#include "unit.h"
#include "pathfinder.h"
#include "terrainmovementmanager.h"
#include <algorithm>
#include <cmath>

Unit::Unit(int uId, int pId, const UnitConfig &cfg, int startX, int startY, float groundZ)
    : id(uId), playerId(pId), config(cfg), tileX(startX), tileY(startY),
      health((float)cfg.health), maxHealth((float)cfg.health),
      buildCharges(cfg.buildCharges),
      state(UnitState::Idle), pathIndex(0), moveProgress(0.0f),
      targetTileX(startX), targetTileY(startY), attackFlashTimer(0.0f),
      buildProgress(0.0f), buildDuration(0.0f), buildingImprovementId("")
{
    QVector2D w = Pathfinder::hexToWorld(startX, startY);
    worldPos = QVector3D(w.x(), w.y(), groundZ);
}

float Unit::getTerrainHeight(float worldX, float worldY, Matrix2D<TerrainPoint> *mapPoints, int numPoints05)
{
    if (!mapPoints || numPoints05 <= 0) return 1.0f;

    float scaleX = numPoints05 * 2.0f;
    float scaleY = numPoints05 / LOD_0_SIZE_Y;

    int mapX = (int) std::round(worldX * scaleX);
    int mapY = (int) std::round(worldY * scaleY);

    if (mapX < 0) mapX = 0;
    if (mapX >= (int)mapPoints->getWidth()) mapX = (int)mapPoints->getWidth() - 1;
    if (mapY < 0) mapY = 0;
    if (mapY >= (int)mapPoints->getHeight()) mapY = (int)mapPoints->getHeight() - 1;

    unsigned char h = mapPoints->operator()(mapX, mapY).height;
    return (h / 255.0f) * 3.5f + 1.0f;
}

bool Unit::queueAction(const UnitAction &action)
{
    if ((int)actionQueue.size() >= maxQueueSize) {
        return false;
    }
    actionQueue.push_back(action);
    return true;
}

void Unit::clearActionQueue()
{
    actionQueue.clear();
}

bool Unit::hasQueuedActionType(UnitActionType type) const
{
    for (const auto &act : actionQueue) {
        if (act.type == type) return true;
    }
    return false;
}

void Unit::removeQueuedActionsOfType(UnitActionType type)
{
    for (auto it = actionQueue.begin(); it != actionQueue.end(); ) {
        if (it->type == type) {
            it = actionQueue.erase(it);
        } else {
            ++it;
        }
    }
}

UnitAction Unit::popNextQueuedAction()
{
    if (actionQueue.empty()) return UnitAction();
    UnitAction act = actionQueue.front();
    actionQueue.pop_front();
    return act;
}

const UnitAction* Unit::peekNextQueuedAction() const
{
    if (actionQueue.empty()) return nullptr;
    return &actionQueue.front();
}

QString Unit::getQueuedActionSummary() const
{
    if (actionQueue.empty()) return "";
    switch (actionQueue.front().type) {
    case UnitActionType::Move:
        return "Move";
    case UnitActionType::BuildImprovement:
        return "Build Farm";
    case UnitActionType::BuildCity:
        return "Found City";
    case UnitActionType::BuildRoad:
        return "Build Road";
    case UnitActionType::Attack:
        return "Attack";
    default:
        return "Action";
    }
}

void Unit::setPath(const std::vector<std::pair<int, int>> &newPath)
{
    path = newPath;
    pathIndex = 0;
    moveProgress = 0.0f;

    if (path.size() > 1) {
        state = UnitState::Moving;
        targetTileX = path.back().first;
        targetTileY = path.back().second;
    } else {
        state = UnitState::Idle;
    }
}

void Unit::stopMovement()
{
    path.clear();
    pathIndex = 0;
    moveProgress = 0.0f;
    state = UnitState::Idle;
    clearActionQueue();
    clearRoadRoute();
}

void Unit::startBuilding(const QString &impId, float duration)
{
    path.clear();
    pathIndex = 0;
    moveProgress = 0.0f;
    state = UnitState::Building;
    buildingImprovementId = impId;
    buildDuration = std::max(0.1f, duration);
    buildProgress = 0.0f;
}

