var h = require('hyperscript')
var pull = require('pull-stream')
var paramap = require('pull-paramap')
var cat = require('pull-cat')
var human = require('human-time')
var combobox = require('hypercombo')
var KVGraph = require('kvgraph')
var mergeRepo = require('ssb-git/merge')
var self_id = require('../keys').id
var messageLink = require('./helpers').message_link
var markdown = require('./helpers').markdown
var links = require('./scuttlebot').links
var get = require('./scuttlebot').get
var avatar = require('./avatar')


exports.needs = {
  message_confirm: 'first',
  message_compose: 'first'
}

exports.gives = {
  message_action: true,
  message_meta: true,
  message_content: true
}


function shortRefName(ref) {
  return ref.replace(/^refs\/(heads|tags)\//, '')
}

exports.create = function (api) {
  function getRefs(msg) {
    var updates = new KVGraph('key')
    var _cb, _refs
    pull(
      links({
        reverse: true,
        // source: msg.value.author,
        dest: msg.key,
        rel: 'repo',
        values: true
      }),
      pull.drain(function (link) {
        if (link.value.content.type === 'git-update') {
          updates.add(link)
        }
      }, function (err) {
        var refs = updates.reduceRight(mergeRepo).refs
        var cb = _cb
        if (cb) _cb = null, cb(err, refs)
        else _refs = refs
      })
    )

    return pull(
      function fn(end, cb) {
        if (end || fn.ended) cb(true)
        fn.ended = true
        if (_refs) cb(_refs)
        else _cb = cb
      },
      pull.flatten()
    )
  }

  function getForks(id) {
    return pull(
      links({
        reverse: true,
        dest: id,
        rel: 'upstream'
      }),
      pull.map(function (link) {
        return {
          id: link.key,
          author: link.source
        }
      })
    )
  }

  function repoLink(id) {
    return h('a', {href: '#'+id}, messageLink(id))
  }

  function repoName(id) {
    return h('ins', messageLink(id))
  }

  function getIssueState(id, cb) {
    pull(
      links({dest: id, rel: 'issues', values: true, reverse: true}),
      pull.map(function (msg) {
        return msg.value.content.issues
      }),
      pull.flatten(),
      pull.filter(function (issue) {
        return issue.link === id
      }),
      pull.map(function (issue) {
        return issue.merged ? 'merged' : issue.open ? 'open' : 'closed'
      }),
      pull.take(1),
      pull.collect(function (err, updates) {
        cb(err, updates && updates[0] || 'open')
      })
    )
  }

  //todo: 
  function messageTimestampLink(msg) {
    var date = new Date(msg.value.timestamp)
    return h('a.timestamp', {
      timestamp: msg.value.timestamp,
      title: date,
      href: '#'+msg.key
    }, human(date))
  }

  // a thead+tbody where the thead only is added when the first row is added
  function tableRows(headerRow) {
    var thead = h('thead'), tbody = h('tbody')
    var first = true
    var t = [thead, tbody]
    t.append = function (row) {
      if (first) {
        first = false
        thead.appendChild(headerRow)
      }
      tbody.appendChild(row)
    }
    return t
  }

  function renderIssueEdit(c) {
    var id = c.issue || c.link
    return [
      c.title ? h('p', 'renamed issue ', messageLink(id),
        ' to ', h('ins', c.title)) : null,
      c.open === false ? h('p', 'closed issue ', messageLink(id)) : null,
      c.open === true ? h('p', 'reopened issue ', messageLink(id)) : null]
  }

  function findMessageContent(el) {
    for(; el; el = el.parentNode) {
      if(el.classList.contains('message')) {
        return el.querySelector('.message_content')
      }
    }
  }

  function issueForm(msg, contentEl) {
    var form = h('form',
      h('strong', 'New Issue:'),
      api.message_compose(
        {type: 'issue', project: msg.key},
        function (value) { return value },
        function (err, issue) {
          if(err) return alert(err)
          if(!issue) return
          var title = issue.value.content.text
          if(title.length > 70) title = title.substr(0, 70) + '…'
          form.appendChild(h('div',
            h('a', {href: '#'+issue.key}, title)
          ))
        }
      )
    )
    return form
  }

  function branchMenu(msg, full) {
    return combobox({
      style: {'max-width': '14ex'},
      placeholder: 'branch…',
      default: 'master',
      read: msg && pull(getRefs(msg), pull.map(function (ref) {
        var m = /^refs\/heads\/(.*)$/.exec(ref.name)
        if(!m) return
        var branch = m[1]
        var label = branch
        if(full) {
          var updated = new Date(ref.link.value.timestamp)
          label = branch +
            ' · ' + human(updated) +
            ' · ' + ref.hash.substr(1, 8) +
            (ref.title ? ' · "' + ref.title + '"' : '')
        }
        return h('option', {value: branch}, label)
      }))
    })
  }

