using FlaUI.Core.AutomationElements;
using FlaUI.Core.Definitions;
using WxAgent.Core;

namespace WxAgent.Windows;

public static partial class WechatChatClient
{
    private static FlaUI.Core.AutomationElements.TextBox GetSearchBox(AutomationElement main) =>
        (main.FindFirstDescendant(cf => cf.ByControlType(ControlType.Edit).And(cf.ByName(WechatLocators.Search)))
            ?? throw new WxAgentException(WxAgentErrorCode.ControlNotFound, "Search input was not found.")).AsTextBox();

    private static AutomationElement[] GetSearchRows(AutomationElement main) =>
        (FindByAutomationId(main, WechatLocators.SearchList)
            ?? throw new WxAgentException(WxAgentErrorCode.UiStructureChanged, "Local search list was not found."))
        .FindAllChildren(cf => cf.ByControlType(ControlType.ListItem));

    private static WechatSearchPage ReadSearchPage(AutomationElement[] rows, string query, string? category = null) =>
        WechatSearchRules.Parse(rows.Select(row => (SafeAutomationId(row), SafeName(row))).ToArray(), query, category);

    private static async Task<WechatSearchPage> ResetLocalSearchAsync(AutomationElement main, string query, CancellationToken cancellationToken)
    {
        GetSearchBox(main).Text = string.Empty;
        GetSearchBox(main).Text = query;
        if (!string.Equals(GetSearchBox(main).Text, query, StringComparison.Ordinal))
            throw new WxAgentException(WxAgentErrorCode.ResultUnconfirmed, "Search input did not retain the exact query.");
        await Task.Delay(500, cancellationToken).ConfigureAwait(false);
        return ReadSearchPage(GetSearchRows(main), query);
    }

    private static async Task<WechatSearchPage> ExpandLocalCategoryAsync(
        AutomationElement main, string query, WechatSearchExpansion expansion, CancellationToken cancellationToken)
    {
        var rows = GetSearchRows(main);
        var current = ReadSearchPage(rows, query).Expansions.SingleOrDefault(item => item.Category == expansion.Category)
            ?? throw new WxAgentException(WxAgentErrorCode.UiStructureChanged, "Local expansion control changed before activation.");
        // This row was classified under a local header, not found by a global keyword/name search.
        rows[current.RowIndex].Click();
        for (var attempt = 0; attempt < 25; attempt++)
        {
            await Task.Delay(100, cancellationToken).ConfigureAwait(false);
            var page = ReadSearchPage(GetSearchRows(main), query, current.Category);
            if (page.Results.Count(result => result.Category == current.Category) >= current.ExpectedCount
                && !page.Expansions.Any(item => item.Category == current.Category)) return page;
        }
        throw new WxAgentException(WxAgentErrorCode.UiStructureChanged, "Not all local search results became available; refusing a partial selection.");
    }

    private static async Task<IReadOnlyList<WechatSessionSearchResult>> SearchLocalSessionsCoreAsync(
        AutomationElement main, string query, CancellationToken cancellationToken)
    {
        var overview = await ResetLocalSearchAsync(main, query, cancellationToken).ConfigureAwait(false);
        var results = overview.Results.ToList();
        foreach (var expansion in overview.Expansions)
        {
            await ResetLocalSearchAsync(main, query, cancellationToken).ConfigureAwait(false);
            var full = await ExpandLocalCategoryAsync(main, query, expansion, cancellationToken).ConfigureAwait(false);
            results.RemoveAll(result => result.Category == expansion.Category);
            results.AddRange(full.Results.Where(result => result.Category == expansion.Category));
        }
        return results;
    }

    private static async Task<WechatSessionSearchResult> OpenLocalSearchSessionAsync(AutomationElement main, string name, CancellationToken cancellationToken, string? query = null)
    {
        query ??= name;
        var results = await SearchLocalSessionsCoreAsync(main, query, cancellationToken).ConfigureAwait(false);
        var selected = WechatSearchRules.RequireExact(results, name);
        var page = await ResetLocalSearchAsync(main, query, cancellationToken).ConfigureAwait(false);
        var expansion = page.Expansions.SingleOrDefault(item => item.Category == selected.Category);
        if (expansion is not null)
            await ExpandLocalCategoryAsync(main, query, expansion, cancellationToken).ConfigureAwait(false);
        var rows = GetSearchRows(main);
        var current = ReadSearchPage(rows, query, expansion?.Category);
        var fresh = WechatSearchRules.RequireExact(current.Results, name);
        if (fresh.Category != selected.Category)
            throw new WxAgentException(WxAgentErrorCode.InvalidOperationState, "Local search category changed before selection.");
        var matches = rows.Where(row => SafeAutomationId(row) == fresh.AutomationId && SessionNameMatches(SafeName(row), name)).ToArray();
        if (matches.Length != 1)
            throw new WxAgentException(WxAgentErrorCode.InvalidOperationState, "Local search target is no longer unique.");
        if (matches[0].IsOffscreen)
        {
            var scroll = matches[0].Patterns.ScrollItem.PatternOrDefault
                ?? throw new WxAgentException(WxAgentErrorCode.ControlNotFound, "Local result is offscreen and cannot be scrolled into view.");
            scroll.ScrollIntoView();
        }
        matches[0].Click();
        await WaitForSessionPageAsync(main, name, cancellationToken).ConfigureAwait(false);
        return fresh;
    }
}