import {inputRules, wrappingInputRule, textblockTypeInputRule,
        smartQuotes, emDash, ellipsis} from "prosemirror-inputrules"
import {NodeType, Schema} from "prosemirror-model"

/// Given a blockquote node type, returns an input rule that turns `"> "`
/// at the start of a textblock into a blockquote.
export function blockQuoteRule(nodeType: NodeType) {
  return wrappingInputRule(/^\s*>\s$/, nodeType)
}

/// Given a list node type, returns an input rule that turns a number
/// followed by a dot at the start of a textblock into an ordered list.
export function orderedListRule(nodeType: NodeType) {
  return wrappingInputRule(/^(\d+)\.\s$/, nodeType, match => ({order: +match[1]}),
                           (match, node) => node.childCount + node.attrs.order == +match[1])
}

/// Given a list node type, returns an input rule that turns a bullet
/// (dash, plush, or asterisk) at the start of a textblock into a
/// bullet list.
export function bulletListRule(nodeType: NodeType) {
  return wrappingInputRule(/^\s*([-+*])\s$/, nodeType)
}

/// Given a code block node type, returns an input rule that turns a
/// textblock starting with three backticks into a code block.
export function codeBlockRule(nodeType: NodeType) {
  return textblockTypeInputRule(/^```$/, nodeType)
}

/// Given a node type and a maximum level, creates an input rule that
/// turns up to that number of `#` characters followed by a space at
/// the start of a textblock into a heading whose level corresponds to
/// the number of `#` signs.
export function headingRule(nodeType: NodeType, maxLevel: number) {
  return textblockTypeInputRule(new RegExp("^(#{1," + maxLevel + "})\\s$"),
                                nodeType, match => ({level: match[1].length}))
}

/// A set of input rules for creating the basic block quotes, lists,
/// code blocks, and heading.
export function buildInputRules(schema: Schema) {
  let rules = smartQuotes.concat(ellipsis, emDash), type
  if (type = schema.nodes.blockquote) rules.push(blockQuoteRule(type))
  if (type = schema.nodes.ordered_list) rules.push(orderedListRule(type))
  if (type = schema.nodes.bullet_list) rules.push(bulletListRule(type))
  if (type = schema.nodes.code_block) rules.push(codeBlockRule(type))
  if (type = schema.nodes.heading) rules.push(headingRule(type, 6))
  return inputRules({rules})
}