#![allow(dead_code)]

use buffer::Buffer;
use formatter::LineFormatter;
use formatter::RoundingBehavior::*;
use std::path::{Path, PathBuf};
use std::cmp::{min, max};
use string_utils::{grapheme_count, str_to_line_ending, LineEnding};
use utils::digit_count;
use self::cursor::CursorSet;

mod cursor;


pub struct Editor<T: LineFormatter> {
    pub buffer: Buffer,
    pub formatter: T,
    pub file_path: PathBuf,
    pub line_ending_type: LineEnding,
    pub soft_tabs: bool,
    pub soft_tab_width: u8,
    pub dirty: bool,
    
    // The dimensions of the total editor in screen space, including the
    // header, gutter, etc.
    pub editor_dim: (usize, usize),
    
    // The dimensions and position of just the text view portion of the editor
    pub view_dim: (usize, usize),  // (height, width)
    pub view_pos: (usize, usize),  // (grapheme index, visual horizontal offset)
    
    // The editing cursor position
    pub cursors: CursorSet,  
}


impl<T: LineFormatter> Editor<T> {
    /// Create a new blank editor
    pub fn new(formatter: T) -> Editor<T> {
        Editor {
            buffer: Buffer::new(),
            formatter: formatter,
            file_path: PathBuf::new(""),
            line_ending_type: LineEnding::LF,
            soft_tabs: false,
            soft_tab_width: 4,
            dirty: false,
            editor_dim: (0, 0),
            view_dim: (0, 0),
            view_pos: (0, 0),
            cursors: CursorSet::new(),
        }
    }
    
    
    pub fn new_from_file(formatter: T, path: &Path) -> Editor<T> {
        let buf = match Buffer::new_from_file(path) {
            Ok(b) => {b},
            // TODO: handle un-openable file better
            _ => panic!("Could not open file!"),
        };
        
        let mut ed = Editor {
            buffer: buf,
            formatter: formatter,
            file_path: path.to_path_buf(),
            line_ending_type: LineEnding::LF,
            soft_tabs: false,
            soft_tab_width: 4,
            dirty: false,
            editor_dim: (0, 0),
            view_dim: (0, 0),
            view_pos: (0, 0),
            cursors: CursorSet::new(),
        };
        
        // For multiple-cursor testing
        //let mut cur = Cursor::new();
        //cur.range.0 = 30;
        //cur.range.1 = 30;
        //cur.update_vis_start(&(ed.buffer), &(ed.formatter));
        //ed.cursors.add_cursor(cur);
        
        ed.auto_detect_line_ending();
        ed.auto_detect_indentation_style();
        
        return ed;
    }
    
    
    pub fn save_if_dirty(&mut self) {
        if self.dirty && self.file_path != PathBuf::new("") {
            let _ = self.buffer.save_to_file(&self.file_path);
            self.dirty = false;
        }
    }
    
    
    pub fn auto_detect_line_ending(&mut self) {
        let mut line_ending_histogram: [usize; 8] = [0, 0, 0, 0, 0, 0, 0, 0];
        
        // Collect statistics
        let mut line_i: usize = 0;
        for line in self.buffer.line_iter() {
            // Get the line ending
            let ending = if line.grapheme_count() > 0 {
                let g = line.grapheme_at_index(line.grapheme_count() - 1);
                str_to_line_ending(g)
            }
            else {
                LineEnding::None
            };
            
            // Record which line ending it is
            match ending {
                LineEnding::None => {
                },
                LineEnding::CRLF => {
                    line_ending_histogram[0] += 1;
                },
                LineEnding::LF => {
                    line_ending_histogram[1] += 1;
                },
                LineEnding::VT => {
                    line_ending_histogram[2] += 1;
                },
                LineEnding::FF => {
                    line_ending_histogram[3] += 1;
                },
                LineEnding::CR => {
                    line_ending_histogram[4] += 1;
                },
                LineEnding::NEL => {
                    line_ending_histogram[5] += 1;
                },
                LineEnding::LS => {
                    line_ending_histogram[6] += 1;
                },
                LineEnding::PS => {
                    line_ending_histogram[7] += 1;
                },
            }
            
            // Stop after 100 lines
            line_i += 1;
            if line_i > 100 {
                break;
            }
        }
        
        // Analyze stats and make a determination
        let mut lei = 0;
        let mut le_count = 0;
        for i in 0usize..8 {
            if line_ending_histogram[i] >= le_count {
                lei = i;
                le_count = line_ending_histogram[i];
            }
        }
        
        if le_count > 0 {
            self.line_ending_type = match lei {
                0 => LineEnding::CRLF,
                1 => LineEnding::LF,
                2 => LineEnding::VT,
                3 => LineEnding::FF,
                4 => LineEnding::CR,
                5 => LineEnding::NEL,
                6 => LineEnding::LS,
                7 => LineEnding::PS,
                
