use anyhow::{anyhow, Context, Result};
use serde::Deserialize;
use std::collections::HashMap;

use crate::{
	handle::SpriteHandle, resolve_edge_as_edge, Content, ContentBuildContext, EffectHandle,
	OutfitHandle, OutfitSpace, SectionEdge,
};

pub(crate) mod syntax {
	use crate::{effect, part::outfitspace, sprite::syntax::SectionEdge, ContentBuildContext};
	use anyhow::{bail, Result};
	use galactica_util::to_radians;
	use serde::Deserialize;
	// Raw serde syntax structs.
	// These are never seen by code outside this crate.

	#[derive(Debug, Deserialize)]
	pub struct Outfit {
		pub thumbnail: String,
		pub engine: Option<Engine>,
		pub steering: Option<Steering>,
		pub space: outfitspace::syntax::OutfitSpace,
		pub shield: Option<Shield>,
		pub gun: Option<Gun>,
	}

	#[derive(Debug, Deserialize)]
	pub struct Shield {
		pub strength: Option<f32>,
		pub generation: Option<f32>,
		pub delay: Option<f32>,
		// more stats: permiability, shield armor, ramp, etc
	}

	#[derive(Debug, Deserialize)]
	pub struct Engine {
		pub thrust: f32,
		pub flare: EngineFlare,
	}

	#[derive(Debug, Deserialize)]
	pub struct EngineFlare {
		pub sprite: String,
		pub on_start: Option<SectionEdge>,
		pub on_stop: Option<SectionEdge>,
	}

	#[derive(Debug, Deserialize)]
	pub struct Steering {
		pub power: f32,
	}

	#[derive(Debug, Deserialize)]
	pub struct Gun {
		pub projectile: Projectile,
		pub rate: f32,
		pub rate_rng: Option<f32>,
	}

	impl Gun {
		pub fn build(
			self,
			build_context: &mut ContentBuildContext,
			content: &mut crate::Content,
		) -> Result<super::Gun> {
			let projectile_sprite_handle = match content.sprite_index.get(&self.projectile.sprite) {
				None => bail!(
					"projectile sprite `{}` doesn't exist",
					self.projectile.sprite,
				),
				Some(t) => *t,
			};

			let impact_effect = match self.projectile.impact_effect {
				Some(e) => Some(e.to_handle(build_context, content)?),
				None => None,
			};

			let expire_effect = match self.projectile.expire_effect {
				Some(e) => Some(e.to_handle(build_context, content)?),
				None => None,
			};

			return Ok(super::Gun {
				rate: self.rate,
				rate_rng: self.rate_rng.unwrap_or(0.0),
				projectile: super::Projectile {
					force: self.projectile.force,
					sprite: projectile_sprite_handle,
					size: self.projectile.size,
					size_rng: self.projectile.size_rng,
					speed: self.projectile.speed,
					speed_rng: self.projectile.speed_rng,
					lifetime: self.projectile.lifetime,
					lifetime_rng: self.projectile.lifetime_rng,
					damage: self.projectile.damage,

					// Divide by 2, so the angle matches the angle of the fire cone.
					// This should ALWAYS be done in the content parser.
					angle_rng: to_radians(self.projectile.angle_rng / 2.0).into(),
					impact_effect,
					expire_effect,
					collider: self.projectile.collider,
				},
			});
		}
	}

	#[derive(Debug, Deserialize)]
	pub struct Projectile {
		pub sprite: String,
		pub size: f32,
		pub size_rng: f32,
		pub speed: f32,
		pub speed_rng: f32,
		pub lifetime: f32,
		pub lifetime_rng: f32,
		pub damage: f32,
		pub angle_rng: f32,
		pub impact_effect: Option<effect::syntax::EffectReference>,
		pub expire_effect: Option<effect::syntax::EffectReference>,
		pub collider: super::ProjectileCollider,
		pub force: f32,
	}
}

/// Represents an outfit that may be attached to a ship.
#[derive(Debug, Clone)]
pub struct Outfit {
	/// This outfit's thumbnail
	pub thumbnail: SpriteHandle,

	/// How much space this outfit requires
	pub space: OutfitSpace,

	/// This outfit's handle
	pub handle: OutfitHandle,

	/// The name of this outfit
	pub name: String,

	/// How much engine thrust this outfit produces
	pub engine_thrust: f32,

	/// How much steering power this outfit provids
	pub steer_power: f32,

	/// The engine flare sprite this outfit creates.
	/// Its location and size is determined by a ship's
	/// engine points.
	pub engine_flare_sprite: Option<SpriteHandle>,

	/// Jump to this edge when engines turn on
	pub engine_flare_on_start: Option<SectionEdge>,

	/// Jump to this edge when engines turn off
	pub engine_flare_on_stop: Option<SectionEdge>,

	/// Shield hit points
	pub shield_strength: f32,

	/// Shield regeneration rate, per second
	pub shield_generation: f32,

	/// Wait this many seconds after taking damage before regenerating shields
	pub shield_delay: f32,

	/// This outfit's gun stats.
	/// If this is some, this outfit requires a gun point.
	pub gun: Option<Gun>,
}

/// Defines a projectile's collider
#[derive(Debug, Deserialize, Clone)]
pub enum ProjectileCollider {
	/// A ball collider
	#[serde(rename = "ball")]
	Ball(BallCollider),
}

/// A simple ball-shaped collider, centered at the object's position
#[derive(Debug, Deserialize, Clone)]
pub struct BallCollider {
	/// The radius of this ball
	pub radius: f32,
}

/// Represents gun stats of an outfit.
/// If an outfit has this value, it requires a gun point.
#[derive(Debug, Clone)]
pub struct Gun {
	/// The projectile this gun produces
	pub projectile: Projectile,

