'use strict'

const h = require('highland')
const fs = require('fs')
const rheo = require('rheo')
const indent = require('indent-string')

const toLines = string =>
  string.split('\n').map((s, i, arr) => (i === arr.length - 1 ? s : s + '\n'))

const getTemplate = name =>
  fs.readFileSync(`${__dirname}/templates/${name}.html`, 'utf8')

const findMain = /^(\s+)<main/m
const baseIndentLevel = findMain.exec(getTemplate('layout'))[1].length
const postIndentLevel =
  baseIndentLevel + findMain.exec(getTemplate('post'))[1].length

function indentForTemplate (text, indentLevel) {
  return indent(text, indentLevel).slice(indentLevel).replace(/\n+$/, '')
}

function templateReader (template, indentLevel) {
  const content = toLines(indentForTemplate(getTemplate(template), indentLevel))
  console.log(template, content)
  return () => h(content)
}

const templates = {
  layout: templateReader('layout'),
  home: templateReader('home', baseIndentLevel),
  post: templateReader('post', baseIndentLevel),
  taxon: templateReader('taxon', baseIndentLevel)
}

function setTitle (siteTitle, pageTitle) {
  return rheo.template(function (s) {
    return s
      .inner('title', rheo((pageTitle ? ' &middot; ' : '') + siteTitle))
      .inner('body header h1', rheo(siteTitle))
  })
}

function renderPostListItem (ctx) {
  return function (template, [, post]) {
    return template
      .attribute('a', 'href', () => ctx.getURL('post', post.basename))
      .inner('a', () => rheo(post.data.get('title')))
  }
}

function showPage (name) {
  return function (els) {
    return rheo(templates[name]())
  }
}

module.exports = {
  baseIndentLevel,
  postIndentLevel,
  indentForTemplate,

  home (ctx, config, postsStream) {
    ctx.type = 'html'
    ctx.body = templates
      .layout()
      .pipe(rheo())
      .outer('main', showPage('home'))
      .inner('.posts', function (postsTemplate) {
        return postsStream.pipe(postsTemplate.map(renderPostListItem(ctx)))
      })
      .pipe(setTitle(config.site.title))
      .render()
  },

  post (ctx, config, post) {
    ctx.type = 'html'
    ctx.body = templates
      .layout()
      .pipe(rheo())
      .outer('main', showPage('post'))
      .inner('article h1', rheo(post.data.get('title')))
      .outer('article main', rheo(post.body))
      .pipe(setTitle(config.site.title, post.data.get('title')))
      .render()
  },

  taxon (ctx, config, taxonItems) {
    ctx.type = 'html'
    ctx.body = templates
      .layout()
      .pipe(rheo())
      .outer('main', showPage('taxon'))
      .inner('h1', rheo(config.site.title))
      .inner('.posts', function (postsTemplate) {
        return taxonItems.pipe(postsTemplate.map(renderPostListItem(ctx)))
      })
      .pipe(setTitle(config.site.title))
      .render()
  }
}