package couchdb

import (
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strconv"
	"strings"
)

// Server represents a CouchDB server instance.
type Server struct {
	resource *Resource
}

// NewServer creates a CouchDB server instance in address urlStr.
func NewServer(urlStr string) (*Server, error) {
	return newServer(urlStr, true)
}

// NewServerNoFullCommit creates a CouchDB server instance in address urlStr
// with X-Couch-Full-Commit disabled.
func NewServerNoFullCommit(urlStr string) (*Server, error) {
	return newServer(urlStr, false)
}

func newServer(urlStr string, fullCommit bool) (*Server, error) {
	res, err := NewResource(urlStr, nil)
	if err != nil {
		return nil, err
	}

	s := &Server{
		resource: res,
	}

	if !fullCommit {
		s.resource.header.Set("X-Couch-Full-Commit", "false")
	}
	return s, nil
}

// Config returns the entire CouchDB server configuration as JSON structure.
func (s *Server) Config(node string) (map[string]map[string]string, error) {
	_, data, err := s.resource.GetJSON(fmt.Sprintf("_node/%s/_config", node), nil, nil)
	if err != nil {
		return nil, err
	}
	var config map[string]map[string]string
	err = json.Unmarshal(data, &config)
	if err != nil {
		return nil, err
	}
	return config, nil
}

// Version returns the version info about CouchDB instance.
func (s *Server) Version() (string, error) {
	var jsonMap map[string]interface{}

	_, data, err := s.resource.GetJSON("", nil, nil)
	if err != nil {
		return "", err
	}
	err = json.Unmarshal(data, &jsonMap)
	if err != nil {
		return "", err
	}

	return jsonMap["version"].(string), nil
}

func (s *Server) String() string {
	return fmt.Sprintf("Server %s", s.resource.base)
}

// ActiveTasks lists of running tasks.
func (s *Server) ActiveTasks() ([]interface{}, error) {
	var tasks []interface{}
	_, data, err := s.resource.GetJSON("_active_tasks", nil, nil)
	if err != nil {
		return nil, err
	}
	err = json.Unmarshal(data, &tasks)
	if err != nil {
		return nil, err
	}
	return tasks, nil
}

// DBs returns a list of all the databases in the CouchDB server instance.
func (s *Server) DBs() ([]string, error) {
	var dbs []string
	_, data, err := s.resource.GetJSON("_all_dbs", nil, nil)
	if err != nil {
		return nil, err
	}
	err = json.Unmarshal(data, &dbs)
	if err != nil {
		return nil, err
	}
	return dbs, nil
}

// Stats returns a JSON object containing the statistics for the running server.
func (s *Server) Stats(node, entry string) (map[string]interface{}, error) {
	var stats map[string]interface{}
	_, data, err := s.resource.GetJSON(fmt.Sprintf("_node/%s/_stats/%s", node, entry), nil, url.Values{})
	if err != nil {
		return nil, err
	}
	err = json.Unmarshal(data, &stats)
	if err != nil {
		return nil, err
	}
	return stats, nil
}

// Len returns the number of dbs in CouchDB server instance.
func (s *Server) Len() (int, error) {
	dbs, err := s.DBs()
	if err != nil {
		return -1, err
	}
	return len(dbs), nil
}

// Create returns a database instance with the given name, returns true if created,
// if database already existed, returns false, *Database will be nil if failed.
func (s *Server) Create(name string) (*Database, error) {
	_, _, err := s.resource.PutJSON(name, nil, nil, nil)

	// ErrPreconditionFailed means database with the given name already existed
	if err != nil && err != ErrPreconditionFailed {
		return nil, err
	}

	db, getErr := s.Get(name)
	if getErr != nil {
		return nil, getErr
	}
	return db, err
}

// Delete deletes a database with the given name. Return false if failed.
func (s *Server) Delete(name string) error {
	_, _, err := s.resource.DeleteJSON(name, nil, nil)
	return err
}

// Get gets a database instance with the given name. Return nil if failed.
func (s *Server) Get(name string) (*Database, error) {
	res, err := s.resource.NewResourceWithURL(name)
	if err != nil {
		return nil, err
	}

	db, err := NewDatabaseWithResource(res)
	if err != nil {
		return nil, err
	}

	_, _, err = db.resource.Head("", nil, nil)
	if err != nil {
		return nil, err
	}
	return db, nil
}

// Contains returns true if a db with given name exsited.
func (s *Server) Contains(name string) bool {
	_, _, err := s.resource.Head(name, nil, nil)
	return err == nil
}

