using ClawdDotNet.Core.Accounting;
using ClawdDotNet.Core.Activity;
using ClawdDotNet.Core.Audit;
using ClawdDotNet.Core.Config;
using ClawdDotNet.Core.Engine;
using ClawdDotNet.Core.Organisation;
using ClawdDotNet.Core.Staging;

namespace ClawdDotNet.App.Services;

/// <summary>What an agent is doing, as the team overview shows it (#711).</summary>
public enum TeamState
{
    /// <summary>Nothing running, nothing open, the last run went fine (or there was none).</summary>
    Idle,

    /// <summary>At least one run in progress.</summary>
    Working,

    /// <summary>A run has taken much longer than this agent's runs usually take.</summary>
    Stuck,

    /// <summary>Tool calls of this agent wait for a human decision.</summary>
    WaitingForApproval,

    /// <summary>The last run failed, hit a limit or found the target busy.</summary>
    Problem,

    /// <summary>The last run was refused because the budget is used up.</summary>
    BudgetExhausted
}

/// <summary>One agent in the team overview.</summary>
public sealed record TeamMember(
    string AgentId,
    string DisplayName,
    string Model,
    TeamState State,
    IReadOnlyList<ActiveRun> Runs,
    int PendingApprovals,
    string? LastRunStatus,
    DateTime? LastRunAtUtc,
    string? LastRunResult,
    long TypicalRunMs,
    string? UnitId = null,
    bool IsLead = false);

/// <summary>
/// One unit in the team overview (#711, stage 1), with what happens inside it rolled up —
/// its own members and those of every unit below. A collapsed container shows this, so a
/// problem three levels down is still visible from the top.
/// </summary>
public sealed record TeamUnit(
    string Id,
    string Name,
    string? ParentId,
    string Path,
    string? LeaderAgentId,
    string? Goal,
    int Agents,
    IReadOnlyDictionary<TeamState, int> States,
    int PendingApprovals,
    TeamState Worst);

/// <summary>The whole picture at one moment: every agent and unit, and who reached whom recently.</summary>
public sealed record TeamSnapshot(
    IReadOnlyList<TeamMember> Members,
    IReadOnlyList<AgentLink> RecentLinks,
    DateTime AtUtc,
    IReadOnlyList<TeamUnit>? Units = null,
    IReadOnlyList<Core.Files.FileConflictHotspot>? ConflictHotspots = null);

/// <summary>
/// #711: The team overview — who is working, who reached whom, where something is stuck.
///
/// <para><b>Detecting is code, interpreting is model</b> (Organisation-Konzept, 10a). Every
/// state here comes from a fact the instance recorded: a run in progress, an open staged
/// call, the status of the last receipt. Nothing is judged by a model, so the picture is
/// the same for everyone who looks and costs nothing to draw.</para>
///
/// <para><b>Order of states.</b> When several apply, the one that needs someone first wins:
/// stuck, then waiting for approval, then working; a problem or an exhausted budget only
/// shows while nothing new is running — a new run is the attempt to get past it.</para>
/// </summary>
public sealed class TeamOverview(
    AgentEngine? engine,
    StagingService? staging,
    IAuditRepository? audit,
    IUsageRepository? usage,
    Func<IReadOnlyList<AgentConfig>> agents,
    TimeProvider? clock = null,
    Func<OrgChart>? organisation = null)
{
    /// <summary>How far back the last receipt of each agent is looked for.</summary>
    public static readonly TimeSpan ReceiptWindow = TimeSpan.FromDays(3);

    /// <summary>How long recent links stay in the snapshot — the overview fades them out.</summary>
    public static readonly TimeSpan LinkWindow = TimeSpan.FromMinutes(10);

    /// <summary>A run counts as stuck after this many times the agent's typical duration…</summary>
    public const int StuckFactor = 3;

    /// <summary>…but never before this — short runs vary a lot in relative terms.</summary>
    public static readonly TimeSpan StuckFloor = TimeSpan.FromMinutes(5);

