// FILE: ./internal/sources/common/config.go
package common

import (
	"fmt"
	"strings"

	"gitea.maximumdirect.net/ejr/feedkit/config"
)

// This file centralizes small, boring config-validation patterns shared across
// weatherfeeder source drivers.
//
// Goal: keep driver constructors (New*Source) easy to read and consistent, while
// keeping driver-specific options in cfg.Params (feedkit remains domain-agnostic).

// HTTPSourceConfig is the standard "HTTP-polling source" config shape used across drivers.
type HTTPSourceConfig struct {
	Name      string
	URL       string
	UserAgent string
}

// RequireHTTPSourceConfig enforces weatherfeeder's standard HTTP source config:
//
//   - cfg.Name must be present
//   - cfg.Params must be present
//   - params.url must be present (accepts "url" or "URL")
//   - params.user_agent must be present (accepts "user_agent" or "userAgent")
//
// We intentionally require a User-Agent for *all* sources, even when upstreams
// do not strictly require one. This keeps config uniform across providers.
func RequireHTTPSourceConfig(driver string, cfg config.SourceConfig) (HTTPSourceConfig, error) {
	if strings.TrimSpace(cfg.Name) == "" {
		return HTTPSourceConfig{}, fmt.Errorf("%s: name is required", driver)
	}
	if cfg.Params == nil {
		return HTTPSourceConfig{}, fmt.Errorf("%s %q: params are required (need params.url and params.user_agent)", driver, cfg.Name)
	}

	url, ok := cfg.ParamString("url", "URL")
	if !ok {
		return HTTPSourceConfig{}, fmt.Errorf("%s %q: params.url is required", driver, cfg.Name)
	}

	ua, ok := cfg.ParamString("user_agent", "userAgent")
	if !ok {
		return HTTPSourceConfig{}, fmt.Errorf("%s %q: params.user_agent is required", driver, cfg.Name)
	}

	return HTTPSourceConfig{
		Name:      cfg.Name,
		URL:       url,
		UserAgent: ua,
	}, nil
}

// --- The helpers below remain useful for future drivers; they are not required
// --- by the observation sources after adopting RequireHTTPSourceConfig.

// RequireName ensures cfg.Name is present and non-whitespace.
func RequireName(driver string, cfg config.SourceConfig) error {
	if strings.TrimSpace(cfg.Name) == "" {
		return fmt.Errorf("%s: name is required", driver)
	}
	return nil
}

// RequireParams ensures cfg.Params is non-nil. The "want" string should be a short
// description of required keys, e.g. "need params.url and params.user_agent".
func RequireParams(driver string, cfg config.SourceConfig, want string) error {
	if cfg.Params == nil {
		return fmt.Errorf("%s %q: params are required (%s)", driver, cfg.Name, want)
	}
	return nil
}

// RequireURL returns the configured URL for a source.
// Canonical key is "url"; we also accept "URL" as a convenience.
func RequireURL(driver string, cfg config.SourceConfig) (string, error) {
	if cfg.Params == nil {
		return "", fmt.Errorf("%s %q: params are required (need params.url)", driver, cfg.Name)
	}

	u, ok := cfg.ParamString("url", "URL")
	if !ok {
		return "", fmt.Errorf("%s %q: params.url is required", driver, cfg.Name)
	}
	return u, nil
}

// RequireUserAgent returns the configured User-Agent for a source.
// Canonical key is "user_agent"; we also accept "userAgent" as a convenience.
func RequireUserAgent(driver string, cfg config.SourceConfig) (string, error) {
	if cfg.Params == nil {
		return "", fmt.Errorf("%s %q: params are required (need params.user_agent)", driver, cfg.Name)
	}

	ua, ok := cfg.ParamString("user_agent", "userAgent")
	if !ok {
		return "", fmt.Errorf("%s %q: params.user_agent is required", driver, cfg.Name)
	}
	return ua, nil
}