package ezhandler_test

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

	"codeberg.org/danjones000/ezhandler"
	"github.com/stretchr/testify/assert"
)

func TestHandlerFunc_ServeHTTP(t *testing.T) {
	tests := []struct {
		name        string
		handlerFunc ezhandler.HandlerFunc
		expectedErr error
	}{
		{
			name: "no error",
			handlerFunc: ezhandler.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
				w.WriteHeader(http.StatusOK)
				return nil
			}),
			expectedErr: nil,
		},
		{
			name: "with error",
			handlerFunc: ezhandler.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
				return errTest
			}),
			expectedErr: errTest,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req := httptest.NewRequest(http.MethodGet, "/", http.NoBody)
			rec := httptest.NewRecorder()

			err := tt.handlerFunc.ServeHTTP(rec, req)
			if tt.expectedErr != nil {
				assert.Equal(t, tt.expectedErr, err)
			} else {
				assert.NoError(t, err)
			}
		})
	}
}

type testBody struct {
	Name string `json:"name"`
	Age  int    `json:"age"`
}

type jsonBodyTest struct {
	name                string
	requestBody         string
	handler             ezhandler.JSONBodyHandler[testBody]
	expectedStatus      int
	expectedBody        string
	expectedErr         error
	expectedErrContains string
	additionAssert      func(*assert.Assertions, testBody)
}

var jsonBodyHandlerTests = []jsonBodyTest{
	{
		name:        "successful decoding and handler execution",
		requestBody: `{"name":"John Doe","age":30}`,
		handler: ezhandler.JSONBodyHandler[testBody](func(w http.ResponseWriter, r *http.Request, body testBody) error {
			w.WriteHeader(http.StatusOK)
			_, _ = w.Write([]byte("success"))
			return nil
		}),
		expectedStatus: http.StatusOK,
		expectedBody:   "success",
		expectedErr:    nil,
		additionAssert: func(as *assert.Assertions, body testBody) {
			as.Equal("John Doe", body.Name)
			as.Equal(30, body.Age)
		},
	},
	{
		name:        "invalid JSON body",
		requestBody: `{"name":"John Doe","age":}`,
		handler: ezhandler.JSONBodyHandler[testBody](func(w http.ResponseWriter, r *http.Request, body testBody) error {
			return nil // Should not be called
		}),
		expectedErrContains: "invalid character",
	},
	{
		name:        "empty body for struct type",
		requestBody: "",
		handler: ezhandler.JSONBodyHandler[testBody](func(w http.ResponseWriter, r *http.Request, body testBody) error {
			return nil // Should not be called
		}),
		expectedErr: io.EOF,
	},
	{
		name:        "handler function returns error",
		requestBody: `{"name":"Jane Doe","age":25}`,
		handler: ezhandler.JSONBodyHandler[testBody](func(w http.ResponseWriter, r *http.Request, body testBody) error {
			return errTest
		}),
		expectedErr: errTest,
	},
}

func TestJSONBodyHandler_ServeHTTP(t *testing.T) {
	for _, tc := range jsonBodyHandlerTests {
		runJSONBodyHandlerTest(t, tc)
	}
}

func runJSONBodyHandlerTest(tt *testing.T, tc jsonBodyTest) {
	tt.Run(tc.name, func(t *testing.T) {
		handler := ezhandler.JSONBodyHandler[testBody](func(w http.ResponseWriter, r *http.Request, body testBody) error {
			if err := tc.handler(w, r, body); err != nil {
				return err
			}
			if tc.additionAssert != nil {
				as := assert.New(t)
				tc.additionAssert(as, body)
			}
			return nil
		})
		req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(tc.requestBody))
		rec := httptest.NewRecorder()

		err := handler.ServeHTTP(rec, req)

		switch {
		case tc.expectedErr != nil:
			assert.Equal(t, tc.expectedErr, err)
		case tc.expectedErrContains != "":
			assert.ErrorContains(t, err, tc.expectedErrContains)
		default:
			assert.NoError(t, err)
			assert.Equal(t, tc.expectedStatus, rec.Code)
			assert.Equal(t, tc.expectedBody, rec.Body.String())
		}

	})
}

type jsonBodyResponderTest struct {
	name                string
	requestBody         string
	handler             ezhandler.JSONResponder[testBody]
	expectedStatus      int
	expectedBody        testBody
	expectedErr         error
	expectedErrContains string
}

var jsonBodyResponderTests = []jsonBodyResponderTest{
	{
		name:        "successful decoding and response",
		requestBody: `{"name":"John Doe","age":30}`,
		handler: ezhandler.JSONResponder[testBody](func(r *http.Request, body testBody) (ezhandler.ResponseHelper, error) {
			return ezhandler.JSONResponse(body), nil
		}),
		expectedStatus: http.StatusOK,
		expectedBody:   testBody{Name: "John Doe", Age: 30},
		expectedErr:    nil,
	},
	{
		name:        "invalid JSON body",
		requestBody: `{"name":"John Doe","age":}`,
		handler: ezhandler.JSONResponder[testBody](func(r *http.Request, body testBody) (ezhandler.ResponseHelper, error) {
			return nil, nil // Should not be called
		}),
		expectedErrContains: "invalid character",
	},
	{
		name:        "empty body for struct type",
		requestBody: "",
		handler: ezhandler.JSONResponder[testBody](func(r *http.Request, body testBody) (ezhandler.ResponseHelper, error) {
			return nil, nil // Should not be called
		}),
		expectedErr: io.EOF,
	},
	{
		name:        "handler function returns error",
		requestBody: `{"name":"Jane Doe","age":25}`,
		handler: ezhandler.JSONResponder[testBody](func(r *http.Request, body testBody) (ezhandler.ResponseHelper, error) {
			return nil, errTest
		}),
		expectedErr: errTest,
	},
}

func TestJSONResponder_ServeHTTP(t *testing.T) {
	for _, tc := range jsonBodyResponderTests {
		runJSONResponderTest(t, tc)
	}
}

func runJSONResponderTest(tt *testing.T, tc jsonBodyResponderTest) {
	tt.Run(tc.name, func(t *testing.T) {
		req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(tc.requestBody))
		rec := httptest.NewRecorder()

		err := tc.handler.ServeHTTP(rec, req)

		switch {
		case tc.expectedErr != nil:
			assert.Equal(t, tc.expectedErr, err)
		case tc.expectedErrContains != "":
			assert.ErrorContains(t, err, tc.expectedErrContains)
		default:
			assert.NoError(t, err)
			assert.Equal(t, tc.expectedStatus, rec.Code)
			// Marshal expectedBody to JSON string for comparison
			expectedBodyBytes, marshalErr := json.Marshal(tc.expectedBody)
			assert.NoError(t, marshalErr)
			assert.JSONEq(t, string(expectedBodyBytes), rec.Body.String())
			assert.Equal(t, "application/json", rec.Header().Get("Content-Type"))
		}
	})
}