package voiceprovider

import (
	"context"
	"errors"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

type roundTripFunc func(*http.Request) (*http.Response, error)

func (f roundTripFunc) RoundTrip(request *http.Request) (*http.Response, error) {
	return f(request)
}

type failingReadCloser struct {
	err error
}

func (f failingReadCloser) Read([]byte) (int, error) { return 0, f.err }
func (f failingReadCloser) Close() error             { return nil }

func TestNewHTTPClientValidatesConfiguration(t *testing.T) {
	tests := []struct {
		name    string
		baseURL string
		apiKey  string
		timeout time.Duration
	}{
		{name: "missing base URL", apiKey: "key", timeout: time.Second},
		{name: "missing API key", baseURL: "http://provider", timeout: time.Second},
		{name: "zero timeout", baseURL: "http://provider", apiKey: "key"},
		{name: "negative timeout", baseURL: "http://provider", apiKey: "key", timeout: -time.Second},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			if _, err := NewHTTPClient(test.baseURL, test.apiKey, test.timeout); err == nil {
				t.Fatal("expected invalid provider configuration to be rejected")
			}
		})
	}

	client, err := NewHTTPClient("http://provider///", "key", time.Second)
	if err != nil {
		t.Fatal(err)
	}
	if client.baseURL != "http://provider" {
		t.Fatalf("base URL was not normalized: %q", client.baseURL)
	}
}

func TestHTTPClientStartsAndStopsProviderTask(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, request *http.Request) {
		if request.Method != http.MethodPost || request.Header.Get("Content-Type") != "application/json" || request.Header.Get("X-Mock-Provider-Key") != "provider-secret" {
			t.Errorf("unexpected provider request: method=%s content_type=%q key=%q", request.Method, request.Header.Get("Content-Type"), request.Header.Get("X-Mock-Provider-Key"))
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		switch request.URL.Path {
		case "/mock/v1/voice-chats:start":
			_, _ = io.WriteString(w, `{"task_ref":"task-1","status":"ACTIVE"}`)
		case "/mock/v1/voice-chats:stop":
			_, _ = io.WriteString(w, `{"task_ref":"task-1","status":"STOPPED"}`)
		default:
			w.WriteHeader(http.StatusNotFound)
		}
	}))
	defer server.Close()

	client, err := NewHTTPClient(server.URL, "provider-secret", time.Second)
	if err != nil {
		t.Fatal(err)
	}
	started, err := client.Start(context.Background(), StartRequest{TaskRef: "task-1", RoomID: "room-1", DeviceUserID: "device-user", AgentUserID: "agent-user", ConversationID: "conversation-1"})
	if err != nil || started.Status != "ACTIVE" {
		t.Fatalf("start result=%+v error=%v", started, err)
	}
	stopped, err := client.Stop(context.Background(), StopRequest{TaskRef: "task-1", ConversationID: "conversation-1", Reason: "user_request"})
	if err != nil || stopped.Status != "STOPPED" {
		t.Fatalf("stop result=%+v error=%v", stopped, err)
	}
}

func TestHTTPClientRejectsInvalidProviderResponses(t *testing.T) {
	tests := []struct {
		name string
		body string
	}{
		{name: "malformed JSON", body: "{"},
		{name: "mismatched task", body: `{"task_ref":"other-task","status":"ACTIVE"}`},
		{name: "missing status", body: `{"task_ref":"task-1"}`},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
				_, _ = io.WriteString(w, test.body)
			}))
			defer server.Close()
			client, err := NewHTTPClient(server.URL, "provider-secret", time.Second)
			if err != nil {
				t.Fatal(err)
			}

			if _, err := client.Start(context.Background(), StartRequest{TaskRef: "task-1"}); err == nil || err.Error() != "provider start returned an invalid response" {
				t.Fatalf("unexpected start error: %v", err)
			}
			if _, err := client.Stop(context.Background(), StopRequest{TaskRef: "task-1"}); err == nil || err.Error() != "provider stop returned an invalid response" {
				t.Fatalf("unexpected stop error: %v", err)
			}
			if _, err := client.Query(context.Background(), QueryRequest{TaskRef: "task-1"}); err == nil || err.Error() != "provider query returned an invalid response" {
				t.Fatalf("unexpected query error: %v", err)
			}
		})
	}
}

func TestHTTPClientClassifiesStopHTTPResponses(t *testing.T) {
	for _, test := range []struct {
		status    int
		temporary bool
	}{
		{status: http.StatusTooManyRequests, temporary: true},
		{status: http.StatusBadGateway, temporary: true},
		{status: http.StatusConflict, temporary: false},
	} {
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
			w.WriteHeader(test.status)
		}))
		client, err := NewHTTPClient(server.URL, "provider-secret", time.Second)
		if err != nil {
			server.Close()
			t.Fatal(err)
		}
		_, err = client.Stop(context.Background(), StopRequest{TaskRef: "task-1"})
		server.Close()
		if err == nil || IsTemporary(err) != test.temporary {
			t.Fatalf("status=%d error=%v temporary=%v", test.status, err, IsTemporary(err))
		}
		var providerError *Error
		if !errors.As(err, &providerError) || providerError.StatusCode != test.status || !strings.Contains(err.Error(), "HTTP") {
			t.Fatalf("status=%d unexpected provider error: %v", test.status, err)
		}
	}
}

func TestHTTPClientWrapsTransportAndBodyReadFailures(t *testing.T) {
	transportFailure := errors.New("provider connection reset")
	readFailure := errors.New("provider response read failed")

	for _, operation := range []string{"start", "stop", "query"} {
		t.Run(operation+" transport failure", func(t *testing.T) {
			client, err := NewHTTPClient("http://provider", "provider-secret", time.Second)
			if err != nil {
				t.Fatal(err)
			}
			client.client.Transport = roundTripFunc(func(*http.Request) (*http.Response, error) {
				return nil, transportFailure
			})
			err = invokeProviderOperation(client, operation)
			if !errors.Is(err, transportFailure) || !IsTemporary(err) || !strings.Contains(err.Error(), "provider "+operation+" failed") {
				t.Fatalf("unexpected transport error: %v", err)
			}
		})

		t.Run(operation+" body read failure", func(t *testing.T) {
			client, err := NewHTTPClient("http://provider", "provider-secret", time.Second)
			if err != nil {
				t.Fatal(err)
			}
			client.client.Transport = roundTripFunc(func(*http.Request) (*http.Response, error) {
				return &http.Response{StatusCode: http.StatusOK, Body: failingReadCloser{err: readFailure}, Header: make(http.Header)}, nil
			})
			err = invokeProviderOperation(client, operation)
			if !errors.Is(err, readFailure) || !IsTemporary(err) {
				t.Fatalf("unexpected body read error: %v", err)
			}
		})
	}
}

func invokeProviderOperation(client *HTTPClient, operation string) error {
	switch operation {
	case "start":
		_, err := client.Start(context.Background(), StartRequest{TaskRef: "task-1"})
		return err
	case "stop":
		_, err := client.Stop(context.Background(), StopRequest{TaskRef: "task-1"})
		return err
	default:
		_, err := client.Query(context.Background(), QueryRequest{TaskRef: "task-1"})
		return err
	}
}