package main

// will this help things?
// this is a hack for testing for now
// cram a mutex in the pb.go file

import (
	"fmt"
	"io"
	"os"
	"strings"

	"go.wit.com/log"
)

func (pf *File) syncLock(w io.Writer) {
	var LOCK string = pf.Base.Lockname // if the Marshall code changes, this will have to change

	fmt.Fprintln(w, "// a simple global lock")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "// this is needed because it seems Marshal() fails if locks are in the structs (?)")
	fmt.Fprintln(w, "// this might just be a syntactical runtime error. notsure.")
	fmt.Fprintln(w, "// maybe this autogen tool will help someone that actually knows what is going on inside")
	fmt.Fprintln(w, "// go/src/google.golang.org/protobuf/proto/proto_methods.go")
	fmt.Fprintln(w, "// go/src/google.golang.org/protobuf/proto/encode.go")
	fmt.Fprintln(w, "// my guess is that Marshal() needs to be told to ignore sync.RWMutex as it ephemeral and can't be stored")
	fmt.Fprintln(w, "")
	fmt.Fprintln(w, "var "+LOCK+" sync.RWMutex")
	fmt.Fprintln(w, "")
}

func (pb *Files) addMutex(f *File) error {
	fullname := f.Pbfilename
	log.Info("pb filename:", fullname)
	data, err := os.ReadFile(fullname)
	if err != nil {
		log.Info("pb filename failed to read:", err)
		return err
	}

	// check if autogenpb has already looked at this file
	for _, line := range strings.Split(string(data), "\n") {
		if strings.Contains(line, "autogenpb DO NOT EDIT") {
			log.Info("autogenpb has already been run on", fullname)
			return nil
		}
	}

	w, _ := os.OpenFile(f.Pbfilename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)

	pbHeaderComment(w)

	lines := strings.Split(string(data), "\n")
	for _, line := range lines {
		if strings.HasPrefix(line, "package ") {
			log.Info("CHANGING package:", line, "to package:", f.Package)
			fmt.Fprintln(w, "package "+f.Package)
			// log.Info("CHANGING package:", line, "to package:main")
			// fmt.Fprintln(w, "package "+"main")
			continue
		}

		if f.structMatch(line) {
			if argv.Mutex {
				log.Info("Adding Mutex to:", line)
				fmt.Fprintln(w, line)
				fmt.Fprintln(w, "\tLock sync.RWMutex // auto-added by go.wit.com/apps/autogenpb") // this must be 'Lock' or Marshal() panics?
				// fmt.Fprintln(w, "\t// auto-added by go.wit.com/apps/autogenpb")
				// fmt.Fprintln(w, "\tsync.RWMutex")
				fmt.Fprintln(w, "")
			} else {
				log.Info("Skipping. Mutex = false for:", line)
				fmt.Fprintln(w, line)
				fmt.Fprintln(w, "\t// Lock sync.RWMutex // autogenpb skipped this. needs --mutex command line arg")
				fmt.Fprintln(w, "")
			}
		} else {
			fmt.Fprintln(w, line)
		}
	}
	for _, msg := range f.MsgNames {
		if !msg.MutexFound && msg.DoMutex {
			return fmt.Errorf("addMutex() parse didn't work for %s", msg.Name)
		}
	}
	return nil
}

// is this struct supposed to have a Mutex added?
func (pf *File) structMatch(line string) bool {
	var msg *MsgName
	var start string

	msg = pf.Bases
	start = "type " + msg.Name + " struct {"
	if strings.HasPrefix(line, start) {
		msg.MutexFound = true
		msg.Lockname = "x.Lock"
		return true
	}

	// ONLY PASS THIS IF YOU DO NOT WANT TO USE MARSHAL()

	msg = pf.Base
	start = "type " + msg.Name + " struct {"
	if strings.HasPrefix(line, start) {
		msg.MutexFound = true
		// msg.Lockname = "x.Lock"
		return true
	}

	for _, msg = range pf.MsgNames {
		start = "type " + msg.Name + " struct {"
		if strings.HasPrefix(line, start) {
			msg.MutexFound = true
			// msg.Lockname = "x.Lock"
			return true
		}
	}
	return false
}