use crate::{
    theme::{Color, ColorSet},
    token::Token,
};

#[derive(Eq, Debug, Clone)]
pub enum Component {
    X(usize),
    String(String),
    Fg(Color),
    Bg(Color),
}

impl PartialEq for Component {
    fn eq(&self, other: &Self) -> bool {
        match self {
            Self::X(x) => match other {
                Self::X(other_x) => x == other_x,
                _ => false,
            },
            Self::String(s) => match other {
                Self::String(other_s) => s == other_s,
                _ => false,
            },
            Self::Fg(c) => match other {
                Self::Fg(other_c) => c == other_c,
                _ => false,
            },
            Self::Bg(c) => match other {
                Self::Bg(other_c) => c == other_c,
                _ => false,
            },
        }
    }
}

#[derive(Debug, Clone)]
pub struct Line {
    color: ColorSet,
    components: Vec<Component>,
}

#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub enum SectionWidth {
    Full,
    Third,
    TwoThirds,
}

impl SectionWidth {
    pub fn abs_size(&self, max_width: usize) -> usize {
        match self {
            SectionWidth::Full => max_width,
            SectionWidth::Third => max_width / 3,
            SectionWidth::TwoThirds => (max_width / 3) * 2,
        }
    }
}

#[derive(Debug, Clone, Eq)]
pub struct Widget {
    want_width: SectionWidth,
    per_line: Vec<Token>,
}

impl PartialEq for Widget {
    fn eq(&self, other: &Self) -> bool {
        self.want_width == other.want_width
            && self.per_line.len() == other.per_line.len()
            && (&self.per_line)
                .into_iter()
                .enumerate()
                .all(|(i, token)| token.eq(&other.per_line[i]))
    }
}

impl Widget {
    pub fn new(
        width: SectionWidth,
        tokens_per_line: Vec<Token>,
    ) -> Self {
        Self {
            want_width: width,
            per_line: tokens_per_line,
        }
    }

    fn get_line(&self, line: usize) -> Option<&Token> {
        self.per_line.get(line - 1)
    }
}

#[derive(Debug, Clone, Eq)]
pub enum Instruction {
    FixedHeight(Box<Instruction>, usize, Vec<Widget>),
    End,
}

impl PartialEq for Instruction {
    fn eq(&self, other: &Self) -> bool {
        match self {
            Instruction::FixedHeight(next, size, widgets) => {
                match other {
                    Instruction::FixedHeight(
                        other_next,
                        other_size,
                        other_widgets,
                    ) => {
                        if size == other_size
                            && next.eq(other_next)
                            && widgets.len() == other_widgets.len()
                        {
                            widgets.into_iter().enumerate().all(
                                |(i, widget)| {
                                    widget.eq(&other_widgets[i])
                                },
                            )
                        } else {
                            false
                        }
                    }
                    _ => false,
                }
            }
            Instruction::End => match other {
                Instruction::End => true,
                _ => false,
            },
        }
    }
}

impl Instruction {
    pub fn make(
        self,
        (term_width, term_height): (u16, u16),
    ) -> String {
        todo!()
    }

    pub fn start() -> Self {
        Self::End
    }

    pub fn fixed(self, height: usize, widgets: Vec<Widget>) -> Self {
        Self::FixedHeight(Box::new(self), height, widgets)
    }
}

#[derive(Clone, Debug)]
pub enum Plan {
    FixedHeight(Box<Plan>, usize, Vec<Widget>),
    Fill(Box<Plan>, Vec<Widget>),
    End,
}

impl Plan {
    pub fn start() -> Self {
        Self::End
    }

    fn fit_check(widgets: &Vec<Widget>) {
        if widgets
            .into_iter()
            .map(|wd| wd.want_width.abs_size(100))
            .sum::<usize>()
            >= 100
        {
            panic!("widgets do not fit screen")
        }
    }

    fn to_instruction_set(self, max_height: usize) -> Instruction {
        let fill_height = {
            let (reserved_lines, fill_count) = self.count();
            (max_height - reserved_lines) / 1.max(fill_count)
        };
        self.to_instruction_fixed_fill_height(fill_height)
    }

    fn to_instruction_fixed_fill_height(
        self,
        fill_height: usize,
    ) -> Instruction {
        match self {
            Plan::FixedHeight(next, height, widgets) => {
                Instruction::FixedHeight(
                    Box::new(next.to_instruction_fixed_fill_height(
                        fill_height,
                    )),
                    height,
                    widgets,
                )
            }
            Plan::Fill(next, widgets) => {
                Instruction::FixedHeight(
                    Box::new(next.to_instruction_fixed_fill_height(
                        fill_height,
                    )),
                    fill_height,
                    widgets,
                )
            }
            Plan::End => Instruction::End,
        }
    }

