//
// Figma project stats
// Pulls statistics like number of files, frames, versions etc for a project.
//
// Usage:
//   export FIGMA_API_ACCESS_TOKEN='your-token'
//   node figma-project-stats.js <project-id>
//
// You can generate tokens in your account settings or at
// https://www.figma.com/developers/explorer#personal-access-token
//
// <project-id> is the last number in the URL path of a project.
// For instance, in this URL:
//   https://www.figma.com/files/5027479082769520/project/712/Project-Title
// The project id is "712"
//
const http = require('https')

let FIGMA_API_ACCESS_TOKEN = ''  // populated from env
let FIGMA_API_HOST = 'api.figma.com'  // may be populated from env


function findfkey(url) {
  return url.match(/\.com\/file\/([^\/]+)/)[1]
}


function apiget(path) {
  return new Promise((resolve, reject) => {
    let shortCircuited = false
    let req = http.request(
      {
        protocol: 'https:',
        host: FIGMA_API_HOST,
        method: 'GET',
        path: '/v1/' + path,
        headers: {
          'X-FIGMA-TOKEN': FIGMA_API_ACCESS_TOKEN,
        },
      },
      res => {
        if (res.statusCode == 504 || res.statusCode == '504') {
          console.log(`${path} failed with status ${res.statusCode} -- retrying...`)
          shortCircuited = true
          return setTimeout(() => {
            apiget(path).then(resolve).catch(reject)
          }, 1000)
        }
        // console.log(`STATUS: ${res.statusCode}`)
        // console.log(`HEADERS:`, JSON.parse(JSON.stringify(res.headers)))
        let buf = ''
        res.setEncoding('utf8')
        res.on('data', chunk => { buf += chunk })
        res.on('end', () => {
          let r = null
          try {
            r = JSON.parse(buf)
          } catch (err) {
            console.error(`failed to parse response body: ${err}`)
            console.error(`original body:\n------${buf}\n------`)
            return reject(err)
          }
          resolve(r, { status: res.statusCode })
        })
      }
    )
    req.on('error', err => {
      if (!shortCircuited) {
        reject(err)
      }
    })
    req.end()
  }) // promise
}


const frameLikeTypes = new Set('FRAME GROUP COMPONENT INSTANCE'.split(' '))

function countFrameLikeNodes(parent) {
  let n = 0
  for (let node of parent.children) {
    if (frameLikeTypes.has(node.type)) {
      n++
    }
  }
  return n
}


function usage() {
  console.error(
    `usage: ${require('path').basename(__filename)} <project-id>\n` +
    `Environment variables:\n` +
    `  FIGMA_API_ACCESS_TOKEN  API access token (required)\n` +
    `  FIGMA_API_HOST          API server hostname (e.g. "local-api.figma.com")\n`
  )
  process.exit(1)
}


function main(args) {

  FIGMA_API_ACCESS_TOKEN = process.env['FIGMA_API_ACCESS_TOKEN'] || ''
  FIGMA_API_HOST = process.env['FIGMA_API_HOST'] || FIGMA_API_HOST

  if (args.length < 1) {
    console.error('missing project id')
    usage()
  }

  if (args.indexOf('-h') != -1 || args.indexOf('--help') != -1) {
    usage()
  }

  if (FIGMA_API_ACCESS_TOKEN.length == 0) {
    console.error(
      `Missing env variable FIGMA_API_ACCESS_TOKEN\n` +
      `Visit the following URL to generate a token:\n` +
      `  https://www.figma.com/developers/explorer#personal-access-token\n`
    )
    usage()
  }
  
  let projectId = args[0].replace(/[^\d]+/g, '')

  console.log(`collecting stats for project ${projectId} on ${FIGMA_API_HOST}`)

  apiget(`projects/${projectId}/files`).then(r => {
    console.log(`inspecting ${r.files.length} project files...`)

    let nextFileIndex = 0
    let nTotalPages = 0
    let nTotalVersions = 0
    let nTotalFrames = 0

    let doNextFile = (key) => {
      let file = r.files[nextFileIndex++]
      if (!file) {
        // done
        console.log('project summary:')
        console.log('files:           ', r.files.length)
        console.log('pages:           ', nTotalPages)
        console.log('versions:        ', nTotalVersions)
        console.log('top-level frames:', nTotalFrames)
        return
      }

      console.log(`file ${file.key} "${file.name}":`)
      let nversions = 0
      let npages = 0
      let nTopLevelFrames = 0

      Promise.all([

        apiget(`files/${file.key}/versions`).then(r => {
          nversions = r.versions.length
        }),

        apiget(`files/${file.key}`).then(r => {
          let pages = r.document.children
          npages = pages.length
          for (let page of pages) {
            nTopLevelFrames += countFrameLikeNodes(page)
          }
        }),

      ]).then(() => {
        console.log('  versions:        ', nversions)
        console.log('  pages:           ', npages)
        console.log('  top-level frames:', nTopLevelFrames)

        nTotalPages += npages
        nTotalVersions += nversions
        nTotalFrames += nTopLevelFrames

        doNextFile()
      }).catch(err => {
        console.error(err.stack || String(err))
      })
    }

    doNextFile()
  })
}

main(process.argv.slice(2))