// Copyright Sam Xie
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package otelsql

import (
	"database/sql/driver"
	"errors"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.opentelemetry.io/otel/codes"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
)

type mockRows struct {
	shouldError bool

	closeCount, nextCount int
	nextDest              []driver.Value
}

func (m *mockRows) Columns() []string {
	return nil
}

func (m *mockRows) Close() error {
	m.closeCount++
	if m.shouldError {
		return errors.New("close")
	}
	return nil
}

func (m *mockRows) Next(dest []driver.Value) error {
	m.nextDest = dest
	m.nextCount++
	if m.shouldError {
		return errors.New("next")
	}
	return nil
}

func newMockRows(shouldError bool) *mockRows {
	return &mockRows{shouldError: shouldError}
}

var _ driver.Rows = (*mockRows)(nil)

func TestOtRows_Close(t *testing.T) {
	testCases := []struct {
		name  string
		error bool
	}{
		{
			name: "no error",
		},
		{
			name:  "with error",
			error: true,
		},
	}

	for _, spanFilterFn := range []SpanFilter{nil, omit, keep} {
		testname := testSpanFilterOmit
		if spanFilterFn == nil {
			testname = testSpanFilterNil
		} else if spanFilterFn(nil, "", "", []driver.NamedValue{}) {
			testname = testSpanFilterKeep
		}

		t.Run(testname, func(t *testing.T) {
			for _, tc := range testCases {
				t.Run(tc.name, func(t *testing.T) {
					// Prepare traces
					ctx, sr, tracer, _ := prepareTraces(false)

					mr := newMockRows(tc.error)
					t.Setenv("OTEL_SEMCONV_STABILITY_OPT_IN", "database")
					cfg := newConfig()
					cfg.Tracer = tracer
					cfg.SpanOptions.SpanFilter = spanFilterFn

					// New rows
					rows := newRows(ctx, mr, cfg)
					// Close
					err := rows.Close()

					spanList := sr.Ended()

					omit := !filterSpan(ctx, cfg.SpanOptions, MethodRows, "", []driver.NamedValue{})

					expectedSpanCount := getExpectedSpanCount(false, omit)

					// A span created in newRows()
					require.Len(t, spanList, expectedSpanCount)

					if !omit {
						span := spanList[1]
						assert.False(t, span.EndTime().IsZero())

						assert.Equal(t, 1, mr.closeCount)
						if tc.error {
							require.Error(t, err)
							assert.Equal(t, codes.Error, span.Status().Code)
							assert.Len(t, span.Events(), 1)
						} else {
							require.NoError(t, err)
							assert.Equal(t, codes.Unset, span.Status().Code)
						}
					}
				})
			}
		})
	}
}

func TestOtRows_Next(t *testing.T) {
	testCases := []struct {
		name           string
		error          bool
		rowsNextOption bool
	}{
		{
			name: "no error",
		},
		{
			name:  "with error",
			error: true,
		},
		{
			name:           "with RowsNextOption",
			rowsNextOption: true,
		},
	}

	for _, spanFilterFn := range []SpanFilter{nil, omit, keep} {
		testname := testSpanFilterOmit
		if spanFilterFn == nil {
			testname = testSpanFilterNil
		} else if spanFilterFn(nil, "", "", []driver.NamedValue{}) {
			testname = testSpanFilterKeep
		}

		t.Run(testname, func(t *testing.T) {
			for _, tc := range testCases {
				t.Run(tc.name, func(t *testing.T) {
					// Prepare traces
					ctx, sr, tracer, _ := prepareTraces(false)

					mr := newMockRows(tc.error)
					t.Setenv("OTEL_SEMCONV_STABILITY_OPT_IN", "database")
					cfg := newConfig()
					cfg.Tracer = tracer
					cfg.SpanOptions.RowsNext = tc.rowsNextOption
					cfg.SpanOptions.SpanFilter = spanFilterFn

