package main

import (
  "context"
  "fmt"
  "log"

  "github.com/solher/arangolite/v2"
  "github.com/solher/arangolite/v2/requests"
)

type Node struct {
  arangolite.Document
}

func main() {
  ctx := context.Background()

  // We declare the database definition.
  db := arangolite.NewDatabase(
    arangolite.OptEndpoint("http://localhost:8529"),
    arangolite.OptBasicAuth("root", "rootPassword"),
    arangolite.OptDatabaseName("_system"),
  )

  // The Connect method does two things:
  // - Initializes the connection if needed (JWT authentication).
  // - Checks the database connectivity.
  if err := db.Connect(ctx); err != nil {
    log.Fatal(err)
  }

  // We create a new database.
  err := db.Run(ctx, nil, &requests.CreateDatabase{
    Name: "testDB",
    Users: []map[string]interface{}{
      {"username": "root", "passwd": "rootPassword"},
      {"username": "user", "passwd": "password"},
    },
  })
  if err != nil {
    log.Fatal(err)
  }

  // We sign in as the new created user on the new database.
  // We could eventually rerun a "db.Connect()" to confirm the connectivity.
  db.Options(
    arangolite.OptBasicAuth("user", "password"),
    arangolite.OptDatabaseName("testDB"),
  )

  // We create a new "nodes" collection.
  if err := db.Run(ctx, nil, &requests.CreateCollection{Name: "nodes"}); err != nil {
    log.Fatal(err)
  }

  // We declare a new AQL query with options and bind parameters.
  key := "48765564346"
  r := requests.NewAQL(`
    FOR n
    IN nodes
    FILTER n._key == @key
    RETURN n
  `, key).
    Bind("key", key).
    Cache(true).
    BatchSize(500) // The caching feature is unavailable prior to ArangoDB 2.7

  // The Run method returns all the query results of every pages
  // available in the cursor and unmarshal it into the given struct.
  // Cancelling the context cancels every running request. 
  nodes := []Node{}
  if err := db.Run(ctx, &nodes, r); err != nil {
    log.Fatal(err)
  }

  // The Send method gives more control to the user and doesn't follow an eventual cursor.
  // It returns a raw result object.
  result, err := db.Send(ctx, r)
  if err != nil {
    log.Fatal(err)
  }
  nodes = []Node{}
  result.UnmarshalResult(&nodes)

  for result.HasMore() {
    result, err = db.Send(ctx, &requests.FollowCursor{Cursor: result.Cursor()})
    if err != nil {
      log.Fatal(err)
    }
    tmp := []Node{}
    result.UnmarshalResult(&tmp)

    nodes = append(nodes, tmp...)
  }

  fmt.Println(nodes)
}

// Document represents a basic ArangoDB document
type Document struct {
  // The document handle. Format: ':collection/:key'
  ID string `json:"_id,omitempty"`
  // The document's revision token. Changes at each update.
  Rev string `json:"_rev,omitempty"`
  // The document's unique key.
  Key string `json:"_key,omitempty"`
}

// Edge represents a basic ArangoDB edge
type Edge struct {
  Document
  // Reference to another document. Format: ':collection/:key'
  From string `json:"_from,omitempty"`
  // Reference to another document. Format: ':collection/:key'
  To string `json:"_to,omitempty"`
}

t := requests.NewTransaction([]string{"nodes"}, nil).
  AddAQL("nodes", `
    FOR n
    IN nodes
    RETURN n
`).
  AddAQL("ids", `
    FOR n
    IN {{.nodes}}
    RETURN n._id
`).
  Return("ids")

ids := []string{}
if err := db.Run(ctx, ids, t); err != nil {
  log.Fatal(err)
}

// Check graph existence.
if err := db.Run(ctx, nil, &requests.GetGraph{Name: "graphName"}); err != nil {
  switch {
  case arangolite.IsErrNotFound(err):
    // If graph does not exist, create a new one.
    edgeDefinitions := []requests.EdgeDefinition{
      {
        Collection: "edgeCollectionName",
        From:       []string{"firstCollectionName"},
        To:         []string{"secondCollectionName"},
      },
    }
    db.Run(ctx, nil, &requests.CreateGraph{Name: "graphName", EdgeDefinitions: edgeDefinitions})
  default:
    log.Fatal(err)
  }
}

// List existing graphs.
list := &requests.GraphList{}
db.Run(ctx, list, &requests.ListGraphs{})
fmt.Printf("Graph list: %v\n", list)

// Destroy the graph we just created, and the related collections.
db.Run(ctx, nil, &requests.DropGraph{Name: "graphName", DropCollections: true})

// IsErrInvalidRequest returns true when the database returns a 400.
func IsErrInvalidRequest(err error) bool {
  return HasStatusCode(err, 400)
}

// IsErrUnauthorized returns true when the database returns a 401.
func IsErrUnauthorized(err error) bool {
  return HasStatusCode(err, 401)
}

// IsErrForbidden returns true when the database returns a 403.
func IsErrForbidden(err error) bool {
  return HasStatusCode(err, 403)
}

// IsErrUnique returns true when the error num is a 1210 - ERROR_ARANGO_UNIQUE_CONSTRAINT_VIOLATED.
func IsErrUnique(err error) bool {
  return HasErrorNum(err, 1210)
}

// IsErrNotFound returns true when the database returns a 404 or when the error num is:
// 1202 - ERROR_ARANGO_DOCUMENT_NOT_FOUND
// 1203 - ERROR_ARANGO_COLLECTION_NOT_FOUND
func IsErrNotFound(err error) bool {
  return HasStatusCode(err, 404) || HasErrorNum(err, 1202, 1203)
}

// Runnable defines requests runnable by the Run and Send methods.
// A Runnable library is located in the 'requests' package.
type Runnable interface {
  // The body of the request.
  Generate() []byte
  // The path where to send the request.
  Path() string
  // The HTTP method to use.
  Method() string
}