use std::ops::Range;

use druid::{Data, Lens};
use ropey::Rope;

#[derive(Clone, Data, PartialEq, Eq, Debug)]
pub enum EditMode {
    Normal,
    Insert,
}

#[derive(Data, Lens, Clone, PartialEq, Debug)]
pub struct EditorData {
    #[data(same_fn = "PartialEq::eq")]
    pub content: Rope,
    pub cursor_pos: usize,
    pub mode: EditMode,
    pub cursor_opactiy: f64,
    pub cursor_fade: f64,
    pub selection_pos: Option<usize>,
}

impl Default for EditorData {
    fn default() -> Self {
        Self {
            content: Rope::from_str(""),
            cursor_pos: 0,
            selection_pos: None,
            mode: EditMode::Normal,
            cursor_opactiy: 255.0,
            cursor_fade: 1.0,
        }
    }
}

impl EditorData {
    pub fn new(content: &str) -> Self {
        Self {
            content: Rope::from_str(content),
            ..Default::default()
        }
    }

    pub fn move_cursor(&mut self, idx: usize) {
        self.cursor_pos = idx;
    }

    pub fn select_range(&self) -> Range<usize> {
        if let Some(selection_pos) = self.selection_pos {
            if self.cursor_pos > selection_pos {
                selection_pos..self.cursor_pos
            } else {
                self.cursor_pos..selection_pos
            }
        } else {
            self.cursor_pos..self.cursor_pos
        }
    }

    pub fn push_str(&mut self, s: &str) {
        if self.selection_pos.is_some() {
            self.content.remove(self.select_range());
            self.content.insert(self.select_range().start, s);
        } else {
            self.content.insert(self.cursor_pos, s);
        }
        self.move_cursor(self.select_range().start + s.len());
    }

    pub fn push(&mut self, c: char) {
        self.content.insert_char(self.cursor_pos, c);
        self.cursor_right();
    }

    // pub fn cursor_to_end(&mut self) {
    //     self.move_cursor(self.content.len_chars());
    // }

    pub fn deselect(&mut self) {
        self.selection_pos = None;
    }

    pub fn delete_current_line(&mut self) {
        if self.current_line_index() < self.content.len_lines() {
            self.content.remove(
                self.current_line_start()
                    ..(self.current_line_start()
                        + self
                            .current_line()
                            .len_chars()
                            .min(self.content.len_chars())),
            );
        } else {
            self.cursor_up();
            self.content.remove(
                self.current_line_start()..(self.cursor_pos + self.current_line().len_chars()),
            );
        }
        if self.cursor_pos > self.content.len_chars() && self.content.len_chars() > 0 {
            self.cursor_pos = self.content.len_chars() - 1;
        } else if self.cursor_pos > self.content.len_chars() {
            self.cursor_pos = 0;
        }
        self.deselect();
    }

    pub fn word_scan_forward(&mut self) {
        while self.cursor_pos < self.content.len_chars() {
            self.cursor_pos += 1;
            if !self
                .current_char()
                .map(|c| c.is_alphanumeric())
                .unwrap_or(false)
            {
                break;
            }
            self.deselect();
        }
    }

    pub fn word_scan_backward(&mut self) {
        if self.cursor_pos > 0 {
            self.cursor_pos -= 1;
        }
        while self.cursor_pos > 0 {
            if !self
                .content
                .get_char(self.cursor_pos - 1)
                .map(|c| c.is_alphanumeric())
                .unwrap_or(false)
            {
                break;
            } else {
                self.cursor_pos -= 1;
            }
            self.deselect();
        }
    }

    pub fn delete_char_forward(&mut self) {
        if !self.select_range().is_empty() {
            let range = self.select_range();
            self.content.remove(self.select_range());
            self.move_cursor(range.start);
            self.deselect();
            return;
        }

        if self.cursor_pos < self.content.len_chars() {
            self.content.remove((self.cursor_pos)..self.cursor_pos + 1);
        }
    }

    pub fn delete_char_back(&mut self) {
        // Delete selection
        if !self.select_range().is_empty() {
            let range = self.select_range();
            self.content.remove(self.select_range());
            self.move_cursor(range.start);
            self.deselect();
            return;
        }