					// New rows
					rows := newRows(ctx, mr, cfg)
					// Next
					err := rows.Next([]driver.Value{"test"})

					omit := !filterSpan(ctx, cfg.SpanOptions, MethodRows, "", []driver.NamedValue{})
					expectedSpanCount := getExpectedSpanCount(false, omit)

					spanList := sr.Started()
					// A span created in newRows()
					require.Len(t, spanList, expectedSpanCount)

					if !omit {
						span := spanList[1]
						assert.True(t, span.EndTime().IsZero())

						assert.Equal(t, 1, mr.nextCount)
						assert.Equal(t, []driver.Value{"test"}, mr.nextDest)
						var expectedEventCount int
						if tc.error {
							require.Error(t, err)
							assert.Equal(t, codes.Error, span.Status().Code)
							expectedEventCount++
						} else {
							require.NoError(t, err)
							assert.Equal(t, codes.Unset, span.Status().Code)
						}

						if tc.rowsNextOption {
							expectedEventCount++
						}
						assert.Len(t, span.Events(), expectedEventCount)
					}
				})
			}
		})
	}
}

func TestNewRows(t *testing.T) {
	for _, omitRows := range []bool{true, false} {
		var testname string
		if omitRows {
			testname = "OmitRows"
		}

		t.Run(testname, func(t *testing.T) {
			testCases := []struct {
				name             string
				noParentSpan     bool
				attributesGetter AttributesGetter
			}{
				{
					name: "default config",
				},
				{
					name:         "no parent span",
					noParentSpan: true,
				},
				{
					name:             "with attribute getter",
					attributesGetter: getDummyAttributesGetter(),
				},
			}

			for _, spanFilterFn := range []SpanFilter{nil, omit, keep} {
				testname := testSpanFilterOmit
				if spanFilterFn == nil {
					testname = testSpanFilterNil
				} else if spanFilterFn(nil, "", "", []driver.NamedValue{}) {
					testname = testSpanFilterKeep
				}

				t.Run(testname, func(t *testing.T) {
					for _, tc := range testCases {
						t.Run(tc.name, func(t *testing.T) {
							// Prepare traces
							ctx, sr, tracer, dummySpan := prepareTraces(tc.noParentSpan)

							mr := newMockRows(false)
							t.Setenv("OTEL_SEMCONV_STABILITY_OPT_IN", "database")
							cfg := newConfig()
							cfg.Tracer = tracer
							cfg.SpanOptions.OmitRows = omitRows
							cfg.SpanOptions.SpanFilter = spanFilterFn
							cfg.AttributesGetter = tc.attributesGetter
							cfg.InstrumentAttributesGetter = InstrumentAttributesGetter(tc.attributesGetter)

							// New rows
							rows := newRows(ctx, mr, cfg)

							spanList := sr.Started()
							omit := omitRows
							if !omit {
								omit = !filterSpan(ctx, cfg.SpanOptions, MethodRows, "", []driver.NamedValue{})
							}
							expectedSpanCount := getExpectedSpanCount(tc.noParentSpan, omit)
							// One dummy span and one span created in newRows()
							require.Len(t, spanList, expectedSpanCount)

							// Convert []sdktrace.ReadWriteSpan to []sdktrace.ReadOnlySpan explicitly due to the limitation of Go
							var readOnlySpanList []sdktrace.ReadOnlySpan
							for _, v := range spanList {
								readOnlySpanList = append(readOnlySpanList, v)
							}

							assertSpanList(t, readOnlySpanList, spanAssertionParameter{
								parentSpan:         dummySpan,
								error:              false,
								expectedAttributes: cfg.Attributes,
								method:             MethodRows,
								noParentSpan:       tc.noParentSpan,
								spanNotEnded:       true,
								omitSpan:           omit,
								attributesGetter:   tc.attributesGetter,
							})

							assert.Equal(t, mr, rows.Rows)
						})
					}
				})
			}
		})
	}
}