// Copyright 2021 Fahmi Akbar Wildana <~drsensor/public-inbox@lists.sr.ht>
// SPDX-License-Identifier: FSFAP

package utils

import (
	"path/filepath"
	"sort"
	"strings"
)

// BUG: probably 🤔 (plus it's not optimized)
// BUG: updir `..` not handled properly
// TODO: handle absoulute path
// TODO: document this algorithm step-by-step-explain-output as Stack Overflow question
func NearestWorkDirs(paths []string) []string {
	if !sort.StringsAreSorted(paths) {
		sort.Strings(paths)
	}

	var workdir []string
	keys := map[string]bool{}
	reset := func() {
		paths = workdir
		workdir = []string{}
		keys = map[string]bool{}
	}

	depths := map[string]int{} // depth of path
	for _, entry := range paths {
		if filepath.Ext(entry) != "" {
			entry = filepath.Dir(entry)
		}
		if _, isDuplicate := keys[entry]; !isDuplicate {
			keys[entry] = true
			workdir = append(workdir, entry)
			if spath := SlicePath(entry); spath[0] == ".." {
				k := Count(spath, "..")
				depths[filepath.Join(spath[:k]...)] = len(spath[k:])
			} else {
				depths[spath[0]] = len(spath)
			}
		}
	}

	reset()
	counts := map[string]int{} // count spath[0]
	for _, entry := range paths {
		spath := SlicePath(entry)
		if depths[spath[0]] == 1 && len(spath) > 1 {
			entry = filepath.Dir(entry)
		}
		if _, isDuplicate := keys[entry]; !isDuplicate {
			keys[entry] = true
			workdir = append(workdir, entry)
			if spath := SlicePath(entry); spath[0] != ".." {
				counts[spath[0]]++
			}
		}
	}

	reset()
	for _, entry := range paths { // dedupe based on spath[0]
		if spath := SlicePath(entry); counts[spath[0]] > 1 && len(spath) > 1 {
			entry = filepath.Join(spath[:len(spath)-depths[spath[0]]+1]...)
		}
		if _, isDuplicate := keys[entry]; !isDuplicate {
			keys[entry] = true
			workdir = append(workdir, entry)
		}
	}
	return workdir
}
func SlicePath(pathfile string) []string {
	return strings.Split(filepath.ToSlash(pathfile), "/")
}