package bot

import (
	"regexp"
	"strings"
)

// The deterministic command floor: the Go port of agent/commands.mjs — the
// slash-commands a helper answers WITHOUT a model, mapping text to the same
// client-whitelisted one-tap action chips the LLM can propose, so "/dark" (no
// AI) and "make it dark" (AI) reach the identical chip.
//
// The command NAMES + help below mirror web/static/bot-commands.js — the one
// source of truth the browser typeahead and the Node sidecar share. Go can't
// import that module, so TestCommandsMatchJS parses it and fails the build on
// drift, same pattern as the e2ee test vectors.
var botCommands = []struct{ Name, Help string }{
	{"/help", "what I can do"},
	{"/theme", "switch colour theme, e.g. /theme lagoon"},
	{"/themes", "browse the theme picker"},
	{"/dark", "switch to dark mode"},
	{"/light", "switch to light mode"},
	{"/profile", "edit your screen name & photo"},
}

// Mirrors agent/actions.mjs THEMES (drift-checked alongside the commands).
var themes = []string{"litroom", "lagoon", "sunny", "plum", "linen", "classic"}

// Human-friendly theme names for the reply text (the chip carries the id).
var themeLabels = map[string]string{
	"litroom": "Lit Room (warm amber)",
	"lagoon":  "Lagoon (teal)",
	"sunny":   "Sunny (yellow)",
	"plum":    "Plum (purple)",
	"linen":   "Linen (soft neutral)",
	"classic": "Classic (blue)",
}

// RunCommand answers a registered command, or ok=false when the text isn't one
// (no leading "/", or a name we don't own — "/unknown …" falls through to
// normal chat, exactly like the Node floor).
func RunCommand(text string, aiEnabled bool) (Reply, bool) {
	t := strings.TrimSpace(text)
	if !strings.HasPrefix(t, "/") {
		return Reply{}, false
	}
	name, args, _ := strings.Cut(t, " ")
	name = strings.ToLower(name)
	args = strings.TrimSpace(args)
	switch name {
	case "/help":
		return Reply{Text: helpText(aiEnabled)}, true
	case "/theme":
		return themeCmd(args), true
	case "/themes":
		return Reply{Text: "Here you go — tap to browse themes.",
			Actions: []map[string]any{{"type": "open_theme_picker"}}}, true
	case "/dark":
		return appearanceCmd("dark"), true
	case "/light":
		return appearanceCmd("light"), true
	case "/profile":
		return Reply{Text: "Here you go — tap to open your profile.",
			Actions: []map[string]any{{"type": "open_profile"}}}, true
	}
	return Reply{}, false
}

func themeCmd(args string) Reply {
	name := strings.ToLower(strings.TrimSpace(args))
	if label, ok := themeLabels[name]; ok {
		return Reply{Text: "Here you go — tap to switch to " + label + ".",
			Actions: []map[string]any{{"type": "set_theme", "theme": name}}}
	}
	// No/unknown theme → list the options and offer the picker.
	return Reply{Text: "Themes: " + strings.Join(themes, ", ") + ". Tap to browse, or try e.g. /theme lagoon.",
		Actions: []map[string]any{{"type": "open_theme_picker"}}}
}

func appearanceCmd(mode string) Reply {
	return Reply{Text: "Here you go — tap to switch to " + mode + " mode.",
		Actions: []map[string]any{{"type": "set_appearance", "appearance": mode}}}
}

func helpText(aiEnabled bool) string {
	var b strings.Builder
	b.WriteString("Here's what I can do right now:\n")
	for _, c := range botCommands {
		b.WriteString("• " + c.Name + " — " + c.Help + "\n")
	}
	if aiEnabled {
		b.WriteString("\nOr just ask me anything in your own words — I'll do my best to help.")
	} else {
		b.WriteString("\nConversational AI answers aren't enabled on this server, so I stick to the commands above.")
	}
	return b.String()
}

// degradeText is the reply when there's no model brain and the message wasn't
// a command.
const degradeText = "I can help with a few quick commands — try /help. (Conversational AI answers aren't enabled on this server.)"

// mentionStripper removes a leading "@Name" so a group command
// ("@Eleven /help") parses; a bare command in a DM passes through unchanged.
func mentionStripper(name string) func(string) string {
	strip := regexp.MustCompile(`(?i)^\s*@` + regexp.QuoteMeta(name) + `\b[:,]?\s*`)
	return func(text string) string {
		return strings.TrimSpace(strip.ReplaceAllString(text, ""))
	}
}

// CommandFloor is the deterministic Handler: when addressed, commands are
// answered in place and anything else gets the no-AI hint — the exact
// behaviour of the Node sidecar running without an ANTHROPIC_API_KEY.
// (Recipes fold the same floor in via the "commands" action.)
func CommandFloor(name string, aiEnabled bool) func(*ThreadCtx, Incoming) (Reply, bool) {
	strip := mentionStripper(name)
	return func(_ *ThreadCtx, in Incoming) (Reply, bool) {
		if !in.Triggered {
			return Reply{}, false
		}
		if rep, ok := RunCommand(strip(in.Text), aiEnabled); ok {
			return rep, true
		}
		return Reply{Text: degradeText}, true
	}
}