package html_builder

import "core:fmt"
import "core:slice"
import "core:strings"

Element :: struct {
	tag_name:   string,
	id:         string,
	children:   [dynamic]Node,
	attributes: map[string]string,
	class_list: [dynamic]string,
}

Node :: union {
	Element,
	string,
}

empty_tags: map[string]bool = {
	"img" = true,
	"br"  = true,
	"hr"  = true,
}

indent :: proc(sb: ^strings.Builder, depth: int) {
	for i in 0 ..< depth {
		fmt.sbprintf(sb, "\t")
	}
}

element_to_string :: proc(sb: ^strings.Builder, e: Element, depth: int = 0) -> string {
	indent(sb, depth)

	fmt.sbprintf(sb, "<%s", e.tag_name)

	for name, attr in e.attributes {
		fmt.sbprintf(sb, " %s=\"%s\"", name, attr)
	}

	fmt.sbprintf(sb, ">")

	children_len := len(e.children)

	if children_len == 1 {
		switch ch in e.children[0] {
		case string:
			fmt.sbprintf(sb, "%s", ch)
		case Element:
			fmt.sbprintf(sb, "\n")
			element_to_string(sb, ch, depth + 1)
			fmt.sbprintf(sb, "\n")
			indent(sb, depth)
		}
	}
	if children_len > 1 {
		for child, idx in e.children {
			fmt.sbprintf(sb, "\n")
			switch ch in child {
			case string:
				indent(sb, depth + 1)
				fmt.sbprintf(sb, "%s", ch)
			case Element:
				element_to_string(sb, ch, depth + 1)
			}
		}
		fmt.sbprintf(sb, "\n")
		indent(sb, depth)
	}
	if !empty_tags[e.tag_name] do fmt.sbprintf(sb, "</%s>", e.tag_name)

	return strings.to_string(sb^)
}

parent_element: ^Element
elements_by_id: map[string]^Element
elements_by_classes: map[string][dynamic]^Element

_element_scope_start :: proc(tag_name: string, id: string = "") -> (previous_parent: ^Element) {

	children := &parent_element.children
	new_idx := len(children^)
	new_element := Element {
		tag_name = tag_name,
		children = make([dynamic]Node),
	}
	append(children, new_element)

	previous_parent = parent_element
	parent_element = &children[new_idx].(Element)


	return previous_parent
}

_element_scope_end :: proc(previous_parent: ^Element) {
	parent_element = previous_parent
}

// @(deferred_out = free_html)
html :: proc() -> ^Element {
	parent_element = new(Element)
	parent_element.tag_name = "html"
	parent_element.children = make([dynamic]Node)

	return parent_element
}

text :: proc(txt: string) {
	append(&parent_element.children, txt)
}

attr :: proc(name: string, value: string) {
	if name == "class" {
		class(value)
		return
	}
	map_insert(&parent_element.attributes, name, value)
}
id :: proc(id: string) {
	if id != "" {
		parent_element.id = id
		parent_element.attributes["id"] = id
		elements_by_id[id] = parent_element
	}
}

class :: proc(class_names: string) {
	classes: [dynamic]string
	for class in strings.split(class_names, " ") {
		_, found := slice.linear_search(parent_element.class_list[:], class)

		if elements_by_classes[class] == nil do elements_by_classes[class] = make([dynamic]^Element)
		if !found {
			append(&classes, class)
			append(&elements_by_classes[class], parent_element)
		}
	}
	append(&parent_element.class_list, ..classes[:])
	map_insert(
		&parent_element.attributes,
		"class",
		strings.join(parent_element.class_list[:], " "),
	)
}

free_html :: proc(el: ^Element) {
	defer parent_element = nil
	handle_children :: proc(children: [dynamic]Node) {
		for e in children {
			_e, ok := e.(Element)
			if ok do handle_children(_e.children)
		}
		delete(children)
	}

	handle_children(el.children)
	free(el)
}

@(deferred_out = _element_scope_end)
body :: proc(id: string = "") -> (previous_parent: ^Element) {
	return _element_scope_start("body", id)
}

@(deferred_out = _element_scope_end)
head :: proc(id: string = "") -> (previous_parent: ^Element) {
	return _element_scope_start("head", id)
}

@(deferred_out = _element_scope_end)
title :: proc(txt: string = "") -> (previous_parent: ^Element) {
	el := _element_scope_start("title")
	text(txt)
	return el
}

@(deferred_out = _element_scope_end)
h1 :: proc(txt: string = "") -> (previous_parent: ^Element) {
	el := _element_scope_start("h1")
	text(txt)
	return el
}
@(deferred_out = _element_scope_end)
h2 :: proc(txt: string = "") -> (previous_parent: ^Element) {
	el := _element_scope_start("h2")
	text(txt)
	return el
}
@(deferred_out = _element_scope_end)
h3 :: proc(txt: string = "") -> (previous_parent: ^Element) {
	el := _element_scope_start("h3")
	text(txt)
	return el
}
@(deferred_out = _element_scope_end)
h4 :: proc(txt: string = "") -> (previous_parent: ^Element) {
	el := _element_scope_start("h4")
	text(txt)
	return el
}
@(deferred_out = _element_scope_end)
h5 :: proc(txt: string = "") -> (previous_parent: ^Element) {
	el := _element_scope_start("h5")
	text(txt)
	return el
}
@(deferred_out = _element_scope_end)
h6 :: proc(txt: string = "") -> (previous_parent: ^Element) {
	el := _element_scope_start("h6")
	text(txt)
	return el
}

@(deferred_out = _element_scope_end)
div :: proc(id: string = "") -> (previous_parent: ^Element) {
	previous_parent = _element_scope_start("div", id)
	return previous_parent
}

@(deferred_out = _element_scope_end)
img :: proc(src: string = "", alt: string = "") -> (previous_parent: ^Element) {
	previous_parent = _element_scope_start("img")
	parent_element.children = nil
	parent_element.attributes["src"] = src
	if alt != "" do parent_element.attributes["alt"] = alt
	return previous_parent
}

@(deferred_out = _element_scope_end)
a :: proc(txt: string, href: string = "") -> (previous_parent: ^Element) {
	previous_parent = _element_scope_start("a")
	append(&parent_element.children, txt)
	parent_element.attributes["href"] = href
	return previous_parent
}