package main

import (
	"io"
	"io/ioutil"
	"net/http"
	"strconv"
	"strings"
)

type Leaf struct {
	Meta    Meta
	Content string
}

type Meta struct {
	Title    string
	ReadOnly bool
	Deleted  bool
}

func NewHTTPRequestLeaf(r *http.Request) (Leaf, error) {
	var leaf Leaf
	if b, err := ioutil.ReadAll(r.Body); err != nil {
		return leaf, err
	} else {
		leaf.Content = string(b)
	}
	if leaf.Meta.Title = r.Header.Get("Title"); leaf.Meta.Title == "" {
		leaf.Meta.Title = "Untitled"
	}
	if readOnly := r.Header.Get("Read-Only"); readOnly == "true" {
		leaf.Meta.ReadOnly = true
	} else if readOnly == "false" {
		leaf.Meta.ReadOnly = false
	}
	leaf.Meta.Deleted = r.Method == http.MethodDelete
	return leaf, nil
}

func NewLeaf(title string, content string) (Leaf, error) {
	return NewHTTPRequestLeaf(&http.Request{
		Header: http.Header{
			"Title": []string{title},
		},
		Body: io.NopCloser(strings.NewReader(content)),
	})
}

func (leaf Leaf) WriteHTTP(w http.ResponseWriter) error {
	w.Header().Set("Title", leaf.Meta.Title)
	w.Header().Set("Read-Only", strconv.FormatBool(leaf.Meta.ReadOnly))
	_, err := w.Write([]byte(leaf.Content))
	return err
}

func (base Leaf) Merge(updated Leaf) Leaf {
	if updated.Meta.Title != "" {
		base.Meta.Title = updated.Meta.Title
	}
	if base.Meta.Title == "" {
		base.Meta.Title = "Untitled"
	}
	base.Meta.Deleted = updated.Meta.Deleted
	base.Meta.ReadOnly = updated.Meta.ReadOnly
	base.Content = updated.Content
	return base
}