package assertions

import (
	"fmt"
	"path/filepath"
	"reflect"
	"runtime"
	"strings"

	"github.com/sirupsen/logrus/hooks/test"
)

// AssertionTestingTB exposes enough testing.TB methods for assertions.
type AssertionTestingTB interface {
	Errorf(format string, args ...interface{})
	Fatalf(format string, args ...interface{})
}

type assertionLoggerFn func(string, ...interface{})

// Equal compares values using comparison operator.
func Equal(loggerFn assertionLoggerFn, expected, actual interface{}, msg ...interface{}) {
	errMsg := parseMsg("Values are not equal", msg...)
	if expected != actual {
		_, file, line, _ := runtime.Caller(2)
		loggerFn("%s:%d %s, want: %[4]v (%[4]T), got: %[5]v (%[5]T)", filepath.Base(file), line, errMsg, expected, actual)
	}
}

// NotEqual compares values using comparison operator.
func NotEqual(loggerFn assertionLoggerFn, expected, actual interface{}, msg ...interface{}) {
	errMsg := parseMsg("Values are equal", msg...)
	if expected == actual {
		_, file, line, _ := runtime.Caller(2)
		loggerFn("%s:%d %s, both values are equal: %[4]v (%[4]T)", filepath.Base(file), line, errMsg, expected)
	}
}

// DeepEqual compares values using DeepEqual.
func DeepEqual(loggerFn assertionLoggerFn, expected, actual interface{}, msg ...interface{}) {
	errMsg := parseMsg("Values are not equal", msg...)
	if !reflect.DeepEqual(expected, actual) {
		_, file, line, _ := runtime.Caller(2)
		loggerFn("%s:%d %s, want: %#v, got: %#v", filepath.Base(file), line, errMsg, expected, actual)
	}
}

// NoError asserts that error is nil.
func NoError(loggerFn assertionLoggerFn, err error, msg ...interface{}) {
	errMsg := parseMsg("Unexpected error", msg...)
	if err != nil {
		_, file, line, _ := runtime.Caller(2)
		loggerFn("%s:%d %s: %v", filepath.Base(file), line, errMsg, err)
	}
}

// ErrorContains asserts that actual error contains wanted message.
func ErrorContains(loggerFn assertionLoggerFn, want string, err error, msg ...interface{}) {
	errMsg := parseMsg("Expected error not returned", msg...)
	if err == nil || !strings.Contains(err.Error(), want) {
		_, file, line, _ := runtime.Caller(2)
		loggerFn("%s:%d %s, got: %v, want: %s", filepath.Base(file), line, errMsg, err, want)
	}
}

// NotNil asserts that passed value is not nil.
func NotNil(loggerFn assertionLoggerFn, obj interface{}, msg ...interface{}) {
	errMsg := parseMsg("Unexpected nil value", msg...)
	if obj == nil {
		_, file, line, _ := runtime.Caller(2)
		loggerFn("%s:%d %s", filepath.Base(file), line, errMsg)
	}
}

// LogsContain checks whether a given substring is a part of logs. If flag=false, inverse is checked.
func LogsContain(loggerFn assertionLoggerFn, hook *test.Hook, want string, flag bool, msg ...interface{}) {
	_, file, line, _ := runtime.Caller(2)
	entries := hook.AllEntries()
	var logs []string
	match := false
	for _, e := range entries {
		msg, err := e.String()
		if err != nil {
			loggerFn("%s:%d Failed to format log entry to string: %v", filepath.Base(file), line, err)
			return
		}
		if strings.Contains(msg, want) {
			match = true
		}
		for _, field := range e.Data {
			fieldStr, ok := field.(string)
			if !ok {
				continue
			}
			if strings.Contains(fieldStr, want) {
				match = true
			}
		}
		logs = append(logs, msg)
	}
	var errMsg string
	if flag && !match {
		errMsg = parseMsg("Expected log not found", msg...)
	} else if !flag && match {
		errMsg = parseMsg("Unexpected log found", msg...)
	}
	if errMsg != "" {
		loggerFn("%s:%d %s: %v\nSearched logs:\n%v", filepath.Base(file), line, errMsg, want, logs)
	}
}

func parseMsg(defaultMsg string, msg ...interface{}) string {
	if len(msg) >= 1 {
		msgFormat, ok := msg[0].(string)
		if !ok {
			return defaultMsg
		}
		return fmt.Sprintf(msgFormat, msg[1:]...)
	}
	return defaultMsg
}

// TBMock exposes enough testing.TB methods for assertions.
type TBMock struct {
	ErrorfMsg string
	FatalfMsg string
}

// Errorf writes testing logs to ErrorfMsg.
func (tb *TBMock) Errorf(format string, args ...interface{}) {
	tb.ErrorfMsg = fmt.Sprintf(format, args...)
}

// Fatalf writes testing logs to FatalfMsg.
func (tb *TBMock) Fatalf(format string, args ...interface{}) {
	tb.FatalfMsg = fmt.Sprintf(format, args...)
}