package http

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

	"git.defalsify.org/vise.git/engine"
	"git.grassecon.net/urdt/ussd/internal/handlers"
	"git.grassecon.net/urdt/ussd/internal/mocks/httpmocks"
)

func TestNewATSessionHandler(t *testing.T) {
	mockHandler := &httpmocks.MockRequestHandler{}
	ash := NewATSessionHandler(mockHandler)

	if ash == nil {
		t.Fatal("NewATSessionHandler returned nil")
	}

	if ash.SessionHandler == nil {
		t.Fatal("SessionHandler is nil")
	}
}

func TestATSessionHandler_ServeHTTP(t *testing.T) {
	tests := []struct {
		name           string
		setupMocks     func(*httpmocks.MockRequestHandler, *httpmocks.MockRequestParser, *httpmocks.MockEngine)
		formData       url.Values
		expectedStatus int
		expectedBody   string
	}{
		{
			name: "Successful request",
			setupMocks: func(mh *httpmocks.MockRequestHandler, mrp *httpmocks.MockRequestParser, me *httpmocks.MockEngine) {
				mrp.GetSessionIdFunc = func(rq any) (string, error) {
					req := rq.(*http.Request)
					return req.FormValue("phoneNumber"), nil
				}
				mrp.GetInputFunc = func(rq any) ([]byte, error) {
					req := rq.(*http.Request)
					text := req.FormValue("text")
					parts := strings.Split(text, "*")
					return []byte(parts[len(parts)-1]), nil
				}
				mh.ProcessFunc = func(rqs handlers.RequestSession) (handlers.RequestSession, error) {
					rqs.Continue = true
					rqs.Engine = me
					return rqs, nil
				}
				mh.GetConfigFunc = func() engine.Config { return engine.Config{} }
				mh.GetRequestParserFunc = func() handlers.RequestParser { return mrp }
				mh.OutputFunc = func(rs handlers.RequestSession) (handlers.RequestSession, error) { return rs, nil }
				mh.ResetFunc = func(rs handlers.RequestSession) (handlers.RequestSession, error) { return rs, nil }
				me.WriteResultFunc = func(context.Context, io.Writer) (int, error) { return 0, nil }
			},
			formData: url.Values{
				"phoneNumber": []string{"+1234567890"},
				"text":        []string{"1*2*3"},
			},
			expectedStatus: http.StatusOK,
			expectedBody:   "CON ",
		},
		{
			name: "GetSessionId error",
			setupMocks: func(mh *httpmocks.MockRequestHandler, mrp *httpmocks.MockRequestParser, me *httpmocks.MockEngine) {
				mrp.GetSessionIdFunc = func(rq any) (string, error) {
					return "", errors.New("no phone number found")
				}
				mh.GetConfigFunc = func() engine.Config { return engine.Config{} }
				mh.GetRequestParserFunc = func() handlers.RequestParser { return mrp }
			},
			formData: url.Values{
				"text": []string{"1*2*3"},
			},
			expectedStatus: http.StatusBadRequest,
			expectedBody:   "",
		},
		{
			name: "GetInput error",
			setupMocks: func(mh *httpmocks.MockRequestHandler, mrp *httpmocks.MockRequestParser, me *httpmocks.MockEngine) {
				mrp.GetSessionIdFunc = func(rq any) (string, error) {
					req := rq.(*http.Request)
					return req.FormValue("phoneNumber"), nil
				}
				mrp.GetInputFunc = func(rq any) ([]byte, error) {
					 return nil, errors.New("no input found")
				}
				mh.GetConfigFunc = func() engine.Config { return engine.Config{} }
				mh.GetRequestParserFunc = func() handlers.RequestParser { return mrp }
			},
			formData: url.Values{
				"phoneNumber": []string{"+1234567890"},
			},
			expectedStatus: http.StatusBadRequest,
			expectedBody:   "",
		},
		{
			name: "Process error",
			setupMocks: func(mh *httpmocks.MockRequestHandler, mrp *httpmocks.MockRequestParser, me *httpmocks.MockEngine) {
				mrp.GetSessionIdFunc = func(rq any) (string, error) {
					req := rq.(*http.Request)
					return req.FormValue("phoneNumber"), nil
				}
				mrp.GetInputFunc = func(rq any) ([]byte, error) {
					req := rq.(*http.Request)
					text := req.FormValue("text")
					parts := strings.Split(text, "*")
					return []byte(parts[len(parts)-1]), nil
				}
				mh.ProcessFunc = func(rqs handlers.RequestSession) (handlers.RequestSession, error) {
					return rqs, handlers.ErrStorage
				}
				mh.GetConfigFunc = func() engine.Config { return engine.Config{} }
				mh.GetRequestParserFunc = func() handlers.RequestParser { return mrp }
			},
			formData: url.Values{
				"phoneNumber": []string{"+1234567890"},
				"text":        []string{"1*2*3"},
			},
			expectedStatus: http.StatusInternalServerError,
			expectedBody:   "",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			mockHandler := &httpmocks.MockRequestHandler{}
			mockRequestParser := &httpmocks.MockRequestParser{}
			mockEngine := &httpmocks.MockEngine{}
			tt.setupMocks(mockHandler, mockRequestParser, mockEngine)

			ash := NewATSessionHandler(mockHandler)

			req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(tt.formData.Encode()))
			req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
			w := httptest.NewRecorder()

			ash.ServeHTTP(w, req)

			if w.Code != tt.expectedStatus {
				t.Errorf("Expected status %d, got %d", tt.expectedStatus, w.Code)
			}

			if tt.expectedBody != "" && w.Body.String() != tt.expectedBody {
				t.Errorf("Expected body %q, got %q", tt.expectedBody, w.Body.String())
			}
		})
	}
}

func TestATSessionHandler_Output(t *testing.T) {
	tests := []struct {
		name           string
		input          handlers.RequestSession
		expectedPrefix string
		expectedError  bool
	}{
		{
			name: "Continue true",
			input: handlers.RequestSession{
				Continue: true,
				Engine: &httpmocks.MockEngine{
					WriteResultFunc: func(context.Context, io.Writer) (int, error) {
						return 0, nil
					},
				},
				Writer: &httpmocks.MockWriter{},
			},
			expectedPrefix: "CON ",
			expectedError:  false,
		},
		{
			name: "Continue false",
			input: handlers.RequestSession{
				Continue: false,
				Engine: &httpmocks.MockEngine{
					WriteResultFunc: func(context.Context, io.Writer) (int, error) {
						return 0, nil
					},
				},
				Writer: &httpmocks.MockWriter{},
			},
			expectedPrefix: "END ",
			expectedError:  false,
		},
		{
			name: "WriteResult error",
			input: handlers.RequestSession{
				Continue: true,
				Engine: &httpmocks.MockEngine{
					WriteResultFunc: func(context.Context, io.Writer) (int, error) {
						return 0, errors.New("write error")
					},
				},
				Writer: &httpmocks.MockWriter{},
			},
			expectedPrefix: "CON ",
			expectedError:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			ash := &ATSessionHandler{}
			_, err := ash.Output(tt.input)

			if tt.expectedError && err == nil {
				t.Error("Expected an error, but got nil")
			}

			if !tt.expectedError && err != nil {
				t.Errorf("Unexpected error: %v", err)
			}

			mw := tt.input.Writer.(*httpmocks.MockWriter)
			if !mw.WriteStringCalled {
				t.Error("WriteString was not called")
			}

			if mw.WrittenString != tt.expectedPrefix {
				t.Errorf("Expected prefix %q, got %q", tt.expectedPrefix, mw.WrittenString)
			}
		})
	}
}