// Copyright 2015, 2016 Eris Industries (UK) Ltd.
// This file is part of Eris-RT

// Eris-RT is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Eris-RT is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Eris-RT.  If not, see <http://www.gnu.org/licenses/>.

package commands

import (
  "os"
  "path"

  cobra "github.com/spf13/cobra"

  log  "github.com/eris-ltd/eris-logger"

  core "github.com/eris-ltd/eris-db/core"
  util "github.com/eris-ltd/eris-db/util"
)

var ServeCmd = &cobra.Command {
  Use:   "serve",
  Short: "Eris-DB serve starts an eris-db node with client API enabled by default.",
  Long:  `Eris-DB serve starts an eris-db node with client API enabled by default.
The Eris-DB node is modularly configured for the consensus engine and application
manager.  The client API can be disabled.`,
  Example: `$ eris-db serve -- will start the Eris-DB node based on the configuration file "server_config.toml" in the current working directory
$ eris-db serve --work-dir <path-to-working-directory> -- will start the Eris-DB node based on the configuration file "server_config.toml" in the provided working directory`,
  PreRun: func(cmd *cobra.Command, args []string) {
    // if WorkDir was not set by a flag or by $ERIS_DB_WORKDIR
    // NOTE [ben]: we can consider an `Explicit` flag that eliminates
    // the use of any assumptions while starting Eris-DB
    if do.WorkDir == "" {
      if currentDirectory, err := os.Getwd(); err != nil {
        log.Fatalf("No directory provided and failed to get current working directory: %v", err)
        os.Exit(1)
      } else {

        do.WorkDir = currentDirectory
      }
    }
    if !util.IsDir(do.WorkDir) {
      log.Fatalf("Provided working directory %s is not a directory", do.WorkDir)
    }
  },
  Run: Serve,
}

// build the serve subcommand
func buildServeCommand() {
  addServeFlags()
}

func addServeFlags() {
  ServeCmd.PersistentFlags().StringVarP(&do.WorkDir, "work-dir", "w",
    defaultWorkDir(), "specify the working directory for the chain to run.  If omitted, and no path set in $ERIS_DB_WORKDIR, the current working directory is taken.")
  ServeCmd.PersistentFlags().StringVarP(&do.DataDir, "data-dir", "a",
    defaultDataDir(), "specify the data directory.  If omitted and not set in $ERIS_DB_DATADIR, <working_directory>/data is taken.")
}

//------------------------------------------------------------------------------
// functions

// serve() prepares the environment and sets up the core for Eris_DB to run.
// After the setup succeeds, serve() starts the core and halts for core to
// terminate.
func Serve(cmd *cobra.Command, args []string) {
  // load configuration from a single location to avoid a wrong configuration
  // file is loaded.
  if err := do.ReadConfig(do.WorkDir, "server_config", "toml"); err != nil {
    log.WithFields(log.Fields{
        "directory": do.WorkDir,
        "file": "server_config.toml",
      }).Fatalf("Fatal error reading configuration")
    os.Exit(1)
  }
  // load chain_id for assertion
  if do.ChainId = do.Config.GetString("chain.assert_chain_id");
    do.ChainId == "" {
    log.Fatalf("Failed to read non-empty string for ChainId from config.")
    os.Exit(1)
  }
  // load the genesis file path
  if do.GenesisFile = path.Join(do.WorkDir,
    do.Config.GetString("chain.genesis_file"));
    do.GenesisFile == "" {
    log.Fatalf("Failed to read non-empty string for genesis file from config.")
    os.Exit(1)
  }
  // Ensure data directory is set and accesible
  if err := do.InitialiseDataDirectory(); err != nil {
    log.Fatalf("Failed to initialise data directory (%s): %v", do.DataDir, err)
    os.Exit(1)
  }
  log.WithFields(log.Fields{
    "chainId": do.ChainId,
    "workingDirectory": do.WorkDir,
    "dataDirectory": do.DataDir,
    }).Info("Eris-DB serve configuring")

  consensusConfig, err := core.LoadConsensusModuleConfig(do)
  if err != nil {
    log.Fatalf("Failed to load consensus module configuration: %s.", err)
    os.Exit(1)
  }

  managerConfig, err := core.LoadApplicationManagerModuleConfig(do)
  if err != nil {
    log.Fatalf("Failed to load application manager module configuration: %s.", err)
    os.Exit(1)
  }
  log.WithFields(log.Fields{
    "consensusModule": consensusConfig.Version,
    "applicationManager": managerConfig.Version,
  }).Debug("Modules configured")
  core.NewCore(do.ChainId, do.GenesisFile, consensusConfig, managerConfig)
}

//------------------------------------------------------------------------------
// Defaults

func defaultWorkDir() string {
  // if ERIS_DB_WORKDIR environment variable is not set, keep do.WorkDir empty
  return setDefaultString("ERIS_DB_WORKDIR", "")
}

func defaultDataDir() string {
  // As the default data directory depends on the default working directory,
  // wait setting a default value, and initialise the data directory from serve()
  return setDefaultString("ERIS_DB_DATADIR", "")
}