void Unit::cancelBuilding()
{
    if (state == UnitState::Building) {
        state = UnitState::Idle;
        buildProgress = 0.0f;
        buildDuration = 0.0f;
        buildingImprovementId = "";
    }
}

void Unit::update(float deltaTime, float tickDuration, float simSpeedMultiplier,
                 Matrix2D<TerrainPoint> *mapPoints, int numPoints05)
{
    if (attackFlashTimer > 0.0f) {
        attackFlashTimer = std::max(0.0f, attackFlashTimer - deltaTime);
    }

    if (state == UnitState::Building) {
        if (buildDuration > 0.001f) {
            buildProgress += (deltaTime * simSpeedMultiplier) / buildDuration;
        }
        return;
    }

    if (state != UnitState::Moving || path.size() <= 1) {
        return;
    }

    // Current segment movement step cost (considering terrain type and slope)
    float stepCost = 1.0f;
    if (pathIndex + 1 < path.size()) {
        int fromX = path[pathIndex].first;
        int fromY = path[pathIndex].second;
        int toX = path[pathIndex + 1].first;
        int toY = path[pathIndex + 1].second;
        stepCost = TerrainMovementManager::instance().calculateStepCost(
            fromX, fromY, toX, toY, config.movementDomain, mapPoints, numPoints05, &config
        );
        if (stepCost <= 0.05f) stepCost = 1.0f;
    }

    // Speed in hexes per second: movementSpeed points per tickDuration seconds divided by stepCost
    float effectiveTickDuration = std::max(0.1f, tickDuration);
    float hexesPerSec = (config.movementSpeed / (effectiveTickDuration * stepCost)) * simSpeedMultiplier;

    moveProgress += deltaTime * hexesPerSec;

    while (moveProgress >= 1.0f && pathIndex + 1 < path.size()) {
        moveProgress -= 1.0f;
        pathIndex++;
        tileX = path[pathIndex].first;
        tileY = path[pathIndex].second;
    }

    if (pathIndex + 1 >= path.size()) {
        // Reached destination
        tileX = path.back().first;
        tileY = path.back().second;
        QVector2D dest = Pathfinder::hexToWorld(tileX, tileY);
        float gz = getTerrainHeight(dest.x(), dest.y(), mapPoints, numPoints05);
        worldPos = QVector3D(dest.x(), dest.y(), gz);
        state = UnitState::Idle;
        path.clear();
        moveProgress = 0.0f;
        return;
    }

    // Smoothly interpolate between current waypoint and next waypoint
    QVector2D from = Pathfinder::hexToWorld(path[pathIndex].first, path[pathIndex].second);
    QVector2D to = Pathfinder::hexToWorld(path[pathIndex + 1].first, path[pathIndex + 1].second);

    float t = std::max(0.0f, std::min(1.0f, moveProgress));
    float curX = from.x() + t * (to.x() - from.x());
    float curY = from.y() + t * (to.y() - from.y());
    float curZ = getTerrainHeight(curX, curY, mapPoints, numPoints05);

    worldPos = QVector3D(curX, curY, curZ);
}

bool Unit::canAttack(const Unit &other) const
{
    if (other.playerId == playerId) return false;
    if (other.isDead() || isDead()) return false;
    if (!config.canAttack()) return false;

    int dist = Pathfinder::hexDistance(tileX, tileY, other.tileX, other.tileY);
    return dist <= config.attackRange;
}

void Unit::performAttack(Unit &target)
{
    if (!canAttack(target)) return;

    attackFlashTimer = 0.5f; // Visual flash duration
    target.takeDamage((float)config.attackDamage);

    // Retaliation if target is adjacent melee military unit
    if (!target.isDead() && target.config.isMilitary() && !config.isRanged()) {
        int dist = Pathfinder::hexDistance(tileX, tileY, target.tileX, target.tileY);
        if (dist <= target.config.attackRange) {
            takeDamage(target.config.attackDamage * 0.5f); // 50% counterattack damage
        }
    }
}

void Unit::takeDamage(float damage)
{
    health = std::max(0.0f, health - damage);
    attackFlashTimer = 0.4f;
}