package web

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"
)

// Site holds display settings SimpleAdmin has no place for: rank labels, colours and the plain
// descriptions on the public staff page. Ranks are keyed by SimpleAdmin group name.
type Site struct {
	Title string          `json:"title"`
	Ranks map[string]Rank `json:"ranks"`
}

type Rank struct {
	Label string `json:"label"`
	Color string `json:"color"`
	About string `json:"about"`
	// Supporter ranks (VIPs) are listed apart from staff and don't count as staff online.
	Supporter bool `json:"supporter"`
}

func defaultSite() Site {
	return Site{
		Title: "zio.sh",
		Ranks: map[string]Rank{
			"#rank/owner":       {Label: "Owner", Color: "#fe113d", About: "Runs the server."},
			"#rank/senioradmin": {Label: "Senior admin", Color: "#ff7a45", About: "Manages the staff team and server settings."},
			"#rank/admin":       {Label: "Admin", Color: "#f0a63a", About: "Handles appeals and longer bans."},
			"#rank/trialadmin":  {Label: "Trial admin", Color: "#e8d25a", About: "Admins on trial."},
			"#rank/mod":         {Label: "Moderator", Color: "#37c58f", About: "Keeps matches fair. Can kick, gag and issue short bans."},
			"#rank/trialmod":    {Label: "Trial mod", Color: "#4fb3d9", About: "Moderators on trial."},
			"#rank/helper":      {Label: "Helper", Color: "#7c8cf5", About: "Answers questions and handles chat."},
			"#rank/guardian":    {Label: "Guardian", Color: "#c77dff", About: "Supporters of the server. Not staff, and can't punish anyone.", Supporter: true},
		},
	}
}

func loadSite(path string) (Site, error) {
	s := defaultSite()
	if path == "" {
		return s, nil
	}
	data, err := os.ReadFile(path)
	if err != nil {
		return s, err
	}
	var file Site
	if err := json.Unmarshal(data, &file); err != nil {
		return s, fmt.Errorf("%s: %w", path, err)
	}
	if file.Title != "" {
		s.Title = file.Title
	}
	if file.Ranks != nil {
		s.Ranks = file.Ranks
	}
	return s, nil
}

var fallbackColors = []string{"#7c8cf5", "#4fb3d9", "#37c58f", "#e8d25a", "#f0a63a", "#ff7a45", "#c77dff"}

// rank returns display settings for a group, deriving a label ("#rank/mod" -> "Mod") and a colour
// for groups the site config doesn't list.
func (s Site) rank(group string, index int) Rank {
	if r, ok := s.Ranks[group]; ok {
		if r.Label == "" {
			r.Label = defaultLabel(group)
		}
		if r.Color == "" {
			r.Color = fallbackColors[index%len(fallbackColors)]
		}
		return r
	}
	return Rank{Label: defaultLabel(group), Color: fallbackColors[index%len(fallbackColors)]}
}

func defaultLabel(group string) string {
	name := strings.TrimPrefix(group, "#")
	if i := strings.LastIndex(name, "/"); i >= 0 {
		name = name[i+1:]
	}
	if name == "" {
		return group
	}
	return strings.ToUpper(name[:1]) + name[1:]
}