//!  A library for manipulating SMPTE timecodes.

#![feature(step_trait)]

use std::fmt;
use std::iter;
use std::marker;
use std::ops;
use std::str;

mod frame_rate;

pub use frame_rate::{
    FrameRate, FrameRate2398, FrameRate24, FrameRate25, FrameRate2997, FrameRate30, FrameRate50,
    FrameRate5994, FrameRate60,
};

#[derive(Debug)]
/// All [Result](https://doc.rust-lang.org/std/result/enum.Result.html) values
/// returned by this library will use this for error values.
pub struct TimecodeError {
    pub kind: TimecodeErrorKind,
}

#[derive(Debug)]
/// Error values for this library.
pub enum TimecodeErrorKind {
    /// Timecode parsing failed due to input having an invalid format.
    InvalidFormat,

    /// Timecode had an invalid value. For instance the frame field might have
    /// a value higher than the frame rate allows.
    InvalidTimecode,
}

/// Representation of a timecode as a struct, generic over types implementing
/// the trait [FrameRate](trait.FrameRate.html).
///
/// **Note**: Currently the user-facing values are open properties. These may
///           be replaced by getters to facilitate lazy evaluation.
///
/// ```
/// use video_timecode::*;
/// use std::str::FromStr;
///
/// let tc1 = Timecode::<FrameRate24>::new(0, 0, 0, 10).unwrap();
/// assert_eq!(tc1.frame_number, 10);
///
/// let tc2 = Timecode::<FrameRate24>::from_str("00:00:10:00").unwrap();
/// assert_eq!(tc2.frame_number, 240);
///
/// let mut tc3 = Timecode::<FrameRate24>::from(240);
/// assert_eq!(tc3.hour, 0);
/// assert_eq!(tc3.minute, 0);
/// assert_eq!(tc3.second, 10);
/// assert_eq!(tc3.frame, 0);
/// assert_eq!(tc3.frame_number, 240);
///
/// tc3 += tc1;
/// assert_eq!(tc3.hour, 0);
/// assert_eq!(tc3.minute, 0);
/// assert_eq!(tc3.second, 10);
/// assert_eq!(tc3.frame, 10);
/// assert_eq!(tc3.frame_number, 250);
/// ```
#[derive(Clone, PartialEq, PartialOrd)]
pub struct Timecode<T: FrameRate> {
    /// Frame number. The count of frames after `00:00:00:00`
    pub frame_number: u32,
    pub hour: u8,
    pub minute: u8,
    pub second: u8,
    pub frame: u8,
    frame_rate: marker::PhantomData<T>,
}

impl<T: FrameRate> Timecode<T> {
    /// Returns a timecode with the given hour/minute/second/frame fields.
    ///
    /// ```
    /// use video_timecode::*;
    ///
    /// let timecode = Timecode::<FrameRate24>::new(10, 0, 0, 0).unwrap();
    /// assert_eq!(timecode.frame_number, 864000);
    /// ```
    pub fn new(hour: u8, minute: u8, second: u8, frame: u8) -> Result<Timecode<T>, TimecodeError> {
        use self::TimecodeErrorKind::*;

        let result = T::calculate_frame_number(
            u32::from(hour),
            u32::from(minute),
            u32::from(second),
            u32::from(frame),
        );

        match result {
            Some(frame_number) => Ok(Timecode {
                frame_number,
                hour,
                minute,
                second,
                frame,
                frame_rate: marker::PhantomData,
            }),
            None => Err(TimecodeError {
                kind: InvalidTimecode,
            }),
        }
    }
}

