(ns markdown.core

(:use [markdown.transformers

:only [*next-line* *substring* transformer-vector]])

(:require [clojure.java.io :as io])

(:import [java.io StringReader StringWriter]))

(defn- write [^java.io.Writer writer ^String text]

(doseq [c text] (.write writer (int c))))

(defn- init-transformer [writer {:keys [replacement-transformers custom-transformers]}]

(fn [line next-line state]

(binding [*next-line* next-line]

(let [[text new-state]

(reduce

(fn [[text, state] transformer]

(transformer text state))

[line state]

(or replacement-transformers

(into transformer-vector custom-transformers)))]

(write writer text)

new-state))))

(defn md-to-html

"reads markdown content from the input stream and writes HTML to the provided output stream"

[in out & params]

(binding [markdown.transformers/*substring* (fn [^String s n] (.substring s n))]

(with-open [^java.io.BufferedReader rdr (io/reader in)

^java.io.BufferedWriter wrt (io/writer out)]

(let [transformer (init-transformer wrt params)]

(loop [^String line (.readLine rdr)

next-line (.readLine rdr)

state (apply (partial assoc {} :last-line-empty? true) params)]

(let [state (if (:buf state)

(transformer (:buf state) next-line (-> state (dissoc :buf :lists) (assoc :last-line-empty? true)))

state)]

(if line

(recur next-line

(.readLine rdr)

(assoc (transformer line next-line state)

:last-line-empty? (empty? (.trim line))))

(transformer "" nil (assoc state :eof true))))))

(.flush wrt))))

(defn md-to-html-string

"converts a markdown formatted string to an HTML formatted string"

[text & params]

(when text

(let [input (new StringReader text)

output (new StringWriter)]

(apply (partial md-to-html input output) params)

(.toString output))))