// Membership displays the nodes that are part of the cluster as clusterNodes.
// The field allNodes displays all nodes this node knows about, including the
// ones that are part of cluster.
func (s *Server) Membership() ([]string, []string, error) {
	var jsonMap map[string]*json.RawMessage

	_, data, err := s.resource.GetJSON("_membership", nil, nil)
	if err != nil {
		return nil, nil, err
	}

	err = json.Unmarshal(data, &jsonMap)
	if err != nil {
		return nil, nil, err
	}

	var allNodes []string
	var clusterNodes []string

	err = json.Unmarshal(*jsonMap["all_nodes"], &allNodes)
	if err != nil {
		return nil, nil, err
	}

	err = json.Unmarshal(*jsonMap["cluster_nodes"], &clusterNodes)
	if err != nil {
		return nil, nil, err
	}

	return allNodes, clusterNodes, nil
}

// Replicate requests, configure or stop a replication operation.
func (s *Server) Replicate(source, target string, options map[string]interface{}) (map[string]interface{}, error) {
	var result map[string]interface{}

	body := map[string]interface{}{
		"source": source,
		"target": target,
	}

	if options != nil {
		for k, v := range options {
			body[k] = v
		}
	}

	_, data, err := s.resource.PostJSON("_replicate", nil, body, nil)
	if err != nil {
		return nil, err
	}
	json.Unmarshal(data, &result)

	return result, nil
}

// UUIDs requests one or more Universally Unique Identifiers from the CouchDB instance.
// The response is a JSON object providing a list of UUIDs.
// count - Number of UUIDs to return. Default is 1.
func (s *Server) UUIDs(count int) ([]string, error) {
	if count <= 0 {
		count = 1
	}

	values := url.Values{}
	values.Set("count", strconv.Itoa(count))

	_, data, err := s.resource.GetJSON("_uuids", nil, values)
	if err != nil {
		return nil, err
	}

	var jsonMap map[string]*json.RawMessage
	err = json.Unmarshal(data, &jsonMap)
	if err != nil {
		return nil, err
	}

	var uuids []string
	err = json.Unmarshal(*jsonMap["uuids"], &uuids)
	if err != nil {
		return nil, err
	}

	return uuids, nil
}

// newResource returns an url string representing a resource under server.
func (s *Server) newResource(resource string) string {
	resourceURL, err := s.resource.base.Parse(resource)
	if err != nil {
		return ""
	}
	return resourceURL.String()
}

// AddUser adds regular user in authentication database.
// Returns id and rev of the registered user.
func (s *Server) AddUser(name, password string, roles []string) (string, string, error) {
	var id, rev string
	db, err := s.Get("_users")
	if err != nil {
		return "", "", err
	}

	if roles == nil {
		roles = []string{}
	}

	userDoc := map[string]interface{}{
		"_id":      "org.couchdb.user:" + name,
		"name":     name,
		"password": password,
		"roles":    roles,
		"type":     "user",
	}

	id, rev, err = db.Save(userDoc, nil)
	if err != nil {
		return id, rev, err
	}
	return id, rev, nil
}

// Login regular user in CouchDB, returns authentication token.
func (s *Server) Login(name, password string) (string, error) {
	body := map[string]interface{}{
		"name":     name,
		"password": password,
	}
	header, _, err := s.resource.PostJSON("_session", nil, body, nil)
	if err != nil {
		return "", err
	}

	tokenPart := strings.Split(header.Get("Set-Cookie"), ";")[0]
	token := strings.Split(tokenPart, "=")[1]
	return token, err
}

// VerifyToken returns error if user's token is invalid.
func (s *Server) VerifyToken(token string) error {
	header := http.Header{}
	header.Set("Cookie", strings.Join([]string{"AuthSession", token}, "="))
	_, _, err := s.resource.GetJSON("_session", header, nil)
	return err
}

// Logout regular user in CouchDB
func (s *Server) Logout(token string) error {
	header := http.Header{}
	header.Set("Cookie", strings.Join([]string{"AuthSession", token}, "="))
	_, _, err := s.resource.DeleteJSON("_session", header, nil)
	return err
}

// RemoveUser removes regular user in authentication database.
func (s *Server) RemoveUser(name string) error {
	db, err := s.Get("_users")
	if err != nil {
		return err
	}
	docID := "org.couchdb.user:" + name
	return db.Delete(docID)
}