                _ => LineEnding::LF,
            };
        }
    }
    
    
    pub fn auto_detect_indentation_style(&mut self) {
        let mut tab_blocks: usize = 0;
        let mut space_blocks: usize = 0;
        let mut space_histogram: [usize; 9] = [0, 0, 0, 0, 0, 0, 0, 0, 0];
        
        let mut last_indent = (false, 0usize);  // (was_tabs, indent_count)
        
        // Collect statistics
        let mut line_i: usize = 0;
        for line in self.buffer.line_iter() {
            let mut g_iter = line.grapheme_iter();
            match g_iter.next() {
                Some("\t") => {
                    // Count leading tabs
                    let mut count = 1;
                    for g in g_iter {
                        if g == "\t" {
                            count += 1;
                        }
                        else {
                            break;
                        }
                    }
                    
                    // Update stats
                    if last_indent.0 && last_indent.1 < count {
                        tab_blocks += 1;
                    }
                    
                    // Store last line info
                    last_indent = (true, count);
                },
                
                Some(" ") => {
                    // Count leading spaces
                    let mut count = 1;
                    for g in g_iter {
                        if g == " " {
                            count += 1;
                        }
                        else {
                            break;
                        }
                    }
                    
                    // Update stats
                    if !last_indent.0 && last_indent.1 < count {
                        space_blocks += 1;
                        let amount = count - last_indent.1;
                        if amount < 9 {
                            space_histogram[amount] += 1;
                        }
                        else {
                            space_histogram[8] += 1;
                        }
                    }
                    
                    // Store last line info
                    last_indent = (false, count);
                },
                
                _ => {},
            }
            
            // Stop after 1000 lines
            line_i += 1;
            if line_i > 1000 {
                break;
            }
        }
        
        // Analyze stats and make a determination
        if space_blocks == 0 && tab_blocks == 0 {
            return;
        }
        
        if space_blocks > (tab_blocks * 2) {
            let mut width = 0;
            let mut width_count = 0;
            for i in 0usize..9 {
                if space_histogram[i] > width_count {
                    width = i;
                    width_count = space_histogram[i];
                }
            }
            
            self.soft_tabs = true;
            self.soft_tab_width = width as u8;
        }
        else {
            self.soft_tabs = false;
        }
    }
    
    
    pub fn update_dim(&mut self, h: usize, w: usize) {
        self.editor_dim = (h, w);
        self.update_view_dim();
    }
    
    
    pub fn update_view_dim(&mut self) {
        // TODO: generalize for non-terminal UI.  Maybe this isn't where it
        // belongs, in fact.  But for now, this is the easiest place to put
        // it.
        let line_count_digits = digit_count(self.buffer.line_count() as u32, 10) as usize;
        // Minus 1 vertically for the header, minus one more than the digits in
        // the line count for the gutter.
        self.view_dim = (self.editor_dim.0 - 1, self.editor_dim.1 - line_count_digits - 1);
    }
    
    
    pub fn undo(&mut self) {
        // TODO: handle multiple cursors properly
        if let Some(pos) = self.buffer.undo() {
            self.cursors.truncate(1);
            self.cursors[0].range.0 = pos;
            self.cursors[0].range.1 = pos;
            self.cursors[0].update_vis_start(&(self.buffer), &(self.formatter));
            
            self.move_view_to_cursor();
            
            self.dirty = true;
            
            self.cursors.make_consistent();
        }
    }
    
    
    pub fn redo(&mut self) {
        // TODO: handle multiple cursors properly
        if let Some(pos) = self.buffer.redo() {
            self.cursors.truncate(1);
            self.cursors[0].range.0 = pos;
            self.cursors[0].range.1 = pos;
            self.cursors[0].update_vis_start(&(self.buffer), &(self.formatter));
            
            self.move_view_to_cursor();
            
            self.dirty = true;
            
            self.cursors.make_consistent();
        }
    }
    
    
    /// Moves the editor's view the minimum amount to show the cursor
    pub fn move_view_to_cursor(&mut self) {
        // TODO: account for the horizontal offset of the editor view.

        // TODO: handle multiple cursors properly.  Should only move if
        // there are no cursors currently in view, and should jump to
        // the closest cursor.
        
