use crate::game::{Entity, Game, PickupType};
use crate::texture::TEX_SIZE;

// ---- simple 5×5 ASCII glyphs ----
// ---- simple 5×5 ASCII glyphs for letters & symbols (incomplete — add as needed) ----

const LETTERS: &[(&str, [u8; 5])] = &[
    // Uppercase A-Z
    ("A", [0b01110, 0b10001, 0b11111, 0b10001, 0b10001]),
    ("B", [0b11110, 0b10001, 0b11110, 0b10001, 0b11110]),
    ("C", [0b01110, 0b10001, 0b10000, 0b10001, 0b01110]),
    ("D", [0b11110, 0b10001, 0b10001, 0b10001, 0b11110]),
    ("E", [0b11111, 0b10000, 0b11110, 0b10000, 0b11111]),
    ("F", [0b11111, 0b10000, 0b11110, 0b10000, 0b10000]),
    ("G", [0b01110, 0b10000, 0b10111, 0b10001, 0b01110]),
    ("H", [0b10001, 0b10001, 0b11111, 0b10001, 0b10001]),
    ("I", [0b01110, 0b00100, 0b00100, 0b00100, 0b01110]),
    ("J", [0b00011, 0b00001, 0b00001, 0b10001, 0b01110]),
    ("K", [0b10001, 0b10010, 0b11100, 0b10010, 0b10001]),
    ("L", [0b10000, 0b10000, 0b10000, 0b10000, 0b11111]),
    ("M", [0b10001, 0b11011, 0b10101, 0b10001, 0b10001]),
    ("N", [0b10001, 0b11001, 0b10101, 0b10011, 0b10001]),
    ("O", [0b01110, 0b10001, 0b10001, 0b10001, 0b01110]),
    ("P", [0b11110, 0b10001, 0b11110, 0b10000, 0b10000]),
    ("Q", [0b01110, 0b10001, 0b10001, 0b10010, 0b01101]),
    ("R", [0b11110, 0b10001, 0b11110, 0b10010, 0b10001]),
    ("S", [0b01110, 0b10000, 0b01110, 0b00001, 0b11110]),
    ("T", [0b11111, 0b00100, 0b00100, 0b00100, 0b00100]),
    ("U", [0b10001, 0b10001, 0b10001, 0b10001, 0b01110]),
    ("V", [0b10001, 0b10001, 0b10001, 0b01010, 0b00100]),
    ("W", [0b10001, 0b10001, 0b10101, 0b10101, 0b01010]),
    ("X", [0b10001, 0b01010, 0b00100, 0b01010, 0b10001]),
    ("Y", [0b10001, 0b01010, 0b00100, 0b00100, 0b00100]),
    ("Z", [0b11111, 0b00010, 0b00100, 0b01000, 0b11111]),
    // Digits
    ("0", [0b01110, 0b10011, 0b10101, 0b11001, 0b01110]),
    ("1", [0b00100, 0b01100, 0b00100, 0b00100, 0b01110]),
    ("2", [0b01110, 0b10001, 0b00010, 0b00100, 0b11111]),
    ("3", [0b01110, 0b10001, 0b00110, 0b10001, 0b01110]),
    ("4", [0b00010, 0b00110, 0b01010, 0b11111, 0b00010]),
    ("5", [0b11111, 0b10000, 0b11110, 0b10001, 0b01110]),
    ("6", [0b01110, 0b10000, 0b11110, 0b10001, 0b01110]),
    ("7", [0b11111, 0b00001, 0b00010, 0b00100, 0b00100]),
    ("8", [0b01110, 0b10001, 0b01110, 0b10001, 0b01110]),
    ("9", [0b01110, 0b10001, 0b01111, 0b00001, 0b01110]),
    // Punctuation & symbols
    ("!", [0b00100, 0b00100, 0b00100, 0b00000, 0b00100]),
    ("@", [0b01110, 0b10001, 0b10111, 0b10000, 0b01110]),
    ("+", [0b00000, 0b00100, 0b01110, 0b00100, 0b00000]),
    (":", [0b00000, 0b00100, 0b00000, 0b00100, 0b00000]),
    ("%", [0b10001, 0b00010, 0b00100, 0b01000, 0b10001]),
    ("/", [0b00001, 0b00010, 0b00100, 0b01000, 0b10000]),
    (".", [0b00000, 0b00000, 0b00000, 0b00000, 0b00100]),
    (",", [0b00000, 0b00000, 0b00000, 0b00100, 0b01000]),
    ("(", [0b00010, 0b00100, 0b00100, 0b00100, 0b00010]),
    (")", [0b01000, 0b00100, 0b00100, 0b00100, 0b01000]),
    ("-", [0b00000, 0b00000, 0b01110, 0b00000, 0b00000]),
    ("'", [0b00100, 0b00000, 0b00000, 0b00000, 0b00000]),
    // Unicode symbols
    ("♥", [0b01010, 0b11111, 0b11111, 0b01110, 0b00100]),
    ("♦", [0b00100, 0b01110, 0b11111, 0b01110, 0b00100]),
    ("⌂", [0b01110, 0b10001, 0b10101, 0b10001, 0b11111]),
    ("[", [0b01110, 0b01000, 0b01000, 0b01000, 0b01110]),
    ("]", [0b01110, 0b00010, 0b00010, 0b00010, 0b01110]),
    (" ", [0b00000; 5]),
];

