//! Village map: grid, obstacles, named places, pathfinding, building meshes.

use bevy::prelude::*;
use std::collections::{HashMap, VecDeque};

pub const GRID: i32 = 64;

#[derive(Resource)]
pub struct WorldMap {
    /// true = blocked (buildings, props)
    pub blocked: Vec<bool>,
    /// lowercase place name -> cell
    pub pois: HashMap<String, IVec2>,
}

impl WorldMap {
    pub fn idx(cell: IVec2) -> usize {
        (cell.y * GRID + cell.x) as usize
    }

    pub fn inside(cell: IVec2) -> bool {
        cell.x >= 0 && cell.y >= 0 && cell.x < GRID && cell.y < GRID
    }

    pub fn walkable(&self, cell: IVec2) -> bool {
        Self::inside(cell) && !self.blocked[Self::idx(cell)]
    }

    pub fn place(&self, name: &str) -> Option<IVec2> {
        self.pois.get(&name.to_lowercase()).copied()
    }

    /// 4-directional BFS. If `to` is blocked, targets its nearest walkable neighbor.
    pub fn path(&self, from: IVec2, to: IVec2) -> Option<Vec<IVec2>> {
        let goal = if self.walkable(to) {
            to
        } else {
            self.nearest_walkable(to)?
        };
        if from == goal {
            return Some(vec![]);
        }
        let mut queue = VecDeque::from([from]);
        let mut parent: HashMap<IVec2, IVec2> = HashMap::new();
        parent.insert(from, from);
        let dirs = [IVec2::X, IVec2::NEG_X, IVec2::Y, IVec2::NEG_Y];
        while let Some(cur) = queue.pop_front() {
            for d in dirs {
                let next = cur + d;
                if !self.walkable(next) || parent.contains_key(&next) {
                    continue;
                }
                parent.insert(next, cur);
                if next == goal {
                    let mut path = vec![next];
                    let mut c = next;
                    while c != from {
                        c = parent[&c];
                        path.push(c);
                    }
                    path.pop(); // drop start cell
                    path.reverse();
                    return Some(path);
                }
                queue.push_back(next);
            }
        }
        None
    }

    fn nearest_walkable(&self, cell: IVec2) -> Option<IVec2> {
        let mut queue = VecDeque::from([cell]);
        let mut seen = HashMap::from([(cell, ())]);
        while let Some(c) = queue.pop_front() {
            if self.walkable(c) {
                return Some(c);
            }
            for d in [IVec2::X, IVec2::NEG_X, IVec2::Y, IVec2::NEG_Y] {
                let n = c + d;
                if Self::inside(n) && !seen.contains_key(&n) {
                    seen.insert(n, ());
                    queue.push_back(n);
                }
            }
        }
        None
    }

    pub fn random_walkable(&self) -> IVec2 {
        // Deterministic-ish wander using a cheap LCG seeded by position hash is
        // overkill; callers pass their own randomness. Fallback: scan.
        for i in 0..self.blocked.len() {
            if !self.blocked[i] && i % 7 == 3 {
                return IVec2::new((i % GRID as usize) as i32, (i / GRID as usize) as i32);
            }
        }
        IVec2::new(GRID / 2, GRID / 2)
    }
}

fn cell_to_world(cell: IVec2) -> Vec3 {
    Vec3::new(cell.x as f32 + 0.5, 0.0, cell.y as f32 + 0.5)
}

/// Marker for the main isometric camera (pan/zoom/pick target).
#[derive(Component)]
pub struct VillageCamera;

pub fn spawn_village(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    let mut blocked = vec![false; (GRID * GRID) as usize];
    let mut pois: HashMap<String, IVec2> = HashMap::new();

    let ground = meshes.add(Cuboid::from_size(Vec3::new(GRID as f32, 0.2, GRID as f32)));
    commands.spawn((
        Mesh3d(ground),
        MeshMaterial3d(materials.add(StandardMaterial {
            base_color: Color::srgb(0.36, 0.47, 0.28),
            perceptual_roughness: 1.0,
            ..default()
        })),
        Transform::from_xyz(GRID as f32 / 2.0, -0.1, GRID as f32 / 2.0),
    ));

