/* SRD Website
````````````````````````````````````````````````````````````````````````````````
This is a webapp for serving an RPG SRD in a publicly available format
constructed from a collection of md and configuration files in a git repository
located at `srd`.
*/
/* ==== REQUIRES ============================================================ */
const express     = require('express')
const doT         = require('dot')
const path        = require('path')
const fs          = require('fs')

/* ==== CONFIGURATION ======================================================= */
const exp = express()
const app = {
  config: {
    srd: 'srd',
    plugins: {},
    port: 7331,
  },
  live: {
    dictionary: {},
    conf: {},
    menu: '',
  },
  express: exp,
  dot: null,
}

const pub = __dirname + '/public'
const views = __dirname + '/views'
const routes = __dirname + '/routes'

app.dot = doT.process({'path': views})

try { 
  app.config = {...app.config, ...require(__dirname + '/config.js')}
} catch(err) {
  if (err.code === 'MODULE_NOT_FOUND') {
    console.error('missing config')
  }
}

exp.use(express.static(pub))
exp.use(express.static(path.join(__dirname, app.config.srd)))
exp.engine('dot', (template, options, cb) => {
  return cb(null, app.dot[path.parse(template).name](options))
})

exp.set('views', views)
exp.set('view engine', 'dot')

/* ==== PLUGINS ============================================================= */
const plugins = []
try {
  fs.readdirSync('plugins').forEach(f => {
    let plugin_path = path.resolve('plugins', f)
    if (fs.lstatSync(plugin_path).isDirectory()) {
      console.log('plugin require:', f)
      try {
        let plugin = {
          defaults: null,
          config: {},
          log: (...args) => {
            console.log.apply(console, [f+':', ...args])
          },
          error: (...args) => {
            console.error.apply(console, [f+':', ...args])
          },
          module: require(plugin_path),
        }
        if (app.config.plugins[f]) {
          plugin.config = app.config.plugins[f]
        }
        plugin.defaults = o => {
          plugin.config = {...o, ...plugin.config}
        }
        console.log('...ok')
        plugins.push(plugin)
      } catch(err) {
        if (err.code === 'MODULE_NOT_FOUND') {
          console.error('plugin', plugin_path, 'is not a valid module')
        } else {
          console.error('...fail: ', err)
        }
      }
    }
  })
  if (plugins.length === 0) {
    console.warn('no plugins found');
  } else {
    // Sort our plugins according to desired priorities. Higher numbers 
    plugins.sort((first, second) => {
      let first_priority = 0
      let second_priority = 0
      if (first.config.priority !== undefined) {
        first_priority = first.config.priority
      } else if (first.module === Object(first.module)) {
        if (first.module.priority !== undefined) {
          first_priority = first.module.priority
        }
      }
      if (second.config.priority !== undefined) {
        second_priority = second.config.priority
      } else if (second.module === Object(second.module)) {
        if (second.module.priority !== undefined) {
          second_priority = second.module.priority
        }
      }
      if (first_priority > second_priority) {
        return -1
      } else if (first_priority < second_priority) {
        return 1
      }
      return 0
    })
    // Call any needed preloads.
    for (let plugin of plugins) {
      // Call preload if the module is an object.
      if (plugin.module === Object(plugin.module)) {
        if (plugin.module.preload) {
          console.log('plugin preload:', f)
          try {
            plugin.module.preload(plugin, app)
            console.log('...ok')
          } catch(err) {
            console.error('...fail: ', err)
          }
        }
      }
    }
  }
} catch(err) {
  if (err.code === 'ENOENT') {
    console.warn('no plugins directory')
  } else {
    console.error('plugins', err)
  }
}

/* ==== CMDLINE ============================================================= */
const port = app.config.port
process.argv.forEach((val, index, array) => {
  let parts = val.split('=')
  let key = ''
  let value = ''
  if (parts[0].substr(0, 2) == '--') {
    key = parts[0].substr(2)
    value = parts[1]
  }
  if (key == 'port') {
    if (value != '') {
      port = Number(value)
    }
  }
})

/* ==== RUN ================================================================= */
const server = exp.listen(port, async () => {
  const host = server.address().address
  const port = server.address().port

  for (let plugin of plugins) {
    try {
      if (plugin.module instanceof Function) {
        await plugin.module(plugin, app)
      } else if (plugin.module === Object(plugin.module)) {
        if (plugin.module.load) {
          await plugin.module.load(plugin, app)
        }
      }
    } catch(err) {
      console.error('plugin', err)
    }
  }
  console.log('running on', port)
})

process.on('SIGINT', () => {
  process.exit()
})

process.on('exit', () => {
  fs.writeFileSync(path.join(__dirname + '/config.js'), 'module.exports = ' + JSON.stringify(app.config, null, '\t'))
})