package main

import (
	"errors"
	"fmt"
	"math"
	"strings"
)

// Optional filters must remain optional across JSON-schema clients. In
// particular, null means unspecified; zero is not a wildcard process ID.
func windowQuery(args obj) (obj, error) {
	query := obj{}
	for key, value := range args {
		if value != nil {
			query[key] = value
		}
	}
	if value, ok := query["app"]; ok {
		app, valid := value.(string)
		if !valid {
			return nil, errors.New("app must be an application name or null")
		}
		if app = strings.TrimSpace(app); app == "" {
			delete(query, "app")
		} else {
			query["app"] = app
		}
	}
	if value, ok := query["pid"]; ok {
		valid := num(value) > 0 && num(value) <= math.MaxUint32
		switch n := value.(type) {
		case float64:
			valid = valid && n == math.Trunc(n)
		case int, int64:
		default:
			valid = false
		}
		if !valid {
			return nil, errors.New("pid must be a positive Windows process ID from a matching list_windows result. If unknown, omit pid or use null and search by app, e.g. {\"app\":\"Brave\",\"on_screen_only\":true}. Never use 0 or a different app's foreground PID")
		}
	}
	return query, nil
}

// Upstream's empty-result hint names the unrelated foreground process. Do not
// present that PID as a recovery candidate. Keep the exact filters and provide
// a separate suggested query; never silently widen the caller's PID scope.
func windowListing(result obj, query obj) obj {
	if result["isError"] == true {
		return result
	}
	data := object(result["structuredContent"])
	windows, ok := data["windows"].([]any)
	if !ok {
		return failure("Driver returned no window list; this is an observation error, not evidence that the application is absent", "not_started", "none", "invalid_window_list")
	}
	lookup := obj{"status": "matched", "filters": query, "count": len(windows)}
	lines := []string{fmt.Sprintf("Found %d matching window(s).", len(windows))}
	for _, value := range windows {
		window := object(value)
		lines = append(lines, fmt.Sprintf("- %s (pid %d), window_id %d, title %q", str(window["app_name"]), num(window["pid"]), num(window["window_id"]), str(window["title"])))
	}
	if len(windows) == 0 {
		lookup["status"] = "no_match"
		lines = append(lines, "No windows match these filters. This alone does not prove the application is unavailable or screenshot capture is broken. Do not substitute another application's foreground PID.")
		if str(query["app"]) != "" && query["pid"] != nil {
			next := obj{}
			for key, value := range query {
				if key != "pid" {
					next[key] = value
				}
			}
			lookup["suggested_arguments"] = next
			lines = append(lines, "app and pid are combined filters. Retry list_windows for the same app with pid omitted; use only a PID returned for that app.")
		} else if query["on_screen_only"] == true {
			next := obj{}
			for key, value := range query {
				next[key] = value
			}
			next["on_screen_only"] = false
			lookup["suggested_arguments"] = next
			lines = append(lines, "Retry the same filters with on_screen_only=false to check for minimized/off-screen windows. A listed window still needs a fresh get_window_state before interaction.")
		} else {
			lines = append(lines, "Verify the requested application name or PID. When the PID is unknown, search by the known app name with pid omitted. Do not guess a PID or operate an unrelated window.")
		}
	}
	data["lookup"] = lookup
	result["structuredContent"] = data
	result["content"] = []any{textBlock(strings.Join(lines, "\n"))}
	return result
}