package redis

import (
	"context"
	"time"
)

type StringCmdable interface {
	Append(ctx context.Context, key, value string) *IntCmd
	Decr(ctx context.Context, key string) *IntCmd
	DecrBy(ctx context.Context, key string, decrement int64) *IntCmd
	Get(ctx context.Context, key string) *StringCmd
	GetRange(ctx context.Context, key string, start, end int64) *StringCmd
	GetSet(ctx context.Context, key string, value interface{}) *StringCmd
	GetEx(ctx context.Context, key string, expiration time.Duration) *StringCmd
	GetDel(ctx context.Context, key string) *StringCmd
	Incr(ctx context.Context, key string) *IntCmd
	IncrBy(ctx context.Context, key string, value int64) *IntCmd
	IncrByFloat(ctx context.Context, key string, value float64) *FloatCmd
	LCS(ctx context.Context, q *LCSQuery) *LCSCmd
	MGet(ctx context.Context, keys ...string) *SliceCmd
	MSet(ctx context.Context, values ...interface{}) *StatusCmd
	MSetNX(ctx context.Context, values ...interface{}) *BoolCmd
	MSetEX(ctx context.Context, args MSetEXArgs, values ...interface{}) *IntCmd
	Set(ctx context.Context, key string, value interface{}, expiration time.Duration) *StatusCmd
	SetArgs(ctx context.Context, key string, value interface{}, a SetArgs) *StatusCmd
	SetEx(ctx context.Context, key string, value interface{}, expiration time.Duration) *StatusCmd
	SetNX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd
	SetXX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd
	SetRange(ctx context.Context, key string, offset int64, value string) *IntCmd
	StrLen(ctx context.Context, key string) *IntCmd
}

func (c cmdable) Append(ctx context.Context, key, value string) *IntCmd {
	cmd := NewIntCmd(ctx, "append", key, value)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) Decr(ctx context.Context, key string) *IntCmd {
	cmd := NewIntCmd(ctx, "decr", key)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) DecrBy(ctx context.Context, key string, decrement int64) *IntCmd {
	cmd := NewIntCmd(ctx, "decrby", key, decrement)
	_ = c(ctx, cmd)
	return cmd
}

// Get Redis `GET key` command. It returns redis.Nil error when key does not exist.
func (c cmdable) Get(ctx context.Context, key string) *StringCmd {
	cmd := NewStringCmd(ctx, "get", key)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) GetRange(ctx context.Context, key string, start, end int64) *StringCmd {
	cmd := NewStringCmd(ctx, "getrange", key, start, end)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) GetSet(ctx context.Context, key string, value interface{}) *StringCmd {
	cmd := NewStringCmd(ctx, "getset", key, value)
	_ = c(ctx, cmd)
	return cmd
}

// GetEx An expiration of zero removes the TTL associated with the key (i.e. GETEX key persist).
// Requires Redis >= 6.2.0.
func (c cmdable) GetEx(ctx context.Context, key string, expiration time.Duration) *StringCmd {
	args := make([]interface{}, 0, 4)
	args = append(args, "getex", key)
	if expiration > 0 {
		if usePrecise(expiration) {
			args = append(args, "px", formatMs(ctx, expiration))
		} else {
			args = append(args, "ex", formatSec(ctx, expiration))
		}
	} else if expiration == 0 {
		args = append(args, "persist")
	}

	cmd := NewStringCmd(ctx, args...)
	_ = c(ctx, cmd)
	return cmd
}

// GetDel redis-server version >= 6.2.0.
func (c cmdable) GetDel(ctx context.Context, key string) *StringCmd {
	cmd := NewStringCmd(ctx, "getdel", key)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) Incr(ctx context.Context, key string) *IntCmd {
	cmd := NewIntCmd(ctx, "incr", key)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) IncrBy(ctx context.Context, key string, value int64) *IntCmd {
	cmd := NewIntCmd(ctx, "incrby", key, value)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) IncrByFloat(ctx context.Context, key string, value float64) *FloatCmd {
	cmd := NewFloatCmd(ctx, "incrbyfloat", key, value)
	_ = c(ctx, cmd)
	return cmd
}

type SetCondition string

const (
	// NX only set the keys and their expiration if none exist
	NX SetCondition = "NX"
	// XX only set the keys and their expiration if all already exist
	XX SetCondition = "XX"
)

