package main

import (
	"log"
	"io/ioutil"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	sitter "github.com/smacker/go-tree-sitter"
	"github.com/smacker/go-tree-sitter/ruby"
)

const NUM_WORKERS = 32

func gatherFiles(root string, ch chan string) {
	defer close(ch)
	i := 0
	err := filepath.Walk(root,
		func(path string, info os.FileInfo, err error) error {
			if err != nil {
				log.Printf("Error reading directory %s: %s\n", root, err)
				return nil
			}
			i += 1
			name := info.Name()
			if strings.HasSuffix(name, ".rb") {
				ch <- path
			}
			return nil
		})
	log.Printf("Checked %d files\n", i)
	if err != nil {
		log.Fatalf("Error reading directory %s: %s\n", root, err)
		return
	}
}

func findTypedLine(path string, tree *sitter.Tree, buf []byte) *string {
	r := regexp.MustCompile("# typed: (ignore|false|true|strict|strong|__STDLIB_INTERNAL)")
	root := tree.RootNode()
	for i := 0; i < int(root.ChildCount()); i++ {
		n := root.Child(i)
		if n.Type() == "comment" {
			matches := r.FindStringSubmatch(n.Content(buf))
			if matches == nil {
				continue
			}
			return &matches[1]
		}
	}
	return nil
}

func worker(ch chan string, finished chan int) {
	parser := sitter.NewParser()
	parser.SetLanguage(ruby.GetLanguage())

	for {
		path, more := <-ch
		if !more {
			finished <- -1
			return
		}

		buf, err := ioutil.ReadFile(path)
		if err != nil {
			log.Printf("Error reading %s: %s\n", path, err)
			continue
		}

		node := parser.Parse(nil, buf)
		sigil := findTypedLine(path, node, buf)
		if sigil == nil {
			log.Printf("File %s: missing typed sigil", path)
		} else if *sigil == "false" || *sigil == "ignore" {
			log.Printf("File %s: expected at least `true`, but got `%s`", path, *sigil)
		}
		finished <- 1
	}
}

func main() {
	ch := make(chan string)
	go gatherFiles(".", ch)

	finished := make(chan int)

	for i := 0; i < NUM_WORKERS; i++ {
		go worker(ch, finished)
	}

	all_files := 0
	done := 0
	for done < NUM_WORKERS {
		n := <- finished
		if n == -1 {
			done += 1
		} else {
			all_files += 1
		}
	}
	log.Printf("Parsed %d files\n", all_files)
}