// ------------------------------------------------------------------------
//   Project active2
//   Active Thing (activething.com) git.activething.com/go
//
//   File name  logger_core.go
//   Created by DEV
//   Modified   25/04/2024
//
//   Copyright 2024 activething.com 
// ------------------------------------------------------------------------
// 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 alogs

import (
	"errs"
	"iosys"
)

type (

	LoggerCore 			struct {
		loggerObject

		filters 		EntryFilters
		appender		EntryAppender

		onStartFn 		LoggerCoreEventFnc
		onStopFn  		LoggerCoreEventFnc
		onFlushFn 		LoggerCoreEventFnc

		onErrorFn 		LoggerCoreErrorFnc

		onEntryFatalFn 	LoggerCoreEntryFnc
		onEntryErrorFn 	LoggerCoreEntryFnc
	}

	LoggerCoreFnc 		func(l *LoggerCore) error

	LoggerCoreEventFnc	func (l *LoggerCore) error
	LoggerCoreEntryFnc 	func (l *LoggerCore, entry *Entry)
	LoggerCoreErrorFnc 	func (l *LoggerCore, entry *Entry, err error)
)




func NewLoggerCore (name string, level Level, options ...LoggerCoreFnc) (*LoggerCore,error) {
	l := &LoggerCore {
		appender : AppendEntryFnc(nopEntryAppender),
		onStartFn: nopOnEvent,
		onStopFn : nopOnEvent,
	}
	l.loggerObject = *newLoggerObject(name,level,l.log)
	for _,o := range options {
		if er:=o(l); er != nil {
			return nil,er
		}
	}
	if l.onFlushFn == nil {
		if fl,is := l.appender.(iosys.Flusher); is {
			l.onFlushFn = func(c *LoggerCore) error {
				return fl.Flush() }
		} else {
			l.onFlushFn = nopOnEvent
		}
	}
	return l,nil
}



func (l *LoggerCore) Start () error {
	l.Lock()
	er := l.start()
	l.Unlock()
	return er
}

func (l *LoggerCore) start () error {
	if l.state == StateStarted {
		return G.ErrLoggerStarted.WrapWithFieldString(entryFieldLogger,l.name)
	}
	l.errors = l.errors.Reset()
	if er := l.onStartFn(l); er != nil {
		er = errs.WrapWithFieldString(er,entryFieldLogger,l.name)
		l.handleError(er,nil)
		return er
	}
	l.state = StateStarted
	return nil
}

func (l *LoggerCore) Stop () error {
	l.Lock()
	er := l.stop()
	l.Unlock()
	return er
}

func (l *LoggerCore) stop () error {
	if l.state != StateStarted {

		return G.ErrLoggerNotStarted.WrapWithFieldString(entryFieldLogger,l.name)
	}
	l.state = StateStopped
	er := l.onStopFn(l)
	if er != nil {
		er = errs.WrapWithFieldString(er,entryFieldLogger,l.name)
		l.handleError(er,nil)
		return er
	}
	return nil
}


func (l *LoggerCore) Flush () error {
	l.Lock()
	er := l.flush()
	l.Unlock()
	return er
}

func (l *LoggerCore) flush () error {
	if l.onFlushFn == nil {
		return nil
	}
	er := l.onFlushFn(l)
	if er == nil {
		return nil
	}
	er = errs.WrapWithFieldString(er,entryFieldLogger,l.name)
	l.handleError(er,nil)
	return er
}


func (l *LoggerCore) log(level Level, msg string, err error, options []EntryFnc) {
	l.Lock()

	en := l.extenders.ExtendEntry(AcquireEntry(l,level,msg,err,options...))
	_ = l.handleEntry(en,true)

	l.Unlock()
}


func (l *LoggerCore) Log(entry *Entry) error {
	l.Lock()

	er := l.handleEntry(entry,false)

	l.Unlock()
	return er
}


func (l *LoggerCore) handleEntry (entry *Entry, self bool) error {
	if l.state != StateStarted  {
		return G.ErrLoggerNotStarted.WrapWithFieldString(entryFieldLogger,l.name)
	}
	if !l.level.Has(entry.Level) {
		return nil
	}
	if !self {
		if entry.Excludes.Has(l.name) || !l.filters.Filter(entry) {
			return nil
		}
	}

	er := l.appender.AppendEntry(entry)

	if er != nil {
		er = errs.WrapWithFieldString(er,errFieldLogger,l.name)
		l.handleError(er,nil)
	}

	if self {
		if entry.Logger == l {
			if entry.Level == LevelFatal {
				l.onEntryFatalFn(l, entry)
			}
			if entry.Level == LevelError {
				l.onEntryErrorFn(l, entry)
			}
			ReleaseEntry(entry)
		}
	}

	return er
}



func (l *LoggerCore) handleError (err error, entry *Entry) {
	if err == nil {
		return
	}
	l.errors = l.errors.Append(err)
	if l.onEntryErrorFn != nil {
		l.onErrorFn(l, entry, err)
	}
}



func LoggerCoreWithEvents (onStart, onStop, onFlush LoggerCoreEventFnc) LoggerCoreFnc {
	return func(a *LoggerCore) error {
		if onStart != nil {
			a.onStartFn = onStart
		}
		if onStop != nil {
			a.onStopFn = onStop
		}
		if onFlush != nil {
			a.onFlushFn = onFlush
		}
		return nil
	}
}


func LoggerCoreWithOnError (onError LoggerCoreErrorFnc) LoggerCoreFnc {
	return func(a *LoggerCore) error {
		if a.State() != StateCreated {
			return G.ErrInvalidState.WrapWithMessage("config-logger-core-with-on-error")
		}
		a.onErrorFn = onError
		return nil
	}
}


func LoggerCoreWithOnEntryFatal (onFatal LoggerCoreEntryFnc) LoggerCoreFnc {
	return func(a *LoggerCore) error {
		if a.State() != StateCreated {
			return G.ErrInvalidState.WrapWithMessage("config-logger-core-with-on-fatal")
		}
		a.onEntryFatalFn = onFatal
		return nil
	}
}


func LoggerCoreWithOnEntryError (onError LoggerCoreEntryFnc) LoggerCoreFnc {
	return func(a *LoggerCore) error {
		if a.State() != StateCreated {
			return G.ErrInvalidState.WrapWithMessage("config-logger-core-with-entry-on-error")
		}
		a.onEntryErrorFn = onError
		return nil
	}
}


func LoggerCoreWithExtender (extender ...EntryExtender) LoggerCoreFnc {
	return func(a *LoggerCore) error {
		if a.State() != StateCreated {
			return G.ErrInvalidState.WrapWithMessage("config-logger-core-with-extender")
		}
		a.extenders = append(a.extenders,extender...)
		return nil
	}
}


func LoggerCoreWithFilters (configFilters EntryFiltersFnc) LoggerCoreFnc {
	return func(a *LoggerCore) error {
		if a.State() != StateCreated {
			return G.ErrInvalidState.WrapWithMessage("config-logger-core-with-filters")
		}
		configFilters(&a.filters)
		return nil
	}
}


func LoggerCoreWithAppender(appender EntryAppender) LoggerCoreFnc {
	return func(a *LoggerCore) error {
		if a.State() != StateCreated {
			return G.ErrInvalidState.WrapWithMessage("config-logger-core-with-appender")
		}
		a.appender = appender
		return nil
	}
}