    /// <summary>Without history, a run counts as stuck after this long.</summary>
    public static readonly TimeSpan StuckWithoutHistory = TimeSpan.FromMinutes(15);

    /// <summary>#720: How far back conflicts count for a hotspot…</summary>
    public static readonly TimeSpan HotspotWindow = TimeSpan.FromDays(7);

    /// <summary>…and how many make one. One conflict is an accident; three in a week are a pattern.</summary>
    public const int HotspotMinimum = 3;

    private readonly TimeProvider _clock = clock ?? TimeProvider.System;

    public async Task<TeamSnapshot> SnapshotAsync(CancellationToken ct)
    {
        var now = _clock.GetUtcNow().UtcDateTime;
        var configured = agents();

        var active = engine?.Activity.ActiveRuns() ?? [];
        var links = engine?.Activity.RecentLinks(LinkWindow) ?? [];

        var pending = staging is null ? [] : await staging.ListPendingAsync(ct);
        var pendingByAgent = pending
            .GroupBy(c => c.AgentId, StringComparer.OrdinalIgnoreCase)
            .ToDictionary(g => g.Key, g => g.Count(), StringComparer.OrdinalIgnoreCase);

        var lastReceipt = new Dictionary<string, RunReceipt>(StringComparer.OrdinalIgnoreCase);
        if (audit is not null)
        {
            var receipts = await audit.ListReceiptsAsync(now - ReceiptWindow, now, 5_000, ct);
            foreach (var receipt in receipts)
            {
                if (!lastReceipt.TryGetValue(receipt.AgentId, out var known) || receipt.OccurredAt > known.OccurredAt)
                    lastReceipt[receipt.AgentId] = receipt;
            }
        }

        var org = organisation?.Invoke() ?? new OrgChart([], configured);

        var members = new List<TeamMember>();
        foreach (var agent in configured)
        {
            var runs = active
                .Where(r => string.Equals(r.AgentId, agent.AgentId, StringComparison.OrdinalIgnoreCase))
                .OrderBy(r => r.StartedAtUtc)
                .ToList();
            var approvals = pendingByAgent.GetValueOrDefault(agent.AgentId);
            lastReceipt.TryGetValue(agent.AgentId, out var last);
            var typical = await TypicalRunAsync(agent.AgentId, ct);

            var state = Classify(runs, approvals, last?.Status, typical, now);
            members.Add(new TeamMember(
                agent.AgentId, agent.DisplayName, agent.Model, state, runs, approvals,
                last?.Status, last?.OccurredAt, last?.ResultRef, (long)typical.TotalMilliseconds,
                org.UnitOf(agent.AgentId)?.Id, org.LedBy(agent.AgentId) is not null));
        }

        // #720: files where agents keep getting in each other's way — for a human to decide
        // whether they should be split, appended to, or become a table.
        var hotspots = engine?.Files is { } files
            ? (await files.HotspotsAsync(now - HotspotWindow, HotspotMinimum, 10, ct))
                .Select(h => h with { Path = Readable(h.Path, configured) }).ToList()
            : [];

        return new TeamSnapshot(members, links, now, RollUp(org, members), hotspots);
    }

    /// <summary>
    /// #720: A file path as a human finds it — relative to the instance's <c>Agents</c> folder,
    /// where the shared workspaces live. A path elsewhere stays as it is.
    /// </summary>
    public static string Readable(string path, IReadOnlyList<AgentConfig> agents)
    {
        var shared = agents.Select(a => a.SharedWorkspacePath).FirstOrDefault(p => !string.IsNullOrWhiteSpace(p));
        if (shared is null
            || Path.GetDirectoryName(Path.TrimEndingDirectorySeparator(Path.GetFullPath(shared))) is not { } agentsDir)
            return path;
        var relative = Path.GetRelativePath(agentsDir, path);
        return relative.StartsWith("..", StringComparison.Ordinal) || Path.IsPathRooted(relative)
            ? path
            : relative.Replace(Path.DirectorySeparatorChar, '/');
    }