type ExpirationMode string

const (
	// EX sets expiration in seconds
	EX ExpirationMode = "EX"
	// PX sets expiration in milliseconds
	PX ExpirationMode = "PX"
	// EXAT sets expiration as Unix timestamp in seconds
	EXAT ExpirationMode = "EXAT"
	// PXAT sets expiration as Unix timestamp in milliseconds
	PXAT ExpirationMode = "PXAT"
	// KEEPTTL keeps the existing TTL
	KEEPTTL ExpirationMode = "KEEPTTL"
)

type ExpirationOption struct {
	Mode  ExpirationMode
	Value int64
}

func (c cmdable) LCS(ctx context.Context, q *LCSQuery) *LCSCmd {
	cmd := NewLCSCmd(ctx, q)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) MGet(ctx context.Context, keys ...string) *SliceCmd {
	args := make([]interface{}, 1+len(keys))
	args[0] = "mget"
	for i, key := range keys {
		args[1+i] = key
	}
	cmd := NewSliceCmd(ctx, args...)
	_ = c(ctx, cmd)
	return cmd
}

// MSet is like Set but accepts multiple values:
//   - MSet("key1", "value1", "key2", "value2")
//   - MSet([]string{"key1", "value1", "key2", "value2"})
//   - MSet(map[string]interface{}{"key1": "value1", "key2": "value2"})
//   - MSet(struct), For struct types, see HSet description.
func (c cmdable) MSet(ctx context.Context, values ...interface{}) *StatusCmd {
	args := make([]interface{}, 1, 1+len(values))
	args[0] = "mset"
	args = appendArgs(args, values)
	cmd := NewStatusCmd(ctx, args...)
	_ = c(ctx, cmd)
	return cmd
}

// MSetNX is like SetNX but accepts multiple values:
//   - MSetNX("key1", "value1", "key2", "value2")
//   - MSetNX([]string{"key1", "value1", "key2", "value2"})
//   - MSetNX(map[string]interface{}{"key1": "value1", "key2": "value2"})
//   - MSetNX(struct), For struct types, see HSet description.
func (c cmdable) MSetNX(ctx context.Context, values ...interface{}) *BoolCmd {
	args := make([]interface{}, 1, 1+len(values))
	args[0] = "msetnx"
	args = appendArgs(args, values)
	cmd := NewBoolCmd(ctx, args...)
	_ = c(ctx, cmd)
	return cmd
}

type MSetEXArgs struct {
	Condition  SetCondition
	Expiration *ExpirationOption
}

// MSetEX sets the given keys to their respective values.
// This command is an extension of the MSETNX that adds expiration and XX options.
// Available since Redis 8.4
// Important: When this method is used with Cluster clients, all keys
// must be in the same hash slot, otherwise CROSSSLOT error will be returned.
// For more information, see https://redis.io/commands/msetex
func (c cmdable) MSetEX(ctx context.Context, args MSetEXArgs, values ...interface{}) *IntCmd {
	expandedArgs := appendArgs([]interface{}{}, values)
	numkeys := len(expandedArgs) / 2

	cmdArgs := make([]interface{}, 0, 2+len(expandedArgs)+3)
	cmdArgs = append(cmdArgs, "msetex", numkeys)
	cmdArgs = append(cmdArgs, expandedArgs...)

	if args.Condition != "" {
		cmdArgs = append(cmdArgs, string(args.Condition))
	}

	if args.Expiration != nil {
		switch args.Expiration.Mode {
		case EX:
			cmdArgs = append(cmdArgs, "ex", args.Expiration.Value)
		case PX:
			cmdArgs = append(cmdArgs, "px", args.Expiration.Value)
		case EXAT:
			cmdArgs = append(cmdArgs, "exat", args.Expiration.Value)
		case PXAT:
			cmdArgs = append(cmdArgs, "pxat", args.Expiration.Value)
		case KEEPTTL:
			cmdArgs = append(cmdArgs, "keepttl")
		}
	}

	cmd := NewIntCmd(ctx, cmdArgs...)
	_ = c(ctx, cmd)
	return cmd
}

// Set Redis `SET key value [expiration]` command.
// Use expiration for `SETEx`-like behavior.
//
// Zero expiration means the key has no expiration time.
// KeepTTL is a Redis KEEPTTL option to keep existing TTL, it requires your redis-server version >= 6.0,
// otherwise you will receive an error: (error) ERR syntax error.
func (c cmdable) Set(ctx context.Context, key string, value interface{}, expiration time.Duration) *StatusCmd {
	args := make([]interface{}, 3, 5)
	args[0] = "set"
	args[1] = key
	args[2] = value
	if expiration > 0 {
		if usePrecise(expiration) {
			args = append(args, "px", formatMs(ctx, expiration))
		} else {
			args = append(args, "ex", formatSec(ctx, expiration))
		}
	} else if expiration == KeepTTL {
		args = append(args, "keepttl")
	}

	cmd := NewStatusCmd(ctx, args...)
	_ = c(ctx, cmd)
	return cmd
}

// SetArgs provides arguments for the SetArgs function.
type SetArgs struct {
	// Mode can be `NX` or `XX` or empty.
	Mode string

