package cli

import (
	"encoding/json"
	"fmt"
	"os"
	"reflect" // #nosec
	"sort"
	"strconv"
	"strings"

	"github.com/manifoldco/promptui"
	"github.com/spf13/cobra"

	"github.com/cosmos/cosmos-sdk/client"
	"github.com/cosmos/cosmos-sdk/codec"
	sdk "github.com/cosmos/cosmos-sdk/types"
	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"

	"github.com/atomone-hub/atomone/x/gov/types"
)

const (
	proposalText          = "text"
	proposalOther         = "other"
	draftProposalFileName = "draft_proposal.json"
	draftMetadataFileName = "draft_metadata.json"
)

var suggestedProposalTypes = []proposalType{
	{
		Name:    proposalText,
		MsgType: "", // no message for text proposal
	},
	{
		Name:    "community-pool-spend",
		MsgType: "/cosmos.distribution.v1beta1.MsgCommunityPoolSpend",
	},
	{
		Name:    "software-upgrade",
		MsgType: "/cosmos.upgrade.v1beta1.MsgSoftwareUpgrade",
	},
	{
		Name:    "cancel-software-upgrade",
		MsgType: "/cosmos.upgrade.v1beta1.MsgCancelUpgrade",
	},
	{
		Name:    proposalOther,
		MsgType: "", // user will input the message type
	},
}

// Prompt prompts the user for all values of the given type.
// data is the struct to be filled
// namePrefix is the name to be displayed as "Enter <namePrefix> <field>"
func Prompt[T any](data T, namePrefix string) (T, error) {
	v := reflect.ValueOf(&data).Elem()
	if v.Kind() == reflect.Interface {
		v = reflect.ValueOf(data)
		if v.Kind() == reflect.Ptr {
			v = v.Elem()
		}
	}

	for i := 0; i < v.NumField(); i++ {
		// if the field is a struct skip or not slice of string or int then skip
		switch v.Field(i).Kind() {
		case reflect.Struct:
			// TODO(@julienrbrt) in the future we can add a recursive call to Prompt
			continue
		case reflect.Slice:
			if v.Field(i).Type().Elem().Kind() != reflect.String && v.Field(i).Type().Elem().Kind() != reflect.Int {
				continue
			}
		}

		// create prompts
		prompt := promptui.Prompt{
			Label:    fmt.Sprintf("Enter %s %s", namePrefix, strings.ToLower(client.CamelCaseToString(v.Type().Field(i).Name))),
			Validate: client.ValidatePromptNotEmpty,
		}

		fieldName := strings.ToLower(v.Type().Field(i).Name)

		if strings.EqualFold(fieldName, "authority") {
			// pre-fill with gov address
			prompt.Default = authtypes.NewModuleAddress(types.ModuleName).String()
			prompt.Validate = client.ValidatePromptAddress
		}

		// TODO(@julienrbrt) use scalar annotation instead of dumb string name matching
		if strings.Contains(fieldName, "addr") ||
			strings.Contains(fieldName, "sender") ||
			strings.Contains(fieldName, "voter") ||
			strings.Contains(fieldName, "depositor") ||
			strings.Contains(fieldName, "granter") ||
			strings.Contains(fieldName, "grantee") ||
			strings.Contains(fieldName, "recipient") {
			prompt.Validate = client.ValidatePromptAddress
		}

		result, err := prompt.Run()
		if err != nil {
			return data, fmt.Errorf("failed to prompt for %s: %w", fieldName, err)
		}

		switch v.Field(i).Kind() {
		case reflect.String:
			v.Field(i).SetString(result)
		case reflect.Int:
			resultInt, err := strconv.ParseInt(result, 10, 0)
			if err != nil {
				return data, fmt.Errorf("invalid value for int: %w", err)
			}
			// If a value was successfully parsed the ranges of:
			//      [minInt,     maxInt]
			// are within the ranges of:
			//      [minInt64, maxInt64]
			// of which on 64-bit machines, which are most common,
			// int==int64
			v.Field(i).SetInt(resultInt)
		case reflect.Slice:
			switch v.Field(i).Type().Elem().Kind() {
			case reflect.String:
				v.Field(i).Set(reflect.ValueOf([]string{result}))
			case reflect.Int:
				resultInt, err := strconv.ParseInt(result, 10, 0)
				if err != nil {
					return data, fmt.Errorf("invalid value for int: %w", err)
				}

				v.Field(i).Set(reflect.ValueOf([]int{int(resultInt)}))
			}
		default:
			// skip any other types
			continue
		}
	}

	return data, nil
}

type proposalType struct {
	Name    string
	MsgType string
	Msg     sdk.Msg
}

// Prompt the proposal type values and return the proposal and its metadata
func (p *proposalType) Prompt(cdc codec.Codec, skipMetadata bool) (*proposal, types.ProposalMetadata, error) {
	metadata, err := PromptMetadata(skipMetadata)
	if err != nil {
		return nil, metadata, fmt.Errorf("failed to set proposal metadata: %w", err)
	}

	proposal := &proposal{
		Metadata: "ipfs://CID", // the metadata must be saved on IPFS, set placeholder
		Title:    metadata.Title,
		Summary:  metadata.Summary,
	}

