import * as I from 'immutable';

import {Trait} from '@avocado/entity';
import {behaviorItemFromJSON, createContext} from '@avocado/behavior';
import {hasGraphics, TextNodeRenderer} from '@avocado/graphics';

import {DamageEmitter} from './emitter';

export class Vulnerable extends Trait {

  static defaultParams() {
    return {
      tookDamageActions: {
        type: 'actions',
        traversals: [
          {
            type: 'traversal',
            steps: [
              {
                type: 'key',
                key: 'entity',
              },
              {
                type: 'key',
                key: 'emitParticle',
              },
              {
                type: 'invoke',
                args: [
                  {
                    type: 'literal',
                    value: 'damage',
                  },
                  {
                    type: 'traversal',
                    steps: [
                      {
                        type: 'key',
                        key: 'entity',
                      },
                      {
                        type: 'key',
                        key: 'position',
                      },
                    ],
                  },
                  {
                    type: 'traversal',
                    steps: [
                      {
                        type: 'key',
                        key: 'damage',
                      },
                    ],
                  },
                ],
              },
            ],
          },
          {
            type: 'traversal',
            steps: [
              {
                type: 'key',
                key: 'damage',
              },
              {
                type: 'key',
                key: 'from',
              },
              {
                type: 'key',
                key: 'playSound',
              },
              {
                type: 'invoke',
                args: [
                  {
                    type: 'traversal',
                    steps: [
                      {
                        type: 'key',
                        key: 'damage',
                      },
                      {
                        type: 'key',
                        key: 'from',
                      },
                      {
                        type: 'key',
                        key: 'damagingSound',
                      },
                    ],
                  },
                ],
              },
            ],
          },
        ],
      },
    }
  }

  static defaultState() {
    return {
      damageList: I.Map(),
    };
  }

  initialize() {
    this.damageId = 0;
    this.damageList = {};
    this._hasAddedEmitter = false;
    this._hasAddedEmitterRenderer = false;
    this._isHydrating  = false;
    this._isInvulnerable = false;
    this.locks = new Map();
    this._tookDamageActionsJSON = this.params.get('tookDamageActions').toJS();
    this.tookDamageActions = [];
  }

  hydrate() {
    this._isHydrating = true;
    this.addEmitter();
    this.addEmitterRenderer();
  }

  patchStateStep(key, step) {
    if ('state' !== key) {
      return;
    }
    const stateKey = step.path.substr(1);
    const value = this.transformPatchValue(stateKey, step.value);
    const stateKeyParts = stateKey.split('/');
    switch (stateKeyParts[0]) {
      case 'damageList':
        for (let i = 0; i < value.length; ++i) {
          const damage = value[i];
          if (this.entity.is('listed')) {
            damage.from = this.entity.list.findEntity(damage.from);
          }
          else {
            damage.from = undefined;
          }
          this.entity.emit('tookDamage', damage, 'client');
        }
        break;
      default:
        super.patchStateStep(key, step);
        break;
    }
  }

  addEmitter() {
    if (!this._isHydrating) {
      return;
    }
    if (this._hasAddedEmitter) {
      return;
    }
    if (!this.entity.is('emitter')) {
      return;
    }
    this.entity.addEmitter('damage', new DamageEmitter());
    this._hasAddedEmitter = true;
  }

  addEmitterRenderer() {
    if (!this._isHydrating) {
      return;
    }
    if (this._hasAddedEmitterRenderer) {
      return;
    }
    if (!this.entity.is('emitter')) {
      return;
    }
    if (!this.entity.is('staged') || !this.entity.stage) {
      return;
    }
    const renderer = new TextNodeRenderer('.damage', this.entity.stage);
    this.entity.addEmitterRenderer('damage', renderer);
    this._hasAddedEmitterRenderer = true;
  }

  get isInvulnerable() {
    return this._isInvulnerable;
  }

  set isInvulnerable(isInvulnerable) {
    this._isInvulnerable = isInvulnerable;
  }

  listeners() {
    return {

      tookDamage: (damage, source) => {
        if ('server' === source) {
          return;
        }
        const context = createContext();
        context.add('entity', this.entity);
        context.add('damage', damage);
        const actions = behaviorItemFromJSON(
          this._tookDamageActionsJSON
        );
        const tuple = {
          context,
          actions,
        };
        this.tookDamageActions.push(tuple);
        actions.on('actionsFinished', () => {
          const index = this.tookDamageActions.indexOf(tuple);
          this.tookDamageActions.splice(tuple);
        });
      },

      dying: () => {
        this._isInvulnerable = true;
      },

      stageChanged: () => {
        this.addEmitterRenderer();
      },

      traitsChanged: () => {
        this.addEmitter();
        this.addEmitterRenderer();
      },

    };
  }

  methods() {
    return {

      takeDamageFrom: (entity) => {
        const damageSpecs = entity.damageSpecs;
        for (let i = 0; i < damageSpecs.length; ++i) {
          const damageSpec = damageSpecs[i];
          if (this.locks.has(damageSpec)) {
            return;
          }
          this.locks.set(damageSpec, damageSpec.lock);
          const variance = Math.random() * damageSpec.variance * 2 - damageSpec.variance;
          const difference = damageSpec.power * variance;
          // Account for variance past 0, so track if it's damage or not.
          let amount = Math.round(damageSpec.power + difference);
          let isDamage;
          if (damageSpec.power < 0) {
            isDamage = false;
            if (amount > 0) {
              amount = 0;
            }
          }
          else {
            isDamage = true;
            if (amount < 0) {
              amount = 0;
            }
          }
          amount = Math.abs(amount);
          if (!this.damageList[entity.instanceUuid]) {
            this.damageList[entity.instanceUuid] = [];
          }
          const damage = {
            id: this.damageId++,
            isDamage,
            amount,
            damageSpec,
            from: entity.instanceUuid,
          };
          this.damageList[entity.instanceUuid].push(damage);
          this.entity.emit('tookDamage', damage, 'server');
        }
      },

    };
  }

  tick(elapsed) {
    for (let i = 0; i < this.tookDamageActions.length; ++i) {
      const {context, actions} = this.tookDamageActions[i];
      actions.tick(context, elapsed);
    }
    if (this.state.get('damageList').size > 0) {
      this.state = this.state.set('damageList', I.Map());
    }
    if (Object.keys(this.damageList).length > 0) {
      this.state = this.state.set('damageList', I.Map(this.damageList));
      this.isDirty = true;
      this.damageList = {};
    }
    const keys = Array.from(this.locks.keys());
    for (let i = 0; i < keys.length; ++i) {
      const key = keys[i];
      const remaining = this.locks.get(key) - elapsed;
      if (remaining <= 0) {
        this.locks.delete(key);
      }
      else {
        this.locks.set(key, remaining);
      }
    }
  }

}