package to

import (
	"context"
	"encoding/json"
	"fmt"

	"gitea.com/gitea/gitea-mcp/pkg/debug"
	"gitea.com/gitea/gitea-mcp/pkg/flag"
	"gitea.com/gitea/gitea-mcp/pkg/log"

	"github.com/mark3labs/mcp-go/mcp"
	"go.uber.org/zap"
)

func TextResult(v any) (*mcp.CallToolResult, error) {
	resultBytes, err := json.Marshal(v)
	if err != nil {
		return nil, fmt.Errorf("marshal result err: %v", err)
	}
	if flag.DebugScopeEnabled("tools") {
		// We can't take a context here without breaking every caller, so we
		// log without the request_id correlation. The middleware's exit log
		// records the request_id + duration; this entry adds a (truncated)
		// payload preview for callers that want to see what came back.
		log.Debug("tool call: result",
			zap.Int("bytes", len(resultBytes)),
			zap.String("preview", debug.TruncatePreview(string(resultBytes))),
		)
	}
	return mcp.NewToolResultText(string(resultBytes)), nil
}

// TextResultCtx is the context-aware variant of TextResult. New call sites
// should prefer it so log lines carry the request_id and tool name. The
// non-context TextResult above is kept for backwards compatibility with
// the many existing tool handlers.
func TextResultCtx(ctx context.Context, v any) (*mcp.CallToolResult, error) {
	resultBytes, err := json.Marshal(v)
	if err != nil {
		return nil, fmt.Errorf("marshal result err: %v", err)
	}
	if flag.DebugScopeEnabled("tools") {
		log.Debug("tool call: result",
			zap.String("tool", debug.ToolNameFromContext(ctx)),
			zap.String("request_id", debug.RequestIDFromContext(ctx)),
			zap.Int("bytes", len(resultBytes)),
			zap.String("preview", debug.TruncatePreview(string(resultBytes))),
		)
	}
	return mcp.NewToolResultText(string(resultBytes)), nil
}

// ErrorResult returns the error to the MCP layer. We no longer log here —
// the ToolLogging middleware emits a structured error entry that includes
// the tool name and request_id, which is far more useful than the bare
// `log.Errorf("%s", err)` this used to do.
func ErrorResult(err error) (*mcp.CallToolResult, error) {
	return nil, err
}