// Copyright 2017 Pilosa Corp.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package pilosa

import (
	"encoding/json"
	"regexp"
	"time"

	"github.com/pkg/errors"
)

// System errors.
var (
	ErrHostRequired = errors.New("host required")

	ErrIndexRequired = errors.New("index required")
	ErrIndexExists   = errors.New("index already exists")
	ErrIndexNotFound = errors.New("index not found")

	ErrForeignIndexNotFound = errors.New("foreign index not found")

	// ErrFieldRequired is returned when no field is specified.
	ErrFieldRequired  = errors.New("field required")
	ErrColumnRequired = errors.New("column required")
	ErrFieldExists    = errors.New("field already exists")
	ErrFieldNotFound  = errors.New("field not found")

	ErrBSIGroupNotFound         = errors.New("bsigroup not found")
	ErrBSIGroupExists           = errors.New("bsigroup already exists")
	ErrBSIGroupNameRequired     = errors.New("bsigroup name required")
	ErrInvalidBSIGroupType      = errors.New("invalid bsigroup type")
	ErrInvalidBSIGroupRange     = errors.New("invalid bsigroup range")
	ErrInvalidBSIGroupValueType = errors.New("invalid bsigroup value type")
	ErrBSIGroupValueTooLow      = errors.New("bsigroup value too low")
	ErrBSIGroupValueTooHigh     = errors.New("bsigroup value too high")
	ErrInvalidRangeOperation    = errors.New("invalid range operation")
	ErrInvalidBetweenValue      = errors.New("invalid value for between operation")
	ErrDecimalOutOfRange        = errors.New("decimal value out of range")

	ErrInvalidView      = errors.New("invalid view")
	ErrInvalidCacheType = errors.New("invalid cache type")

	ErrName = errors.New("invalid index or field name, must match [a-z][a-z0-9_-]* and contain at most 230 characters")

	// ErrFragmentNotFound is returned when a fragment does not exist.
	ErrFragmentNotFound = errors.New("fragment not found")
	ErrQueryRequired    = errors.New("query required")
	ErrQueryCancelled   = errors.New("query cancelled")
	ErrQueryTimeout     = errors.New("query timeout")
	ErrTooManyWrites    = errors.New("too many write commands")

	// TODO(2.0) poorly named - used when a *node* doesn't own a shard. Probably
	// we won't need this error at all by 2.0 though.
	ErrClusterDoesNotOwnShard = errors.New("node does not own shard")

	// ErrPreconditionFailed is returned when specified index/field createdAt timestamps don't match
	ErrPreconditionFailed = errors.New("precondition failed")

	ErrNodeIDNotExists    = errors.New("node with provided ID does not exist")
	ErrNodeNotCoordinator = errors.New("node is not the coordinator")
	ErrResizeNotRunning   = errors.New("no resize job currently running")
	ErrResizeNoReplicas   = errors.New("not enough data to perform resize (replica factor may need to be increased)")

	ErrNotImplemented            = errors.New("not implemented")
	ErrFieldsArgumentRequired    = errors.New("fields argument required")
	ErrExpectedFieldListArgument = errors.New("expected field list argument")

	ErrIntFieldWithKeys     = errors.New("int field cannot be created with 'keys=true' option")
	ErrDecimalFieldWithKeys = errors.New("decimal field cannot be created with 'keys=true' option")
)

// apiMethodNotAllowedError wraps an error value indicating that a particular
// API method is not allowed in the current cluster state.
type apiMethodNotAllowedError struct {
	error
}

// newAPIMethodNotAllowedError returns err wrapped in an ApiMethodNotAllowedError.
func newAPIMethodNotAllowedError(err error) apiMethodNotAllowedError {
	return apiMethodNotAllowedError{err}
}

// BadRequestError wraps an error value to signify that a request could not be
// read, decoded, or parsed such that in an HTTP scenario, http.StatusBadRequest
// would be returned.
type BadRequestError struct {
	error
}

// NewBadRequestError returns err wrapped in a BadRequestError.
func NewBadRequestError(err error) BadRequestError {
	return BadRequestError{err}
}

// ConflictError wraps an error value to signify that a conflict with an
// existing resource occurred such that in an HTTP scenario, http.StatusConflict
// would be returned.
type ConflictError struct {
	error
}

// newConflictError returns err wrapped in a ConflictError.
func newConflictError(err error) ConflictError {
	return ConflictError{err}
}

// NotFoundError wraps an error value to signify that a resource was not found
// such that in an HTTP scenario, http.StatusNotFound would be returned.
type NotFoundError error

// newNotFoundError returns err wrapped in a NotFoundError.
func newNotFoundError(err error, name string) NotFoundError {
	return NotFoundError(errors.WithMessage(err, name))
}

type PreconditionFailedError struct {
	error
}

// newPreconditionFailedError returns err wrapped in a PreconditionFailedError.
func newPreconditionFailedError(err error) PreconditionFailedError {
	return PreconditionFailedError{err}
}

// Regular expression to validate index and field names.
var nameRegexp = regexp.MustCompile(`^[a-z][a-z0-9_-]{0,229}$`)

// ColumnAttrSet represents a set of attributes for a vertical column in an index.
// Can have a set of attributes attached to it.
type ColumnAttrSet struct {
	ID    uint64                 `json:"id"`
	Key   string                 `json:"key,omitempty"`
	Attrs map[string]interface{} `json:"attrs,omitempty"`
}

// MarshalJSON marshals the ColumnAttrSet to JSON such that
// either a Key or an ID is included.
func (cas ColumnAttrSet) MarshalJSON() ([]byte, error) {
	if cas.Key != "" {
		return json.Marshal(struct {
			Key   string                 `json:"key,omitempty"`
			Attrs map[string]interface{} `json:"attrs,omitempty"`
		}{
			Key:   cas.Key,
			Attrs: cas.Attrs,
		})
	}
	return json.Marshal(struct {
		ID    uint64                 `json:"id"`
		Attrs map[string]interface{} `json:"attrs,omitempty"`
	}{
		ID:    cas.ID,
		Attrs: cas.Attrs,
	})
}

// TimeFormat is the go-style time format used to parse string dates.
const TimeFormat = "2006-01-02T15:04"

// validateName ensures that the index or field or view name is a valid format.
func validateName(name string) error {
	if !nameRegexp.Match([]byte(name)) {
		return errors.Wrapf(ErrName, "'%s'", name)
	}
	return nil
}

// stringSlicesAreEqual determines if two string slices are equal.
func stringSlicesAreEqual(a, b []string) bool {

	if a == nil && b == nil {
		return true
	}

	if a == nil || b == nil {
		return false
	}

	if len(a) != len(b) {
		return false
	}

	for i := range a {
		if a[i] != b[i] {
			return false
		}
	}

	return true
}

func timestamp() int64 {
	return time.Now().UnixNano()
}

// AddressWithDefaults converts addr into a valid address,
// using defaults when necessary.
func AddressWithDefaults(addr string) (*URI, error) {
	if addr == "" {
		return defaultURI(), nil
	}
	return NewURIFromAddress(addr)
}