/// Parse a string into a timecode.
///
/// Colon separator is alright for all types.
///
/// ```
/// use video_timecode::*;
/// use std::str::FromStr;
///
/// let tc1 = Timecode::<FrameRate24>::from_str("00:00:10:00").unwrap();
/// assert_eq!(tc1.frame_number, 240);
///
/// let tc2 = Timecode::<FrameRate2997>::from_str("00:00:10:00").unwrap();
/// assert_eq!(tc2.frame_number, 300);
/// ```
///
/// For frame rates with drop frame, the following formats are also allowed:
///
/// * `00:00:00;00`
/// * `00;00;00;00`
/// * `00.00.00.00`
/// * `00:00:00.00`
///
/// ```
/// use video_timecode::*;
/// use std::str::FromStr;
///
/// let tc1 = Timecode::<FrameRate2997>::from_str("00:00:10;00").unwrap();
/// assert_eq!(tc1.frame_number, 300);
///
/// let tc2 = Timecode::<FrameRate2997>::from_str("00;00;10;00").unwrap();
/// assert_eq!(tc2.frame_number, 300);
///
/// let tc3 = Timecode::<FrameRate2997>::from_str("00:00:10.00").unwrap();
/// assert_eq!(tc3.frame_number, 300);
///
/// let tc4 = Timecode::<FrameRate2997>::from_str("00.00.10.00").unwrap();
/// assert_eq!(tc4.frame_number, 300);
/// ```
impl<T: FrameRate> str::FromStr for Timecode<T> {
    /// If parsing fails, a timecode error is returned.
    ///
    /// If the input format is invalid in some way, the `TimecodeErrorKind` field
    /// of the [TimecodeError](struct.TimecodeError.html) will be
    /// [InvalidFormat](enum.TimecodeErrorKind.html#variant.InvalidFormat).
    ///
    /// ```
    /// use video_timecode::*;
    /// use video_timecode::TimecodeErrorKind::*;
    /// use std::str::FromStr;
    ///
    /// // Semicolon notation only allowed for drop frame frame rates.
    /// match Timecode::<FrameRate24>::from_str("00:00:10;00") {
    ///     Err(TimecodeError { kind: InvalidFormat }) => {}
    ///     _ => panic!()
    /// }
    /// ```
    ///
    /// If the timecode is not valid for the given frame rate, it will be
    /// [InvalidTimecode](enum.TimecodeErrorKind.html#variant.Timecode).
    ///
    /// ```
    /// use video_timecode::*;
    /// use video_timecode::TimecodeErrorKind::*;
    /// use std::str::FromStr;
    ///
    /// // This is a dropped frame.
    /// match Timecode::<FrameRate2997>::from_str("00:01:00;00") {
    ///     Err(TimecodeError { kind: InvalidTimecode }) => {}
    ///     _ => panic!()
    /// }
    /// ```
    type Err = TimecodeError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        use self::TimecodeErrorKind::*;

        let mut colon_notation = false;
        let mut semi_colon_notation = false;
        let mut dot_notation = false;

        let mut it = s.chars();

        let hour_string = it.by_ref().take(2).collect::<String>();
        let hour: u8 = match hour_string.parse() {
            Ok(n) if n < 60 => n,
            _ => {
                return Err(TimecodeError {
                    kind: InvalidFormat,
                });
            }
        };

        let minute_sep_char = it.next();
        match minute_sep_char {
            Some(':') => colon_notation = true,
            Some(';') => semi_colon_notation = true,
            Some('.') => dot_notation = true,
            _ => {
                return Err(TimecodeError {
                    kind: InvalidFormat,
                });
            }
        };

        let minute_string = it.by_ref().take(2).collect::<String>();
        let minute: u8 = match minute_string.parse() {
            Ok(n) if n < 60 => n,
            _ => {
                return Err(TimecodeError {
                    kind: InvalidFormat,
                });
            }
        };

        let second_sep_char = it.next();
        match second_sep_char {
            Some(':') if colon_notation => {}
            Some(';') if semi_colon_notation => {}
            Some('.') if dot_notation => {}
            _ => {
                return Err(TimecodeError {
                    kind: InvalidFormat,
                });
            }
        }

        let second_string = it.by_ref().take(2).collect::<String>();
        let second: u8 = match second_string.parse() {
            Ok(n) if n < 60 => n,
            _ => {
                return Err(TimecodeError {
                    kind: InvalidFormat,
                });
            }
        };

        let frame_sep_char = it.next();
        let drop_frame = match frame_sep_char {
            Some(':') if colon_notation => false,
            Some(';') if semi_colon_notation || colon_notation => true,
            Some('.') if dot_notation || colon_notation => true,
            _ => {
                return Err(TimecodeError {
                    kind: InvalidFormat,
                });
            }
        };

        let frame_string = it.by_ref().take(2).collect::<String>();
        let frame: u8 = match frame_string.parse() {
            Ok(n) => n,
            _ => {
                return Err(TimecodeError {
                    kind: InvalidFormat,
                });
            }
        };

        if it.next() != None {
            return Err(TimecodeError {
                kind: InvalidFormat,
            });
        }

        if drop_frame && !T::DROP_FRAME {
            return Err(TimecodeError {
                kind: InvalidFormat,
            });
        }

        match Timecode::<T>::new(hour, minute, second, frame) {
            Ok(timecode) => Ok(timecode),
            Err(_) => Err(TimecodeError {
                kind: InvalidTimecode,
            }),
        }
    }
}

impl<T: FrameRate> fmt::Display for Timecode<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let separator = if T::DROP_FRAME { ';' } else { ':' };

        write!(
            f,
            "{:02}:{:02}:{:02}{}{:02}",
            self.hour, self.minute, self.second, separator, self.frame
        )
    }
}

impl<T: FrameRate> fmt::Debug for Timecode<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let separator = if T::DROP_FRAME { ';' } else { ':' };

        write!(
            f,
            "Timecode {{ timecode: {:02}:{:02}:{:02}{}{:02}, frame_number: {}, frame_rate: {} }}",
            self.hour,
            self.minute,
            self.second,
            separator,
            self.frame,
            self.frame_number,
            T::DISPLAY,
        )
    }
}


