package tools

import (
	"context"
	"strconv"
	"strings"
	"time"

	"github.com/modelcontextprotocol/go-sdk/mcp"

	"isphere-ai-bridge/internal/isphere"
)

const ToolNameReceiveMessages = "isphere_receive_messages"

type ReceiveMessagesSource interface {
	ReceiveMessages(ctx context.Context, query isphere.ReceiveMessagesQuery) (isphere.ReceiveMessagesResult, error)
}

type ReceiveMessagesArgs struct {
	Limit int `json:"limit,omitempty" jsonschema:"maximum number of messages to return; zero or negative returns all available messages"`
}

func RegisterISphereReadTools(server *mcp.Server, source ReceiveMessagesSource) {
	if source == nil {
		source = isphere.EncryptedPacketLogSource{}
	}

	mcp.AddTool[ReceiveMessagesArgs, map[string]any](server, &mcp.Tool{
		Name:        ToolNameReceiveMessages,
		Description: "Return iSphere messages from the configured read-only log-backed source.",
	}, func(ctx context.Context, _ *mcp.CallToolRequest, input ReceiveMessagesArgs) (*mcp.CallToolResult, map[string]any, error) {
		started := time.Now().UTC()
		result, err := source.ReceiveMessages(ctx, isphere.ReceiveMessagesQuery{Limit: input.Limit})
		if err != nil {
			return nil, nil, err
		}
		return nil, receiveMessagesResultToMap(result, started, time.Now().UTC()), nil
	})
}

func receiveMessagesResultToMap(result isphere.ReceiveMessagesResult, started time.Time, finished time.Time) map[string]any {
	messages := make([]map[string]any, 0, len(result.Messages))
	for _, message := range result.Messages {
		attachments := receiveMessageAttachments(message)
		messages = append(messages, map[string]any{
			"id":                message.ID,
			"message_id":        message.ID,
			"conversation_id":   message.ConversationID,
			"conversation_type": message.ConversationType,
			"sender_id":         message.SenderID,
			"sender_name":       nil,
			"receiver_id":       message.ReceiverID,
			"text":              message.Text,
			"content_type":      receiveMessageContentType(message, attachments),
			"content_text":      message.Text,
			"attachments":       attachments,
			"timestamp":         message.Timestamp,
			"created_at":        packetTimestampToRFC3339(message.Timestamp),
			"received_at":       nil,
			"subject":           message.Subject,
			"receipt_id":        message.ReceiptID,
			"read":              message.Read,
			"source":            "local_readonly",
			"raw_ref":           "packetlog_message",
		})
	}
	return map[string]any{
		"ok":           true,
		"conversation": receiveMessagesConversation(result.Messages),
		"messages":     messages,
		"next_cursor":  nil,
		"audit": map[string]any{
			"tool":           ToolNameReceiveMessages,
			"source":         "local_readonly",
			"execution_mode": "read",
			"started_at":     started.Format(time.RFC3339Nano),
			"finished_at":    finished.Format(time.RFC3339Nano),
			"result":         "ok",
		},
	}
}

func receiveMessagesConversation(messages []isphere.Message) any {
	if len(messages) == 0 {
		return nil
	}
	first := messages[0]
	return map[string]any{
		"conversation_id":   first.ConversationID,
		"conversation_type": contractConversationType(first.ConversationType),
		"display_name":      first.ConversationID,
	}
}

func contractConversationType(value string) string {
	switch strings.ToLower(strings.TrimSpace(value)) {
	case "groupchat", "group":
		return "group"
	case "chat", "direct":
		return "direct"
	case "system":
		return "system"
	default:
		return "unknown"
	}
}

func receiveMessageAttachments(message isphere.Message) []map[string]any {
	files := isphere.ListFilesFromMessages([]isphere.Message{message}, isphere.ListFilesQuery{})
	attachments := make([]map[string]any, 0, len(files.Files))
	for _, file := range files.Files {
		attachments = append(attachments, map[string]any{
			"file_id":      file.FileID,
			"file_name":    file.FileName,
			"size_bytes":   file.SizeBytes,
			"download_ref": nullableString(file.DownloadRef),
		})
	}
	return attachments
}

func receiveMessageContentType(message isphere.Message, attachments []map[string]any) string {
	if len(attachments) > 0 {
		return "file"
	}
	if strings.TrimSpace(message.Text) != "" {
		return "text"
	}
	if strings.TrimSpace(message.Subject) != "" {
		return "notify"
	}
	return "unknown"
}

func packetTimestampToRFC3339(value string) any {
	trimmed := strings.TrimSpace(value)
	if trimmed == "" {
		return nil
	}
	epoch, err := strconv.ParseInt(trimmed, 10, 64)
	if err != nil {
		return nil
	}
	var ts time.Time
	if epoch > 1_000_000_000_000 {
		ts = time.UnixMilli(epoch)
	} else {
		ts = time.Unix(epoch, 0)
	}
	formatted := ts.UTC().Format(time.RFC3339)
	return formatted
}