        // Find the first and last grapheme index visible within the editor.
        let g_first = self.formatter.index_set_horizontal_v2d(&self.buffer, self.view_pos.0, 0, Floor);
        let mut g_last = self.formatter.index_offset_vertical_v2d(&self.buffer, g_first, self.view_dim.0 as isize, (Floor, Floor));
        g_last = self.formatter.index_set_horizontal_v2d(&self.buffer, g_last, self.view_dim.1, Floor);

        // Adjust the view depending on where the cursor is        
        if self.cursors[0].range.0 < g_first {
            self.view_pos.0 = self.cursors[0].range.0;
        }
        else if self.cursors[0].range.0 > g_last {
            self.view_pos.0 = self.formatter.index_offset_vertical_v2d(&self.buffer, self.cursors[0].range.0, -(self.view_dim.0 as isize), (Floor, Floor));
        }
    }
    
    
    pub fn insert_text_at_cursor(&mut self, text: &str) {
        self.cursors.make_consistent();
        
        let str_len = grapheme_count(text);
        let mut offset = 0;
        
        for c in self.cursors.iter_mut() {
            // Insert text
            self.buffer.insert_text(text, c.range.0 + offset);
            self.dirty = true;
            
            // Move cursor
            c.range.0 += str_len + offset;
            c.range.1 += str_len + offset;
            c.update_vis_start(&(self.buffer), &(self.formatter));
            
            // Update offset
            offset += str_len;
        }
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn insert_tab_at_cursor(&mut self) {
        self.cursors.make_consistent();
        
        if self.soft_tabs {
            let mut offset = 0;
            
            for c in self.cursors.iter_mut() {
                // Update cursor with offset
                c.range.0 += offset;
                c.range.1 += offset;
                
                // Figure out how many spaces to insert
                let vis_pos = self.formatter.index_to_horizontal_v2d(&self.buffer, c.range.0);
                // TODO: handle tab settings
                let next_tab_stop = ((vis_pos / self.soft_tab_width as usize) + 1) * self.soft_tab_width as usize;
                let space_count = min(next_tab_stop - vis_pos, 8);
                
                
                // Insert spaces
                let space_strs = ["", " ", "  ", "   ", "    ", "     ", "      ", "       ", "        "];
                self.buffer.insert_text(space_strs[space_count], c.range.0);
                self.dirty = true;
                
                // Move cursor
                c.range.0 += space_count;
                c.range.1 += space_count;
                c.update_vis_start(&(self.buffer), &(self.formatter));
                    
                // Update offset
                offset += space_count;
            }
            
            // Adjust view
            self.move_view_to_cursor();
        }
        else {
            self.insert_text_at_cursor("\t");
        }
    }
    
    
    pub fn backspace_at_cursor(&mut self) {
        self.remove_text_behind_cursor(1);
    }
    
    
    pub fn insert_text_at_grapheme(&mut self, text: &str, pos: usize) {
        self.dirty = true;
        let buf_len = self.buffer.grapheme_count();
        self.buffer.insert_text(text, if pos < buf_len {pos} else {buf_len});
    }
    
    
    pub fn remove_text_behind_cursor(&mut self, grapheme_count: usize) {
        self.cursors.make_consistent();
        
        let mut offset = 0;
        
        for c in self.cursors.iter_mut() {
            // Update cursor with offset
            c.range.0 -= offset;
            c.range.1 -= offset;
            
            // Do nothing if there's nothing to delete.
            if c.range.0 == 0 {
                continue;
            }
            
            let len = min(c.range.0, grapheme_count);
            
            // Remove text
            self.buffer.remove_text_before(c.range.0, len);
            self.dirty = true;
            
            // Move cursor
            c.range.0 -= len;
            c.range.1 -= len;
            c.update_vis_start(&(self.buffer), &(self.formatter));
            
            // Update offset
            offset += len;
        }
        
        self.cursors.make_consistent();
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn remove_text_in_front_of_cursor(&mut self, grapheme_count: usize) {
        self.cursors.make_consistent();
        
        let mut offset = 0;
        
        for c in self.cursors.iter_mut() {
            // Update cursor with offset
            c.range.0 -= min(c.range.0, offset);
            c.range.1 -= min(c.range.1, offset);
        
            // Do nothing if there's nothing to delete.
            if c.range.1 == self.buffer.grapheme_count() {
                return;
            }
            
            let max_len = if self.buffer.grapheme_count() > c.range.1 {self.buffer.grapheme_count() - c.range.1} else {0};
            let len = min(max_len, grapheme_count);
            
            // Remove text
            self.buffer.remove_text_after(c.range.1, len);
            self.dirty = true;
            
            // Move cursor
            c.update_vis_start(&(self.buffer), &(self.formatter));
            
