use crate::table_theme::TableTheme;
use crate::wrap::{column_width, split_sublines, wrap, Alignment, Subline, WrappedCell};
use crate::{StyledString, TextStyle};
use nu_ansi_term::{AnsiString, AnsiStrings, Style};
use nu_protocol::{Config, FooterMode};
use std::collections::HashMap;
use std::fmt::Write;

enum SeparatorPosition {
    Top,
    Middle,
    Bottom,
}

#[derive(Debug)]
pub struct Table {
    pub headers: Vec<StyledString>,
    pub data: Vec<Vec<StyledString>>,
    pub theme: TableTheme,
}

impl Table {
    pub fn new(
        headers: Vec<StyledString>,
        data: Vec<Vec<StyledString>>,
        theme: TableTheme,
    ) -> Table {
        Table {
            headers,
            data,
            theme,
        }
    }
}

#[derive(Debug)]
pub struct ProcessedTable {
    pub headers: Vec<ProcessedCell>,
    pub data: Vec<Vec<ProcessedCell>>,
    pub theme: TableTheme,
}

#[derive(Debug)]
pub struct ProcessedCell {
    pub contents: Vec<Vec<Subline>>,
    pub style: TextStyle,
}

#[derive(Debug)]
pub struct WrappedTable {
    pub column_widths: Vec<usize>,
    pub headers: Vec<WrappedCell>,
    pub data: Vec<Vec<WrappedCell>>,
    pub theme: TableTheme,
    pub footer: Vec<WrappedCell>,
}

impl WrappedTable {
    fn print_separator(
        &self,
        separator_position: SeparatorPosition,
        color_hm: &HashMap<String, Style>,
    ) -> String {
        let column_count = self.column_widths.len();
        let mut output: Vec<AnsiString> = Vec::new();
        let sep_color = color_hm
            .get("separator")
            .unwrap_or(&Style::default())
            .to_owned();

        match separator_position {
            SeparatorPosition::Top => {
                for column in self.column_widths.iter().enumerate() {
                    if column.0 == 0 && self.theme.print_left_border {
                        output.push(sep_color.paint(self.theme.top_left.to_string()));
                    }

                    for _ in 0..*column.1 {
                        output.push(sep_color.paint(self.theme.top_horizontal.to_string()));
                    }

                    output.push(sep_color.paint(self.theme.top_horizontal.to_string()));
                    output.push(sep_color.paint(self.theme.top_horizontal.to_string()));
                    if column.0 == column_count - 1 {
                        if self.theme.print_right_border {
                            output.push(sep_color.paint(self.theme.top_right.to_string()));
                        }
                    } else {
                        output.push(sep_color.paint(self.theme.top_center.to_string()));
                    }
                }
                output.push(AnsiString::from("\n".to_string()));
            }
            SeparatorPosition::Middle => {
                for column in self.column_widths.iter().enumerate() {
                    if column.0 == 0 && self.theme.print_left_border {
                        output.push(sep_color.paint(self.theme.middle_left.to_string()));
                    }

                    for _ in 0..*column.1 {
                        output.push(sep_color.paint(self.theme.middle_horizontal.to_string()));
                    }

                    output.push(sep_color.paint(self.theme.middle_horizontal.to_string()));
                    output.push(sep_color.paint(self.theme.middle_horizontal.to_string()));

                    if column.0 == column_count - 1 {
                        if self.theme.print_right_border {
                            output.push(sep_color.paint(self.theme.middle_right.to_string()));
                        }
                    } else {
                        output.push(sep_color.paint(self.theme.center.to_string()));
                    }
                }
                output.push(AnsiString::from("\n".to_string()));
            }
            SeparatorPosition::Bottom => {
                for column in self.column_widths.iter().enumerate() {
                    if column.0 == 0 && self.theme.print_left_border {
                        output.push(sep_color.paint(self.theme.bottom_left.to_string()));
                    }
                    for _ in 0..*column.1 {
                        output.push(sep_color.paint(self.theme.bottom_horizontal.to_string()));
                    }
                    output.push(sep_color.paint(self.theme.bottom_horizontal.to_string()));
                    output.push(sep_color.paint(self.theme.bottom_horizontal.to_string()));

