// Throwaway spike to validate that mark3labs/mcp-go's stdio client can drive
// mcp-garmin (spawn, initialize handshake, call tools, parse results).
// Not part of the production build — delete once internal/garmin is built.
package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"os"
	"strconv"
	"time"

	"github.com/mark3labs/mcp-go/client"
	"github.com/mark3labs/mcp-go/client/transport"
	"github.com/mark3labs/mcp-go/mcp"
)

func main() {
	pythonPath := flag.String("python", "", "path to mcp-garmin .venv python executable")
	serverPath := flag.String("server", "", "path to mcp-garmin server.py")
	limit := flag.Int("limit", 5, "activity limit for get_activities")
	startDate := flag.String("start", "", "start date YYYY-MM-DD for get_activities (default: 365 days ago)")
	endDate := flag.String("end", "", "end date YYYY-MM-DD for get_activities (default: today)")
	flag.Parse()

	if *pythonPath == "" || *serverPath == "" {
		log.Fatal("usage: mcpspike -python <path to .venv/bin/python> -server <path to server.py>")
	}

	email := os.Getenv("GARMIN_EMAIL")
	password := os.Getenv("GARMIN_PASSWORD")
	if email == "" || password == "" {
		log.Fatal("GARMIN_EMAIL and GARMIN_PASSWORD must be set in the environment")
	}

	env := []string{
		"GARMIN_EMAIL=" + email,
		"GARMIN_PASSWORD=" + password,
		"PYTHONUNBUFFERED=1",
	}

	c, err := client.NewStdioMCPClient(*pythonPath, env, *serverPath)
	if err != nil {
		log.Fatalf("spawn subprocess: %v", err)
	}
	defer c.Close()

	if stdio, ok := c.GetTransport().(*transport.Stdio); ok {
		go func() {
			buf := make([]byte, 4096)
			for {
				n, err := stdio.Stderr().Read(buf)
				if n > 0 {
					fmt.Fprint(os.Stderr, string(buf[:n]))
				}
				if err != nil {
					return
				}
			}
		}()
	} else {
		log.Println("warning: could not get stdio transport to forward subprocess stderr")
	}

	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
	defer cancel()

	initReq := mcp.InitializeRequest{}
	initReq.Params.ProtocolVersion = mcp.LATEST_PROTOCOL_VERSION
	initReq.Params.ClientInfo = mcp.Implementation{Name: "mcpspike", Version: "0.0.1"}

	initRes, err := c.Initialize(ctx, initReq)
	if err != nil {
		log.Fatalf("initialize handshake failed: %v", err)
	}
	fmt.Printf("initialized OK: server=%s version=%s protocol=%s\n",
		initRes.ServerInfo.Name, initRes.ServerInfo.Version, initRes.ProtocolVersion)

	tools, err := c.ListTools(ctx, mcp.ListToolsRequest{})
	if err != nil {
		log.Fatalf("list tools failed: %v", err)
	}
	fmt.Printf("server exposes %d tools:\n", len(tools.Tools))
	for _, t := range tools.Tools {
		fmt.Printf("  - %s: %s\n", t.Name, t.Description)
	}

	fmt.Println("\ncalling authenticate()...")
	authRes, err := callTool(ctx, c, "authenticate", nil)
	if err != nil {
		log.Fatalf("authenticate call failed: %v", err)
	}
	fmt.Printf("authenticate() -> %s\n", authRes)

	if containsMFAPrompt(authRes) {
		fmt.Print("MFA required. Enter code: ")
		var code string
		fmt.Scanln(&code)
		mfaRes, err := callTool(ctx, c, "complete_mfa", map[string]any{"code": code})
		if err != nil {
			log.Fatalf("complete_mfa call failed: %v", err)
		}
		fmt.Printf("complete_mfa() -> %s\n", mfaRes)
	}

	start := *startDate
	if start == "" {
		start = time.Now().AddDate(0, 0, -365).Format("2006-01-02")
	}
	end := *endDate
	if end == "" {
		end = time.Now().Format("2006-01-02")
	}

	fmt.Printf("\ncalling get_activities(start_date=%s, end_date=%s, limit=%d)...\n", start, end, *limit)
	actRes, err := callTool(ctx, c, "get_activities", map[string]any{
		"start_date": start,
		"end_date":   end,
		"limit":      *limit,
	})
	if err != nil {
		log.Fatalf("get_activities call failed: %v", err)
	}

	var activities []map[string]any
	if err := json.Unmarshal([]byte(actRes), &activities); err != nil {
		fmt.Printf("get_activities() returned non-JSON (likely an error string): %s\n", actRes)
		return
	}
	pretty, _ := json.MarshalIndent(activities, "", "  ")
	fmt.Printf("get_activities() parsed OK, %d activities, %d bytes:\n%s\n", len(activities), len(actRes), truncate(string(pretty), 4000))

	if len(activities) == 0 {
		fmt.Println("\nno activities in range, skipping get_activity_details")
		return
	}

