package main

import (
	"bufio"
	"os"
	"path/filepath"
	"regexp"
	"sort"

	"git.dev.alexdunmow.com/block/check-safety/internal/helpers"
	"strings"
)

type todoViolation struct {
	file    string
	line    int
	snippet string
}

type todoScanRoot struct {
	root          string
	displayPrefix string
}

var todoFileExts = map[string]bool{
	".css":   true,
	".go":    true,
	".html":  true,
	".js":    true,
	".jsx":   true,
	".scss":  true,
	".sql":   true,
	".templ": true,
	".ts":    true,
	".tsx":   true,
}

var todoDirSkips = map[string]bool{
	".git":         true,
	"dist":         true,
	"node_modules": true,
	"vendor":       true,
}

var reTODO = regexp.MustCompile(`(?i)\bTODO(?:\([^)]*\))?\b`)

func checkTODOs(roots []todoScanRoot) []todoViolation {
	var violations []todoViolation

	for _, scanRoot := range roots {
		if scanRoot.root == "" {
			continue
		}

		if err := filepath.Walk(scanRoot.root, func(path string, info os.FileInfo, err error) error {
			if err != nil {
				return nil
			}
			if info.IsDir() {
				if todoDirSkips[info.Name()] {
					return filepath.SkipDir
				}
				return nil
			}

			slashPath := filepath.ToSlash(path)
			ext := filepath.Ext(path)
			if !todoFileExts[ext] {
				return nil
			}
			if strings.Contains(slashPath, "cmd/check-safety/") {
				return nil
			}
			if strings.HasSuffix(path, "_test.go") ||
				strings.HasSuffix(path, ".test.ts") ||
				strings.HasSuffix(path, ".test.tsx") ||
				strings.HasSuffix(path, ".spec.ts") ||
				strings.HasSuffix(path, ".spec.tsx") {
				return nil
			}

			f, openErr := os.Open(path)
			if openErr != nil {
				return nil
			}
			defer helpers.LogDeferredError(nil, "close TODO scan file", f.Close, "path", path)

			relPath, _ := filepath.Rel(scanRoot.root, path)
			if relPath == "" {
				relPath = path
			}
			relPath = filepath.ToSlash(relPath)
			if scanRoot.displayPrefix != "" {
				relPath = scanRoot.displayPrefix + "/" + relPath
			}

			scanner := bufio.NewScanner(f)
			lineNum := 0
			for scanner.Scan() {
				lineNum++
				line := scanner.Text()
				if !reTODO.MatchString(line) {
					continue
				}

				violations = append(violations, todoViolation{
					file:    relPath,
					line:    lineNum,
					snippet: strings.TrimSpace(line),
				})
			}

			return nil
		}); err != nil {
			_ = err // Walk errors are non-fatal for TODO checks
		}
	}

	sort.Slice(violations, func(i, j int) bool {
		if violations[i].file == violations[j].file {
			return violations[i].line < violations[j].line
		}
		return violations[i].file < violations[j].file
	})

	return violations
}