module xml

import strings

fn write_indent(mut builder strings.Builder, indent string, depth int) {
    for _ in 0 .. depth {
        builder.write_string(indent)
    }
}

fn write_pretty_xml_node(mut builder strings.Builder, node XMLNode, original_indent string, depth int, reverse_entities map[string]string) {
    write_indent(mut builder, original_indent, depth)
    builder.write_u8(`<`)
    builder.write_string(node.name)

    for key, value in node.attributes {
        builder.write_u8(` `)
        builder.write_string(key)
        builder.write_string('="')
        builder.write_string(value)
        builder.write_u8(`"`)
    }
    if node.children.len > 0 {
        builder.write_string('>\n')
        for child in node.children {
            match child {
                string {
                    write_indent(mut builder, original_indent, depth + 1)
                    builder.write_string(escape_text(child, reverse_entities: reverse_entities))
                }
                XMLNode {
                    write_pretty_xml_node(mut builder, child, original_indent, depth + 1,
                        reverse_entities)
                }
                XMLComment {
                    write_indent(mut builder, original_indent, depth + 1)
                    builder.write_string('<!--')
                    builder.write_string(child.text)
                    builder.write_string('-->')
                }
                XMLCData {
                    write_indent(mut builder, original_indent, depth + 1)
                    builder.write_string('<![CDATA[')
                    builder.write_string(child.text)
                    builder.write_string(']]>')
                }
            }

            builder.write_u8(`\n`)
        }
        write_indent(mut builder, original_indent, depth)
        builder.write_string('</')
        builder.write_string(node.name)
        builder.write_u8(`>`)
    } else {
        builder.write_string('/>')
    }
}

fn write_pretty_dtd_list(mut builder strings.Builder, list []DTDListItem, indent string) bool {
    if list.len == 0 {
        return false
    }

    builder.write_u8(`[`)
    builder.write_u8(`\n`)

    for item in list {
        match item {
            DTDEntity {
                builder.write_string(indent)
                builder.write_string('<!ENTITY ')
                builder.write_string(item.name)
                builder.write_string(' "')
                builder.write_string(item.value)
                builder.write_string('">')
            }
            DTDElement {
                builder.write_string(indent)
                builder.write_string('<!ELEMENT ')
                builder.write_string(item.name)
                builder.write_string(' [')
                builder.write_string(item.definition.join(', '))
                builder.write_string(']>')
            }
        }

        builder.write_u8(`\n`)
    }
    builder.write_u8(`]`)
    return true
}

fn write_pretty_doctype(mut builder strings.Builder, doctype DocumentType, indent string) bool {
    match doctype.dtd {
        string {
            content := doctype.dtd
            if content.len == 0 {
                return false
            }
            builder.write_string('<!DOCTYPE ')
            builder.write_string(doctype.name)
            builder.write_string(' SYSTEM ')
            builder.write_string(content)
            builder.write_string('>\n')
            return true
        }
        DocumentTypeDefinition {
            if doctype.dtd.list.len == 0 {
                return false
            }

            builder.write_string('<!DOCTYPE ')
            builder.write_string(doctype.name)
            builder.write_string(' ')
            write_pretty_dtd_list(mut builder, doctype.dtd.list, indent)
            builder.write_string('>\n')
            return true
        }
    }
}

// pretty_str returns a pretty-printed version of the XML node. It requires the current indentation
// the node is at, the depth of the node in the tree, and a map of reverse entities to use when
// escaping text.
pub fn (node XMLNode) pretty_str(original_indent string, depth int, reverse_entities map[string]string) string {
    mut builder := strings.new_builder(1024)
    write_pretty_xml_node(mut builder, node, original_indent, depth, reverse_entities)
    return builder.str()
}

fn (list []DTDListItem) pretty_str(indent string) string {
    mut builder := strings.new_builder(1024)
    if !write_pretty_dtd_list(mut builder, list, indent) {
        return ''
    }
    return builder.str()
}

fn (doctype DocumentType) pretty_str(indent string) string {
    mut builder := strings.new_builder(1024)
    if !write_pretty_doctype(mut builder, doctype, indent) {
        return ''
    }
    return builder.str()
}

// pretty_str returns a pretty-printed version of the XML document. It requires the string used to
// indent each level of the document.
pub fn (doc XMLDocument) pretty_str(indent string) string {
    mut document_builder := strings.new_builder(1024)

    document_builder.write_string('<?xml version="')
    document_builder.write_string(doc.version)
    document_builder.write_string('" encoding="')
    document_builder.write_string(doc.encoding)
    document_builder.write_string('"?>\n')

    if write_pretty_doctype(mut document_builder, doc.doctype, indent) {
        document_builder.write_u8(`\n`)
    }
    for comment in doc.comments {
        document_builder.write_string('<!--')
        document_builder.write_string(comment.text)
        document_builder.write_string('-->')
        document_builder.write_u8(`\n`)
    }
    write_pretty_xml_node(mut document_builder, doc.root, indent, 0, doc.parsed_reverse_entities)

    return document_builder.str()
}

// str returns a string representation of the XML document. It uses a 2-space indentation
// to pretty-print the document.
pub fn (doc XMLDocument) str() string {
    return doc.pretty_str('  ')
}