using UnityEngine;

public class DialogueManager : MonoBehaviour
{
    [Header("References")]
    [SerializeField] private DialogueUI ui;
    [SerializeField] private DialogueBillboard billboard;

    [Header("Starting Dialogue")]
    [SerializeField] private DialogueData startingDialogue;
    [SerializeField] private Transform startingTarget;
    [SerializeField] private bool startOnAwake = false;

    [Header("Settings")]
    [SerializeField] private bool allowRestartWhileOpen = true;
    [SerializeField] private bool showDebugLog = true;

    private DialogueData currentDialogue;
    private int currentNodeIndex = -1;
    private Transform currentNpcTarget;

    public bool IsDialogueActive { get; private set; }

    private void Awake()
    {
        AutoFindReferences();
        ValidateReferences();
    }

    private void Start()
    {
        if (ui != null)
        {
            ui.SetVisible(false);
            ui.ClearChoices();
        }

        if (startOnAwake && startingDialogue != null)
            StartDialogue(startingDialogue, startingTarget);
    }

    private void AutoFindReferences()
    {
        if (ui == null)
            ui = FindFirstObjectByType<DialogueUI>();

        if (billboard == null)
            billboard = FindFirstObjectByType<DialogueBillboard>();
    }

    private void ValidateReferences()
    {
        if (ui == null)
            Debug.LogWarning("[DialogueManager] DialogueUI가 연결되지 않았습니다.");

        if (billboard == null)
            Debug.LogWarning("[DialogueManager] DialogueBillboard가 연결되지 않았습니다. VR 위치 추적 기능은 동작하지 않습니다.");
    }

    public void StartDialogue(DialogueData dialogue)
    {
        StartDialogue(dialogue, currentNpcTarget);
    }

    public void StartDialogue(DialogueData dialogue, Transform npc)
    {
        if (dialogue == null)
        {
            Debug.LogWarning("[DialogueManager] 시작할 DialogueData가 null입니다.");
            return;
        }

        if (!allowRestartWhileOpen && IsDialogueActive)
            return;

        if (!dialogue.HasNodes)
        {
            Debug.LogWarning($"[DialogueManager] DialogueData '{dialogue.name}'에 노드가 없습니다.");
            EndDialogue();
            return;
        }

        currentDialogue = dialogue;
        currentNodeIndex = 0;
        currentNpcTarget = npc;
        IsDialogueActive = true;

        if (ui != null)
            ui.SetVisible(true);

        if (billboard != null)
            billboard.SetTarget(npc);

        ShowCurrentNode();

        if (showDebugLog)
            Debug.Log($"[DialogueManager] Dialogue Start: {dialogue.name}");
    }

    public void StartDialogueFromNPC(DialogueData dialogue, Transform npc)
    {
        StartDialogue(dialogue, npc);
    }

    public void NextDialogue()
    {
        if (!IsDialogueActive)
            return;

        GoToNodeIndex(currentNodeIndex + 1);
    }

    public void GoToNodeIndex(int index)
    {
        if (currentDialogue == null)
        {
            EndDialogue();
            return;
        }

        if (!currentDialogue.IsValidIndex(index))
        {
            EndDialogue();
            return;
        }

        currentNodeIndex = index;
        ShowCurrentNode();
    }

    public void GoToNodeId(string nodeId)
    {
        if (currentDialogue == null)
        {
            EndDialogue();
            return;
        }

        int index = currentDialogue.GetNodeIndexById(nodeId);

        if (index < 0)
        {
            Debug.LogWarning($"[DialogueManager] nodeId '{nodeId}'를 찾을 수 없습니다.");
            EndDialogue();
            return;
        }

        GoToNodeIndex(index);
    }

    private void ShowCurrentNode()
    {
        if (currentDialogue == null)
        {
            EndDialogue();
            return;
        }

        if (!currentDialogue.TryGetNode(currentNodeIndex, out DialogueNode node))
        {
            Debug.LogWarning("[DialogueManager] 현재 노드를 가져올 수 없습니다.");
            EndDialogue();
            return;
        }

        if (ui == null)
            return;

        ui.SetSpeaker(node.speaker);
        ui.SetDialogueText(node.dialogue);

        if (HasChoices(node))
        {
            ui.SetNextButtonVisible(false);
            ui.CreateChoices(node.choices, OnChoiceClicked);
        }
        else
        {
            ui.ClearChoices();
            ui.SetNextButtonVisible(true);
            ui.SetupNextButton(NextDialogue);
        }
    }

    private bool HasChoices(DialogueNode node)
    {
        return node != null &&
               node.choices != null &&
               node.choices.Length > 0;
    }

    private void OnChoiceClicked(int choiceIndex)
    {
        if (!IsDialogueActive)
            return;

        if (currentDialogue == null)
            return;

        if (!currentDialogue.TryGetNode(currentNodeIndex, out DialogueNode node))
            return;

        if (node.choices == null ||
            choiceIndex < 0 ||
            choiceIndex >= node.choices.Length)
            return;

        ChoiceData choice = node.choices[choiceIndex];

        if (choice == null)
            return;

        HandleChoice(choice);
    }

    private void HandleChoice(ChoiceData choice)
    {
        choice.onSelected?.Invoke();

        if (choice.endDialogue)
        {
            EndDialogue();
            return;
        }

        if (choice.nextDialogue != null)
        {
            StartDialogue(choice.nextDialogue, currentNpcTarget);
            return;
        }

        if (!string.IsNullOrWhiteSpace(choice.nextNodeId))
        {
            GoToNodeId(choice.nextNodeId);
            return;
        }

        if (choice.nextNodeIndex >= 0)
        {
            GoToNodeIndex(choice.nextNodeIndex);
            return;
        }

        NextDialogue();
    }

    public void EndDialogue()
    {
        if (ui != null)
        {
            ui.ClearChoices();
            ui.SetNextButtonVisible(false);
            ui.SetVisible(false);
        }

        if (billboard != null)
            billboard.ClearTarget();

        currentDialogue = null;
        currentNodeIndex = -1;
        currentNpcTarget = null;
        IsDialogueActive = false;

        if (showDebugLog)
            Debug.Log("[DialogueManager] Dialogue End");
    }

    public void CloseDialogue()
    {
        EndDialogue();
    }
}