package infra

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

// --- HTTPJSONResponse ---

func TestHTTPJSONResponse(t *testing.T) {
	t.Run("escribe status code correcto", func(t *testing.T) {
		rec := httptest.NewRecorder()
		HTTPJSONResponse(rec, http.StatusCreated, map[string]string{"ok": "true"})
		if rec.Code != http.StatusCreated {
			t.Errorf("got status %d, want 201", rec.Code)
		}
	})

	t.Run("setea Content-Type application/json", func(t *testing.T) {
		rec := httptest.NewRecorder()
		HTTPJSONResponse(rec, http.StatusOK, "test")
		ct := rec.Header().Get("Content-Type")
		if ct != "application/json" {
			t.Errorf("got Content-Type=%q, want application/json", ct)
		}
	})

	t.Run("serializa datos correctamente a JSON", func(t *testing.T) {
		rec := httptest.NewRecorder()
		data := map[string]int{"count": 42}
		HTTPJSONResponse(rec, http.StatusOK, data)

		var got map[string]int
		if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
			t.Fatalf("failed to parse response JSON: %v", err)
		}
		if got["count"] != 42 {
			t.Errorf("got count=%d, want 42", got["count"])
		}
	})
}

// --- HTTPErrorResponse ---

func TestHTTPErrorResponse(t *testing.T) {
	t.Run("escribe el status code del HTTPError", func(t *testing.T) {
		rec := httptest.NewRecorder()
		HTTPErrorResponse(rec, HTTPError{Status: http.StatusBadRequest, Code: "bad", Message: "err"})
		if rec.Code != http.StatusBadRequest {
			t.Errorf("got status %d, want 400", rec.Code)
		}
	})

	t.Run("setea Content-Type application/json", func(t *testing.T) {
		rec := httptest.NewRecorder()
		HTTPErrorResponse(rec, HTTPError{Status: 500, Code: "err", Message: "fail"})
		ct := rec.Header().Get("Content-Type")
		if ct != "application/json" {
			t.Errorf("got Content-Type=%q, want application/json", ct)
		}
	})

	t.Run("serializa Code y Message en el body JSON", func(t *testing.T) {
		rec := httptest.NewRecorder()
		HTTPErrorResponse(rec, HTTPError{Status: 422, Code: "validation_error", Message: "campo requerido"})

		var got HTTPError
		if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
			t.Fatalf("failed to parse response JSON: %v", err)
		}
		if got.Code != "validation_error" {
			t.Errorf("got Code=%q, want validation_error", got.Code)
		}
		if got.Message != "campo requerido" {
			t.Errorf("got Message=%q, want 'campo requerido'", got.Message)
		}
	})
}

// --- HTTPParseBody ---

func TestHTTPParseBody(t *testing.T) {
	t.Run("decodifica JSON valido correctamente", func(t *testing.T) {
		body := `{"name":"Lucas","age":30}`
		req := httptest.NewRequest("POST", "/", strings.NewReader(body))
		req.Header.Set("Content-Type", "application/json")

		var dst struct {
			Name string `json:"name"`
			Age  int    `json:"age"`
		}
		err := HTTPParseBody(req, &dst, 1<<20)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if dst.Name != "Lucas" || dst.Age != 30 {
			t.Errorf("got {%q, %d}, want {Lucas, 30}", dst.Name, dst.Age)
		}
	})

	t.Run("retorna error si el body supera maxBytes", func(t *testing.T) {
		body := strings.Repeat("x", 100)
		payload := `{"data":"` + body + `"}`
		req := httptest.NewRequest("POST", "/", strings.NewReader(payload))

		var dst struct {
			Data string `json:"data"`
		}
		err := HTTPParseBody(req, &dst, 10) // limite de 10 bytes
		if err == nil {
			t.Error("expected error for oversized body, got nil")
		}
	})

	t.Run("retorna error si el JSON es invalido", func(t *testing.T) {
		req := httptest.NewRequest("POST", "/", strings.NewReader(`{invalid json`))
		var dst map[string]any
		err := HTTPParseBody(req, &dst, 1<<20)
		if err == nil {
			t.Error("expected error for invalid JSON, got nil")
		}
	})

	t.Run("retorna error si hay campos desconocidos", func(t *testing.T) {
		req := httptest.NewRequest("POST", "/", strings.NewReader(`{"name":"test","unknown":"field"}`))
		var dst struct {
			Name string `json:"name"`
		}
		err := HTTPParseBody(req, &dst, 1<<20)
		if err == nil {
			t.Error("expected error for unknown fields, got nil")
		}
	})
}