  function newPullRequestButton(msg) {
    return h('div', [
      h('a', {
        href: '#',
        onclick: function (e) {
          e.preventDefault()
          this.parentNode.replaceChild(pullRequestForm(msg), this)
        }},
        'New Pull Request…'
      )
    ])
  }

  function pullRequestForm(msg) {
    var headRepoInput
    var headBranchInput = branchMenu()
    var branchInput = branchMenu(msg)
    var form = h('form',
      h('strong', 'New Pull Request:'),
      h('div',
        'from ',
        headRepoInput = combobox({
          style: {'max-width': '26ex'},
          onchange: function () {
            // list branches for selected repo
            var repoId = this.value
            if(repoId) get(repoId, function (err, value) {
              if(err) console.error(err)
              var msg = value && {key: repoId, value: value}
              headBranchInput = headBranchInput.swap(branchMenu(msg, true))
            })
            else headBranchInput = headBranchInput.swap(branchMenu())
          },
          read: pull(cat([
            pull.once({id: msg.key, author: msg.value.author}),
            getForks(msg.key)
          ]), pull.map(function (fork) {
            return h('option', {value: fork.id},
              repoLink(fork.id), ' by ', avatar.name(fork.author))
          }))
        }),
        ':',
        headBranchInput,
        ' to ',
        repoName(msg.key),
        ':',
        branchInput),
      api.message_compose(
        {
          type: 'pull-request',
          project: msg.key,
          repo: msg.key,
        },
        function (value) {
          value.branch = branchInput.value
          value.head_repo = headRepoInput.value
          value.head_branch = headBranchInput.value
          return value
        },
        function (err, issue) {
          if(err) return alert(err)
          if(!issue) return
          var title = issue.value.content.text
          if(title.length > 70) title = title.substr(0, 70) + '…'
          form.appendChild(h('div',
            h('a', {href: '#'+issue.key}, title)
          ))
        }
      )
    )
    return form
  }

  return {
    message_content: function (msg, sbot) {
      var c = msg.value.content

      if(c.type === 'git-repo') {
        var branchesT, tagsT, openIssuesT, closedIssuesT, openPRsT, closedPRsT
        var forksT
        var div = h('div',
          h('p', 'git repo ', repoName(msg.key)),
          c.upstream ? h('p', 'fork of ', repoLink(c.upstream)) : '',
          h('p', h('code', 'ssb://' + msg.key)),
          h('div.git-table-wrapper', {style: {'max-height': '12em'}},
            h('table',
              branchesT = tableRows(h('tr',
                h('th', 'branch'),
                h('th', 'commit'),
                h('th', 'last update'))),
              tagsT = tableRows(h('tr',
                h('th', 'tag'),
                h('th', 'commit'),
                h('th', 'last update'))))),
          h('div.git-table-wrapper', {style: {'max-height': '16em'}},
            h('table',
              openIssuesT = tableRows(h('tr',
                h('th', 'open issues'))),
              closedIssuesT = tableRows(h('tr',
                h('th', 'closed issues'))))),
          h('div.git-table-wrapper', {style: {'max-height': '16em'}},
            h('table',
              openPRsT = tableRows(h('tr',
                h('th', 'open pull requests'))),
              closedPRsT = tableRows(h('tr',
                h('th', 'closed pull requests'))))),
          h('div.git-table-wrapper',
            h('table',
              forksT = tableRows(h('tr',
                h('th', 'forks'))))),
          h('div', h('a', {href: '#', onclick: function (e) {
            e.preventDefault()
            this.parentNode.replaceChild(issueForm(msg), this)
          }}, 'New Issue…')),
          newPullRequestButton.call(this, msg)
        )

        pull(getRefs(msg), pull.drain(function (ref) {
          var name = ref.realname || ref.name
          var author = ref.link && ref.link.value.author
          var parts = /^refs\/(heads|tags)\/(.*)$/.exec(name) || []
          var shortName = parts[2]
          var t
          if(parts[1] === 'heads') t = branchesT
          else if(parts[1] === 'tags') t = tagsT
          if(t) t.append(h('tr',
            h('td', shortName,
              ref.conflict ? [
                h('br'),
                h('a', {href: '#'+author}, avatar.name(author))
              ] : ''),
            h('td', h('code', ref.hash)),
            h('td', messageTimestampLink(ref.link))))
        }, function (err) {
          if(err) console.error(err)
        }))