	// Zero `TTL` or `Expiration` means that the key has no expiration time.
	TTL      time.Duration
	ExpireAt time.Time

	// When Get is true, the command returns the old value stored at key, or nil when key did not exist.
	Get bool

	// KeepTTL is a Redis KEEPTTL option to keep existing TTL, it requires your redis-server version >= 6.0,
	// otherwise you will receive an error: (error) ERR syntax error.
	KeepTTL bool
}

// SetArgs supports all the options that the SET command supports.
// It is the alternative to the Set function when you want
// to have more control over the options.
func (c cmdable) SetArgs(ctx context.Context, key string, value interface{}, a SetArgs) *StatusCmd {
	args := []interface{}{"set", key, value}

	if a.KeepTTL {
		args = append(args, "keepttl")
	}

	if !a.ExpireAt.IsZero() {
		args = append(args, "exat", a.ExpireAt.Unix())
	}
	if a.TTL > 0 {
		if usePrecise(a.TTL) {
			args = append(args, "px", formatMs(ctx, a.TTL))
		} else {
			args = append(args, "ex", formatSec(ctx, a.TTL))
		}
	}

	if a.Mode != "" {
		args = append(args, a.Mode)
	}

	if a.Get {
		args = append(args, "get")
	}

	cmd := NewStatusCmd(ctx, args...)
	_ = c(ctx, cmd)
	return cmd
}

// SetEx Redis `SETEx key expiration value` command.
func (c cmdable) SetEx(ctx context.Context, key string, value interface{}, expiration time.Duration) *StatusCmd {
	cmd := NewStatusCmd(ctx, "setex", key, formatSec(ctx, expiration), value)
	_ = c(ctx, cmd)
	return cmd
}

// SetNX Redis `SET key value [expiration] NX` command.
//
// Zero expiration means the key has no expiration time.
// KeepTTL is a Redis KEEPTTL option to keep existing TTL, it requires your redis-server version >= 6.0,
// otherwise you will receive an error: (error) ERR syntax error.
func (c cmdable) SetNX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd {
	var cmd *BoolCmd
	switch expiration {
	case 0:
		// Use old `SETNX` to support old Redis versions.
		cmd = NewBoolCmd(ctx, "setnx", key, value)
	case KeepTTL:
		cmd = NewBoolCmd(ctx, "set", key, value, "keepttl", "nx")
	default:
		if usePrecise(expiration) {
			cmd = NewBoolCmd(ctx, "set", key, value, "px", formatMs(ctx, expiration), "nx")
		} else {
			cmd = NewBoolCmd(ctx, "set", key, value, "ex", formatSec(ctx, expiration), "nx")
		}
	}

	_ = c(ctx, cmd)
	return cmd
}

// SetXX Redis `SET key value [expiration] XX` command.
//
// Zero expiration means the key has no expiration time.
// KeepTTL is a Redis KEEPTTL option to keep existing TTL, it requires your redis-server version >= 6.0,
// otherwise you will receive an error: (error) ERR syntax error.
func (c cmdable) SetXX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd {
	var cmd *BoolCmd
	switch expiration {
	case 0:
		cmd = NewBoolCmd(ctx, "set", key, value, "xx")
	case KeepTTL:
		cmd = NewBoolCmd(ctx, "set", key, value, "keepttl", "xx")
	default:
		if usePrecise(expiration) {
			cmd = NewBoolCmd(ctx, "set", key, value, "px", formatMs(ctx, expiration), "xx")
		} else {
			cmd = NewBoolCmd(ctx, "set", key, value, "ex", formatSec(ctx, expiration), "xx")
		}
	}

	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) SetRange(ctx context.Context, key string, offset int64, value string) *IntCmd {
	cmd := NewIntCmd(ctx, "setrange", key, offset, value)
	_ = c(ctx, cmd)
	return cmd
}

func (c cmdable) StrLen(ctx context.Context, key string) *IntCmd {
	cmd := NewIntCmd(ctx, "strlen", key)
	_ = c(ctx, cmd)
	return cmd
}