package keeper

import (
	"context"
	"errors"
	"fmt"
	"time"

	"cosmossdk.io/collections"
	"cosmossdk.io/core/appmodule"
	"cosmossdk.io/x/gov/types"
	v1 "cosmossdk.io/x/gov/types/v1"
	"cosmossdk.io/x/gov/types/v1beta1"

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

// Keeper defines the governance module Keeper
type Keeper struct {
	appmodule.Environment

	authKeeper types.AccountKeeper
	bankKeeper types.BankKeeper
	poolKeeper types.PoolKeeper
	// The reference to the DelegationSet and ValidatorSet to get information about validators and delegators
	sk types.StakingKeeper

	// GovHooks
	hooks types.GovHooks

	// The codec for binary encoding/decoding.
	cdc codec.Codec

	// Legacy Proposal router
	legacyRouter v1beta1.Router

	// Config represent extra module configuration
	config Config

	// the address capable of executing a MsgUpdateParams message. Typically, this
	// should be the x/gov module account.
	authority string

	Schema collections.Schema
	// Constitution value: constitution
	Constitution collections.Item[string]
	// Params stores the governance parameters
	Params collections.Item[v1.Params]
	// MessageBasedParams store message-based governance parameters
	// key:proposal-msg-url | value MessageBasedParams
	MessageBasedParams collections.Map[string, v1.MessageBasedParams]
	// Deposits key: proposalID+depositorAddr | value: Deposit
	Deposits collections.Map[collections.Pair[uint64, sdk.AccAddress], v1.Deposit]
	// Votes key: proposalID+voterAddr | value: Vote
	Votes collections.Map[collections.Pair[uint64, sdk.AccAddress], v1.Vote]
	// ProposalID is a counter for proposals. It tracks the next proposal ID to be issued.
	ProposalID collections.Sequence
	// Proposals key:proposalID | value: Proposal
	Proposals collections.Map[uint64, v1.Proposal]
	// ProposalVoteOptions key: proposalID | value:
	// This is used to store multiple choice vote options
	ProposalVoteOptions collections.Map[uint64, v1.ProposalVoteOptions]
	// ActiveProposalsQueue key: votingEndTime+proposalID | value: proposalID
	ActiveProposalsQueue collections.Map[collections.Pair[time.Time, uint64], uint64] // TODO(tip): this should be simplified and go into an index.
	// InactiveProposalsQueue key: depositEndTime+proposalID | value: proposalID
	InactiveProposalsQueue collections.Map[collections.Pair[time.Time, uint64], uint64] // TODO(tip): this should be simplified and go into an index.
}

// GetAuthority returns the x/gov module's authority.
func (k Keeper) GetAuthority() string {
	return k.authority
}

// NewKeeper returns a governance keeper. It handles:
// - submitting governance proposals
// - depositing funds into proposals, and activating upon sufficient funds being deposited
// - users voting on proposals, with weight proportional to stake in the system
// - and tallying the result of the vote.
//
// CONTRACT: the parameter Subspace must have the param key table already initialized
func NewKeeper(
	cdc codec.Codec, env appmodule.Environment, authKeeper types.AccountKeeper,
	bankKeeper types.BankKeeper, sk types.StakingKeeper, pk types.PoolKeeper,
	config Config, authority string,
) *Keeper {
	// ensure governance module account is set
	if addr := authKeeper.GetModuleAddress(types.ModuleName); addr == nil {
		panic(fmt.Sprintf("%s module account has not been set", types.ModuleName))
	}

	if _, err := authKeeper.AddressCodec().StringToBytes(authority); err != nil {
		panic(fmt.Sprintf("invalid authority address: %s", authority))
	}

	defaultConfig := DefaultConfig()
	// If MaxMetadataLen not set by app developer, set to default value.
	if config.MaxTitleLen == 0 {
		config.MaxTitleLen = defaultConfig.MaxTitleLen
	}
	// If MaxMetadataLen not set by app developer, set to default value.
	if config.MaxMetadataLen == 0 {
		config.MaxMetadataLen = defaultConfig.MaxMetadataLen
	}
	// If MaxMetadataLen not set by app developer, set to default value.
	if config.MaxSummaryLen == 0 {
		config.MaxSummaryLen = defaultConfig.MaxSummaryLen
	}
	// If MaxVoteOptionsLen not set by app developer, set to default value, meaning all supported options are allowed
	if config.MaxVoteOptionsLen == 0 {
		config.MaxVoteOptionsLen = defaultConfig.MaxVoteOptionsLen
	}

