package tools

import (
	"context"
	"fmt"
	"strings"

	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"

	"forge.lclr.dev/AI/xdebug-mcp/internal/cache"
	"forge.lclr.dev/AI/xdebug-mcp/internal/cachegrind"
)

// AnalyzeTool returns the MCP tool definition for analyze_profile.
func AnalyzeTool() mcp.Tool {
	return mcp.NewTool("analyze_profile",
		mcp.WithDescription("Analyze an Xdebug cachegrind profiling file. Returns global stats and top N functions sorted by inclusive time cost."),
		mcp.WithString("file_path",
			mcp.Required(),
			mcp.Description("Absolute or relative path to the cachegrind file (.gz or plain text)"),
		),
		mcp.WithNumber("top_n",
			mcp.Description("Number of top functions to return (default: 20)"),
		),
	)
}

// AnalyzeHandler returns the MCP handler for analyze_profile.
func AnalyzeHandler(c *cache.Cache) server.ToolHandlerFunc {
	return func(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
		filePath := req.GetString("file_path", "")
		if filePath == "" {
			return mcp.NewToolResultError("file_path is required"), nil
		}
		topN := req.GetInt("top_n", 20)
		if topN <= 0 {
			topN = 20
		}
		p, err := loadProfile(filePath, c)
		if err != nil {
			return mcp.NewToolResultError(err.Error()), nil
		}
		return mcp.NewToolResultText(Analyze(p, topN)), nil
	}
}

// Analyze formats the top-N analysis of p. Exported for testing.
func Analyze(p *cachegrind.Profile, topN int) string {
	sorted := sortedByTime(p.Functions)
	if topN > len(sorted) {
		topN = len(sorted)
	}

	var sb strings.Builder
	fmt.Fprintf(&sb, "Command: %s\n", p.Cmd)
	fmt.Fprintf(&sb, "Events: %s\n", strings.Join(p.Events, ", "))
	fmt.Fprintf(&sb, "Functions: %d total\n\n", len(p.Functions))

	peak := int64(0)
	if len(sorted) > 0 && len(sorted[0].Costs) > 0 {
		peak = sorted[0].Costs[0]
	}

	if len(p.Events) > 0 {
		fmt.Fprintf(&sb, "Top %d functions by %s:\n", topN, p.Events[0])
	}
	for i, fn := range sorted[:topN] {
		pct := ""
		if peak > 0 && len(fn.Costs) > 0 {
			pct = fmt.Sprintf(" (%.1f%% of peak)", float64(fn.Costs[0])/float64(peak)*100)
		}
		fmt.Fprintf(&sb, " %3d. %-60s  %s%s\n", i+1, fn.Name, formatCosts(fn.Costs, p.Events), pct)
		fmt.Fprintf(&sb, "      %s\n", fn.File)
	}

	return sb.String()
}