	/// Average delay between projectiles, in seconds.
	pub rate: f32,

	/// Random variation of projectile delay, in seconds.
	/// Each shot waits (rate += rate_rng).
	pub rate_rng: f32,
}

/// Represents a projectile that a [`Gun`] produces.
#[derive(Debug, Clone)]
pub struct Projectile {
	/// The projectile sprite
	pub sprite: SpriteHandle,

	/// The average size of this projectile
	/// (height in game units)
	pub size: f32,
	/// Random size variation
	pub size_rng: f32,

	/// The speed of this projectile, in game units / second
	pub speed: f32,
	/// Random speed variation
	pub speed_rng: f32,

	/// The lifespan of this projectile.
	/// It will vanish if it lives this long without hitting anything.
	pub lifetime: f32,
	/// Random lifetime variation
	pub lifetime_rng: f32,

	/// The damage this projectile does
	pub damage: f32,

	/// The force this projectile applies
	pub force: f32,

	/// The angle variation of this projectile, in radians
	pub angle_rng: f32,

	/// The effect this projectile will spawn when it hits something
	pub impact_effect: Option<EffectHandle>,

	/// The effect this projectile will spawn when it expires
	pub expire_effect: Option<EffectHandle>,

	/// Collider parameters for this projectile
	pub collider: ProjectileCollider,
}

impl crate::Build for Outfit {
	type InputSyntaxType = HashMap<String, syntax::Outfit>;

	fn build(
		outfits: Self::InputSyntaxType,
		build_context: &mut ContentBuildContext,
		content: &mut Content,
	) -> Result<()> {
		for (outfit_name, outfit) in outfits {
			let handle = OutfitHandle {
				index: content.outfits.len(),
			};

			let gun = match outfit.gun {
				None => None,
				Some(g) => Some(
					g.build(build_context, content)
						.with_context(|| format!("in outfit {}", outfit_name))?,
				),
			};

			let thumb_handle = match content.sprite_index.get(&outfit.thumbnail) {
				None => {
					return Err(anyhow!(
						"thumbnail sprite `{}` doesn't exist",
						outfit.thumbnail
					))
					.with_context(|| format!("in outfit `{}`", outfit_name));
				}
				Some(t) => *t,
			};

			let mut o = Self {
				thumbnail: thumb_handle,
				gun,
				handle,
				name: outfit_name.clone(),
				engine_thrust: 0.0,
				steer_power: 0.0,
				engine_flare_sprite: None,
				engine_flare_on_start: None,
				engine_flare_on_stop: None,
				space: OutfitSpace::from(outfit.space),
				shield_delay: 0.0,
				shield_generation: 0.0,
				shield_strength: 0.0,
			};

			// Engine stats
			if let Some(engine) = outfit.engine {
				let sprite_handle = match content.sprite_index.get(&engine.flare.sprite) {
					None => {
						return Err(anyhow!(
							"flare sprite `{}` doesn't exist",
							engine.flare.sprite
						))
						.with_context(|| format!("in outfit `{}`", outfit_name));
					}
					Some(t) => *t,
				};
				o.engine_thrust = engine.thrust;
				o.engine_flare_sprite = Some(sprite_handle);
				let sprite = content.get_sprite(sprite_handle);

				// Flare animation will traverse this edge when the player presses the thrust key
				// This leads from the idle animation to the transition animation
				o.engine_flare_on_start = {
					let x = engine.flare.on_start;
					if x.is_none() {
						None
					} else {
						let x = x.unwrap();
						let mut e = resolve_edge_as_edge(&x.val, 0.0, |x| {
							sprite.get_section_handle_by_name(x)
						})
						.with_context(|| format!("in outfit `{}`", outfit_name))?;
						match e {
							// Inherit duration from transition sequence
							SectionEdge::Top {
								section,
								ref mut duration,
							}
							| SectionEdge::Bot {
								section,
								ref mut duration,
							} => {
								*duration = sprite.get_section(section).frame_duration;
							}
							_ => {
								return Err(anyhow!(
									"bad edge `{}`: must be `top` or `bot`",
									x.val
								))
								.with_context(|| format!("in outfit `{}`", outfit_name));
							}
						};
						Some(e)
					}
				};

				// Flare animation will traverse this edge when the player releases the thrust key
				// This leads from the idle animation to the transition animation
				o.engine_flare_on_stop = {
					let x = engine.flare.on_stop;
					if x.is_none() {
						None
					} else {
						let x = x.unwrap();
						let mut e = resolve_edge_as_edge(&x.val, 0.0, |x| {
							sprite.get_section_handle_by_name(x)
						})
						.with_context(|| format!("in outfit `{}`", outfit_name))?;
						match e {
							// Inherit duration from transition sequence
							SectionEdge::Top {
								section,
								ref mut duration,
							}
							| SectionEdge::Bot {
								section,
								ref mut duration,
							} => {
								*duration = sprite.get_section(section).frame_duration;
							}
							_ => {
								return Err(anyhow!(
									"bad edge `{}`: must be `top` or `bot`",
									x.val
								))
								.with_context(|| format!("in outfit `{}`", outfit_name));
							}
						};
						Some(e)
					}
				};
			}

			// Steering stats
			if let Some(steer) = outfit.steering {
				o.steer_power = steer.power;
			}

			// Shield stats
			if let Some(shield) = outfit.shield {
				o.shield_delay = shield.delay.unwrap_or(0.0);
				o.shield_generation = shield.generation.unwrap_or(0.0);
				o.shield_strength = shield.strength.unwrap_or(0.0);
			}

			content.outfits.push(o);
		}

		return Ok(());
	}
}