                    if column.0 == column_count - 1 {
                        if self.theme.print_right_border {
                            output.push(sep_color.paint(self.theme.bottom_right.to_string()));
                        }
                    } else {
                        output.push(sep_color.paint(self.theme.bottom_center.to_string()));
                    }
                }
            }
        }
        AnsiStrings(&output[..]).to_string()
    }

    fn print_cell_contents(
        &self,
        cells: &[WrappedCell],
        color_hm: &HashMap<String, Style>,
    ) -> String {
        let sep_color = color_hm
            .get("separator")
            .unwrap_or(&Style::default())
            .to_owned();

        let mut total_output = String::new();

        for current_line in 0.. {
            let mut lines_printed = 0;

            let mut output = String::new();
            if self.theme.print_left_border {
                output.push_str(
                    &sep_color
                        .paint(&self.theme.left_vertical.to_string())
                        .to_string(),
                );
            }

            for column in cells.iter().enumerate() {
                if let Some(line) = (column.1).lines.get(current_line) {
                    let remainder = self.column_widths[column.0] - line.width;
                    output.push(' ');

                    match column.1.style.alignment {
                        Alignment::Left => {
                            if let Some(color) = column.1.style.color_style {
                                output.push_str(&color.paint(&line.line).to_string());
                            } else {
                                output.push_str(&line.line);
                            }
                            for _ in 0..remainder {
                                output.push(' ');
                            }
                        }
                        Alignment::Center => {
                            for _ in 0..remainder / 2 {
                                output.push(' ');
                            }
                            if let Some(color) = column.1.style.color_style {
                                output.push_str(&color.paint(&line.line).to_string());
                            } else {
                                output.push_str(&line.line);
                            }
                            for _ in 0..(remainder / 2 + remainder % 2) {
                                output.push(' ');
                            }
                        }
                        Alignment::Right => {
                            for _ in 0..remainder {
                                output.push(' ');
                            }
                            if let Some(color) = column.1.style.color_style {
                                output.push_str(&color.paint(&line.line).to_string());
                            } else {
                                output.push_str(&line.line);
                            }
                        }
                    }
                    output.push(' ');
                    lines_printed += 1;
                } else {
                    for _ in 0..self.column_widths[column.0] + 2 {
                        output.push(' ');
                    }
                }
                if column.0 < cells.len() - 1 {
                    output.push_str(
                        &sep_color
                            .paint(&self.theme.center_vertical.to_string())
                            .to_string(),
                    );
                } else if self.theme.print_right_border {
                    output.push_str(
                        &sep_color
                            .paint(&self.theme.right_vertical.to_string())
                            .to_string(),
                    );
                }
            }

            if lines_printed == 0 {
                break;
            }

            writeln!(&mut total_output, "{}", output).expect("writing should be done to buffer");
        }
        total_output
    }

    fn print_table(&self, color_hm: &HashMap<String, Style>, config: &Config) -> String {
        let mut output = String::new();

        // TODO: This may be unnecessary after JTs changes. Let's remove it and see.
        // #[cfg(windows)]
        // {
        //     let _ = nu_ansi_term::enable_ansi_support();
        // }

        if self.data.is_empty() {
            return output;
        }

        // The top border
        if self.theme.print_top_border {
            output.push_str(&self.print_separator(SeparatorPosition::Top, color_hm));
        }

        // The header
        let skip_headers = (self.headers.len() == 2 && self.headers[1].max_width == 0)
            || (self.headers.len() == 1 && self.headers[0].max_width == 0);

        if !self.headers.is_empty() && !skip_headers {
            output.push_str(&self.print_cell_contents(&self.headers, color_hm));
        }

