package flog

import (
	"fmt"
	"runtime"
	"strings"
	"sync"
	"time"
)

// All log functions
var (
	Debug    = logFunc(LevelDebug)
	Info     = logFunc(LevelInfo)
	Warning  = logFunc(LevelWarning)
	Error    = logFunc(LevelError)
	Critical = logFunc(LevelCritical)
)

func logFunc(level LevelType) func(...interface{}) {
	return func(message ...interface{}) {
		writeMessage(level, message)
	}
}

var mu sync.Mutex

func writeMessage(level LevelType, message []interface{}) {
	if MinLevel > level {
		return
	}

	entry := LogEntry{
		Level:   level,
		Time:    time.Now(),
		Message: fmt.Sprint(message...),
	}

	if MinStackLevel <= level {
		entry.StackTrace = getStackTrace()
	}

	mu.Lock()
	defer mu.Unlock()

	Format.FormatMessage(getOutput(), entry)
}

func getStackTrace() (stackTrace []StackTraceEntry) {
	_, filename, _, _ := runtime.Caller(1)

	pc := make([]uintptr, 50)
	entries := runtime.Callers(2, pc)
	frames := runtime.CallersFrames(pc[:entries])

	more, firstLine := true, false
	for more {
		var frame runtime.Frame
		frame, more = frames.Next()

		if !firstLine && frame.File == filename { // Skip frames from the flog cal
			continue
		}
		firstLine = true

		if frame.Function == `runtime.gopanic` { // If a panic occurred, start at the frame that called panic
			stackTrace = nil
			continue
		}

		stackTrace = append(stackTrace, StackTraceEntry{
			Function: cleanFunction(frame.Function),
			File:     cleanFilename(frame.File),
			Line:     frame.Line,
		})
	}

	return
}

func cleanFunction(f string) string {
	parts := strings.Split(f, `/vendor/`)
	return parts[len(parts)-1]
}

func cleanFilename(file string) string {
	parts := strings.Split(file, `/src/`)
	if len(parts) < 2 {
		return file
	}

	return strings.Join(parts[1:], `/`)
}