    // Plaza (walkable, center) + well in its middle (blocked cell, edge used)
    let center = IVec2::new(GRID / 2, GRID / 2);
    let plaza_cells = [
        center,
        center + IVec2::X,
        center + IVec2::NEG_X,
        center + IVec2::Y,
        center + IVec2::NEG_Y,
        center + IVec2::new(1, 1),
        center + IVec2::new(-1, -1),
        center + IVec2::new(1, -1),
        center + IVec2::new(-1, 1),
    ];
    for c in plaza_cells {
        set_floor(&mut blocked, c, Color::srgb(0.55, 0.5, 0.42), &mut commands, &mut meshes, &mut materials, 0.03);
    }
    pois.insert("plaza".into(), center);
    let well = center + IVec2::new(0, -2);
    building(&mut commands, &mut meshes, &mut materials, well, 1.0, 1.4, Color::srgb(0.45, 0.45, 0.5));
    set_blocked(&mut blocked, well);
    pois.insert("well".into(), well);

    // Named buildings around the plaza
    let named: &[(&str, IVec2, Vec3, Color)] = &[
        ("market", center + IVec2::new(6, 0), Vec3::new(4.0, 2.0, 3.0), Color::srgb(0.72, 0.55, 0.3)),
        ("tavern", center + IVec2::new(-6, 1), Vec3::new(3.0, 2.4, 3.0), Color::srgb(0.6, 0.35, 0.25)),
        ("workshop", center + IVec2::new(1, 6), Vec3::new(3.0, 1.8, 2.0), Color::srgb(0.5, 0.42, 0.32)),
        ("weavery", center + IVec2::new(-2, -7), Vec3::new(3.0, 1.8, 2.0), Color::srgb(0.55, 0.45, 0.55)),
        ("scriptorium", center + IVec2::new(7, -6), Vec3::new(2.5, 2.6, 2.5), Color::srgb(0.4, 0.4, 0.6)),
        ("granary", center + IVec2::new(-7, -5), Vec3::new(3.5, 2.2, 2.5), Color::srgb(0.65, 0.6, 0.4)),
    ];
    for (name, cell, size, color) in named {
        building(&mut commands, &mut meshes, &mut materials, *cell, size.x, size.y, *color);
        stamp_blocked(&mut blocked, *cell, *size);
        pois.insert((*name).into(), *cell + IVec2::new(0, size.z as i32 / 2)); // door side
    }

    // Houses: two rings of cottages (cells stay walkable around them)
    let mut homes: Vec<IVec2> = Vec::new();
    let mut house_idx = 0usize;
    for radius in [16i32, 26] {
        for (dx, dy) in [(1, 0), (0, 1), (-1, 0), (0, -1), (1, 1), (-1, -1), (1, -1), (-1, 1)] {
            let base = center + IVec2::new(dx * radius, dy * radius);
            for step in -2..=2 {
                let c = base + IVec2::new(dy * step * 4, dx * step * 4);
                if !WorldMap::inside(c) || blocked[WorldMap::idx(c)] {
                    continue;
                }
                building(&mut commands, &mut meshes, &mut materials, c, 2.0, 1.6, Color::srgb(0.7, 0.62, 0.5));
                set_blocked(&mut blocked, c);
                homes.push(c);
                house_idx += 1;
                if house_idx >= 34 {
                    break;
                }
            }
            if house_idx >= 34 {
                break;
            }
        }
        if house_idx >= 34 {
            break;
        }
    }
    // Homes are per-person, addressed by index in the prompt ("your home: (x,y)")
    for (i, c) in homes.iter().enumerate() {
        pois.insert(format!("home_{i}"), *c);
    }

    // Fields: large walkable work areas at the map edge
    let field_centers = [
        IVec2::new(6, GRID / 2),
        IVec2::new(6, GRID / 2 + 8),
        IVec2::new(GRID - 7, GRID / 2),
        IVec2::new(GRID - 7, GRID / 2 + 8),
        IVec2::new(GRID / 2, GRID - 7),
        IVec2::new(GRID / 2 + 8, GRID - 7),
    ];
    for (i, fc) in field_centers.iter().enumerate() {
        for y in 0..3 {
            for x in 0..3 {
                let c = fc + IVec2::new(x - 1, y - 1);
                if WorldMap::inside(c) {
                    set_floor(
                        &mut blocked,
                        c,
                        Color::srgb(0.5, 0.42 + (i as f32) * 0.01, 0.2),
                        &mut commands,
                        &mut meshes,
                        &mut materials,
                        0.04,
                    );
                }
            }
        }
        pois.insert(format!("field_{i}"), *fc);
        pois.insert("field".into(), *fc); // generic alias
    }

