package authboss

import "net/http"

// ViewDataMaker asks for an HTMLData object to assist with rendering.
type ViewDataMaker func(http.ResponseWriter, *http.Request) HTMLData

// HTMLData is used to render templates with.
type HTMLData map[string]interface{}

// NewHTMLData creates HTMLData from key-value pairs. The input is a key-value
// slice, where odd elements are keys, and the following even element is their value.
func NewHTMLData(data ...interface{}) HTMLData {
	if len(data)%2 != 0 {
		panic("It should be a key value list of arguments.")
	}

	h := make(HTMLData)

	for i := 0; i < len(data)-1; i += 2 {
		k, ok := data[i].(string)
		if !ok {
			panic("Keys must be strings.")
		}

		h[k] = data[i+1]
	}

	return h
}

// Merge adds the data from other to h. If there are conflicting keys
// they are overwritten by other's values.
func (h HTMLData) Merge(other HTMLData) HTMLData {
	for k, v := range other {
		h[k] = v
	}
	return h
}

// MergeKV adds extra key-values to the HTMLData. The input is a key-value
// slice, where odd elements are keys, and the following even element is their value.
func (h HTMLData) MergeKV(data ...interface{}) HTMLData {
	if len(data)%2 != 0 {
		panic("It should be a key value list of arguments.")
	}

	for i := 0; i < len(data)-1; i += 2 {
		k, ok := data[i].(string)
		if !ok {
			panic("Keys must be strings.")
		}

		h[k] = data[i+1]
	}

	return h
}