package settings

import (
	"bytes"
	"crypto/rand"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"log"
	"maps"
	"os"
	"strings"
	"testing"
	"time"
)

var (
	AdditionalKeyValuePairs = map[string]string{
		"D": "d",
		"E": "e",
		"F": "f",
	}
)

func TestSettings(t *testing.T) {
	err := os.Remove(TheTestFilename)
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("error cleaning up %s from previous run: %v\n", TheTestFilename, err)
	}
	var buffer bytes.Buffer
	err = WriteMapToWriter(&buffer, KeyValuePairs)
	if err != nil {
		t.Fatalf("error writing test data to *bytes.Buffer: %v\n", err)
	}
	err = os.WriteFile(TheTestFilename, buffer.Bytes(), 0664)
	if err != nil {
		t.Fatalf("error writing %s: %v\n", TheTestFilename, err)
	}
	defer func() {
		if err := os.Remove(TheTestFilename); err != nil {
			t.Fatalf("error cleaning up %s from this run: %v\n", TheTestFilename, err)
		}
	}()
	settings := TheSettings
	err = settings.Update()
	if err != nil {
		t.Fatalf("error updating settings: %v\n", err)
	} else if want, got := TheTestFilename, settings.GetFilename(); want != got {
		t.Fatalf("error: wanted '%s'; got '%s'\n", want, got)
	} else if got := settings.modtime; got.Equal(time.Time{}) {
		t.Fatalf("error: modtime == (time.Time{}) - not updated when initialized")
	} else {
		for k, v := range KeyValuePairs {
			if !settings.ContainsKey(k) {
				t.Fatalf("error: key '%s' not found\n", k)
			} else if want, got := v, settings.GetKeyValue(k); want != got {
				t.Fatalf("error: wanted '%s' for key '%s'; got '%s'\n", want, k, got)
			}
		}
	}
	// change the filename
	TheNewTestFilename := fmt.Sprintf("New%s", TheTestFilename)
	buffer.Reset()
	err = WriteMapToWriter(&buffer, AdditionalKeyValuePairs)
	if err != nil {
		t.Fatalf("error writing new map to *bytes.Buffer: %v\n", err)
	}
	err = os.WriteFile(TheNewTestFilename, buffer.Bytes(), 0664)
	if err != nil {
		t.Fatalf("error writing new test file %s: %v\n", TheNewTestFilename, err)
	}
	defer func() {
		if err := os.Remove(TheNewTestFilename); err != nil {
			t.Fatalf("error deleting %s: %v", TheNewTestFilename, err)
		}
	}()
	if updated := settings.SetFilename(TheNewTestFilename); !updated {
		t.Fatalf("error: SetFilename() indicated the filename was not updated...\n")
	} else if updated := settings.SetFilename(settings.GetFilename()); updated {
		t.Fatalf("error: setting filename to itself still resulted in updated=true\n")
	}
	for k, v := range AdditionalKeyValuePairs {
		if !settings.ContainsKey(k) {
			t.Fatalf("error: key '%s' not found\n", k)
		} else if want, got := v, settings.GetKeyValue(k); want != got {
			t.Fatalf("error: wanted '%s' for key '%s'; got '%s'\n", want, k, got)
		}
	}
	// update the file, wait, then try again
	newKeyValuePairs := make(map[string]string)
	maps.Copy(newKeyValuePairs, KeyValuePairs)
	maps.Copy(newKeyValuePairs, AdditionalKeyValuePairs)
	newKeyValuePairs["G"] = "g"
	buffer.Reset()
	err = WriteMapToWriter(&buffer, newKeyValuePairs)
	if err != nil {
		t.Fatalf("error writing new key value pairs to *bytes.Buffer: %v\n", err)
	}
	err = os.WriteFile(TheNewTestFilename, buffer.Bytes(), 0664)
	if err != nil {
		t.Fatalf("error writing updates to %s: %v\n", TheNewTestFilename, err)
	}
	select {
	case <-t.Context().Done():
		t.Fatalf("error: timed out before finishing wait")
	case <-time.After(time.Duration(float64(MaintenanceRoutinePace.Nanoseconds()) * 1.1)):
	}
	for k, v := range newKeyValuePairs {
		if !settings.ContainsKey(k) {
			t.Fatalf("error: key '%s' not found in settings\n", k)
		} else if want, got := v, settings.GetKeyValue(k); want != got {
			t.Fatalf("error: wanted '%s' for key '%s'; got '%s'\n", want, k, got)
		}
	}
	buffer.Reset()
	defaultLogWriter := log.Writer()
	log.SetOutput(&buffer)
	// set settings to a fake filename
	WarnIfFileNotFound = true
	if updated := settings.SetFilename("fakefilename.txt"); !updated {
		t.Fatalf("failed to update filename to fake filename...\n")
	}
	log.SetOutput(defaultLogWriter)
	WarnIfFileNotFound = false
	if !strings.Contains(buffer.String(), "no such file or directory") {
		t.Fatalf("error: wanted error indicating 'no such file or directory'; got %v\n", err)
	}
}

