package setup

import (
	"errors"
	"fmt"
	"sort"
	"strconv"
	"strings"

	"charm.land/huh/v2"

	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/config"
)

func editMulti(cfg *config.Config) error {
	multiplexer := cfg.Multi.Multiplexer
	if multiplexer == "" {
		multiplexer = "auto"
	}
	perWindow := ""
	if cfg.Multi.PanesPerWindow > 0 {
		perWindow = strconv.Itoa(cfg.Multi.PanesPerWindow)
	}
	groups := formatGroups(cfg.Groups)
	err := huh.NewForm(huh.NewGroup(
		huh.NewSelect[string]().
			Title("Multiplexer").
			Description("netssh multi opens hosts side by side. auto uses the one you are in, else tmux, else zellij.").
			Options(huh.NewOption("auto", "auto"), huh.NewOption("tmux", "tmux"), huh.NewOption("zellij", "zellij")).
			Value(&multiplexer),
		huh.NewInput().
			Title("Panes per window").
			Description(fmt.Sprintf("More hosts open in further windows or tabs. Leave empty for %d.", config.DefaultPanesPerWindow)).
			Value(&perWindow).
			Validate(func(s string) error {
				if s = strings.TrimSpace(s); s == "" {
					return nil
				}
				if n, err := strconv.Atoi(s); err != nil || n < 1 || n > 64 {
					return errors.New("must be a number between 1 and 64")
				}
				return nil
			}),
		huh.NewText().
			Title("Groups").
			Description("One per line: NAME: host, tag:TAG, cluster:NAME, @other — open with netssh multi @NAME.").
			Lines(4).
			Value(&groups).
			Validate(func(s string) error {
				_, err := parseGroups(s)
				return err
			}),
	).Title("Multi-session")).Run()
	if err != nil {
		return err
	}
	cfg.Multi.Multiplexer = multiplexer
	if multiplexer == "auto" {
		cfg.Multi.Multiplexer = ""
	}
	cfg.Multi.PanesPerWindow, _ = strconv.Atoi(strings.TrimSpace(perWindow))
	cfg.Groups, _ = parseGroups(groups)
	return nil
}

// parseGroups reads "NAME: sel1, sel2" lines into groups:.
func parseGroups(s string) (map[string][]string, error) {
	var out map[string][]string
	for _, line := range parseLines(s) {
		name, members, ok := strings.Cut(line, ":")
		name = strings.ToLower(strings.TrimSpace(name))
		// "tag:x" alone has no group name before the first colon worth keeping.
		if !ok || name == "" || name == "tag" || name == "cluster" {
			return nil, fmt.Errorf("%q: expected NAME: host, tag:TAG, …", line)
		}
		var selectors []string
		for _, field := range strings.FieldsFunc(members, func(r rune) bool { return r == ',' || r == ' ' || r == '\t' }) {
			selectors = append(selectors, field)
		}
		if out == nil {
			out = make(map[string][]string)
		}
		out[name] = append(out[name], selectors...)
	}
	if err := (&config.Config{Groups: out}).ValidateMulti(); err != nil {
		return nil, err
	}
	return out, nil
}

func formatGroups(groups map[string][]string) string {
	names := make([]string, 0, len(groups))
	for name := range groups {
		names = append(names, name)
	}
	sort.Strings(names)
	lines := make([]string, 0, len(names))
	for _, name := range names {
		lines = append(lines, name+": "+strings.Join(groups[name], ", "))
	}
	return strings.Join(lines, "\n")
}