const LETTER_W: usize = 5;
const LETTER_H: usize = 5;

pub struct Renderer {
    screen_w: usize,
    screen_h: usize,
    floor_dist_lut: Vec<f64>,
}

impl Renderer {
    pub fn new(screen_w: usize, screen_h: usize) -> Self {
        let half_h = screen_h as f64 / 2.0;
        let mut floor_dist_lut = vec![0.0f64; screen_h];

        for py in (screen_h / 2 + 1)..screen_h {
            let dy = py as f64 - half_h;
            floor_dist_lut[py] = 0.5 * screen_h as f64 / dy;
        }

        Self {
            screen_w,
            screen_h,
            floor_dist_lut,
        }
    }

    pub fn render(&self, game: &Game, buffer: &mut [u32]) {
        buffer.fill(0xFF00_0000);

        let half_h = self.screen_h as f64 / 2.0;
        let fov = std::f64::consts::PI / 3.0;

        // Per-column wall distances for entity occlusion.
        let mut wall_dists = vec![f64::MAX; self.screen_w];

        for sx in 0..self.screen_w {
            let cam_x = 2.0 * sx as f64 / self.screen_w as f64 - 1.0;
            let ray_angle = game.player.angle + (fov / 2.0) * cam_x;
            let rdx = ray_angle.cos();
            let rdy = ray_angle.sin();

            let cos_diff = (ray_angle - game.player.angle).cos().abs().max(0.001);
            let rdx_floor = rdx / cos_diff;
            let rdy_floor = rdy / cos_diff;

            let mut map_x = game.player.x as isize;
            let mut map_y = game.player.y as isize;

            let ddx = if rdx == 0.0 {
                f64::MAX
            } else {
                (1.0 / rdx).abs()
            };
            let ddy = if rdy == 0.0 {
                f64::MAX
            } else {
                (1.0 / rdy).abs()
            };

            let (step_x, mut side_x) = if rdx < 0.0 {
                (-1isize, (game.player.x - map_x as f64) * ddx)
            } else {
                (1isize, (map_x as f64 + 1.0 - game.player.x) * ddx)
            };

            let (step_y, mut side_y) = if rdy < 0.0 {
                (-1isize, (game.player.y - map_y as f64) * ddy)
            } else {
                (1isize, (map_y as f64 + 1.0 - game.player.y) * ddy)
            };

            let mut hit_side: bool;
            let euclidean: f64;

            loop {
                if side_x < side_y {
                    side_x += ddx;
                    map_x += step_x;
                    hit_side = false;
                } else {
                    side_y += ddy;
                    map_y += step_y;
                    hit_side = true;
                }

                if map_y < 0
                    || map_y >= game.maze.height() as isize
                    || map_x < 0
                    || map_x >= game.maze.width() as isize
                {
                    euclidean = 1.0;
                    break;
                }

