// ------------------------------------------------------------------------
//   Project active2
//   Active Thing (activething.com) git.activething.com/go
//
//   File name  stack_frame.go
//   Created by DEV
//   Modified   20/03/2024
//
//   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 stack

import (
	"bufio"
	"bytes"
	"os"
	"runtime"
	"strings"
)

type (

	Frame struct {
		LineNumber  int    // Number line
		File        string // File FuncName
		FuncName    string // Function name
		Package     string // Package name
		Counter     uintptr

		files 		map[string][]byte
	}

)


func NewFrame(counter uintptr) *Frame {
	if counter == 0 {
		return nil
	}
	sf := &Frame{
		Counter: counter,
	}
	fn := runtime.FuncForPC(counter)
	sf.Package, sf.FuncName = packageAndName(fn)
	sf.File, sf.LineNumber = fn.FileLine(counter-1)
	return sf
}



func (f Frame) SourceLine() (string, error) {
	if f.LineNumber <= 0 {
		return stackUnknownInfo, nil
	}

	file, err := os.Open(f.File)
	if err != nil {
		return "", err
	}

	scanner := bufio.NewScanner(file)
	currentLine := 1
	for scanner.Scan() {
		if currentLine == f.LineNumber {
			return string(bytes.Trim(scanner.Bytes(), " \t")), nil
		}
		currentLine++
	}
	_ = file.Close()
	if err := scanner.Err(); err != nil {
		return "", err
	}

	return stackUnknownInfo, nil

}



func packageAndName (fn *runtime.Func) (string,string) {
	nm := fn.Name()
	pg := ""
	if ls := strings.LastIndex(nm,"/"); ls >= 0 {
		pg = nm[:ls] + "/"
		nm = nm[ls+1:]
	}
	if pd := strings.Index(nm,"."); pd >= 0 {
		pg += nm[:pd]
		nm =  nm[pd+1:]
	}
	return pg,strings.Replace(nm,"·", ".",-1)
}