// Copyright (c) 2026 Lark Technologies Pte. Ltd.
// SPDX-License-Identifier: MIT

package event

import (
	"fmt"
	"sort"
	"strings"

	"github.com/larksuite/cli/errs"
	eventlib "github.com/larksuite/cli/internal/event"
	"github.com/larksuite/cli/internal/suggest"
)

const maxSuggestions = 3

// suggestEventKeys returns up to maxSuggestions keys resembling input (substring match beats edit distance).
func suggestEventKeys(input string) []string {
	type match struct {
		key  string
		dist int
	}
	var hits []match
	threshold := max(2, len(input)/5)

	for _, def := range eventlib.ListAll() {
		if strings.Contains(def.Key, input) {
			hits = append(hits, match{def.Key, 0})
			continue
		}
		if d := suggest.Levenshtein(input, def.Key); d <= threshold {
			hits = append(hits, match{def.Key, d})
		}
	}
	sort.Slice(hits, func(i, j int) bool { return hits[i].dist < hits[j].dist })

	n := min(maxSuggestions, len(hits))
	out := make([]string, n)
	for i := range out {
		out[i] = hits[i].key
	}
	return out
}

// formatSuggestions renders keys as a human-readable quoted tail.
func formatSuggestions(keys []string) string {
	if len(keys) == 0 {
		return ""
	}
	quoted := make([]string, len(keys))
	for i, k := range keys {
		quoted[i] = fmt.Sprintf("%q", k)
	}
	if len(quoted) == 1 {
		return quoted[0]
	}
	return "one of: " + strings.Join(quoted, ", ")
}

// unknownEventKeyErr builds the shared "unknown EventKey" error with a suggestion tail when available.
func unknownEventKeyErr(key string) error {
	msg := fmt.Sprintf("unknown EventKey: %s", key)
	if guesses := suggestEventKeys(key); len(guesses) > 0 {
		msg += " — did you mean " + formatSuggestions(guesses) + "?"
	}
	return errs.NewValidationError(errs.SubtypeInvalidArgument, "%s", msg).
		WithHint("Run 'lark-cli event list' to see available keys.")
}