use std::{fmt::Display};
use rand::prelude::*;

use crate::{time::Time, world::{World}, generators::PersonNameGenerator, state::{GameState, Action}, entity::{Entity, Location, EntityId}, item::ItemGenerator, events::ItemCrafted};

#[derive(Clone, Copy)]
pub enum Profession {
    Peasant,
    Adventurer,
    Blacksmith,
}

#[derive(Clone, Copy)]
pub enum Agenda {
    Idle(u32), // number of days to idle
    Traveling(Location), // destination
    Craft,
}

#[derive(Clone)]
pub struct Creature {
    pub entity: Entity,
    pub name: String,
    pub birth_date: Time,
    pub profession: Profession,
    pub agenda: Agenda,
    pub inventory: Vec<EntityId>,
    pub weapon: Option<EntityId>,
    pub armor: Option<EntityId>,
}

pub struct CreatureGenerator;

impl Display for Profession {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Profession::Peasant => write!(f, "Peasant"),
            Profession::Adventurer => write!(f, "Adventurer"),
            Profession::Blacksmith => write!(f, "Blacksmith"),
        }
    }
}


impl Creature {
    pub fn new(birth_date: Time, location: Location, profession: Profession) -> Creature {
        Creature {
            entity: Entity { id: 0, loc: location },
            name: PersonNameGenerator::name(),
            birth_date: birth_date,
            profession: profession,
            agenda: Agenda::Idle(0),
            inventory: Vec::new(),
            weapon: None,
            armor: None,
        }
    }

    fn travel_to_random_location(&self, world: &World) -> Agenda {
        let mut rng = rand::thread_rng();
        let dest = world.sites.keys().choose(&mut rng);
        if let Some(dest) = dest {
            Agenda::Traveling(*dest)
        } else {
            Agenda::Idle(1)
        }
    }

    fn select_peasant_agenda(&self, _world: &World) -> Agenda {
        Agenda::Idle(10)
    }

    fn select_adventurer_agenda(&self, world: &World) -> Agenda {
        self.travel_to_random_location(world)
    }

    fn select_blacksmith_agenda(&self, _world: &World) -> Agenda {
        let mut rng = rand::thread_rng();
        let p = rng.gen_range(0.0..1.0);
        if p < 0.1 {
            Agenda::Idle(10)
        } else if p < 0.55 {
            Agenda::Craft
        } else {
            self.travel_to_random_location(_world)
        }

    }


    fn select_agenda(&self, world: &World) -> Agenda {
        match self.profession {
            Profession::Peasant => self.select_peasant_agenda(world),
            Profession::Adventurer => self.select_adventurer_agenda(world),
            Profession::Blacksmith => self.select_blacksmith_agenda(world),
        }
    }

    pub fn step(&mut self, world: &World) -> Vec<Box<dyn Action>> {
        match &self.agenda {
            Agenda::Idle(days) => {
                // do nothing
                if *days <= 0 {
                    // pick random destination
                    self.agenda = self.select_agenda(world);
                } else {
                    self.agenda = Agenda::Idle(days - 1);
                }
                Vec::new()
            },
            Agenda::Traveling(destination) => {
                // TDOO: A* pathfinding with terrain costs
                // move towards destination
                if self.entity.loc.x < destination.x {
                    self.entity.loc.x += 1;
                } else if self.entity.loc.x > destination.x {
                    self.entity.loc.x -= 1;
                }
                if self.entity.loc.y < destination.y {
                    self.entity.loc.y += 1;
                } else if self.entity.loc.y > destination.y {
                    self.entity.loc.y -= 1;
                }
                if self.entity.loc == *destination {
                    self.agenda = Agenda::Idle(10);
                }
                Vec::new()
            },
            Agenda::Craft => {
                vec![
                    Box::new(ItemCrafted {
                        crafter: self.entity.id,
                        item: ItemGenerator::generate_item(),
                    })
                ]
            }
        }
    }

    #[allow(dead_code)]
    pub fn set_agenda(&mut self, agenda: Agenda) {
        self.agenda = agenda;
    }

    pub fn say_agenda(&self, state: & GameState) -> String {
        match &self.agenda {
            Agenda::Idle(days) => format!("I'll stay here for {} days", days),
            Agenda::Traveling(destination) => {
                let dest_site = state.world.get_site_at(*destination);
                match dest_site {
                    Some(site) => {
                        return format!("I'm traveling to {}", site);
                    },
                    None => return format!("I'm traveling to an unknown location"),
                }
            },
            Agenda::Craft => {
                return format!("I'm crafting");
            }
        }
    }
}

impl Display for Creature {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.name)
    }
}



impl CreatureGenerator {
    pub fn create_human(birth_date: Time, location: Location) -> Creature {
        // pick random profession
        let mut rng = rand::thread_rng();
        let profession = rng.gen_range(0..3);
        let profession = match profession {
            0 => Profession::Peasant,
            1 => Profession::Adventurer,
            2 => Profession::Blacksmith,
            _ => panic!("Invalid profession"),
        };
        Creature::new(birth_date, location, profession)
    }
}

#[cfg(test)]
mod tests {
    use crate::{world::{World}, site::{Site, Town, Structure}};

    use super::*;

    #[test]
    fn test_person_creation() {
        let person = Creature::new(Time { time: 0 }, Location{x: 0, y: 0}, Profession::Peasant);
        assert_ne!(person.name, "");
    }

    #[test]
    fn test_traveling() {
        let mut person = Creature::new(Time { time: 0 }, Location{x: 0, y: 0}, Profession::Peasant);
        person.agenda = Agenda::Traveling(Location{x: 10, y: 0});
        person.step(&World::new(32));
        assert_eq!(person.entity.loc, Location{x: 1, y: 0});
    }

    #[test]
    fn test_start_traveling() {
        let mut person = Creature::new(Time { time: 0 }, Location{x: 0, y: 0}, Profession::Peasant);
        person.agenda = Agenda::Idle(0);
        let mut world = World::new(32);
        world.add_site(Site{
            entity: Entity { id: 0, loc: Location{x: 10, y: 10} },
            structure: Structure::Town(Town::new()),
        });
        person.step(&world);
        match &person.agenda {
            Agenda::Traveling(_) => {},
            _ => { panic!("Person should be traveling") },
            
        }
    }
}