        // The middle section
        let mut first_row = true;
        for row in &self.data {
            if !first_row {
                if self.theme.separate_rows {
                    output.push_str(&self.print_separator(SeparatorPosition::Middle, color_hm));
                }
            } else {
                first_row = false;

                if self.theme.separate_header && !self.headers.is_empty() && !skip_headers {
                    output.push_str(&self.print_separator(SeparatorPosition::Middle, color_hm));
                }
            }

            output.push_str(&self.print_cell_contents(row, color_hm));
        }

        match config.footer_mode {
            FooterMode::Always => {
                if self.theme.separate_header && !self.headers.is_empty() && !skip_headers {
                    output.push_str(&self.print_separator(SeparatorPosition::Middle, color_hm));
                }

                if !self.headers.is_empty() && !skip_headers {
                    output.push_str(&self.print_cell_contents(&self.footer, color_hm));
                }
            }
            FooterMode::RowCount(r) => {
                if self.data.len() as u64 > r {
                    if self.theme.separate_header && !self.headers.is_empty() && !skip_headers {
                        output.push_str(&self.print_separator(SeparatorPosition::Middle, color_hm));
                    }

                    if !self.headers.is_empty() && !skip_headers {
                        output.push_str(&self.print_cell_contents(&self.footer, color_hm));
                    }
                }
            }
            _ => {} // Never and Auto aka auto get eaten and nothing happens
        }

        // The table finish
        if self.theme.print_bottom_border {
            output.push_str(&self.print_separator(SeparatorPosition::Bottom, color_hm));
        }

        // the atty is for when people do ls from vim, there should be no coloring there
        if !config.use_ansi_coloring || !atty::is(atty::Stream::Stdout) {
            // Draw the table without ansi colors
            if let Ok(bytes) = strip_ansi_escapes::strip(&output) {
                String::from_utf8_lossy(&bytes).to_string()
            } else {
                output
            }
        } else {
            // Draw the table with ansi colors
            output
        }
    }
}

fn process_table(table: &Table) -> ProcessedTable {
    let mut processed_data = vec![];
    for row in &table.data {
        let mut out_row = vec![];
        for column in row {
            let cleaned = clean(&column.contents);
            out_row.push(ProcessedCell {
                contents: split_sublines(&cleaned),
                style: column.style,
            });
        }
        processed_data.push(out_row);
    }

    let mut processed_headers = vec![];
    for header in &table.headers {
        let cleaned = clean(&header.contents);
        processed_headers.push(ProcessedCell {
            contents: split_sublines(&cleaned),
            style: header.style,
        });
    }

    ProcessedTable {
        headers: processed_headers,
        data: processed_data,
        theme: table.theme.clone(),
    }
}

fn clean(input: &str) -> String {
    let input = input.replace('\r', "");

    input.replace('\t', "    ")
}

fn get_max_column_widths(processed_table: &ProcessedTable) -> Vec<usize> {
    use std::cmp::max;

    let mut max_num_columns = 0;

    max_num_columns = max(max_num_columns, processed_table.headers.len());

    for row in &processed_table.data {
        max_num_columns = max(max_num_columns, row.len());
    }

    let mut output = vec![0; max_num_columns];

    for column in processed_table.headers.iter().enumerate() {
        output[column.0] = max(output[column.0], column_width(&column.1.contents));
    }

    for row in &processed_table.data {
        for column in row.iter().enumerate() {
            output[column.0] = max(output[column.0], column_width(&column.1.contents));
        }
    }

    output
}

pub fn maybe_truncate_columns(termwidth: usize, processed_table: &mut ProcessedTable) {
    // Make sure we have enough space for the columns we have
    let max_num_of_columns = termwidth / 10;