                if game.maze.is_wall(map_y as usize, map_x as usize) {
                    euclidean = if !hit_side {
                        (map_x as f64 - game.player.x + (1.0 - step_x as f64) / 2.0) / rdx
                    } else {
                        (map_y as f64 - game.player.y + (1.0 - step_y as f64) / 2.0) / rdy
                    };
                    break;
                }
            }

            let perp_dist = (euclidean * (ray_angle - game.player.angle).cos().abs()).max(0.001);
            wall_dists[sx] = perp_dist;

            let wall_h = (self.screen_h as f64 / perp_dist) as isize;
            let draw_start = ((-wall_h / 2) + self.screen_h as isize / 2).max(0) as usize;
            let draw_end = ((wall_h / 2) + self.screen_h as isize / 2)
                .min(self.screen_h as isize - 1) as usize;

            let wall_x = if !hit_side {
                game.player.y + euclidean * rdy
            } else {
                game.player.x + euclidean * rdx
            };
            let wall_x = wall_x - wall_x.floor();
            let tex_x = ((wall_x * TEX_SIZE as f64) as usize).min(TEX_SIZE - 1);

            let wall_bright_fx = {
                let w = game.weakness_factor();
                let darken_scale = 1.0 + w * 12.0;
                let b = 1.0 / (1.0 + perp_dist * 0.25 * darken_scale);
                (b * 256.0) as u32
            };

            for py in draw_start..=draw_end {
                let tex_y = ((py as f64 - half_h + wall_h as f64 / 2.0) * TEX_SIZE as f64
                    / wall_h as f64) as usize;
                let tex_y = tex_y.min(TEX_SIZE - 1);
                let color = game.wall_texture[tex_y * TEX_SIZE + tex_x];
                buffer[py * self.screen_w + sx] = darken_fx(color, wall_bright_fx);
            }

            let floor_start = draw_end + 1;
            if floor_start < self.screen_h {
                let w = game.weakness_factor();
                let darken_scale = 1.0 + w * 12.0;
                for py in floor_start..self.screen_h {
                    let floor_dist = self.floor_dist_lut[py];
                    let bright = 1.0 / (1.0 + floor_dist * 0.35 * darken_scale);
                    let bright_fx = (bright * 256.0) as u32;

                    if floor_dist > 15.0 {
                        let gray = darken_fx(0xFF80_8080, bright_fx);
                        buffer[py * self.screen_w + sx] = gray;
                    } else {
                        let fx = game.player.x + floor_dist * rdx_floor;
                        let fy = game.player.y + floor_dist * rdy_floor;
                        let ftx = ((fx.fract().abs() * TEX_SIZE as f64) as usize).min(TEX_SIZE - 1);
                        let fty = ((fy.fract().abs() * TEX_SIZE as f64) as usize).min(TEX_SIZE - 1);
                        let color =
                            if fx as usize == game.maze.exit_x && fy as usize == game.maze.exit_y {
                                game.exit_texture[fty * TEX_SIZE + ftx]
                            } else {
                                game.floor_texture[fty * TEX_SIZE + ftx]
                            };
                        buffer[py * self.screen_w + sx] = darken_fx(color, bright_fx);
                    }
                }
            }
        }

        // ---- entity sprites (drawn after walls so occlusion is easy) ----
        self.draw_entities(game, buffer, &wall_dists, fov, half_h);

        // ---- camera bob ----
        let bob = game.camera_bob().round() as isize;
        if bob != 0 {
            if bob > 0 {
                let shift = bob as usize;
                for py in (shift..self.screen_h).rev() {
                    let src = (py - shift) * self.screen_w;
                    let dst = py * self.screen_w;
                    buffer.copy_within(src..src + self.screen_w, dst);
                }
                buffer[0..shift * self.screen_w].fill(0xFF00_0000);
            } else {
                let shift = (-bob) as usize;
                for py in 0..self.screen_h - shift {
                    let src = (py + shift) * self.screen_w;
                    let dst = py * self.screen_w;
                    buffer.copy_within(src..src + self.screen_w, dst);
                }
                let start = (self.screen_h - shift) * self.screen_w;
                buffer[start..].fill(0xFF00_0000);
            }
        }

