package keeper

import (
	"fmt"
	"reflect"

	"github.com/prometheus/client_golang/prometheus"

	sdk "github.com/cosmos/cosmos-sdk/types"

	"github.com/CosmWasm/wasmd/x/wasm/types"
)

type optsFn func(*Keeper)

func (f optsFn) apply(keeper *Keeper) {
	f(keeper)
}

// option that is applied after keeper is setup with the VM. Used for decorators mainly.
type postOptsFn func(*Keeper)

func (f postOptsFn) apply(keeper *Keeper) {
	f(keeper)
}

// WithWasmEngine is an optional constructor parameter to replace the default wasmVM engine with the
// given one.
func WithWasmEngine(x types.WasmEngine) Option {
	return optsFn(func(k *Keeper) {
		k.wasmVM = x
	})
}

// WithWasmEngineDecorator is an optional constructor parameter to decorate the default wasmVM engine.
func WithWasmEngineDecorator(d func(old types.WasmEngine) types.WasmEngine) Option {
	return postOptsFn(func(k *Keeper) {
		k.wasmVM = d(k.wasmVM)
	})
}

// WithMessageHandler is an optional constructor parameter to set a custom handler for wasmVM messages.
// This option should not be combined with Option `WithMessageEncoders` or `WithMessageHandlerDecorator`
func WithMessageHandler(x Messenger) Option {
	return optsFn(func(k *Keeper) {
		k.messenger = x
	})
}

// WithMessageHandlerDecorator is an optional constructor parameter to decorate the wasm handler for wasmVM messages.
// This option should not be combined with Option `WithMessageEncoders` or `WithMessageHandler`
func WithMessageHandlerDecorator(d func(old Messenger) Messenger) Option {
	return postOptsFn(func(k *Keeper) {
		k.messenger = d(k.messenger)
	})
}

// WithQueryHandler is an optional constructor parameter to set custom query handler for wasmVM requests.
// This option should not be combined with Option `WithQueryPlugins` or `WithQueryHandlerDecorator`
func WithQueryHandler(x WasmVMQueryHandler) Option {
	return optsFn(func(k *Keeper) {
		k.wasmVMQueryHandler = x
	})
}

// WithQueryHandlerDecorator is an optional constructor parameter to decorate the default wasm query handler for wasmVM requests.
// This option should not be combined with Option `WithQueryPlugins` or `WithQueryHandler`
func WithQueryHandlerDecorator(d func(old WasmVMQueryHandler) WasmVMQueryHandler) Option {
	return postOptsFn(func(k *Keeper) {
		k.wasmVMQueryHandler = d(k.wasmVMQueryHandler)
	})
}

// WithQueryPlugins is an optional constructor parameter to pass custom query plugins for wasmVM requests.
// This option expects the default `QueryHandler` set and should not be combined with Option `WithQueryHandler` or `WithQueryHandlerDecorator`.
func WithQueryPlugins(x *QueryPlugins) Option {
	return optsFn(func(k *Keeper) {
		q, ok := k.wasmVMQueryHandler.(QueryPlugins)
		if !ok {
			panic(fmt.Sprintf("Unsupported query handler type: %T", k.wasmVMQueryHandler))
		}
		k.wasmVMQueryHandler = q.Merge(x)
	})
}

// WithMessageEncoders is an optional constructor parameter to pass custom message encoder to the default wasm message handler.
// This option expects the `DefaultMessageHandler` set and should not be combined with Option `WithMessageHandler` or `WithMessageHandlerDecorator`.
func WithMessageEncoders(x *MessageEncoders) Option {
	return optsFn(func(k *Keeper) {
		q, ok := k.messenger.(*MessageHandlerChain)
		if !ok {
			panic(fmt.Sprintf("Unsupported message handler type: %T", k.messenger))
		}
		s, ok := q.handlers[0].(SDKMessageHandler)
		if !ok {
			panic(fmt.Sprintf("Unexpected message handler type: %T", q.handlers[0]))
		}
		e, ok := s.encoders.(MessageEncoders)
		if !ok {
			panic(fmt.Sprintf("Unsupported encoder type: %T", s.encoders))
		}
		s.encoders = e.Merge(x)
		q.handlers[0] = s
	})
}