    // If we have too many columns, truncate the table
    if max_num_of_columns < processed_table.headers.len() {
        processed_table.headers.truncate(max_num_of_columns);

        for entry in processed_table.data.iter_mut() {
            entry.truncate(max_num_of_columns);
        }

        processed_table.headers.push(ProcessedCell {
            contents: vec![vec![Subline {
                subline: "...".to_string(),
                width: 3,
            }]],
            style: TextStyle::basic_center(),
        });

        for entry in processed_table.data.iter_mut() {
            entry.push(ProcessedCell {
                contents: vec![vec![Subline {
                    subline: "...".to_string(),
                    width: 3,
                }]],
                style: TextStyle::basic_center(),
            }); // ellipsis is centred
        }
    }
}

pub fn draw_table(
    table: &Table,
    termwidth: usize,
    color_hm: &HashMap<String, Style>,
    config: &Config,
) -> String {
    // Remove the edges, if used
    let edges_width = if table.theme.print_left_border && table.theme.print_right_border {
        3
    } else if table.theme.print_left_border || table.theme.print_right_border {
        1
    } else {
        0
    };

    if termwidth < edges_width {
        return format!("Couldn't fit table into {} columns!", termwidth);
    }

    let raw_termwidth = termwidth;
    let termwidth = termwidth - edges_width;

    let mut processed_table = process_table(table);

    let max_per_column = get_max_column_widths(&processed_table);

    maybe_truncate_columns(termwidth, &mut processed_table);

    let headers_len = processed_table.headers.len();

    // fix the length of the table if there are no headers:
    let headers_len = if headers_len == 0 {
        if !table.data.is_empty() && !table.data[0].is_empty() {
            table.data[0].len()
        } else {
            return String::new();
        }
    } else {
        headers_len
    };

    // Measure how big our columns need to be (accounting for separators also)
    let max_naive_column_width = (termwidth - 3 * (headers_len - 1)) / headers_len;

    let column_space = ColumnSpace::measure(&max_per_column, max_naive_column_width, headers_len);

    // This gives us the max column width
    let max_column_width = column_space.max_width(termwidth);

    // This width isn't quite right, as we're rounding off some of our space
    let column_space = match max_column_width {
        None => return format!("Couldn't fit table into {} columns!", raw_termwidth),
        Some(max_column_width) => column_space.fix_almost_column_width(
            &max_per_column,
            max_naive_column_width,
            max_column_width,
            headers_len,
        ),
    };

    // This should give us the final max column width
    let max_column_width = column_space.max_width(termwidth);
    let re_leading =
        regex::Regex::new(r"(?P<beginsp>^\s+)").expect("error with leading space regex");
    let re_trailing =
        regex::Regex::new(r"(?P<endsp>\s+$)").expect("error with trailing space regex");

    let wrapped_table = match max_column_width {
        None => return format!("Couldn't fit table into {} columns!", raw_termwidth),
        Some(max_column_width) => wrap_cells(
            processed_table,
            max_column_width,
            color_hm,
            &re_leading,
            &re_trailing,
        ),
    };

    wrapped_table.print_table(color_hm, config)
}

fn wrap_cells(
    processed_table: ProcessedTable,
    max_column_width: usize,
    color_hm: &HashMap<String, Style>,
    re_leading: &regex::Regex,
    re_trailing: &regex::Regex,
) -> WrappedTable {
    let mut column_widths = vec![
        0;
        std::cmp::max(
            processed_table.headers.len(),
            if !processed_table.data.is_empty() {
                processed_table.data[0].len()
            } else {
                0
            }
        )
    ];
    let mut output_headers = vec![];
    for header in processed_table.headers.into_iter().enumerate() {
        let mut wrapped = WrappedCell {
            lines: vec![],
            max_width: 0,
            style: header.1.style,
        };

        for contents in header.1.contents.into_iter() {
            let (mut lines, inner_max_width) = wrap(
                max_column_width,
                contents.into_iter(),
                color_hm,
                re_leading,
                re_trailing,
            );
            wrapped.lines.append(&mut lines);
            if inner_max_width > wrapped.max_width {
                wrapped.max_width = inner_max_width;
            }
        }
        if column_widths[header.0] < wrapped.max_width {
            column_widths[header.0] = wrapped.max_width;
        }
        output_headers.push(wrapped);
    }