    // counts how many lines are fixed height, those lines
    // are reserved, and the rest may be split between fills.
    // the return value is (reserved_lines, fill_count)
    // so, fill_height should be reserved_lines/fill_count
    fn count(&self) -> (usize, usize) {
        match self {
            Plan::FixedHeight(next, h, _) => {
                let next = next.count();
                (next.0 + h, next.1)
            }
            Plan::Fill(next, _) => {
                let next = next.count();
                (next.0, next.1 + 1)
            }
            Plan::End => (0, 0),
        }
    }

    pub fn line(self, widgets: Vec<Widget>) -> Self {
        self.fixed(1, widgets)
    }

    pub fn fixed(self, height: usize, widgets: Vec<Widget>) -> Self {
        Self::fit_check(&widgets);
        Self::FixedHeight(Box::new(self), height, widgets)
    }

    pub fn fill(self, widgets: Vec<Widget>) -> Self {
        Self::fit_check(&widgets);
        Self::Fill(Box::new(self), widgets)
    }

    // fn make_line(&self, term_width: u16, )

    // pub fn make(
    //     &self,
    //     (term_width, term_height): (u16, u16),
    // ) -> String {

    // }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_plan_to_instructions() {
        const HEIGHT: usize = 40;
        let (widget_1, widget_2, widget_3) = (
            Widget::new(
                SectionWidth::Third,
                vec![Token::text("hello")],
            ),
            Widget::new(
                SectionWidth::Third,
                vec![Token::text("hello")
                    .pad_char('*', 16)
                    .bg(Color::RED)],
            ),
            Widget::new(
                SectionWidth::Third,
                vec![Token::text("hello").limited(16).padded(20)],
            ),
        );

        vec![
            ("end -> end", Plan::start(), Instruction::End),
            (
                "fill entire screen",
                Plan::start().fill(vec![]),
                Instruction::start().fixed(HEIGHT, vec![]),
            ),
            (
                "5 | fill | 5 -> 5 | HEIGHT - 5 - 5 | 5",
                Plan::start()
                    .fixed(5, vec![widget_1.clone()])
                    .fill(vec![widget_3.clone()])
                    .fixed(5, vec![widget_2.clone()]),
                Instruction::start()
                    .fixed(5, vec![widget_1.clone()])
                    .fixed(HEIGHT - 5 - 5, vec![widget_3.clone()])
                    .fixed(5, vec![widget_2.clone()]),
            ),
            (
                "5 | 5 | fill -> 5 | 5 | HEIGHT - 5 - 5",
                Plan::start()
                    .fixed(5, vec![widget_3.clone()])
                    .fixed(5, vec![widget_2.clone()])
                    .fill(vec![widget_1.clone()]),
                Instruction::start()
                    .fixed(5, vec![widget_3.clone()])
                    .fixed(5, vec![widget_2.clone()])
                    .fixed(HEIGHT - 5 - 5, vec![widget_1.clone()]),
            ),
            (
                "fill -> HEIGHT",
                Plan::start().fill(vec![widget_1.clone()]),
                Instruction::start()
                    .fixed(HEIGHT, vec![widget_1.clone()]),
            ),
            (
                "
                5 | fill | 5 | fill | 5
                          ->
                5 | (HEIGHT - 15) / 2 | 5 | (HEIGHT - 15) / 2 | 5\n",
                Plan::start()
                    .fixed(
                        5,
                        vec![widget_1.clone(), widget_2.clone()],
                    )
                    .fill(vec![widget_1.clone(), widget_3.clone()])
                    .fixed(5, vec![])
                    .fill(vec![widget_2.clone()])
                    .fixed(
                        5,
                        vec![widget_3.clone(), widget_2.clone()],
                    ),
                Instruction::start()
                    .fixed(
                        5,
                        vec![widget_1.clone(), widget_2.clone()],
                    )
                    .fixed(
                        (HEIGHT - 15) / 2,
                        vec![widget_1.clone(), widget_3.clone()],
                    )
                    .fixed(5, vec![])
                    .fixed((HEIGHT - 15) / 2, vec![widget_2.clone()])
                    .fixed(
                        5,
                        vec![widget_3.clone(), widget_2.clone()],
                    ),
            ),
        ]
        .into_iter()
        .for_each(|(name, plan, expected)| {
            eprintln!("running test <{}>", &name);
            let actual = plan.to_instruction_set(HEIGHT);

            assert!(
                expected == actual,
                "<{}>: not equal!
                    expected:\n{:#?}
                    actual:\n{:#?}",
                &name,
                expected,
                actual,
            );
        })
    }
}