use crate::*;
use super::*;
use PhraseLengthFocus::*;
use PhraseLengthCommand::*;
use KeyCode::{Up, Down, Left, Right, Enter, Esc};

/// Displays and edits phrase length.
#[derive(Clone)]
pub struct PhraseLength {
    /// Pulses per beat (quaver)
    pub ppq:    usize,
    /// Beats per bar
    pub bpb:    usize,
    /// Length of phrase in pulses
    pub pulses: usize,
    /// Selected subdivision
    pub focus:  Option<PhraseLengthFocus>,
}

impl PhraseLength {
    pub fn new (pulses: usize, focus: Option<PhraseLengthFocus>) -> Self {
        Self { ppq: PPQ, bpb: 4, pulses, focus }
    }
    pub fn bars  (&self) -> usize {
        self.pulses / (self.bpb * self.ppq)
    }
    pub fn beats (&self) -> usize {
        (self.pulses % (self.bpb * self.ppq)) / self.ppq
    }
    pub fn ticks (&self) -> usize {
        self.pulses % self.ppq
    }
    pub fn bars_string  (&self) -> String {
        format!("{}", self.bars())
    }
    pub fn beats_string (&self) -> String {
        format!("{}", self.beats())
    }
    pub fn ticks_string (&self) -> String {
        format!("{:>02}", self.ticks())
    }
}

/// Focused field of `PhraseLength`
#[derive(Copy, Clone, Debug)]
pub enum PhraseLengthFocus {
    /// Editing the number of bars
    Bar,
    /// Editing the number of beats
    Beat,
    /// Editing the number of ticks
    Tick,
}

impl PhraseLengthFocus {
    pub fn next (&mut self) {
        *self = match self {
            Self::Bar  => Self::Beat,
            Self::Beat => Self::Tick,
            Self::Tick => Self::Bar,
        }
    }
    pub fn prev (&mut self) {
        *self = match self {
            Self::Bar  => Self::Tick,
            Self::Beat => Self::Bar,
            Self::Tick => Self::Beat,
        }
    }
}

render!(Tui: (self: PhraseLength) => {
    let bars  = ||self.bars_string();
    let beats = ||self.beats_string();
    let ticks = ||self.ticks_string();
    match self.focus {
        None =>
            row!(" ", bars(), ".", beats(), ".", ticks()),
        Some(PhraseLengthFocus::Bar) =>
            row!("[", bars(), "]", beats(), ".", ticks()),
        Some(PhraseLengthFocus::Beat) =>
            row!(" ", bars(), "[", beats(), "]", ticks()),
        Some(PhraseLengthFocus::Tick) =>
            row!(" ", bars(), ".", beats(), "[", ticks()),
    }
});

#[derive(Copy, Clone, Debug, PartialEq)]
pub enum PhraseLengthCommand {
    Begin,
    Cancel,
    Set(usize),
    Next,
    Prev,
    Inc,
    Dec,
}

command!(|self:PhraseLengthCommand,state:PoolModel|{
    match state.phrases_mode_mut().clone() {
        Some(PoolMode::Length(phrase, ref mut length, ref mut focus)) => match self {
            Cancel => { *state.phrases_mode_mut() = None; },
            Prev => { focus.prev() },
            Next => { focus.next() },
            Inc => match focus {
                Bar  => { *length += 4 * PPQ },
                Beat => { *length += PPQ },
                Tick => { *length += 1 },
            },
            Dec => match focus {
                Bar  => { *length = length.saturating_sub(4 * PPQ) },
                Beat => { *length = length.saturating_sub(PPQ) },
                Tick => { *length = length.saturating_sub(1) },
            },
            Set(length) => {
                let mut phrase = state.phrases()[phrase].write().unwrap();
                let old_length = phrase.length;
                phrase.length = length;
                std::mem::drop(phrase);
                *state.phrases_mode_mut() = None;
                return Ok(Some(Self::Set(old_length)))
            },
            _ => unreachable!()
        },
        _ => unreachable!()
    };
    None
});

input_to_command!(PhraseLengthCommand: |state: PoolModel, input: Event|{
    if let Some(PoolMode::Length(_, length, _)) = state.phrases_mode() {
        match input {
            key_pat!(Up)    => Self::Inc,
            key_pat!(Down)  => Self::Dec,
            key_pat!(Right) => Self::Next,
            key_pat!(Left)  => Self::Prev,
            key_pat!(Enter) => Self::Set(*length),
            key_pat!(Esc)   => Self::Cancel,
            _ => return None
        }
    } else {
        unreachable!()
    }
});