package main

import (
	"fmt"
	"os"
	"strings"
	"time"

	"gopkg.in/yaml.v3"
)

type Config struct {
	Bots map[string]BotConfig `yaml:"bots"`
}

type BotConfig struct {
	Handler string `yaml:"handler"`
	// RequireAuth is *bool so "absent" is distinct from "false". When unset
	// (nil) the registry treats it as true — secure by default. Explicit
	// `requireAuth: false` is required to expose a bot publicly.
	// Forced to false for handler=auth (chicken-and-egg).
	RequireAuth *bool `yaml:"requireAuth,omitempty"`
	// HTTP is the per-bot config for the `http` handler. Required when
	// handler=http. See handler_http.go.
	HTTP *HTTPConfig `yaml:"http,omitempty"`

	Token  string `yaml:"-"`
	Secret string `yaml:"-"`
}

// HTTPConfig drives the `http` handler : the gateway POSTs the Telegram
// Update JSON to URL, awaits a JSON `{text}` response within Timeout,
// then sends Text back to the user via sendMessage.
type HTTPConfig struct {
	URL     string        `yaml:"url"`
	Timeout time.Duration `yaml:"timeout,omitempty"`
}

// LoadConfig reads the YAML routing config and merges per-bot secrets pulled
// from the process environment. Per-bot env keys are derived from the bot
// slug uppercased: BOT_<UPPER_SLUG>_TOKEN, BOT_<UPPER_SLUG>_SECRET.
func LoadConfig(path string) (*Config, error) {
	raw, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read config %s: %w", path, err)
	}
	var cfg Config
	if err := yaml.Unmarshal(raw, &cfg); err != nil {
		return nil, fmt.Errorf("parse yaml: %w", err)
	}
	if len(cfg.Bots) == 0 {
		return nil, fmt.Errorf("no bots in %s", path)
	}
	for slug, b := range cfg.Bots {
		envSlug := strings.ToUpper(strings.ReplaceAll(slug, "-", "_"))
		b.Token = os.Getenv("BOT_" + envSlug + "_TOKEN")
		b.Secret = os.Getenv("BOT_" + envSlug + "_SECRET")
		cfg.Bots[slug] = b
	}
	return &cfg, nil
}