    let mut output_data = vec![];
    for row in processed_table.data.into_iter() {
        let mut output_row = vec![];
        for column in row.into_iter().enumerate() {
            let mut wrapped = WrappedCell {
                lines: vec![],
                max_width: 0,
                style: column.1.style,
            };
            for contents in column.1.contents.into_iter() {
                let (mut lines, inner_max_width) = wrap(
                    max_column_width,
                    contents.into_iter(),
                    color_hm,
                    re_leading,
                    re_trailing,
                );
                wrapped.lines.append(&mut lines);
                if inner_max_width > wrapped.max_width {
                    wrapped.max_width = inner_max_width;
                }
            }
            if column_widths[column.0] < wrapped.max_width {
                column_widths[column.0] = wrapped.max_width;
            }
            output_row.push(wrapped);
        }
        output_data.push(output_row);
    }

    let mut footer = vec![
        WrappedCell {
            lines: vec![],
            max_width: 0,
            style: TextStyle {
                ..Default::default()
            },
        };
        output_headers.len()
    ];
    footer.clone_from_slice(&output_headers[..]);

    WrappedTable {
        column_widths,
        headers: output_headers,
        data: output_data,
        theme: processed_table.theme,
        footer,
    }
}

struct ColumnSpace {
    num_overages: usize,
    underage_sum: usize,
    overage_separator_sum: usize,
}

impl ColumnSpace {
    /// Measure how much space we have once we subtract off the columns who are small enough
    fn measure(
        max_per_column: &[usize],
        max_naive_column_width: usize,
        headers_len: usize,
    ) -> ColumnSpace {
        let mut num_overages = 0;
        let mut underage_sum = 0;
        let mut overage_separator_sum = 0;
        let iter = max_per_column.iter().enumerate().take(headers_len);

        for (i, &column_max) in iter {
            if column_max > max_naive_column_width {
                num_overages += 1;
                if i != (headers_len - 1) {
                    overage_separator_sum += 3;
                }
                if i == 0 {
                    overage_separator_sum += 1;
                }
            } else {
                underage_sum += column_max;
                // if column isn't last, add 3 for its separator
                if i != (headers_len - 1) {
                    underage_sum += 3;
                }
                if i == 0 {
                    underage_sum += 1;
                }
            }
        }

        ColumnSpace {
            num_overages,
            underage_sum,
            overage_separator_sum,
        }
    }

    fn fix_almost_column_width(
        self,
        max_per_column: &[usize],
        max_naive_column_width: usize,
        max_column_width: usize,
        headers_len: usize,
    ) -> ColumnSpace {
        let mut num_overages = 0;
        let mut overage_separator_sum = 0;
        let mut underage_sum = self.underage_sum;
        let iter = max_per_column.iter().enumerate().take(headers_len);

        for (i, &column_max) in iter {
            if column_max > max_naive_column_width {
                if column_max <= max_column_width {
                    underage_sum += column_max;
                    // if column isn't last, add 3 for its separator
                    if i != (headers_len - 1) {
                        underage_sum += 3;
                    }
                    if i == 0 {
                        underage_sum += 1;
                    }
                } else {
                    // Column is still too large, so let's count it
                    num_overages += 1;
                    if i != (headers_len - 1) {
                        overage_separator_sum += 3;
                    }
                    if i == 0 {
                        overage_separator_sum += 1;
                    }
                }
            }
        }

        ColumnSpace {
            num_overages,
            underage_sum,
            overage_separator_sum,
        }
    }

    fn max_width(&self, termwidth: usize) -> Option<usize> {
        let ColumnSpace {
            num_overages,
            underage_sum,
            overage_separator_sum,
        } = self;

        if *num_overages > 0 {
            termwidth
                .checked_sub(1)?
                .checked_sub(*underage_sum)?
                .checked_sub(*overage_separator_sum)?
                .checked_div(*num_overages)
        } else {
            Some(99999)
        }
    }
}