    /// <summary>
    /// How much a state needs someone — the higher, the sooner. A container takes the most
    /// urgent state of everything inside it, so "somewhere in here" points at the right thing.
    /// </summary>
    public static int Urgency(TeamState state) => state switch
    {
        TeamState.Stuck => 5,
        TeamState.Problem => 4,
        TeamState.WaitingForApproval => 3,
        TeamState.BudgetExhausted => 2,
        TeamState.Working => 1,
        _ => 0
    };

    /// <summary>
    /// Every unit with the states of all agents in it and below. Pure, like
    /// <see cref="Classify"/>: the page draws the numbers, it does not add them up.
    /// </summary>
    public static IReadOnlyList<TeamUnit> RollUp(OrgChart org, IReadOnlyList<TeamMember> members)
    {
        var result = new List<TeamUnit>();
        foreach (var unit in org.Units.OrderBy(u => org.PathOf(u.Id), StringComparer.OrdinalIgnoreCase))
        {
            // Everyone whose unit is this one or lies below it. Ancestors() stops at a
            // cycle, so a broken tree cannot hang the overview.
            var inside = members
                .Where(m => m.UnitId is { } id
                            && (string.Equals(id, unit.Id, StringComparison.OrdinalIgnoreCase)
                                || org.Ancestors(id).Any(a => string.Equals(a.Id, unit.Id, StringComparison.OrdinalIgnoreCase))))
                .ToList();

            var states = inside
                .GroupBy(m => m.State)
                .ToDictionary(g => g.Key, g => g.Count());
            var worst = inside.Select(m => m.State).DefaultIfEmpty(TeamState.Idle).MaxBy(Urgency);

            result.Add(new TeamUnit(
                unit.Id, unit.Name, unit.ParentId, org.PathOf(unit.Id), org.LeaderOf(unit.Id)?.AgentId, unit.Goal,
                inside.Count, states, inside.Sum(m => m.PendingApprovals), worst));
        }
        return result;
    }

    /// <summary>
    /// The state from the facts. Pure, so the rules can be tested without an instance.
    /// </summary>
    public static TeamState Classify(
        IReadOnlyList<ActiveRun> runs, int pendingApprovals, string? lastRunStatus, TimeSpan typicalRun, DateTime nowUtc)
    {
        if (runs.Count > 0)
        {
            var limit = typicalRun > TimeSpan.Zero
                ? TimeSpan.FromTicks(Math.Max(typicalRun.Ticks * StuckFactor, StuckFloor.Ticks))
                : StuckWithoutHistory;
            if (runs.Any(r => nowUtc - r.StartedAtUtc > limit))
                return TeamState.Stuck;
        }

        if (pendingApprovals > 0)
            return TeamState.WaitingForApproval;

        if (runs.Count > 0)
            return TeamState.Working;

        return lastRunStatus switch
        {
            nameof(AgentRunStatus.BudgetExceeded) => TeamState.BudgetExhausted,
            nameof(AgentRunStatus.Failed)
                or nameof(AgentRunStatus.LoopLimitExceeded)
                or nameof(AgentRunStatus.TargetBusy) => TeamState.Problem,
            _ => TeamState.Idle
        };
    }

    /// <summary>The agent's typical run duration — the median of its recent runs.</summary>
    private async Task<TimeSpan> TypicalRunAsync(string agentId, CancellationToken ct)
    {
        if (usage is null)
            return TimeSpan.Zero;

        var recent = await usage.GetRecentForAgentAsync(agentId, 20, ct);
        var durations = recent.Where(r => r.DurationMs > 0).Select(r => r.DurationMs).Order().ToList();
        return durations.Count == 0 ? TimeSpan.Zero : TimeSpan.FromMilliseconds(durations[durations.Count / 2]);
    }
}