package setup

import (
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"strconv"
	"strings"

	"github.com/charmbracelet/huh"
	"github.com/charmbracelet/lipgloss"

	"github.com/hachem-wtf/benson/internal/config"
	"github.com/hachem-wtf/benson/internal/fabric"
)

func Run() error {
	cfg := loadConfig()

	var (
		mcVersion    = cfg.MinecraftVersion
		fabricLoader = cfg.FabricLoaderVersion
		loaderMeta   = cfg.LoaderMetaVersion
		javaPath     = cfg.JavaPath
		serverLoc    = cfg.ServerLocation
		backupLoc    = cfg.BackupLocation
		preCmd       = cfg.MergePreCommand
		postCmd      = cfg.MergePostCommand
		modsText     = strings.Join(cfg.ModrinthMods, "\n")
		confirm      = true
	)

	games, loaders, installers := fetchFabricVersions()

	form := huh.NewForm(
		huh.NewGroup(
			huh.NewNote().
				Title("Benson setup").
				Description("Configure the server manager.\nThe Discord bot is optional — run `benson setup bot` for that."),
		),
		huh.NewGroup(
			versionField("Minecraft version", "The Minecraft release your server runs — newest stable is recommended", games, &mcVersion, "1.21.10"),
		),
		huh.NewGroup(
			versionField("Fabric loader version", "The Fabric mod loader that boots your mods — newest is recommended", loaders, &fabricLoader, "0.17.3"),
		),
		huh.NewGroup(
			versionField("Fabric installer version", "Builds the server jar from the loader — newest is recommended", installers, &loaderMeta, "1.1.0"),
		),
		huh.NewGroup(
			huh.NewInput().Title("Java path").Description("Leave blank to use 'java' from PATH").Value(&javaPath),
			huh.NewInput().Title("Server location").Description("Live server directory, merged into by 'merge'").Value(&serverLoc),
			huh.NewInput().Title("Backup location").Description("Where server backups are written").Value(&backupLoc),
			huh.NewInput().Title("Pre-merge command").Description("Optional shell command run before merging").Value(&preCmd),
			huh.NewInput().Title("Post-merge command").Description("Optional shell command run after merging").Value(&postCmd),
		).Title("Paths & hooks (optional)"),
		huh.NewGroup(
			huh.NewText().Title("Modrinth mods").Description("One mod slug per line").Lines(8).Value(&modsText),
		).Title("Mods"),
		huh.NewGroup(
			huh.NewConfirm().Title("Write config/config.json?").Affirmative("Write").Negative("Cancel").Value(&confirm),
		),
	)

	if done, err := runForm(form); err != nil || !done {
		return err
	}

	cfg.MinecraftVersion = strings.TrimSpace(mcVersion)
	cfg.FabricLoaderVersion = strings.TrimSpace(fabricLoader)
	cfg.LoaderMetaVersion = strings.TrimSpace(loaderMeta)
	cfg.JavaPath = strings.TrimSpace(javaPath)
	cfg.ServerLocation = strings.TrimSpace(serverLoc)
	cfg.BackupLocation = strings.TrimSpace(backupLoc)
	cfg.MergePreCommand = strings.TrimSpace(preCmd)
	cfg.MergePostCommand = strings.TrimSpace(postCmd)
	cfg.ModrinthMods = parseMods(modsText)

	if err := writeConfigFile(cfg); err != nil {
		return err
	}

	fmt.Printf("\n  %s Wrote %s\n\n  Run `benson` for the CLI, or `benson setup bot` to set up the Discord bot.\n\n",
		check(), config.Path())
	return nil
}

func RunBot() error {
	cfg := loadConfig()
	api := loadAPI()

	interval := cfg.CheckIntervalMinutes
	if interval <= 0 {
		interval = 60
	}

	var (
		token       = api.Token
		channelID   = cfg.ChannelID
		intervalStr = strconv.Itoa(interval)
		confirm     = true
	)

	form := huh.NewForm(
		huh.NewGroup(
			huh.NewNote().
				Title("Benson bot setup").
				Description("Configure the Discord bot that posts Modrinth compatibility reports."),
		),
		huh.NewGroup(
			huh.NewInput().Title("Discord bot token").Description("Developer Portal → Bot → Reset/Copy Token").Password(true).Value(&token).Validate(required("token")),
			huh.NewInput().Title("Channel ID").Description("Channel where reports are posted").Value(&channelID).Validate(required("channel ID")),
			huh.NewInput().Title("Check interval (minutes)").Value(&intervalStr).Validate(positiveInt),
		).Title("Discord"),
		huh.NewGroup(
			huh.NewConfirm().Title("Write config/config.json and config/api.json?").Affirmative("Write").Negative("Cancel").Value(&confirm),
		),
	)