        // Cant delete character sif we are at the start of the buffer
        if self.cursor_pos > 0 {
            self.content.remove((self.cursor_pos - 1)..self.cursor_pos);
            self.cursor_left();
        }
    }

    pub fn delete_to_eol(&mut self) {
        self.content.remove(
            self.cursor_pos
                ..(self.current_line_start() + self.current_line().to_string().len() - 1),
        )
    }

    pub fn cursor_left(&mut self) {
        match self.mode {
            EditMode::Insert => {
                if self.cursor_pos > 0 {
                    self.move_cursor(self.cursor_pos - 1);
                }
            }
            EditMode::Normal => {
                if self.cursor_pos > self.current_line_start() {
                    self.move_cursor(self.cursor_pos - 1);
                }
            }
        }
    }

    pub fn cursor_up(&mut self) {
        let line_idx = self.content.char_to_line(self.cursor_pos);

        if line_idx > 0 {
            let up_line_start = self.content.line_to_char(line_idx - 1);
            let up_line = self.content.line(line_idx - 1);
            self.move_cursor(up_line_start + self.current_column().min(up_line.len_chars() - 1));
        }
    }

    pub fn select_up(&mut self) {
        let line_idx = self.content.char_to_line(self.cursor_pos);

        if line_idx > 0 {
            let start_of_current_line = self.content.line_to_char(line_idx);
            let line_pos = self.cursor_pos - start_of_current_line;
            let up_line_start = self.content.line_to_char(line_idx - 1);
            let up_line = self.content.line(line_idx - 1);
            self.cursor_pos = up_line_start + line_pos.min(up_line.len_chars() - 1);
        }
    }

    pub fn cursor_down(&mut self) {
        let line_idx = self.content.char_to_line(self.cursor_pos);
        if line_idx < self.content.len_lines() - 1 {
            let start_of_next_line = self.content.line_to_char(self.current_line_index() + 1);
            let next_line_len = self.content.line(line_idx + 1).len_chars().max(1) - 1;

            let new_pos = start_of_next_line + self.current_column().min(next_line_len);

            self.move_cursor(new_pos);
        }
    }

    pub fn select_down(&mut self) {
        //12 -> 11
        let line_idx = self.content.char_to_line(self.cursor_pos);
        if line_idx < self.content.len_lines() - 1 {
            let start_of_current_line = self.content.line_to_char(line_idx);
            let line_pos = self.cursor_pos - start_of_current_line;
            let start_of_next_line = self.content.line_to_char(line_idx + 1) + 1;
            let next_line_len = self.content.line(line_idx + 1).len_chars();

            self.cursor_pos =
                (start_of_next_line + line_pos.min(next_line_len)).min(start_of_next_line);
        }
    }

    pub fn cursor_right(&mut self) {
        if self.cursor_pos < self.content.len_chars() {
            self.move_cursor(self.cursor_pos + 1);
        }
    }

    pub fn select_to_end_of_line(&mut self) {
        self.selection_pos = Some(self.cursor_pos);
        self.cursor_to_end_of_line();
    }

    pub fn cursor_to_end_of_line(&mut self) {
        let line_idx = self.content.char_to_line(self.cursor_pos);
        let start_of_line = self.content.line_to_char(line_idx);
        let line = self.content.line(line_idx);
        if line_idx == self.content.len_lines() - 1 {
            self.move_cursor(start_of_line + line.len_chars());
        } else {
            self.move_cursor(start_of_line + line.len_chars() - 1);
        }
    }

    pub fn select_to_start_of_line(&mut self) {
        self.selection_pos = Some(self.cursor_pos);
        self.cursor_to_start_of_line();
    }

    pub fn cursor_to_start_of_line(&mut self) {
        let start_of_line = self
            .content
            .line_to_char(self.content.char_to_line(self.cursor_pos));

        self.move_cursor(start_of_line);
    }

    pub fn normal_mode(&mut self) {
        self.mode = EditMode::Normal;
        if self.cursor_pos == self.content.len_chars() && self.content.len_chars() != 0 {
            self.cursor_pos -= 1;
        }
        self.deselect();
    }

    pub fn select_all(&mut self) {
        self.selection_pos = Some(0);
        self.cursor_pos = self.content.len_chars();
    }

    pub fn select_left(&mut self) {
        if self.cursor_pos > 0 {
            self.cursor_pos -= 1
        }
    }

    pub fn select_right(&mut self) {
        if self.cursor_pos < self.content.len_chars() {
            self.cursor_pos += 1;
        }
    }

    pub fn current_line(&self) -> ropey::RopeSlice {
        self.content
            .get_slice(
                self.current_line_start()
                    ..self
                        .content
                        .line_to_char(self.current_line_index() + 1)
                        .min(self.content.len_chars()),
            )
            .unwrap()
    }

    pub fn current_line_index(&self) -> usize {
        self.content.char_to_line(self.cursor_pos)
    }

    pub fn current_line_start(&self) -> usize {
        self.content
            .line_to_char(self.content.char_to_line(self.cursor_pos))
    }

    pub fn current_column(&self) -> usize {
        self.cursor_pos - self.current_line_start()
    }

    pub fn current_char(&self) -> Option<char> {
        self.content.get_char(self.cursor_pos)
    }
}

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