	// Prefer a running activity if one is present, for the most relevant lap/split shape.
	chosen := activities[0]
	for _, a := range activities {
		if at, ok := a["activityType"].(map[string]any); ok {
			if tk, _ := at["typeKey"].(string); tk == "running" || tk == "trail_running" || tk == "treadmill_running" {
				chosen = a
				break
			}
		}
	}
	var activityID string
	switch v := chosen["activityId"].(type) {
	case float64:
		activityID = strconv.FormatFloat(v, 'f', -1, 64)
	default:
		activityID = fmt.Sprint(v)
	}
	fmt.Printf("\ncalling get_activity_details(activity_id=%s) [activityName=%v]...\n", activityID, chosen["activityName"])

	splitsRes, err := callTool(ctx, c, "get_activity_splits", map[string]any{"activity_id": activityID})
	if err != nil {
		log.Fatalf("get_activity_splits call failed: %v", err)
	}

	var splits map[string]any
	if err := json.Unmarshal([]byte(splitsRes), &splits); err != nil {
		fmt.Printf("get_activity_splits() returned non-JSON: %s\n", splitsRes)
		return
	}
	keys := make([]string, 0, len(splits))
	for k := range splits {
		keys = append(keys, k)
	}
	fmt.Printf("get_activity_splits() top-level keys: %v\n", keys)
	prettySplits, _ := json.MarshalIndent(splits, "", "  ")
	fmt.Printf("get_activity_splits() parsed OK, %d bytes:\n%s\n", len(splitsRes), truncate(string(prettySplits), 8000))

	fmt.Println("\ncalling get_activity_details() again to inspect metricDescriptors + a small metrics sample...")
	detailsRes, err := callTool(ctx, c, "get_activity_details", map[string]any{"activity_id": activityID})
	if err != nil {
		log.Fatalf("get_activity_details call failed: %v", err)
	}
	var details map[string]any
	if err := json.Unmarshal([]byte(detailsRes), &details); err != nil {
		fmt.Printf("get_activity_details() returned non-JSON: %s\n", detailsRes)
		return
	}
	if descriptors, ok := details["metricDescriptors"]; ok {
		pretty, _ := json.MarshalIndent(descriptors, "", "  ")
		fmt.Printf("metricDescriptors:\n%s\n", pretty)
	} else {
		fmt.Println("no metricDescriptors key found")
	}
	if rows, ok := details["activityDetailMetrics"].([]any); ok && len(rows) > 0 {
		sampleN := 5
		if len(rows) < sampleN {
			sampleN = len(rows)
		}
		pretty, _ := json.MarshalIndent(rows[:sampleN], "", "  ")
		fmt.Printf("activityDetailMetrics sample (first %d of %d rows):\n%s\n", sampleN, len(rows), pretty)
	}
}

func callTool(ctx context.Context, c *client.Client, name string, args map[string]any) (string, error) {
	req := mcp.CallToolRequest{}
	req.Params.Name = name
	req.Params.Arguments = args

	res, err := c.CallTool(ctx, req)
	if err != nil {
		return "", err
	}
	if res.IsError {
		return "", fmt.Errorf("tool %s returned an error result", name)
	}
	var out string
	for _, content := range res.Content {
		if tc, ok := content.(mcp.TextContent); ok {
			out += tc.Text
		}
	}
	return out, nil
}

func containsMFAPrompt(s string) bool {
	for _, needle := range []string{"MFA required", "MFA code", "complete_mfa"} {
		if len(s) >= len(needle) {
			for i := 0; i+len(needle) <= len(s); i++ {
				if s[i:i+len(needle)] == needle {
					return true
				}
			}
		}
	}
	return false
}

func truncate(s string, n int) string {
	if len(s) <= n {
		return s
	}
	return s[:n] + "...(truncated)"
}