package configkit

import (
	"bytes"
	"slices"
	"strings"

	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
	yamladapter "gitea.maximumdirect.net/eric/ConfigKit/internal/yaml"
)

// Snapshot projection is the shared redaction boundary for effective YAML
// and explanation values. It borrows frozen trees and returns a detached tree.
func valueSnapshot(root *document.Node, path Path, secrets map[string]bool) ValueSnapshot {
	node, present := documentAtPath(root, path)
	if !present {
		return ValueSnapshot{}
	}
	safe, redacted := safeSnapshotDocument(node, secrets, path)
	var output bytes.Buffer
	if err := yamladapter.Write(&output, safe); err != nil {
		return ValueSnapshot{Present: true, Redacted: true, YAML: "'[REDACTED]'\n"}
	}
	return ValueSnapshot{Present: true, Redacted: redacted, YAML: output.String()}
}

func safeSnapshotDocument(node *document.Node, secrets map[string]bool, path Path) (*document.Node, bool) {
	if node == nil {
		return nil, false
	}
	if pathIsSecret(secrets, path) {
		return &document.Node{Kind: document.String, Text: "[REDACTED]"}, true
	}
	result := *node
	redacted := false
	switch node.Kind {
	case document.Mapping:
		result.Mapping = make([]document.Entry, len(node.Mapping))
		copy(result.Mapping, node.Mapping)
		sortDocumentMapping(result.Mapping)
		for index := range result.Mapping {
			entry := &result.Mapping[index]
			entry.Value, redacted = safeSnapshotChild(entry.Value, secrets, path.Key(entry.Key), redacted)
		}
	case document.Sequence:
		result.Sequence = make([]*document.Node, len(node.Sequence))
		for index, child := range node.Sequence {
			result.Sequence[index], redacted = safeSnapshotChild(child, secrets, path.Index(index), redacted)
		}
	}
	return &result, redacted
}

func safeSnapshotChild(node *document.Node, secrets map[string]bool, path Path, prior bool) (*document.Node, bool) {
	safe, redacted := safeSnapshotDocument(node, secrets, path)
	return safe, prior || redacted
}

func sortDocumentMapping(entries []document.Entry) {
	slices.SortFunc(entries, func(left, right document.Entry) int {
		return strings.Compare(left.Key, right.Key)
	})
}