            // Update offset
            offset += len;
        }
        
        self.cursors.make_consistent();
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn remove_text_inside_cursor(&mut self) {
        self.cursors.make_consistent();
        
        let mut offset = 0;
        
        for c in self.cursors.iter_mut() {
            // Update cursor with offset
            c.range.0 -= min(c.range.0, offset);
            c.range.1 -= min(c.range.1, offset);
        
            // If selection, remove text
            if c.range.0 < c.range.1 {
                let len = c.range.1 - c.range.0;
                
                self.buffer.remove_text_before(c.range.0, c.range.1 - c.range.0);
                self.dirty = true;
            
                // Move cursor
                c.range.1 = c.range.0;
                
                // Update offset
                offset += len;
            }
            
            c.update_vis_start(&(self.buffer), &(self.formatter));
        }
        
        self.cursors.make_consistent();
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn cursor_to_beginning_of_buffer(&mut self) {
        self.cursors = CursorSet::new();
        
        self.cursors[0].range = (0, 0);
        self.cursors[0].update_vis_start(&(self.buffer), &(self.formatter));
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn cursor_to_end_of_buffer(&mut self) {
        let end = self.buffer.grapheme_count();
        
        self.cursors = CursorSet::new();
        self.cursors[0].range = (end, end);
        self.cursors[0].update_vis_start(&(self.buffer), &(self.formatter));
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn cursor_left(&mut self, n: usize) {
        for c in self.cursors.iter_mut() {
            if c.range.0 >= n {
                c.range.0 -= n;
            }
            else {
                c.range.0 = 0;
            }
            
            c.range.1 = c.range.0;
            c.update_vis_start(&(self.buffer), &(self.formatter));
        }
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn cursor_right(&mut self, n: usize) {
        for c in self.cursors.iter_mut() {
            c.range.1 += n;
            
            if c.range.1 > self.buffer.grapheme_count() {
                c.range.1 = self.buffer.grapheme_count();
            }
            
            c.range.0 = c.range.1;
            c.update_vis_start(&(self.buffer), &(self.formatter));
        }
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn cursor_up(&mut self, n: usize) {
        for c in self.cursors.iter_mut() {
            let vmove = -1 * (n * self.formatter.single_line_height()) as isize;
            let mut temp_index = self.formatter.index_offset_vertical_v2d(&self.buffer, c.range.0, vmove, (Round, Round));
            
            if temp_index == 0 {
                c.update_vis_start(&(self.buffer), &(self.formatter));
            }
            else {
                temp_index = self.formatter.index_set_horizontal_v2d(&self.buffer, temp_index, c.vis_start, Round);
            }
            
            c.range.0 = temp_index;
            c.range.1 = temp_index;
        }
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn cursor_down(&mut self, n: usize) {
        for c in self.cursors.iter_mut() {
            let vmove = (n * self.formatter.single_line_height()) as isize;
            let mut temp_index = self.formatter.index_offset_vertical_v2d(&self.buffer, c.range.0, vmove, (Round, Round));
            
            if temp_index == self.buffer.grapheme_count() {
                c.update_vis_start(&(self.buffer), &(self.formatter));
            }
            else {
                temp_index = self.formatter.index_set_horizontal_v2d(&self.buffer, temp_index, c.vis_start, Round);
            }
            
            c.range.0 = temp_index;
            c.range.1 = temp_index;
        }
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn page_up(&mut self) {
        let move_amount = self.view_dim.0 - max((self.view_dim.0 / 8), self.formatter.single_line_height());
        self.view_pos.0 = self.formatter.index_offset_vertical_v2d(&self.buffer, self.view_pos.0, -1 * move_amount as isize, (Round, Round));
        
        self.cursor_up(move_amount);
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn page_down(&mut self) {
        let move_amount = self.view_dim.0 - max((self.view_dim.0 / 8), self.formatter.single_line_height());
        self.view_pos.0 = self.formatter.index_offset_vertical_v2d(&self.buffer, self.view_pos.0, move_amount as isize, (Round, Round));
        
        self.cursor_down(move_amount);
        
        // Adjust view
        self.move_view_to_cursor();
    }
    
    
    pub fn jump_to_line(&mut self, n: usize) {
        let pos = self.buffer.line_col_to_index((n, 0));
        self.cursors.truncate(1);
        self.cursors[0].range.0 = self.formatter.index_set_horizontal_v2d(&self.buffer, pos, self.cursors[0].vis_start, Round);
        self.cursors[0].range.1 = self.cursors[0].range.0;
        
        // Adjust view
        self.move_view_to_cursor();
    }
}