package raft

import (
	"errors"
	"strings"
	"sync"

	"git.giftfish.de/ston1th/raftbbolt/msgpack"
	"github.com/hashicorp/raft"
)

var (
	ErrNotLeader      = errors.New("raft: not leader")
	ErrKeyNotFound    = errors.New("raft: key not found")
	ErrPrefixNotFound = errors.New("raft: prefix not found")
)

type kvm map[string][]byte

type kv struct {
	mu sync.Mutex
	m  kvm
	r  *raft.Raft
}

func (kv *kv) Get(k string) ([]byte, error) {
	kv.mu.Lock()
	defer kv.mu.Unlock()
	v, ok := kv.m[k]
	if !ok {
		return nil, ErrKeyNotFound
	}
	return v, nil
}

func (kv *kv) GetPrefix(pk string) (m map[string][]byte, err error) {
	kv.mu.Lock()
	defer kv.mu.Unlock()
	m = make(map[string][]byte)
	for k, v := range kv.m {
		if strings.HasPrefix(k, pk) {
			m[k] = v
		}
	}
	if len(m) == 0 {
		err = ErrPrefixNotFound
	}
	return
}

func (kv *kv) Set(k string, v []byte) error {
	if kv.r.State() != raft.Leader {
		return ErrNotLeader
	}

	c := &raftCmd{SET, k, v}
	b, err := msgpack.Marshal(c)
	if err != nil {
		return err
	}

	f := kv.r.Apply(b, raftTimeout)
	return f.Error()
}

// Delete deletes the given key.
func (kv *kv) Delete(k string) error {
	if kv.r.State() != raft.Leader {
		return ErrNotLeader
	}

	c := &raftCmd{Op: DELETE, K: k}
	b, err := msgpack.Marshal(c)
	if err != nil {
		return err
	}

	f := kv.r.Apply(b, raftTimeout)
	return f.Error()
}