'use strict';

const threshold = 0.5;


const move_forward = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] > threshold) {
      const dx = { n: 0, e: 1, s: 0, w: -1 }[agent.flags.orientation];
      const dy = { n: -1, e: 0, s: 1, w: 0 }[agent.flags.orientation];
      return [{
        agent_changes: [{
          agent_id: agent.id,
          x: agent.x + dx,
          y: agent.y + dy,
        }],
      }];
    } else {
      return [];
    }
  },
};


const move_backward = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] > threshold) {
      const dx = { n: 0, e: 1, s: 0, w: -1 }[agent.flags.orientation];
      const dy = { n: -1, e: 0, s: 1, w: 0 }[agent.flags.orientation];
      return [{
        agent_changes: [{
          agent_id: agent.id,
          x: agent.x - dx,
          y: agent.y - dy,
        }],
      }];
    } else {
      return [];
    }
  },
};


const turn_left = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] > threshold) {
      const orientation = { n: 'w', e: 'n', s: 'e', w: 's' }[agent.flags.orientation];
      return [{
        agent_changes: [{
          agent_id: agent.id,
          flags: { orientation },
        }],
      }];
    } else {
      return [];
    }
  },
};


const turn_right = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] > threshold) {
      const orientation = { n: 'e', e: 's', s: 'w', w: 'n' }[agent.flags.orientation];
      return [{
        agent_changes: [{
          agent_id: agent.id,
          flags: { orientation },
        }],
      }];
    } else {
      return [];
    }
  },
};


const place = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] < threshold) { return []; }
    else {
      const dx = { n: 0, e: 1, s: 0, w: -1 }[agent.flags.orientation];
      const dy = { n: -1, e: 0, s: 1, w: 0 }[agent.flags.orientation];
      return [
        { lattice_changes: [{
          x: agent.x + dx, y: agent.y + dy,
          from: 'empty', to: 'mutable',
          flags: { emit: [1, 0, 0, 0, 0, 0, 0, 0] },
        }]}
      ];
    }
  },
};


const trigger = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] < threshold) { return []; }
    else {
      const dx = { n: 0, e: 1, s: 0, w: -1 }[agent.flags.orientation];
      const dy = { n: -1, e: 0, s: 1, w: 0 }[agent.flags.orientation];
      return [
        { lattice_changes: [{
          x: agent.x + dx, y: agent.y + dy,
          from: 'mutable', to: 'active',
          flags: { emit: [1, 0, 0, 0, 0, 0, 0, 0] },
        }]}
      ];
    }
  },
};


const pretend_frozen = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] < threshold) { return [{
      agent_changes: [{
        agent_id: agent.id,
        flags: { pretend_frozen: false },
      }],
    }]; }
    else {
      return [{
        agent_changes: [{
          agent_id: agent.id,
          flags: { pretend_frozen: true },
        }]
      }];
    }
  },
};


const unfreeze = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] < threshold) { return []; }
    else {
      const dx = { n: 0, e: 1, s: 0, w: -1 }[agent.flags.orientation];
      const dy = { n: -1, e: 0, s: 1, w: 0 }[agent.flags.orientation];
      const target = world.agents.filter(
        a => a.x === agent.x+dx && a.y === agent.y+dy
      )[0];
      if (target === undefined) { return []; }
      return [
        { agent_changes: [{
          agent_id: target.id,
          flags: { frozen: false, emit: [0, 1, 0, 0, 0, 0, 0, 0] },
        }]}
      ];
    }
  },
};


const take_flag = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] < threshold) { return []; }
    else {
      const dx = { n: 0, e: 1, s: 0, w: -1 }[agent.flags.orientation];
      const dy = { n: -1, e: 0, s: 1, w: 0 }[agent.flags.orientation];
      const target = world.agents.filter(
        a => a.x === agent.x+dx && a.y === agent.y+dy
      )[0];
      if (target === undefined || !target.flags.flag) {
        return [
          { 
            lattice_changes: [{
              x: agent.x + dx, y: agent.y + dy,
              from: 'flag', to: 'empty',
              flags: { emit: [ 0, 0, 1, 0, 0, 0, 0, 0 ] },
            }],
            agent_changes: [{
              agent_id: agent.id,
              flags: { flag: true },
            }],
          }
        ];
      } else {
        return [{
          agent_changes: [
            {
              agent_id: target.id,
              flags: { flag: false },
            },
            {
              agent_id: agent.id,
              flags: { flag: true },
            },
          ],
        }];
      }
    }
  },
};


const drop_flag = {
  size: 1,
  propose: (world, agent, head) => {
    if (head[0] < threshold) { return []; }
    else if (!agent.flags.flag) { return []; }
    else {
      const dx = { n: 0, e: 1, s: 0, w: -1 }[agent.flags.orientation];
      const dy = { n: -1, e: 0, s: 1, w: 0 }[agent.flags.orientation];
      return [
        { 
          lattice_changes: [{
            x: agent.x + dx, y: agent.y + dy,
            from: 'empty', to: 'flag',
            flags: { emit: [ 0, 0, -1, 0, 0, 0, 0, 0 ] },
          }],
          agent_changes: [{
            agent_id: agent.id,
            flags: { flag: false },
          }],
        }
      ];
    }
  },
};


const speak = {
  size: 8,
  propose: (world, agent, head) => {
    return [
      {
        agent_changes: [{
          agent_id: agent.id,
          flags: { emit: head },
        }],
      },
    ];
  },
};


export const actions = [
  move_forward, move_backward, turn_left, turn_right, 
  place, trigger, pretend_frozen, unfreeze, take_flag, drop_flag,
  speak,
];