	// set deposit
	depositPrompt := promptui.Prompt{
		Label:    "Enter proposal deposit",
		Validate: client.ValidatePromptCoins,
	}
	proposal.Deposit, err = depositPrompt.Run()
	if err != nil {
		return nil, metadata, fmt.Errorf("failed to set proposal deposit: %w", err)
	}

	if p.Msg == nil {
		return proposal, metadata, nil
	}

	// set messages field
	result, err := Prompt(p.Msg, "msg")
	if err != nil {
		return nil, metadata, fmt.Errorf("failed to set proposal message: %w", err)
	}

	message, err := cdc.MarshalInterfaceJSON(result)
	if err != nil {
		return nil, metadata, fmt.Errorf("failed to marshal proposal message: %w", err)
	}
	proposal.Messages = append(proposal.Messages, message)

	return proposal, metadata, nil
}

// getProposalSuggestions suggests a list of proposal types
func getProposalSuggestions() []string {
	types := make([]string, len(suggestedProposalTypes))
	for i, p := range suggestedProposalTypes {
		types[i] = p.Name
	}
	return types
}

// PromptMetadata prompts for proposal metadata or only title and summary if skip is true
func PromptMetadata(skip bool) (types.ProposalMetadata, error) {
	var (
		metadata types.ProposalMetadata
		err      error
	)

	if !skip {
		metadata, err = Prompt(types.ProposalMetadata{}, "proposal")
		if err != nil {
			return metadata, fmt.Errorf("failed to set proposal metadata: %w", err)
		}
	} else {
		// prompt for title and summary
		titlePrompt := promptui.Prompt{
			Label:    "Enter proposal title",
			Validate: client.ValidatePromptNotEmpty,
		}

		metadata.Title, err = titlePrompt.Run()
		if err != nil {
			return metadata, fmt.Errorf("failed to set proposal title: %w", err)
		}

		summaryPrompt := promptui.Prompt{
			Label:    "Enter proposal summary",
			Validate: client.ValidatePromptNotEmpty,
		}

		metadata.Summary, err = summaryPrompt.Run()
		if err != nil {
			return metadata, fmt.Errorf("failed to set proposal summary: %w", err)
		}
	}

	return metadata, nil
}

// NewCmdDraftProposal let a user generate a draft proposal.
func NewCmdDraftProposal() *cobra.Command {
	flagSkipMetadata := "skip-metadata"

	cmd := &cobra.Command{
		Use:          "draft-proposal",
		Short:        "Generate a draft proposal json file. The generated proposal json contains only one message (skeleton).",
		SilenceUsage: true,
		RunE: func(cmd *cobra.Command, _ []string) error {
			clientCtx, err := client.GetClientTxContext(cmd)
			if err != nil {
				return err
			}

			// prompt proposal type
			proposalTypesPrompt := promptui.Select{
				Label: "Select proposal type",
				Items: getProposalSuggestions(),
			}

			_, selectedProposalType, err := proposalTypesPrompt.Run()
			if err != nil {
				return fmt.Errorf("failed to prompt proposal types: %w", err)
			}

			var proposal proposalType
			for _, p := range suggestedProposalTypes {
				if strings.EqualFold(p.Name, selectedProposalType) {
					proposal = p
					break
				}
			}

			// create any proposal type
			if proposal.Name == proposalOther {
				// prompt proposal type
				msgPrompt := promptui.Select{
					Label: "Select proposal message type:",
					Items: func() []string {
						msgs := clientCtx.InterfaceRegistry.ListImplementations(sdk.MsgInterfaceProtoName)
						sort.Strings(msgs)
						return msgs
					}(),
				}

				_, result, err := msgPrompt.Run()
				if err != nil {
					return fmt.Errorf("failed to prompt proposal types: %w", err)
				}

				proposal.MsgType = result
			}

			if proposal.MsgType != "" {
				proposal.Msg, err = sdk.GetMsgFromTypeURL(clientCtx.Codec, proposal.MsgType)
				if err != nil {
					// should never happen
					panic(err)
				}
			}

			skipMetadataPrompt, _ := cmd.Flags().GetBool(flagSkipMetadata)

			result, metadata, err := proposal.Prompt(clientCtx.Codec, skipMetadataPrompt)
			if err != nil {
				return err
			}

			if err := writeFile(draftProposalFileName, result); err != nil {
				return err
			}

			if !skipMetadataPrompt {
				if err := writeFile(draftMetadataFileName, metadata); err != nil {
					return err
				}
			}

			cmd.Println("The draft proposal has successfully been generated.\nProposals should contain off-chain metadata, please upload the metadata JSON to IPFS.\nThen, replace the generated metadata field with the IPFS CID.")

			return nil
		},
	}

	cmd.Flags().Bool(flagSkipMetadata, false, "skip metadata prompt")

	return cmd
}

// writeFile writes the input to the file
func writeFile(fileName string, input any) error {
	raw, err := json.MarshalIndent(input, "", " ")
	if err != nil {
		return fmt.Errorf("failed to marshal proposal: %w", err)
	}

	if err := os.WriteFile(fileName, raw, 0o600); err != nil {
		return err
	}

	return nil
}