	sb := collections.NewSchemaBuilder(env.KVStoreService)
	k := &Keeper{
		Environment:            env,
		authKeeper:             authKeeper,
		bankKeeper:             bankKeeper,
		sk:                     sk,
		poolKeeper:             pk,
		cdc:                    cdc,
		config:                 config,
		authority:              authority,
		Constitution:           collections.NewItem(sb, types.ConstitutionKey, "constitution", collections.StringValue),
		Params:                 collections.NewItem(sb, types.ParamsKey, "params", codec.CollValue[v1.Params](cdc)),
		MessageBasedParams:     collections.NewMap(sb, types.MessageBasedParamsKey, "proposal_messaged_based_params", collections.StringKey, codec.CollValue[v1.MessageBasedParams](cdc)),
		Deposits:               collections.NewMap(sb, types.DepositsKeyPrefix, "deposits", collections.PairKeyCodec(collections.Uint64Key, sdk.LengthPrefixedAddressKey(sdk.AccAddressKey)), codec.CollValue[v1.Deposit](cdc)), //nolint: staticcheck // sdk.LengthPrefixedAddressKey is needed to retain state compatibility
		Votes:                  collections.NewMap(sb, types.VotesKeyPrefix, "votes", collections.PairKeyCodec(collections.Uint64Key, sdk.LengthPrefixedAddressKey(sdk.AccAddressKey)), codec.CollValue[v1.Vote](cdc)),          //nolint: staticcheck // sdk.LengthPrefixedAddressKey is needed to retain state compatibility
		ProposalID:             collections.NewSequence(sb, types.ProposalIDKey, "proposal_id"),
		Proposals:              collections.NewMap(sb, types.ProposalsKeyPrefix, "proposals", collections.Uint64Key, codec.CollValue[v1.Proposal](cdc)),
		ProposalVoteOptions:    collections.NewMap(sb, types.ProposalVoteOptionsKeyPrefix, "proposal_vote_options", collections.Uint64Key, codec.CollValue[v1.ProposalVoteOptions](cdc)),
		ActiveProposalsQueue:   collections.NewMap(sb, types.ActiveProposalQueuePrefix, "active_proposals_queue", collections.PairKeyCodec(sdk.TimeKey, collections.Uint64Key), collections.Uint64Value),     // sdk.TimeKey is needed to retain state compatibility
		InactiveProposalsQueue: collections.NewMap(sb, types.InactiveProposalQueuePrefix, "inactive_proposals_queue", collections.PairKeyCodec(sdk.TimeKey, collections.Uint64Key), collections.Uint64Value), // sdk.TimeKey is needed to retain state compatibility
	}
	schema, err := sb.Build()
	if err != nil {
		panic(err)
	}
	k.Schema = schema
	return k
}

// Hooks gets the hooks for governance Keeper
func (k *Keeper) Hooks() types.GovHooks {
	if k.hooks == nil {
		// return a no-op implementation if no hooks are set
		return types.MultiGovHooks{}
	}

	return k.hooks
}

// SetHooks sets the hooks for governance
func (k *Keeper) SetHooks(gh types.GovHooks) *Keeper {
	if k.hooks != nil {
		panic("cannot set governance hooks twice")
	}

	k.hooks = gh

	return k
}

// SetLegacyRouter sets the legacy router for governance
func (k *Keeper) SetLegacyRouter(router v1beta1.Router) {
	// It is vital to seal the governance proposal router here as to not allow
	// further handlers to be registered after the keeper is created since this
	// could create invalid or non-deterministic behavior.
	router.Seal()
	k.legacyRouter = router
}

// LegacyRouter returns the gov keeper's legacy router
func (k Keeper) LegacyRouter() v1beta1.Router {
	return k.legacyRouter
}

// GetGovernanceAccount returns the governance ModuleAccount
func (k Keeper) GetGovernanceAccount(ctx context.Context) sdk.ModuleAccountI {
	return k.authKeeper.GetModuleAccount(ctx, types.ModuleName)
}

// ModuleAccountAddress returns gov module account address
func (k Keeper) ModuleAccountAddress() sdk.AccAddress {
	return k.authKeeper.GetModuleAddress(types.ModuleName)
}

// validateProposalLengths checks message metadata, summary and title
// to have the expected length otherwise returns an error.
func (k Keeper) validateProposalLengths(metadata, title, summary string) error {
	if err := k.assertMetadataLength(metadata); err != nil {
		return err
	}
	if err := k.assertSummaryLength(summary); err != nil {
		return err
	}
	if err := k.assertTitleLength(title); err != nil {
		return err
	}
	return nil
}

// assertTitleLength returns an error if given title length
// is greater than a pre-defined MaxTitleLen.
func (k Keeper) assertTitleLength(title string) error {
	if len(title) == 0 {
		return errors.New("proposal title cannot be empty")
	}

	if uint64(len(title)) > k.config.MaxTitleLen {
		return types.ErrTitleTooLong.Wrapf("got title with length %d", len(title))
	}
	return nil
}

// assertMetadataLength returns an error if given metadata length
// is greater than a pre-defined MaxMetadataLen.
func (k Keeper) assertMetadataLength(metadata string) error {
	if uint64(len(metadata)) > k.config.MaxMetadataLen {
		return types.ErrMetadataTooLong.Wrapf("got metadata with length %d", len(metadata))
	}
	return nil
}

// assertSummaryLength returns an error if given summary length
// is greater than a pre-defined MaxSummaryLen.
func (k Keeper) assertSummaryLength(summary string) error {
	if len(summary) == 0 {
		return errors.New("proposal summary cannot be empty")
	}

	if uint64(len(summary)) > k.config.MaxSummaryLen {
		return types.ErrSummaryTooLong.Wrapf("got summary with length %d", len(summary))
	}
	return nil
}

// assertVoteOptionsLen returns an error if given vote options length
// is greater than a pre-defined MaxVoteOptionsLen.
// It's only being checked when config.MaxVoteOptionsLen > 0 (param enabled)
func (k Keeper) assertVoteOptionsLen(options v1.WeightedVoteOptions) error {
	maxVoteOptionsLen := k.config.MaxVoteOptionsLen
	if maxVoteOptionsLen > 0 && uint64(len(options)) > maxVoteOptionsLen {
		return types.ErrTooManyVoteOptions.Wrapf("got %d weighted vote options, maximum allowed is %d", len(options), k.config.MaxVoteOptionsLen)
	}
	return nil
}