t.Errorf("graceful shutdown error: %v", err)
	}

	if code := <-result; code != http.StatusOK {
		t.Errorf("in-flight request: want 200, got %d", code)
	}
}

func itoa(n int) string {
	return fmt.Sprint(n)
}