//! Basic stack operations: push a value, pop a value, swap, etc.

use crate::prelude::*;
use crate::tile::prelude::*;

/// Pushes a value on the stack, then lets the signal through
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Push {
    value: Value
}

impl Push {
    pub fn new(value: Value) -> Self {
        Self {
            value
        }
    }
}

impl Default for Push {
    fn default() -> Self {
        Self::new(Value::Number(0.0))
    }
}

impl Tile for Push {
    fn update<'b>(&'b mut self, mut context: UpdateContext<'b>) {
        if let Some(mut signal) = context.take_signal() {
            signal.push(self.value.clone());

            if let Some(coords) = context.offset(signal.direction().into_offset()) {
                context.send(coords, signal.direction(), signal).unwrap_or_else(|_| unreachable!());
            }
        }

        if context.state() != State::Idle {
            context.next_state();
        }
    }

    fn draw_simple(&self, ctx: DrawContext) -> TextChar {
        TextChar::from_state('p', ctx.state)
    }
}

/// Pops `n` values from the top of the stack, then lets the signal through
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Pop {
    amount: usize,
}

impl Pop {
    pub fn new(amount: usize) -> Self {
        Self {
            amount
        }
    }
}

impl Default for Pop {
    fn default() -> Self {
        Self::new(1)
    }
}

impl Tile for Pop {
    fn update<'b>(&'b mut self, mut context: UpdateContext<'b>) {
        if let Some(mut signal) = context.take_signal() {
            for _ in 0..self.amount {
                let _ = signal.pop();
            }

            if let Some(coords) = context.offset(signal.direction().into_offset()) {
                context.send(coords, signal.direction(), signal).unwrap_or_else(|_| unreachable!());
            }
        }

        if context.state() != State::Idle {
            context.next_state();
        }
    }

    fn draw_simple(&self, ctx: DrawContext) -> TextChar {
        if self.amount == 1 {
            TextChar::from_state('P', ctx.state)
        } else {
            TextChar::from_state(ctx.blink.scroll(&format!("PPP{}", self.amount)), ctx.state)
        }
    }
}

/// Reverses the order of the top `n` values from the stack, then lets the signal through
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct Swap {
    amount: usize,
}

impl Swap {
    pub fn new(amount: usize) -> Self {
        Self {
            amount
        }
    }
}

impl Default for Swap {
    fn default() -> Self {
        Self::new(2)
    }
}

impl Tile for Swap {
    fn update<'b>(&'b mut self, mut context: UpdateContext<'b>) {
        if let Some(mut signal) = context.take_signal() {
            let len = signal.stack().len();
            let last_elements = if self.amount > len {
                &mut signal.stack_mut()[..]
            } else {
                &mut signal.stack_mut()[(len - self.amount)..len]
            };

            last_elements.reverse();

            if let Some(coords) = context.offset(signal.direction().into_offset()) {
                context.send(coords, signal.direction(), signal).unwrap_or_else(|_| unreachable!());
            }
        }

        if context.state() != State::Idle {
            context.next_state();
        }
    }

    fn draw_simple(&self, ctx: DrawContext) -> TextChar {
        if self.amount == 2 {
            TextChar::from_state('s', ctx.state)
        } else {
            TextChar::from_state(ctx.blink.scroll(&format!("sss{}", self.amount)), ctx.state)
        }
    }
}

// TODO: SwapN, RotateLeft, RotateRight, RotateLeftN, RotateRightN