        // ---- HUD ----
        self.draw_hud(buffer, game);
    }

    // ---- entity sprites ---------------------------------------------------

    fn draw_entities(
        &self,
        game: &Game,
        buffer: &mut [u32],
        wall_dists: &[f64],
        fov: f64,
        half_h: f64,
    ) {
        let mw = game.maze.width();
        let mh = game.maze.height();

        for y in 0..mh {
            for x in 0..mw {
                let entity = match game.maze.entity_at(x, y) {
                    Some(e) => e,
                    None => continue,
                };

                let ex = x as f64 + 0.5;
                let ey = y as f64 + 0.5;

                let dx = ex - game.player.x;
                let dy = ey - game.player.y;

                let fx = game.player.angle.cos();
                let fy = game.player.angle.sin();
                let rx = -fy;
                let ry = fx;

                let cam_z = dx * fx + dy * fy; // depth
                if cam_z <= 0.1 {
                    continue; // behind camera
                }

                let cam_x = dx * rx + dy * ry;

                // Check if entity is within FOV.
                let half_fov_tan = (fov / 2.0).tan();
                let screen_x_norm = cam_x / (cam_z * half_fov_tan);
                if screen_x_norm < -1.0 || screen_x_norm > 1.0 {
                    continue;
                }

                let sx = ((screen_x_norm + 1.0) * 0.5 * self.screen_w as f64) as isize;

                // Entity height on screen.
                let entity_h = (self.screen_h as f64 / cam_z * 0.4) as isize;
                let sy = (half_h - entity_h as f64 * 0.3) as isize;

                let (ch, color) = entity_char_and_color(entity);

                // Check occlusion: is any wall column this entity overlaps with closer?
                let left = (sx - entity_h / 2).max(0) as usize;
                let right = (sx + entity_h / 2).min(self.screen_w as isize - 1) as usize;
                let visible = (left..=right).any(|col| cam_z < wall_dists[col]);

                if !visible {
                    continue;
                }

                let scale = (entity_h.max(6) as f64 / LETTER_H as f64).max(0.5);

                self.draw_char_scaled(
                    buffer,
                    ch,
                    sx,
                    sy,
                    scale,
                    color,
                    cam_z,
                    game.weakness_factor(),
                );
            }
        }
    }

    fn draw_char_scaled(
        &self,
        buffer: &mut [u32],
        ch: char,
        cx: isize,
        cy: isize,
        scale: f64,
        color: u32,
        distance: f64,
        weakness: f64,
    ) {
        let glyph = match find_glyph(ch) {
            Some(g) => g,
            None => return,
        };

        let darken_scale = 1.0 + weakness * 12.0;
        let bright = 1.0 / (1.0 + distance * 0.15 * darken_scale);
        let bright_fx = (bright * 256.0) as u32;
        let final_color = darken_fx(color, bright_fx);

        let draw_w = (LETTER_W as f64 * scale) as isize;
        let draw_h = (LETTER_H as f64 * scale) as isize;

        let start_x = cx - draw_w / 2;
        let start_y = cy - draw_h / 2;

        for gy in 0..LETTER_H {
            let bits = glyph[gy];
            for gx in 0..LETTER_W {
                if (bits >> (LETTER_W - 1 - gx)) & 1 == 0 {
                    continue;
                }
                let px_start = start_x + (gx as f64 * scale) as isize;
                let py_start = start_y + (gy as f64 * scale) as isize;
                let px_end = start_x + ((gx + 1) as f64 * scale) as isize;
                let py_end = start_y + ((gy + 1) as f64 * scale) as isize;

                for py in py_start.max(0)..py_end.min(self.screen_h as isize) {
                    for px in px_start.max(0)..px_end.min(self.screen_w as isize) {
                        let idx = py as usize * self.screen_w + px as usize;
                        buffer[idx] = final_color;
                    }
                }
            }
        }
    }

    // ---- HUD -------------------------------------------------------------

    fn draw_hud(&self, buffer: &mut [u32], game: &Game) {
        let bar_h = 40usize;
        let bar_y = self.screen_h - bar_h;