// WithCoinTransferrer is an optional constructor parameter to set a custom coin transferrer
func WithCoinTransferrer(x CoinTransferrer) Option {
	if x == nil {
		panic("must not be nil")
	}
	return optsFn(func(k *Keeper) {
		k.bank = x
	})
}

// WithAccountPruner is an optional constructor parameter to set a custom type that handles balances and data cleanup
// for accounts pruned on contract instantiate
func WithAccountPruner(x AccountPruner) Option {
	if x == nil {
		panic("must not be nil")
	}
	return optsFn(func(k *Keeper) {
		k.accountPruner = x
	})
}

func WithVMCacheMetrics(r prometheus.Registerer) Option {
	return postOptsFn(func(k *Keeper) {
		NewWasmVMMetricsCollector(k.wasmVM).Register(r)
	})
}

// WithGasRegister set a new gas register to implement custom gas costs.
// When the "gas multiplier" for wasmvm gas conversion is modified inside the new register,
// make sure to also use `WithApiCosts` option for non default values
func WithGasRegister(x types.GasRegister) Option {
	if x == nil {
		panic("must not be nil")
	}
	return optsFn(func(k *Keeper) {
		k.gasRegister = x
	})
}

// WithAPICosts sets custom api costs. Amounts are in cosmwasm gas Not SDK gas.
func WithAPICosts(human, canonical uint64) Option {
	return optsFn(func(_ *Keeper) {
		costHumanize = human
		costCanonical = canonical
	})
}

// WithMaxQueryStackSize overwrites the default limit for maximum query stacks
func WithMaxQueryStackSize(m uint32) Option {
	return optsFn(func(k *Keeper) {
		k.maxQueryStackSize = m
	})
}

func WithMaxCallDepth(m uint32) Option {
	return optsFn(func(k *Keeper) {
		k.maxCallDepth = m
	})
}

// WithAcceptedAccountTypesOnContractInstantiation sets the accepted account types. Account types of this list won't be overwritten or cause a failure
// when they exist for an address on contract instantiation.
//
// Values should be references and contain the `*authtypes.BaseAccount` as default bank account type.
func WithAcceptedAccountTypesOnContractInstantiation(accts ...sdk.AccountI) Option {
	m := asTypeMap(accts)
	return optsFn(func(k *Keeper) {
		k.acceptedAccountTypes = m
	})
}

// WithGovSubMsgAuthZPropagated overwrites the default gov authorization policy for sub-messages
func WithGovSubMsgAuthZPropagated(entries ...types.AuthorizationPolicyAction) Option {
	x := make(map[types.AuthorizationPolicyAction]struct{}, len(entries))
	for _, e := range entries {
		x[e] = struct{}{}
	}
	if got, exp := len(x), len(entries); got != exp {
		panic(fmt.Sprintf("duplicates in %#v", entries))
	}
	return optsFn(func(k *Keeper) {
		k.propagateGovAuthorization = x
	})
}

func asTypeMap(accts []sdk.AccountI) map[reflect.Type]struct{} {
	m := make(map[reflect.Type]struct{}, len(accts))
	for _, a := range accts {
		if a == nil {
			panic(types.ErrEmpty.Wrap("address"))
		}
		at := reflect.TypeOf(a)
		if _, exists := m[at]; exists {
			panic(types.ErrDuplicate.Wrapf("%T", a))
		}
		m[at] = struct{}{}
	}
	return m
}

// split into pre and post VM operations
func splitOpts(opts []Option) ([]Option, []Option) {
	pre, post := make([]Option, 0), make([]Option, 0)
	for _, o := range opts {
		if _, ok := o.(postOptsFn); ok {
			post = append(post, o)
		} else {
			pre = append(pre, o)
		}
	}
	return pre, post
}