// Package configui is the interactive `glint -c` walkthrough: a huh form
// that loads the current config, walks the user through every setting, and
// writes the result to the config file.
package configui

import (
	"fmt"

	"glint/internal/config"

	"github.com/charmbracelet/huh"
)

// dailyPresets are friendly daily-note filename formats (label → Go layout), so
// users never have to write a raw Go time layout by hand.
var dailyPresets = []struct{ label, layout string }{
	{"2026-06-28", "2006-01-02"},
	{"2026-06-28 Sun", "2006-01-02 Mon"},
	{"20260628", "20060102"},
	{"2026.06.28", "2006.01.02"},
	{"28-06-2026", "02-01-2006"},
}

const customLayout = "__custom__"

// Run walks the user through the settings and saves them to the config file.
func Run() error {
	cfg, _ := config.Load() // defaults on error

	theme := orDefault(cfg.Theme, "auto")
	vaultDir := cfg.VaultDir
	inboxDir := cfg.InboxDir
	dailySubdir := orDefault(cfg.DailySubdir, "Daily")
	glamour := cfg.GlamourStyle
	spellcheck := orDefault(cfg.Spellcheck, "auto")

	// Match the current layout to a preset; otherwise offer it as custom.
	fmtChoice := customLayout
	for _, p := range dailyPresets {
		if p.layout == cfg.DailyFormat {
			fmtChoice = p.layout
		}
	}
	customFmt := cfg.DailyFormat

	fmtOpts := make([]huh.Option[string], 0, len(dailyPresets)+1)
	for _, p := range dailyPresets {
		fmtOpts = append(fmtOpts, huh.NewOption(p.label+"  ("+p.layout+")", p.layout))
	}
	fmtOpts = append(fmtOpts, huh.NewOption("Custom…", customLayout))

	form := huh.NewForm(
		huh.NewGroup(
			huh.NewSelect[string]().
				Title("Theme").
				Description("Colors; auto follows your macOS appearance.").
				Options(
					huh.NewOption("auto", "auto"),
					huh.NewOption("flexoki-light", "flexoki-light"),
					huh.NewOption("flexoki-dark", "flexoki-dark"),
					huh.NewOption("charm", "charm"),
				).Value(&theme),
			huh.NewInput().
				Title("Vault directory").
				Description("Where `glint -v` opens, from anywhere. Blank = none.").
				Placeholder("/Users/you/Notes").
				Value(&vaultDir),
			huh.NewInput().
				Title("Inbox directory").
				Description("Where `glint -n -i` and save-as land. Blank = the directory you run glint in.").
				Value(&inboxDir),
			huh.NewInput().
				Title("Daily notes subfolder").
				Description("Daily notes live in <dir>/<this>/.").
				Value(&dailySubdir),
			huh.NewSelect[string]().
				Title("Daily filename format").
				Options(fmtOpts...).
				Value(&fmtChoice),
			huh.NewSelect[string]().
				Title("Preview style").
				Description("Glamour style for the read preview. Blank follows the theme.").
				Options(
					huh.NewOption("follow theme", ""),
					huh.NewOption("dark", "dark"),
					huh.NewOption("light", "light"),
					huh.NewOption("dracula", "dracula"),
					huh.NewOption("tokyo-night", "tokyo-night"),
				).Value(&glamour),
			huh.NewSelect[string]().
				Title("Spellcheck").
				Description("Red undercurl on misspelled prose. auto = on for notes, off for code files.").
				Options(
					huh.NewOption("auto", "auto"),
					huh.NewOption("on", "on"),
					huh.NewOption("off", "off"),
				).Value(&spellcheck),
		),
		huh.NewGroup(
			huh.NewInput().
				Title("Custom daily format (Go layout)").
				Description("Reference date is Mon Jan 2 2006 — e.g. 2006-01-02 or 20060102.").
				Value(&customFmt),
		).WithHideFunc(func() bool { return fmtChoice != customLayout }),
	)

	if err := form.Run(); err != nil {
		return err
	}

	dailyFmt := fmtChoice
	if fmtChoice == customLayout {
		dailyFmt = customFmt
	}

	out := config.Config{
		Theme:        theme,
		VaultDir:     vaultDir,
		InboxDir:     inboxDir,
		DailySubdir:  dailySubdir,
		DailyFormat:  dailyFmt,
		GlamourStyle: glamour,
		Spellcheck:   spellcheck,
		// Export fonts aren't part of the wizard; preserve any existing values
		// so a `glint -c` run doesn't silently drop them.
		FontDisplay: cfg.FontDisplay,
		FontBody:    cfg.FontBody,
		FontMono:    cfg.FontMono,
	}
	path := config.Path()
	if err := config.Save(out, path); err != nil {
		return err
	}
	fmt.Println("Saved", path)
	return nil
}

func orDefault(v, def string) string {
	if v == "" {
		return def
	}
	return v
}