func TestDump(t *testing.T) {
	dump, err := TheSettings.Dump()
	if err != nil {
		t.Fatalf("error dumping settings: %v\n", err)
	}
	scanner := NewScanner(bytes.NewReader(dump))
	var found int
loop:
	for {
		key, value, err := scanner.ReadNextLine()
		if err != nil {
			if !errors.Is(err, io.EOF) {
				t.Fatalf("error reading next line: %v\n", err)
			}
			break loop
		}
		if want, got := TheSettings.GetKeyValue(key), value; want != got {
			t.Fatalf("error: wanted key %q value %q; got %q\n", key, want, got)
		}
		found++
	}
	if want, got := len(TheSettings.contents), found; want != got {
		t.Fatalf("error: wanted %d entries; got %d\n", want, got)
	}
}

func TestDumpJson(t *testing.T) {
	marshaled, err := TheSettings.DumpToJson()
	if err != nil {
		t.Fatalf("error dumping to json: %v\n", err)
	}
	var unmarshaled map[string]string
	err = json.Unmarshal(marshaled, &unmarshaled)
	if err != nil {
		t.Fatalf("error unmarshaling json dump: %v\n", err)
	}
	if want, got := TheSettings.contents, unmarshaled; !maps.Equal(want, got) {
		t.Fatalf("error: wanted %v; got %v\n", want, got)
	}
}

func TestSetKeyValue(t *testing.T) {
	key, value := rand.Text(), rand.Text()
	if !TheSettings.SetKeyValue(key, value) {
		t.Fatalf("SetKeyValue didn't update?\n")
	}
	if want, got := value, TheSettings.GetKeyValue(key); want != got {
		t.Fatalf("error: wanted %q; got %q\n", want, got)
	}
}

func TestParseBool(t *testing.T) {
	TheTestItems := map[string]bool{
		"yes":   true,
		"on":    true,
		"true":  true,
		"True":  true,
		"TRUE":  true,
		"no":    false,
		"off":   false,
		"false": false,
	}
	for boolString, want := range TheTestItems {
		got, err := ParseBool(boolString)
		if err != nil {
			t.Fatalf("error: %v\n", err)
		}
		if want != got {
			t.Fatalf("error: wanted %s=%v; got %v\n", boolString, want, got)
		}
	}
	TheBadTestItems := []string{
		"blue",
		"cat",
		"https://google.com",
	}
	for _, boolString := range TheBadTestItems {
		got, err := ParseBool(boolString)
		if err == nil {
			t.Fatalf("error: successfully parsed %s as bool %v...\n", boolString, got)
		}
	}
}

func TestGetStringOrDefault(t *testing.T) {
	dump, err := TheSettings.Dump()
	if err != nil {
		t.Fatalf("error getting dump: %v\n", err)
	}
	scanner := NewScanner(bytes.NewReader(dump))
loop:
	for {
		key, value, err := scanner.ReadNextLine()
		if err != nil {
			if !errors.Is(err, io.EOF) {
				t.Fatalf("error reading from dump: %v\n", err)
			}
			break loop
		}
		if want, got := value, TheSettings.GetStringOrDefault(key, "SomeInvalidDefault"); want != got {
			t.Fatalf("error: wanted key %q=%q; got %q\n", key, want, got)
		}
	}
	badKey := "some new key"
	badValue := "some invalid value"
	if want, got := badValue, TheSettings.GetStringOrDefault(badKey, badValue); want != got {
		t.Fatalf("error: wanted key %q=%q; got %q\n", badKey, want, got)
	}
}

func TestGetBoolOrDefault(t *testing.T) {
	key, value := "some bool value", "on"
	TheSettings.SetKeyValue(key, value)
	if want, got := true, TheSettings.GetBoolOrDefault(key, false); want != got {
		t.Fatalf("error: wanted %q=%v; got %v\n", key, want, got)
	}
	value = "shark"
	TheSettings.SetKeyValue(key, value)
	if want, got := false, TheSettings.GetBoolOrDefault(key, false); want != got {
		t.Fatalf("error: wanted %q=%v; got %v\n", key, want, got)
	}
}

func TestGetDurationOrDefault(t *testing.T) {
	key, value := "some duration value", "10s"
	TheSettings.SetKeyValue(key, value)
	if want, got := time.Second*10, TheSettings.GetDurationOrDefault(key, time.Minute*10); want != got {
		t.Fatalf("error: wanted %q=%s; got %s\n", key, want, got)
	}
	value = "loud"
	TheSettings.SetKeyValue(key, value)
	if want, got := time.Minute*10, TheSettings.GetDurationOrDefault(key, time.Minute*10); want != got {
		t.Fatalf("error: wanted %q=%s; got %s\n", key, want, got)
	}
}

func TestGetIntOrDefault(t *testing.T) {
	key, value := "some int value", "10"
	TheSettings.SetKeyValue(key, value)
	if want, got := 10, TheSettings.GetIntOrDefault(key, 200); want != got {
		t.Fatalf("error: wanted %q=%d; got %d\n", key, want, got)
	}
	value = "cat"
	TheSettings.SetKeyValue(key, value)
	if want, got := 200, TheSettings.GetIntOrDefault(key, 200); want != got {
		t.Fatalf("error: wanted default value %d for bad key; got %d\n", want, got)
	}
	if want, got := 200, TheSettings.GetIntOrDefault("some fake bad key", 200); want != got {
		t.Fatalf("error: wanted default value %d for bad key; got %d\n", want, got)
	}
}