/// Create a timecode with the the given frame number.
impl<T: FrameRate> From<u32> for Timecode<T> {
    fn from(frame_number: u32) -> Self {
        let new_frame_number = frame_number % T::MAX_FRAMES;

        let (hour, minute, second, frame) = T::calculate_time_code(new_frame_number);

        Timecode {
            frame_number: new_frame_number,
            hour,
            minute,
            second,
            frame,
            frame_rate: marker::PhantomData,
        }
    }
}

/// Make a new timecode by adding a number of frames to a timecode.
impl<T: FrameRate> ops::Add<u32> for Timecode<T> {
    type Output = Self;

    fn add(self, other: u32) -> Self {
        Timecode::<T>::from(self.frame_number + other)
    }
}

/// Add a number of frames to a timecode.
impl<T: FrameRate> ops::AddAssign<u32> for Timecode<T> {
    fn add_assign(&mut self, other: u32) {
        let new_frame_number = (self.frame_number + other) % T::MAX_FRAMES;

        let (hour, minute, second, frame) = T::calculate_time_code(new_frame_number);

        self.hour = hour;
        self.minute = minute;
        self.second = second;
        self.frame = frame;
        self.frame_number = new_frame_number;
    }
}

/// Make a new timecode by removing a number of frames to a timecode.
impl<T: FrameRate> ops::Sub<u32> for Timecode<T> {
    type Output = Self;

    fn sub(self, other: u32) -> Self {
        Timecode::<T>::from(self.frame_number - other)
    }
}

/// Remove a number of frames from a timecode.
impl<T: FrameRate> ops::SubAssign<u32> for Timecode<T> {
    fn sub_assign(&mut self, other: u32) {
        let new_frame_number = (self.frame_number - other) % T::MAX_FRAMES;

        let (hour, minute, second, frame) = T::calculate_time_code(new_frame_number);

        self.hour = hour;
        self.minute = minute;
        self.second = second;
        self.frame = frame;
        self.frame_number = new_frame_number;
    }
}

/// Make a new timecode by adding two timecodes together. The result is a
/// timecode where the field `frame_number` is the sum of the frame numbers
/// of the two added timecodes.
///
/// ```
/// use video_timecode::*;
///
/// let tc1 = Timecode::<FrameRate24>::new(0, 0, 20, 0).unwrap();
/// let tc2 = Timecode::<FrameRate24>::new(0, 0, 10, 0).unwrap();
/// let tc3 = tc1 + tc2;
/// assert_eq!(tc3, Timecode::<FrameRate24>::new(0, 0, 30, 0).unwrap());
/// ```
///
/// # Adding Timecodes of different frame rates
///
/// Adding timecodes of different framerates together is not supported.
///
/// Since adding Timecodes of different frame rates together normally does not make
/// any sense, it is better that the programmer has to mark this, by explicitly
/// adding the number of frames.
///
/// ```compile_fail
/// use video_timecode::*;
///
/// let tc1 = Timecode::<FrameRate2997>::new(0, 0, 0, 0).unwrap();
/// let tc2 = Timecode::<FrameRate24>::new(0, 0, 10, 0).unwrap();
/// let tc3 = tc1 + tc2;
/// ```
///
/// # Timecode roll-over
///
/// The timecode (including the `frame_number` field) will roll over when the
/// timecode reaches 24 hours.
///
/// ```
/// use video_timecode::*;
///
/// let tc1 = Timecode::<FrameRate24>::new(23, 59, 30, 0).unwrap();
/// let tc2 = Timecode::<FrameRate24>::new(0, 1, 0, 0).unwrap();
/// let tc3 = tc1 + tc2;
/// assert_eq!(tc3, Timecode::<FrameRate24>::new(0, 0, 30, 0).unwrap());
/// ```
impl<T: FrameRate> ops::Add for Timecode<T> {
    type Output = Timecode<T>;

    fn add(self, other: Self) -> Self {
        self + other.frame_number
    }
}

/// Add one timecode to another, of the same frame rate. The first timecode
/// will have a `frame_number` that's the sum of the frame numbers of the
/// two timecodes.
///
/// ```
/// use video_timecode::*;
///
/// let mut tc1 = Timecode::<FrameRate24>::new(0, 0, 10, 0).unwrap();
/// let tc2 = Timecode::<FrameRate24>::new(0, 0, 10, 0).unwrap();
/// tc1 += tc2;
///
/// assert_eq!(tc1, Timecode::<FrameRate24>::new(0, 0, 20, 0).unwrap());
/// ```
impl<T: FrameRate> ops::AddAssign for Timecode<T> {
    fn add_assign(&mut self, other: Self) {
        *self += other.frame_number;
    }
}

