package apps

import (
	"path/filepath"
	"strings"

	"codeberg.org/VARASYS/ZDDC/zddc/internal/zddc"
)

// Folder name conventions that gate which tools are virtually available
// at a given path. The names are case-sensitive; ZDDC convention uses
// the capitalized forms. The full canonical list lives in
// zddc/internal/zddc/special.go (SpecialFolderNames) — this file pulls
// the relevant subsets from there to avoid duplication.
var (
	// Subset of zddc.AutoOwnFolderNames where classifier is virtually
	// available (the same three folders that grant mkdir auto-ownership).
	folderNamesIncomingWorkingStaging = zddc.AutoOwnFolderNames
	folderNamesWorking                = []string{"Working"}
	folderNamesStaging                = []string{"Staging"}
)

// AppAvailableAt reports whether app's virtual HTML can be served at
// requestDir. Rules:
//
//   - archive: every directory (multi-project, project, archive, vendor)
//   - browse: every directory (generic file listing — also the default
//     served at folder URLs without an index.html; see directory.go)
//   - classifier: requestDir is, or descends from, a folder named
//     "Incoming", "Working", or "Staging" (the directories where
//     incoming/outgoing files get classified)
//   - mdedit: requestDir is, or descends from, a "Working" folder
//     (where markdown drafts are written and edited)
//   - transmittal: requestDir is, or descends from, a "Staging" folder
//     (where outgoing transmittals are prepared)
//   - landing: only at the deployment root (the project picker)
//
// Operators can always drop a real <name>.html file at any path to override
// — that path is served by the static handler regardless of this function's
// result. AppAvailableAt is consulted only when no real file exists.
func AppAvailableAt(root, requestDir, app string) bool {
	root = filepath.Clean(root)
	requestDir = filepath.Clean(requestDir)

	switch app {
	case "archive":
		return true
	case "browse":
		return true
	case "landing":
		return requestDir == root
	case "classifier":
		return inAncestorWithName(root, requestDir, folderNamesIncomingWorkingStaging)
	case "mdedit":
		return inAncestorWithName(root, requestDir, folderNamesWorking)
	case "transmittal":
		return inAncestorWithName(root, requestDir, folderNamesStaging)
	}
	return false
}

// inAncestorWithName reports whether requestDir is, or has an ancestor
// (not including root itself), named one of names. The match is on the
// last segment of each directory in the chain root → requestDir.
func inAncestorWithName(root, requestDir string, names []string) bool {
	if requestDir == root {
		return false
	}
	rel, err := filepath.Rel(root, requestDir)
	if err != nil || strings.HasPrefix(rel, "..") {
		return false
	}
	for _, part := range strings.Split(rel, string(filepath.Separator)) {
		for _, n := range names {
			if part == n {
				return true
			}
		}
	}
	return false
}