package mcp

import (
	"context"
	"encoding/json"
	"log/slog"
	"time"

	chassisauth "git.d-ma.be/mathias/mcp-chassis/auth"

	"git.d-ma.be/mathias/gitea-mcp/internal/auth"
	"git.d-ma.be/mathias/gitea-mcp/internal/gitea"
)

// auditTargetKeys are the only argument values copied into the audit record:
// they identify what a call acted on without copying what it wrote. Every
// other argument (file content, issue bodies) is reduced to args_bytes so the
// audit trail never becomes a second copy of repo content (gitea-mcp#64).
var auditTargetKeys = []string{"owner", "repo", "number", "branch", "path", "tag"}

// logToolCall emits one structured record per tools/call (OWASP MCP08).
func logToolCall(ctx context.Context, name string, args json.RawMessage, start time.Time, err error) {
	attrs := []any{
		"tool", name,
		"caller", auth.Caller(ctx),
		"args_bytes", len(args),
		"duration_ms", time.Since(start).Milliseconds(),
	}
	if tok, ok := gitea.TokenFromContext(ctx); ok {
		attrs = append(attrs, "token_fp", chassisauth.Fingerprint(tok))
	}
	var parsed map[string]any
	if json.Unmarshal(args, &parsed) == nil {
		for _, k := range auditTargetKeys {
			if v, ok := parsed[k]; ok {
				attrs = append(attrs, k, v)
			}
		}
	}
	outcome := "ok"
	if err != nil {
		outcome = err.Error()
	}
	attrs = append(attrs, "outcome", outcome)
	slog.InfoContext(ctx, "mcp tool call", attrs...)
}