//! This module contains two of the most central structs of GLerminal; [`TextBuffer`](struct.TextBuffer.html) and [`Parser`](parser/struct.Parser.html)
//!
//! `TextBuffer` acts as a "state machine" where you can set foreground color, background color and shakiness for the cursor,
//! move the cursor around, clear the screen and write with the cursor (using the cursor's styles).
//! It's often the most efficient way to write things, especially if you have a very structured way of displaying things, but for a more simple-to-use
//! way of writing, that isn't as structured ie. for a dialogue, you might want to use the Parser.
//!
//! `Parser` is a struct that is able to take in a piece of text and then parse it and change the cursor styles easily using the `TextBuffer`.
//! The `Parser` can handle tags imilar to BBCode tags, and can change fg, bg and shake, meaning the following tags are available to use mid-text:
//! - `[fg=color]`
//! - `[bg=color]`
//! - `[shake=decimal]`
//! - optional closing/style-resetting tags: `[/fg]`, `[/bg]` and `[/shake]`
//!
//! The colors the `Parser` uses mid text must be pre-defined however with `add_color`.
//!
//! ### Example usage of `TextBuffer`:
//! ```no_run
//! use glerminal::terminal::TerminalBuilder;
//! use glerminal::text_buffer::TextBuffer;
//!
//! let terminal = TerminalBuilder::new()
//!     .with_title("Hello GLerminal!")
//!     .with_dimensions((1280, 720))
//!     .build();
//!
//! let mut text_buffer;
//! match TextBuffer::new(&terminal, (80, 24)) {
//!   Ok(buffer) => text_buffer = buffer,
//!   Err(error) => panic!(format!("Failed to initialize text buffer: {}", error)),
//! }
//!
//! // Test TextBuffer
//! text_buffer.change_cursor_fg_color([1.0, 0.0, 0.0, 1.0]);
//! text_buffer.change_cursor_bg_color([1.0, 1.0, 1.0, 1.0]);
//! text_buffer.change_cursor_shakiness(0.5);
//! text_buffer.move_cursor(0, 0);
//! text_buffer.write("This text is shaking in red in a white background!");
//!
//! // Flush to "apply changes"
//! terminal.flush(&mut text_buffer);
//! ```
//!
//! ### Example usage of `Parser`
//! ```no_run
//! use glerminal::terminal::TerminalBuilder;
//! use glerminal::text_buffer::TextBuffer;
//! use glerminal::text_buffer::parser::Parser;
//!
//! let terminal = TerminalBuilder::new()
//!     .with_title("Hello GLerminal!")
//!     .with_dimensions((1280, 720))
//!     .build();
//!
//! let mut text_buffer;
//! match TextBuffer::new(&terminal, (80, 24)) {
//!   Ok(buffer) => text_buffer = buffer,
//!   Err(error) => panic!(format!("Failed to initialize text buffer: {}", error)),
//! }
//!
//! // Test Parser
//! let mut parser = Parser::new();
//! parser.add_color("red", [1.0, 0.0, 0.0, 1.0]);
//! parser.add_color("white", [1.0, 1.0, 1.0, 1.0]);
//! parser.write(&mut text_buffer, "[fg=red][bg=white][shake=1.0]This text is also shaking in red in a white background![/fg][/bg][/shake]");
//! // Note: it is not necessary to close fg/bg/shake tags, parser will automatically revert colors in the TextBuffer.
//!
//! // Flush to "apply changes"
//! terminal.flush(&mut text_buffer);
//! ```

pub mod parser;

use renderer::textbuffermesh::TextBufferMesh;
use renderer::backgroundmesh::BackgroundMesh;
use font::Font;
use terminal::Terminal;

/// Represents a color with values from 0.0 to 1.0 (red, green, blue, alpha)
pub type Color = [f32; 4];

/// Represents a single character in a [`TextBuffer`](struct.TextBuffer.html)
#[derive(Clone, Copy)]
pub struct TermCharacter {
    character: char,
    fg_color: Color,
    bg_color: Color,
    shakiness: f32,
}

impl TermCharacter {
    pub(crate) fn new(
        character: char,
        fg_color: Color,
        bg_color: Color,
        shakiness: f32,
    ) -> TermCharacter {
        TermCharacter {
            character,
            fg_color,
            bg_color,
            shakiness,
        }
    }

    /// Gets the char in the TermCharacter
    pub fn get_char(&self) -> char {
        self.character
    }

    /// Gets the foreground Color in the TermCharacter
    pub fn get_fg_color(&self) -> Color {
        self.fg_color
    }

    /// Gets the background Color in the TermCharacter
    pub fn get_bg_color(&self) -> Color {
        self.bg_color
    }

    /// Gets the shakiness of the TermCharacter, where shakiness is a value from 0.0 to 1.0 (other values are accepted, but these are suggested).
    pub fn get_shakiness(&self) -> f32 {
        self.shakiness
    }
}

struct TermCursor {
    x: i32,
    y: i32,
    foreground_color: Color,
    background_color: Color,
    shakiness: f32,
}