/// Iterate over timecodes in steps.
///
/// ```
/// use video_timecode::*;
///
/// assert_eq!(
///     (Timecode::<FrameRate24>::new(00, 0, 59, 22).unwrap()
///         ..Timecode::<FrameRate24>::new(00, 1, 0, 2).unwrap())
///         .collect::<Vec<Timecode<FrameRate24>>>(),
///     vec![
///         Timecode::<FrameRate24>::new(00, 0, 59, 22).unwrap(),
///         Timecode::<FrameRate24>::new(00, 0, 59, 23).unwrap(),
///         Timecode::<FrameRate24>::new(00, 1, 0, 0).unwrap(),
///         Timecode::<FrameRate24>::new(00, 1, 0, 1).unwrap(),
///     ]
/// );
/// ```
impl<T: FrameRate + Clone + PartialOrd> iter::Step for Timecode<T> {
    fn steps_between(start: &Self, end: &Self) -> Option<usize> {
        if start.frame_number <= end.frame_number {
            Some((end.frame_number - start.frame_number) as usize)
        } else {
            None
        }
    }

    fn replace_one(&mut self) -> Self {
        std::mem::replace(
            self,
            Timecode {
                frame_number: 1,
                hour: 0,
                minute: 0,
                second: 0,
                frame: 1,
                frame_rate: marker::PhantomData,
            },
        )
    }

    fn replace_zero(&mut self) -> Self {
        std::mem::replace(
            self,
            Timecode {
                frame_number: 0,
                hour: 0,
                minute: 0,
                second: 0,
                frame: 0,
                frame_rate: marker::PhantomData,
            },
        )
    }

    fn add_one(&self) -> Self {
        if u32::from(self.frame) < (T::FPS - 1) {
            Timecode {
                frame_number: self.frame_number + 1,
                hour: self.hour,
                minute: self.minute,
                second: self.second,
                frame: self.frame + 1,
                frame_rate: marker::PhantomData,
            }
        } else if self.second < 59 {
            Timecode {
                frame_number: self.frame_number + 1,
                hour: self.hour,
                minute: self.minute,
                second: self.second + 1,
                frame: 0,
                frame_rate: marker::PhantomData,
            }
        } else if self.minute < 59 {
            let new_minute = self.minute + 1;
            let new_frame = if T::DROP_FRAME && (new_minute % 10 != 0) {
                T::DROP_FRAME_COUNT as u8
            } else {
                0
            };
            Timecode {
                frame_number: self.frame_number + 1,
                hour: self.hour,
                minute: new_minute,
                second: 0,
                frame: new_frame,
                frame_rate: marker::PhantomData,
            }
        } else {
            Timecode {
                frame_number: self.frame_number + 1,
                hour: self.hour + 1,
                minute: 0,
                second: 0,
                frame: 0,
                frame_rate: marker::PhantomData,
            }
        }
    }

    fn sub_one(&self) -> Self {
        if u32::from(self.frame) > 0 {
            Timecode {
                frame_number: self.frame_number - 1,
                hour: self.hour,
                minute: self.minute,
                second: self.second,
                frame: self.frame - 1,
                frame_rate: marker::PhantomData,
            }
        } else if self.second > 0 {
            Timecode {
                frame_number: self.frame_number - 1,
                hour: self.hour,
                minute: self.minute,
                second: self.second - 1,
                frame: T::FPS as u8 - 1,
                frame_rate: marker::PhantomData,
            }
        } else if self.minute > 0 {
            Timecode {
                frame_number: self.frame_number - 1,
                hour: self.hour,
                minute: self.minute - 1,
                second: 59,
                frame: T::FPS as u8 - 1,
                frame_rate: marker::PhantomData,
            }
        } else {
            Timecode {
                frame_number: self.frame_number - 1,
                hour: self.hour - 1,
                minute: 59,
                second: 59,
                frame: T::FPS as u8 - 1,
                frame_rate: marker::PhantomData,
            }
        }
    }

    fn add_usize(&self, n: usize) -> Option<Self> {
        if n == 1 {
            Some(self.add_one())
        } else {
            Some(self.clone() + (n as u32))
        }
    }
}