        // Background.
        for py in bar_y..self.screen_h {
            for px in 0..self.screen_w {
                buffer[py * self.screen_w + px] = 0xFF_222222;
            }
        }

        let x = 8usize;
        let y = bar_y + 6;

        // Format the HUD string.
        let hp_str = format!("♥{}/{}", game.hp, game.max_hp);
        let san_str = format!("♦{}%", game.sanity);
        let weak_str = format!("⌂{}%", game.weakness);
        let beats_str = format!("♥♥{}", game.heartbeats());
        let wpn_str = format!("WPN:{}", game.weapon_base_damage);
        let depth_str = format!("DEPTH:{}", game.depth);

        let inv_str: String = game
            .inventory
            .iter()
            .enumerate()
            .map(|(i, item)| match item {
                Some(item) => {
                    let ch = pickup_char(item.pickup);
                    if i == game.selected_slot {
                        format!("[{}]", ch)
                    } else {
                        format!(" {} ", ch)
                    }
                }
                None => {
                    if i == game.selected_slot {
                        "[ ]".to_string()
                    } else {
                        "   ".to_string()
                    }
                }
            })
            .collect();

        let full = format!(
            "{}  {}  {}  {}  {}  {}  {}",
            hp_str, san_str, weak_str, beats_str, wpn_str, inv_str, depth_str
        );

        self.draw_text(buffer, x, y, &full, 0xFF_CCCCCC);

        // ---- message log above the bar ----
        if !game.message.is_empty() {
            let msg_y = bar_y.saturating_sub(LETTER_H + 4);
            self.draw_text(buffer, 8, msg_y, &game.message, 0xFF_DDAA44);
        }
    }

    fn draw_text(&self, buffer: &mut [u32], mut x: usize, y: usize, text: &str, color: u32) {
        for ch in text.to_uppercase().chars() {
            let glyph = match find_glyph(ch) {
                Some(g) => g,
                None => {
                    x += LETTER_W + 1;
                    continue;
                }
            };

            for gy in 0..LETTER_H {
                let bits = glyph[gy];
                for gx in 0..LETTER_W {
                    if (bits >> (LETTER_W - 1 - gx)) & 1 != 0 {
                        let px = x + gx;
                        let py = y + gy;
                        if px < self.screen_w && py < self.screen_h {
                            buffer[py * self.screen_w + px] = color;
                        }
                    }
                }
            }
            x += LETTER_W + 1; // 1px gap
        }
    }
}

// ---- helpers ----

fn find_glyph(ch: char) -> Option<[u8; 5]> {
    let s = ch.to_string();
    for (name, glyph) in LETTERS {
        if *name == s {
            return Some(*glyph);
        }
    }
    None
}

fn entity_char_and_color(entity: &Entity) -> (char, u32) {
    match entity {
        Entity::Enemy { .. } => ('@', 0xFF_CC3333),
        Entity::Hallucination { .. } => ('@', 0xFF_CC3333),
        Entity::Pickup(pt) => (pickup_char(*pt), pickup_color(*pt)),
        Entity::HallucinatedPickup(pt) => (pickup_char(*pt), pickup_color(*pt)),
    }
}

fn pickup_char(pt: PickupType) -> char {
    match pt {
        PickupType::Food => 'F',
        PickupType::Pill => '0',
        PickupType::Bandage => '+',
        PickupType::Weapon { .. } => '!',
    }
}

fn pickup_color(pt: PickupType) -> u32 {
    match pt {
        PickupType::Food => 0xFF_33CC33,
        PickupType::Pill => 0xFF_33CCCC,
        PickupType::Bandage => 0xFF_CCCCCC,
        PickupType::Weapon { .. } => 0xFF_CCCC33,
    }
}

#[inline(always)]
fn darken_fx(color: u32, bright_fx: u32) -> u32 {
    let r = (((color >> 16) & 0xFF) * bright_fx) >> 8;
    let g = (((color >> 8) & 0xFF) * bright_fx) >> 8;
    let b = ((color & 0xFF) * bright_fx) >> 8;
    0xFF00_0000 | (r << 16) | (g << 8) | b
}