        // list issues and pull requests
        pull(
          links({
            reverse: true,
            dest: msg.key,
            rel: 'project',
            values: true
          }),
          paramap(function (link, cb) {
            getIssueState(link.key, function (err, state) {
              if(err) return cb(err)
              link.state = state
              cb(null, link)
            })
          }),
          pull.drain(function (link) {
            var c = link.value.content
            var title = c.title || (c.text ? c.text.length > 70
              ? c.text.substr(0, 70) + '…'
              : c.text : link.key)
            var author = link.value.author
            var t = c.type === 'pull-request'
              ? link.state === 'open' ? openPRsT : closedPRsT
              : link.state === 'open' ? openIssuesT : closedIssuesT
            t.append(h('tr',
              h('td',
                h('a', {href: '#'+link.key}, title), h('br'),
                h('small',
                  'opened ', messageTimestampLink(link),
                  ' by ', h('a', {href: '#'+author}, avatar.name(author))))))
          }, function (err) {
            if (err) console.error(err)
          })
        )

        // list forks
        pull(
          getForks(msg.key),
          pull.drain(function (fork) {
            forksT.append(h('tr', h('td',
              repoLink(fork.id),
              ' by ', h('a', {href: '#'+fork.author}, avatar.name(fork.author)))))
          }, function (err) {
            if (err) console.error(err)
          })
        )

        return div
      }

      if(c.type === 'git-update') {
        return [
          h('p', 'pushed to ', repoLink(c.repo)),
          c.refs ? h('ul', Object.keys(c.refs).map(function (ref) {
            var rev = c.refs[ref]
            return h('li',
              shortRefName(ref) + ': ',
              rev ? h('code', rev) : h('em', 'deleted'))
          })) : null,
          Array.isArray(c.commits) ? [
            h('ul',
              c.commits.map(function (commit) {
                return h('li',
                  typeof commit.sha1 === 'string' ?
                    [h('code', commit.sha1.substr(0, 8)), ' '] : null,
                  commit.title ?
                    h('q', commit.title) : null)
              }),
              c.commits_more > 0 ?
                h('li', '+ ', c.commits_more, ' more') : null)
          ] : null,
          Array.isArray(c.issues) ? c.issues.map(function (issue) {
            if (issue.merged === true)
              return h('p', 'Merged ', messageLink(issue.link), ' in ',
                h('code', issue.object), ' ', h('q', issue.label))
            if (issue.open === false)
              return h('p', 'Closed ', messageLink(issue.link), ' in ',
                h('code', issue.object), ' ', h('q', issue.label))
          }) : null,
          newPullRequestButton.call(this, msg)
        ]
      }

      if(c.type === 'issue-edit'
       || (c.type === 'post' && c.text === '')) {
        return h('div',
          c.issue ? renderIssueEdit(c) : null,
          c.issues ? c.issues.map(renderIssueEdit) : null)
      }

      if(c.type === 'issue') {
        return h('div',
          h('p', 'opened issue on ', repoLink(c.project)),
          c.title ? h('h4', c.title) : '',
          markdown(c)
        )
      }

      if(c.type === 'pull-request') {
        return h('div',
          h('p', 'opened pull-request ',
            'to ', repoLink(c.repo), ':', c.branch, ' ',
            'from ', repoLink(c.head_repo), ':', c.head_branch),
          c.title ? h('h4', c.title) : '',
          markdown(c)
        )
      }
    },

    message_meta: function (msg, sbot) {
      var type = msg.value.content.type
      if (type === 'issue' || type === 'pull-request') {
        var el = h('em', '...')
        // TODO: update if issue is changed
        getIssueState(msg.key, function (err, state) {
          if (err) return console.error(err)
          el.textContent = state
        })
        return el
      }
    },

    message_action: function (msg, sbot) {
      var c = msg.value.content
      if(c.type === 'issue' || c.type === 'pull-request') {
        var isOpen
        var a = h('a', {href: '#', onclick: function (e) {
          e.preventDefault()
          api.message_confirm({
            type: 'issue-edit',
            root: msg.key,
            issues: [{
              link: msg.key,
              open: !isOpen
            }]
          }, function (err, msg) {
            if(err) return alert(err)
            if(!msg) return
            isOpen = msg.value.content.open
            update()
          })
        }})
        getIssueState(msg.key, function (err, state) {
          if (err) return console.error(err)
          isOpen = state === 'open'
          update()
        })
        function update() {
          a.textContent = c.type === 'pull-request'
            ? isOpen ? 'Close Pull Request' : 'Reopen Pull Request'
            : isOpen ? 'Close Issue' : 'Reopen Issue'
        }
        return a
      }
    }
  }
}