/// Represents the text buffer of the terminal; contains the "grid of [`TermCharacters`](struct.TermCharacter.html)" that will be drawn.
///
/// See [text_buffer mod](index.html) for examples and more detailed documentation.
pub struct TextBuffer {
    pub(crate) chars: Vec<TermCharacter>,
    pub(crate) height: i32,
    pub(crate) width: i32,
    pub(crate) mesh: Option<TextBufferMesh>,
    pub(crate) background_mesh: Option<BackgroundMesh>,
    cursor: TermCursor,
}

impl TextBuffer {
    /// Creates a new text buffer with the given dimensions (width in characters, height in characters)
    pub fn new(terminal: &Terminal, dimensions: (i32, i32)) -> Result<TextBuffer, String> {
        let (width, height) = dimensions;

        if width <= 0 || height <= 0 {
            return Err(
                "TextBuffer dimensions are erronous; either width or height is below 1".to_owned(),
            );
        }

        let chars =
            vec![TermCharacter::new(' ', [0.0; 4], [0.0; 4], 0.0); (width * height) as usize];
        let mesh;
        let background_mesh;
        if terminal.headless {
            mesh = None;
            background_mesh = None;
        } else {
            mesh = Some(TextBufferMesh::new(terminal.get_program(), dimensions, &terminal.font));
            background_mesh = Some(BackgroundMesh::new(terminal.get_background_program(), dimensions));
        }
        Ok(TextBuffer {
            chars,
            height,
            width,
            mesh,
            background_mesh,
            cursor: TermCursor {
                x: 0,
                y: 0,
                foreground_color: [1.0; 4],
                background_color: [0.0; 4],
                shakiness: 0.0,
            },
        })
    }

    pub(crate) fn swap_buffers(&self, font: &Font) {
        if let (&Some(ref mesh), &Some(ref background_mesh)) = (&self.mesh, &self.background_mesh) {
            mesh.update(&self, font);
            background_mesh.update(&self);
        }
    }

    pub(crate) fn out_of_bounds(&self, x: i32, y: i32) -> bool {
        (x < 0 || y < 0 || x >= self.width || y >= self.height)
    }

    /// Gets the TermChaacter in the given position
    pub fn get_character(&self, x: i32, y: i32) -> TermCharacter {
        self.chars[(y * self.width + x) as usize]
    }

    /// Clears the screen (makes every character empty and resets their style)
    pub fn clear(&mut self) {
        self.chars = vec![
            TermCharacter::new(' ', [0.0; 4], [0.0; 4], 0.0);
            (self.width * self.height) as usize
        ];
    }

    /// Puts a character to the current position of the cursor with the cursor's style
    pub fn put_char(&mut self, character: char) {
        self.chars[(self.cursor.y * self.width + self.cursor.x) as usize] = TermCharacter::new(
            character,
            self.cursor.foreground_color,
            self.cursor.background_color,
            self.cursor.shakiness,
        );
        self.move_cursor_by(1);
    }

    /// Puts the given text the same way as put_char
    pub fn write<T: Into<String>>(&mut self, text: T) {
        let text = text.into();
        for c in text.chars() {
            self.put_char(c);
        }
    }

    /// Changes the foreground color for the cursor
    pub fn change_cursor_fg_color(&mut self, color: Color) {
        self.cursor.foreground_color = color;
    }

    /// Changes the background color of the cursor
    pub fn change_cursor_bg_color(&mut self, color: Color) {
        self.cursor.background_color = color;
    }

    /// Returns the current foreground color of the cursor
    pub fn get_cursor_fg_color(&mut self) -> Color {
        self.cursor.foreground_color
    }

    /// Returns the current background color of the cursor
    pub fn get_cursor_bg_color(&mut self) -> Color {
        self.cursor.background_color
    }

    /// Changes the shakiness of the cursor
    pub fn change_cursor_shakiness(&mut self, shakiness: f32) {
        self.cursor.shakiness = shakiness;
    }

    /// Gets the current shakiness of the cursor
    pub fn get_cursor_shakiness(&mut self) -> f32 {
        self.cursor.shakiness
    }

    /// Moves the cursor to a specified location in the terminal. If the location does not exist, nothing happens.
    pub fn move_cursor(&mut self, x: i32, y: i32) {
        if !self.out_of_bounds(x, y) {
            self.cursor.x = x;
            self.cursor.y = y;
        }
    }

    /// Returns the current position of the cursor
    pub fn get_cursor_position(&self) -> (i32, i32) {
        (self.cursor.x, self.cursor.y)
    }

    fn move_cursor_by(&mut self, amount: i32) {
        let new_pos = self.cursor.x + amount;
        if new_pos >= 0 {
            self.cursor.x += amount;
            if self.cursor.x >= self.width {
                self.cursor.x = 0;
                self.cursor.y += 1;
                if self.cursor.y >= self.height {
                    self.cursor.y = 0;
                }
            }
        }
    }
}