// Command particulars keeps this mesh's node names out of the modules it covers (novox/hq ADR 0507 §9,
// issue 1838): a module is for any mesh, so no manifest, file, code string, identifier, comment, test name or
// fixture of a covered module names a node of this one.
//
// The names are in the file `particulars` at the catalogue's root, one a line, `#` comments — the one place
// they may be written. The modules covered are in `covered` at checks/particulars/covered, one a line. A name is matched
// whole and in any case; a hyphen, an underscore or a CamelCase boundary parts one, so a longer word holding a name is another word.
// The forge is not a node name: its host (git.novox.be) and the organisation path (novox/<repo>) are blanked
// before a line is read.
//
//	go run . <catalogue root>
//
// Exits 1 naming file:line and the word, 2 when a list cannot be read.
package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
)

// forge is the forge's host and organisation path, blanked before a line is read; a path segment novox/ elsewhere
// (testdata/novox/x, /srv/novox/data) is not blanked.
var forge = regexp.MustCompile(`(?i)git\.novox\.be(?:/novox/[\w.-]+)?|(?:^|[^/\w.-])novox/[\w.-]+`)

func main() {
	root := "."
	if len(os.Args) > 1 {
		root = os.Args[1]
	}
	os.Exit(check(root))
}

// check runs the check over a catalogue and returns the exit code: 0 clean, 1 a finding, 2 a list unreadable.
func check(root string) int {
	names, err := readList(filepath.Join(root, "particulars"))
	if err == nil && len(names) == 0 {
		err = fmt.Errorf("particulars lists no name — the check would pass on anything")
	}
	var covered []string
	if err == nil {
		covered, err = readList(filepath.Join(root, "checks/particulars/covered"))
		if err == nil && len(covered) == 0 {
			err = fmt.Errorf("covered lists no module — the check would pass on anything")
		}
	}
	if err != nil {
		fmt.Fprintln(os.Stderr, "particulars:", err)
		return 2
	}
	findings, err := run(root, names, covered)
	if err != nil {
		fmt.Fprintln(os.Stderr, "particulars:", err)
		return 2
	}
	for _, f := range findings {
		fmt.Println(f)
	}
	if len(findings) > 0 {
		fmt.Printf("particulars: %d node name(s) in a module for any mesh (novox/hq ADR 0507 §9) — say what it shows, not where it was seen\n", len(findings))
		return 1
	}
	fmt.Printf("particulars: none of %d node names in the %d covered modules\n", len(names), len(covered))
	return 0
}

// readList reads a list: one entry a line; blank lines and lines starting with # are not entries.
func readList(path string) ([]string, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer f.Close()
	var out []string
	sc := bufio.NewScanner(f)
	for sc.Scan() {
		line := strings.TrimSpace(sc.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		out = append(out, line)
	}
	return out, sc.Err()
}

// run reads every text file of each covered module and returns the findings, sorted.
func run(root string, names, covered []string) ([]string, error) {
	var out []string
	for _, m := range covered {
		dir := filepath.Join(root, "modules", m)
		err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
			if err != nil {
				return err
			}
			if d.IsDir() {
				switch d.Name() {
				case "node_modules", "dist", "vendor", ".git":
					return filepath.SkipDir
				}
				return nil
			}
			rel, _ := filepath.Rel(root, path)
			// A path is read too: a testdata directory named after a node is a finding.
			for _, n := range hits(filepath.ToSlash(rel), names) {
				out = append(out, fmt.Sprintf("%s:0: node name %q in the path", filepath.ToSlash(rel), n))
			}
			if d.Name() == "go.sum" {
				return nil
			}
			b, err := os.ReadFile(path)
			if err != nil {
				return err
			}
			if bytes.IndexByte(b, 0) >= 0 {
				return nil
			}
			out = append(out, scan(filepath.ToSlash(rel), string(b), names)...)
			return nil
		})
		if err != nil {
			return nil, err
		}
	}
	sort.Strings(out)
	return out, nil
}

// scan returns a finding for each node name in src, whole-word and in any case.
func scan(file, src string, names []string) []string {
	var out []string
	for i, line := range strings.Split(src, "\n") {
		for _, n := range hits(line, names) {
			out = append(out, fmt.Sprintf("%s:%d: node name %q — %s", file, i+1, n, strings.Join(strings.Fields(line), " ")))
		}
	}
	return out
}

// hits returns the node names one line holds: as a word (a hyphen or underscore parts it), as a part of a
// CamelCase identifier (TestAce, novoxTree), the forge's host and organisation path blanked first.
func hits(line string, names []string) []string {
	line = forge.ReplaceAllStringFunc(line, func(s string) string { return strings.Repeat(" ", len(s)) })
	var out []string
	for _, n := range names {
		q := regexp.QuoteMeta(n)
		camel := regexp.QuoteMeta(strings.ToUpper(n[:1]) + n[1:])
		rx := regexp.MustCompile(`(?i:(?:^|[^A-Za-z0-9])` + q + `(?:$|[^A-Za-z0-9]))|[a-z0-9]` + camel + `(?:$|[^a-z])|(?:^|[^A-Za-z0-9])` + q + `[A-Z0-9]`)
		if rx.MatchString(line) {
			out = append(out, strings.ToLower(n))
		}
	}
	return out
}