using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// Sits on the "Radar" overlay object (a disc rendered by the Radar Camera in front of the main camera).
/// Spawns "Target" blips - clones of the child "Target Template" - each of which continuously points from
/// the reference camera toward a world-space transform (visualising the bearing camera -> target) and then
/// destroys itself after a given lifetime. See <see cref="RadarTarget"/> for the per-blip behaviour.
///
/// The whole radar overlay is only shown while it is useful: at least one live target, first-person is active,
/// AND the match is in its Seek phase. It is hidden by switching the overlay camera's rendering off (not by
/// deactivating the GameObjects), so hidden blips keep counting down their lifetime and self-destruct on schedule.
/// </summary>
[DisallowMultipleComponent]
public sealed class Radar : MonoBehaviour
{
    /// <summary>The scene's single radar overlay (lives in the persistent Main scene). Hunter clients spawn
    /// hider blips onto it from MatchManager's radar-ping sweep.</summary>
    public static Radar Instance { get; private set; }

    [Tooltip("Template each spawned Target is cloned from. Auto-resolves to the child \"Target Template\".")]
    [SerializeField] private Transform targetTemplate;

    [Tooltip("Camera the direction is measured FROM (camera -> target). Auto-resolves to the Camera this radar sits under.")]
    [SerializeField] private Camera referenceCamera;

    [Tooltip("Overlay camera that renders the radar. Its rendering is toggled off unless the radar should show " +
             "(at least one live target AND first-person active). Auto-resolves to the Camera this radar sits under.")]
    [SerializeField] private Camera radarCamera;

    [Tooltip("First-person rig. The radar is only shown while first-person is active. Empty = found automatically.")]
    [SerializeField] private FirstPersonController firstPerson;

    // Live blips, pruned as they self-destruct; the radar shows only while at least one is alive.
    private readonly List<RadarTarget> _blips = new List<RadarTarget>();

    private void Awake()
    {
        Instance = this;

        if (!targetTemplate)
        {
            var t = transform.Find("Target Template");
            if (t) targetTemplate = t;
        }
        if (!referenceCamera) referenceCamera = GetComponentInParent<Camera>();
        if (!radarCamera) radarCamera = GetComponentInParent<Camera>();
        if (!firstPerson) firstPerson = FindFirstObjectByType<FirstPersonController>(FindObjectsInactive.Include);

        ApplyVisibility(false); // hidden until a target exists, first-person is live AND the match is seeking
    }

    private void OnDestroy()
    {
        if (Instance == this) Instance = null;
    }

    /// <summary>
    /// Spawns a Target blip that each frame orients toward <paramref name="target"/> (from the reference
    /// camera) and destroys itself after <paramref name="lifetime"/> seconds. Returns the spawned blip, or
    /// null if it could not be created.
    /// </summary>
    public RadarTarget Spawn(Transform target, float lifetime)
    {
        if (!target)
        {
            Debug.LogWarning("[Radar] Spawn called without a target transform.", this);
            return null;
        }
        if (!targetTemplate)
        {
            Debug.LogWarning("[Radar] No Target Template assigned or found.", this);
            return null;
        }

        Transform clone = Instantiate(targetTemplate, targetTemplate.parent);
        clone.name = "Target";
        clone.localPosition = targetTemplate.localPosition;
        clone.localScale = targetTemplate.localScale;
        clone.gameObject.SetActive(true);

        var blip = clone.GetComponent<RadarTarget>();
        blip.Init(target, referenceCamera, lifetime);
        _blips.Add(blip);
        return blip;
    }

    // LateUpdate so the count reflects any blip that self-destructed this frame, in step with RadarTarget's aim.
    private void LateUpdate()
    {
        // Drop self-destructed blips (Destroy leaves a fake-null entry behind).
        for (int i = _blips.Count - 1; i >= 0; i--)
            if (!_blips[i]) _blips.RemoveAt(i);

        bool visible = _blips.Count > 0 && firstPerson && firstPerson.enabled && InSeekPhase();
        ApplyVisibility(visible);
    }

    // The radar only makes sense during the seek phase (hunters chasing hiders). Blips only spawn then anyway,
    // but a blip's lifetime can outlast the phase edge, so gating here hides the overlay the instant Seek ends.
    private static bool InSeekPhase()
    {
        var m = MatchManager.Instance;
        return m && m.MatchActive && m.LocalSubPhase == MatchManager.MatchSubPhase.Seek;
    }

    // Shows/hides the whole radar overlay in one toggle (disc + blips) by switching the overlay camera's
    // rendering. The GameObjects stay active, so blips keep ticking down their lifetime while hidden. The
    // overlay renders only the Radar layer, so nothing else is affected.
    private void ApplyVisibility(bool visible)
    {
        if (radarCamera && radarCamera.enabled != visible)
            radarCamera.enabled = visible;
    }
}