    // Roads: cross through the plaza (visual only)
    for axis in 0..2 {
        for i in 0..GRID {
            let c = if axis == 0 {
                IVec2::new(i, GRID / 2)
            } else {
                IVec2::new(GRID / 2, i)
            };
            if blocked[WorldMap::idx(c)] {
                continue;
            }
            let tile = meshes.add(Cuboid::from_size(Vec3::new(0.9, 0.05, 0.9)));
            commands.spawn((
                Mesh3d(tile),
                MeshMaterial3d(materials.add(StandardMaterial {
                    base_color: Color::srgb(0.48, 0.44, 0.36),
                    perceptual_roughness: 1.0,
                    ..default()
                })),
                Transform::from_translation(cell_to_world(c) + Vec3::new(0.0, 0.03, 0.0)),
            ));
        }
    }

    // Lights + iso camera
    commands.spawn((
        DirectionalLight {
            illuminance: 12_000.0,
            shadow_maps_enabled: false,
            ..default()
        },
        Transform::from_xyz(40.0, 80.0, 20.0).looking_at(Vec3::new(32.0, 0.0, 32.0), Vec3::Y),
    ));
    commands.spawn((
        Camera3d::default(),
        VillageCamera,
        Projection::Orthographic(OrthographicProjection {
            scale: 0.11,
            ..OrthographicProjection::default_3d()
        }),
        Transform::from_xyz(96.0, 96.0, 96.0).looking_at(Vec3::new(32.0, 0.0, 32.0), Vec3::Y),
    ));

    commands.insert_resource(WorldMap { blocked, pois });
}

fn set_blocked(blocked: &mut [bool], cell: IVec2) {
    if WorldMap::inside(cell) {
        blocked[WorldMap::idx(cell)] = true;
    }
}

fn stamp_blocked(blocked: &mut [bool], cell: IVec2, size: Vec3) {
    let w = size.x as i32;
    let h = size.z as i32;
    for dy in 0..h.max(1) {
        for dx in 0..w.max(1) {
            set_blocked(blocked, cell + IVec2::new(dx - w / 2, dy - h / 2));
        }
    }
}

fn building(
    commands: &mut Commands,
    meshes: &mut Assets<Mesh>,
    materials: &mut Assets<StandardMaterial>,
    cell: IVec2,
    w: f32,
    h: f32,
    color: Color,
) {
    let mesh = meshes.add(Cuboid::from_size(Vec3::new(w, h, 2.0)));
    let pos = cell_to_world(cell);
    commands.spawn((
        Mesh3d(mesh),
        MeshMaterial3d(materials.add(StandardMaterial {
            base_color: color,
            perceptual_roughness: 0.9,
            ..default()
        })),
        Transform::from_translation(pos + Vec3::new(0.0, h / 2.0, 0.0)),
    ));
    // pitched-roof suggestion: a smaller cube on top
    let roof = meshes.add(Cuboid::from_size(Vec3::new(w * 0.8, 0.6, 1.6)));
    commands.spawn((
        Mesh3d(roof),
        MeshMaterial3d(materials.add(StandardMaterial {
            base_color: Color::srgb(0.4, 0.26, 0.22),
            perceptual_roughness: 1.0,
            ..default()
        })),
        Transform::from_translation(pos + Vec3::new(0.0, h + 0.3, 0.0)),
    ));
}

fn set_floor(
    _blocked: &mut [bool],
    cell: IVec2,
    color: Color,
    commands: &mut Commands,
    meshes: &mut Assets<Mesh>,
    materials: &mut Assets<StandardMaterial>,
    height: f32,
) {
    if !WorldMap::inside(cell) {
        return;
    }
    let mesh = meshes.add(Cuboid::from_size(Vec3::new(0.96, height * 2.0, 0.96)));
    commands.spawn((
        Mesh3d(mesh),
        MeshMaterial3d(materials.add(StandardMaterial {
            base_color: color,
            perceptual_roughness: 1.0,
            ..default()
        })),
        Transform::from_translation(cell_to_world(cell) + Vec3::new(0.0, height, 0.0)),
    ));
}