	if done, err := runForm(form); err != nil || !done {
		return err
	}

	minutes, _ := strconv.Atoi(strings.TrimSpace(intervalStr))
	cfg.ChannelID = strings.TrimSpace(channelID)
	cfg.CheckIntervalMinutes = minutes
	api.Token = strings.TrimSpace(token)

	if err := writeConfigFile(cfg); err != nil {
		return err
	}
	if err := writeAPIFile(api); err != nil {
		return err
	}

	fmt.Printf("\n  %s Wrote %s\n  %s Wrote %s\n\n  Run `benson bot` to start the bot.\n\n",
		check(), config.Path(), check(), config.APIPath())
	return nil
}

func fetchFabricVersions() (games, loaders, installers []string) {
	client := fabric.NewClient()

	if gv, err := client.GameVersions(); err == nil {
		for _, v := range gv {
			if v.Stable {
				games = append(games, v.Version)
			}
		}
	}
	if lv, err := client.LoaderVersions(); err == nil {
		for _, v := range lv {
			loaders = append(loaders, v.Version)
		}
	}
	if iv, err := client.InstallerVersions(); err == nil {
		for _, v := range iv {
			installers = append(installers, v.Version)
		}
	}
	return games, loaders, installers
}

func versionField(title, desc string, options []string, value *string, placeholder string) huh.Field {
	if len(options) == 0 {
		return huh.NewInput().
			Title(title).
			Placeholder(placeholder).
			Value(value).
			Validate(required(title))
	}

	*value = defaultOr(*value, options)
	return huh.NewSelect[string]().
		Title(title).
		Description(desc).
		Options(recommendedOptions(options)...).
		Height(12).
		Value(value)
}

func recommendedOptions(versions []string) []huh.Option[string] {
	options := make([]huh.Option[string], len(versions))
	for i, v := range versions {
		label := v
		if i == 0 {
			label = v + "  ·  recommended"
		}
		options[i] = huh.NewOption(label, v)
	}
	return options
}

func defaultOr(current string, options []string) string {
	for _, o := range options {
		if o == current {
			return current
		}
	}
	return options[0]
}

func loadConfig() *config.Config {
	if cfg, err := config.Load(); err == nil {
		return cfg
	}
	return &config.Config{}
}

func loadAPI() *config.API {
	if api, err := config.LoadAPI(); err == nil {
		return api
	}
	return &config.API{}
}

func runForm(form *huh.Form) (bool, error) {
	if err := form.WithTheme(emberTheme()).Run(); err != nil {
		if errors.Is(err, huh.ErrUserAborted) {
			fmt.Println("Setup cancelled.")
			return false, nil
		}
		return false, err
	}
	return true, nil
}

func required(label string) func(string) error {
	return func(s string) error {
		if strings.TrimSpace(s) == "" {
			return fmt.Errorf("%s is required", label)
		}
		return nil
	}
}

func positiveInt(s string) error {
	n, err := strconv.Atoi(strings.TrimSpace(s))
	if err != nil || n <= 0 {
		return errors.New("must be a positive number")
	}
	return nil
}

func parseMods(text string) []string {
	mods := []string{}
	for _, line := range strings.Split(text, "\n") {
		if slug := strings.TrimSpace(line); slug != "" {
			mods = append(mods, slug)
		}
	}
	return mods
}

func check() string {
	return lipgloss.NewStyle().Foreground(lipgloss.Color("#22C55E")).Render("✓")
}

func emberTheme() *huh.Theme {
	theme := huh.ThemeCharm()
	ember := lipgloss.Color("#F97316")
	theme.Focused.Title = theme.Focused.Title.Foreground(ember).Bold(true)
	theme.Focused.Base = theme.Focused.Base.BorderForeground(ember)
	return theme
}

func writeConfigFile(cfg *config.Config) error {
	if err := os.MkdirAll(config.Dir, 0o755); err != nil {
		return err
	}
	data, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(config.Path(), append(data, '\n'), 0o644)
}

func writeAPIFile(api *config.API) error {
	if err := os.MkdirAll(config.Dir, 0o755); err != nil {
		return err
	}
	data, err := json.MarshalIndent(api, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(config.APIPath(), append(data, '\n'), 0o600)
}