// --- HTTPLoggerMiddleware ---

func TestHTTPLoggerMiddleware(t *testing.T) {
	t.Run("loguea metodo y path del request", func(t *testing.T) {
		var buf bytes.Buffer
		mw := HTTPLoggerMiddleware(&buf)
		handler := mw(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusOK)
		}))

		rec := httptest.NewRecorder()
		req := httptest.NewRequest("GET", "/api/test", nil)
		handler.ServeHTTP(rec, req)

		log := buf.String()
		if !strings.Contains(log, "GET") {
			t.Errorf("log does not contain method GET: %q", log)
		}
		if !strings.Contains(log, "/api/test") {
			t.Errorf("log does not contain path /api/test: %q", log)
		}
	})

	t.Run("loguea el status code de la respuesta", func(t *testing.T) {
		var buf bytes.Buffer
		mw := HTTPLoggerMiddleware(&buf)
		handler := mw(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusNotFound)
		}))

		rec := httptest.NewRecorder()
		req := httptest.NewRequest("GET", "/missing", nil)
		handler.ServeHTTP(rec, req)

		log := buf.String()
		if !strings.Contains(log, "404") {
			t.Errorf("log does not contain status 404: %q", log)
		}
	})

	t.Run("loguea la duracion en milisegundos", func(t *testing.T) {
		var buf bytes.Buffer
		mw := HTTPLoggerMiddleware(&buf)
		handler := mw(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusOK)
		}))

		rec := httptest.NewRecorder()
		req := httptest.NewRequest("GET", "/", nil)
		handler.ServeHTTP(rec, req)

		log := buf.String()
		if !strings.Contains(log, "ms") {
			t.Errorf("log does not contain duration in ms: %q", log)
		}
	})
}

// --- HTTPRouter ---

func TestHTTPRouter(t *testing.T) {
	t.Run("registra una ruta y responde correctamente", func(t *testing.T) {
		mux := HTTPRouter([]Route{
			{
				Method: "GET",
				Path:   "/api/ping",
				Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
					w.WriteHeader(http.StatusOK)
					w.Write([]byte("pong"))
				}),
			},
		})

		rec := httptest.NewRecorder()
		req := httptest.NewRequest("GET", "/api/ping", nil)
		mux.ServeHTTP(rec, req)

		if rec.Code != http.StatusOK {
			t.Errorf("got status %d, want 200", rec.Code)
		}
		if rec.Body.String() != "pong" {
			t.Errorf("got body %q, want pong", rec.Body.String())
		}
	})

	t.Run("registra multiples rutas en el mismo mux", func(t *testing.T) {
		mux := HTTPRouter([]Route{
			{Method: "GET", Path: "/a", Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.Write([]byte("a"))
			})},
			{Method: "GET", Path: "/b", Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.Write([]byte("b"))
			})},
		})

		recA := httptest.NewRecorder()
		mux.ServeHTTP(recA, httptest.NewRequest("GET", "/a", nil))
		if recA.Body.String() != "a" {
			t.Errorf("route /a: got %q, want a", recA.Body.String())
		}

		recB := httptest.NewRecorder()
		mux.ServeHTTP(recB, httptest.NewRequest("GET", "/b", nil))
		if recB.Body.String() != "b" {
			t.Errorf("route /b: got %q, want b", recB.Body.String())
		}
	})

	t.Run("ruta no registrada retorna 404", func(t *testing.T) {
		mux := HTTPRouter([]Route{
			{Method: "GET", Path: "/known", Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.WriteHeader(http.StatusOK)
			})},
		})

		rec := httptest.NewRecorder()
		req := httptest.NewRequest("GET", "/unknown", nil)
		mux.ServeHTTP(rec, req)

		if rec.Code != http.StatusNotFound {
			t.Errorf("got status %d, want 404", rec.Code)
		}
	})
}

// --- HTTPServe ---

func TestHTTPServe(t *testing.T) {
	t.Run("servidor arranca y responde peticiones", func(t *testing.T) {
		ctx, cancel := context.WithCancel(context.Background())
		defer cancel()

		mux := HTTPRouter([]Route{
			{Method: "GET", Path: "/ping", Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.WriteHeader(http.StatusOK)
				w.Write([]byte("pong"))
			})},
		})

		errCh := make(chan error, 1)
		go func() {
			errCh <- HTTPServe("127.0.0.1:0", mux, ctx)
		}()

		// Cancelar el contexto rapidamente — el servidor deberia cerrarse limpiamente
		time.Sleep(10 * time.Millisecond)
		cancel()

		select {
		case err := <-errCh:
			if err != nil {
				t.Errorf("unexpected error from HTTPServe: %v", err)
			}
		case <-time.After(5 * time.Second):
			t.Error("HTTPServe did not stop after context cancel")
		}
	})

	t.Run("graceful shutdown al cancelar contexto", func(t *testing.T) {
		ctx, cancel := context.WithCancel(context.Background())

		handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.WriteHeader(http.StatusOK)
		})

		done := make(chan error, 1)
		go func() {
			done <- HTTPServe("127.0.0.1:0", handler, ctx)
		}()

		time.Sleep(10 * time.Millisecond)
		cancel()

		select {
		case err := <-done:
			if err != nil {
				t.Errorf("shutdown error: %v", err)
			}
		case <-time.After(5 * time.Second):
			t.Error("server did not shutdown within 5 seconds")
		}
	})
}