"use strict";

const fs = require("fs");
const path = require("path");
const send = require("koa-send");

function home(config, responder, posts) {
  const postsArray = Array.from(posts.values());
  return async function(ctx, next) {
    responder(ctx, config, { posts: postsArray });
  };
}

function posts(config, responder, posts) {
  const postsArray = Array.from(posts.values());
  return async function(ctx, next) {
    responder(ctx, config, {
      listType: null,
      listName: "Posts",
      posts: postsArray
    });
  };
}

function highlightTheme(config) {
  const theme = config.posts.code.theme;
  const themeFile = path.resolve(
    __dirname,
    `../node_modules/highlight.js/styles/${theme}.css`
  );

  if (!fs.existsSync(themeFile)) {
    throw new Error(`Couldn't find highlight theme ${theme}`);
  }

  const css = fs.readFileSync(themeFile, "utf-8");

  return async function(ctx, next) {
    ctx.type = "css";
    ctx.body = css;
  };
}

function post(config, responder, posts) {
  return async function(ctx, next) {
    ctx.assert(posts.has(ctx.params.filename), 404, "Post not found");
    const post = posts.get(ctx.params.filename);

    responder(ctx, config, { post });
  };
}

function taxonGenerator(config, responder, term, items) {
  return async function(ctx, next) {
    const value = ctx.params.value;
    ctx.assert(items.has(ctx.params.value), 404, `${term} ${value} not found`);

    const taxonItems = items.get(value);

    responder(ctx, config, {
      listType: term,
      listName: value,
      posts: taxonItems
    });
  };
}

const prefix = /^\/static\//;
async function serveFiles(ctx) {
  if (prefix.test(ctx.path)) {
    await send(ctx, ctx.path.replace(prefix, ""), {
      root: "./static"
    });
  }
}

module.exports = {
  home,
  posts,
  highlightTheme,
  post,
  taxonGenerator,
  serveFiles
};