charts-rs 0.4.2

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use super::common::AxisScale;
use serde::{Deserialize, Serialize};
use std::fmt;
use substring::Substring;

pub static NIL_VALUE: f32 = f32::MIN;

pub(crate) static THOUSANDS_FORMAT_LABEL: &str = "{t}";
pub(crate) static SERIES_NAME_FORMAT_LABEL: &str = "{a}";
pub(crate) static CATEGORY_NAME_FORMAT_LABEL: &str = "{b}";
pub(crate) static VALUE_FORMAT_LABEL: &str = "{c}";
pub(crate) static PERCENTAGE_FORMAT_LABEL: &str = "{d}";

#[derive(Clone, Copy, PartialEq, Debug, Default)]
pub struct Point {
    pub x: f32,
    pub y: f32,
}
impl From<(f32, f32)> for Point {
    fn from(val: (f32, f32)) -> Self {
        Point { x: val.0, y: val.1 }
    }
}
impl fmt::Display for Point {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let m = format!("({},{})", format_float(self.x), format_float(self.y));
        write!(f, "{m}")
    }
}

#[derive(Serialize, Deserialize, Clone, Debug, Default)]
pub struct Box {
    pub left: f32,
    pub top: f32,
    pub right: f32,
    pub bottom: f32,
}
impl Box {
    pub fn width(&self) -> f32 {
        self.right - self.left
    }
    pub fn height(&self) -> f32 {
        self.bottom - self.top
    }
    pub fn outer_width(&self) -> f32 {
        self.right
    }
    pub fn outer_height(&self) -> f32 {
        self.bottom
    }
}
impl fmt::Display for Box {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let m = format!(
            "({},{},{},{})",
            format_float(self.left),
            format_float(self.top),
            format_float(self.right),
            format_float(self.bottom)
        );
        write!(f, "{m}")
    }
}

impl From<f32> for Box {
    fn from(val: f32) -> Self {
        Box {
            left: val,
            top: val,
            right: val,
            bottom: val,
        }
    }
}
impl From<(f32, f32)> for Box {
    fn from(val: (f32, f32)) -> Self {
        Box {
            left: val.0,
            top: val.1,
            right: val.0,
            bottom: val.1,
        }
    }
}
impl From<(f32, f32, f32)> for Box {
    fn from(val: (f32, f32, f32)) -> Self {
        Box {
            left: val.0,
            top: val.1,
            right: val.2,
            bottom: val.1,
        }
    }
}
impl From<(f32, f32, f32, f32)> for Box {
    fn from(val: (f32, f32, f32, f32)) -> Self {
        Box {
            left: val.0,
            top: val.1,
            right: val.2,
            bottom: val.3,
        }
    }
}

fn parse_precision(formatter: &str) -> Option<usize> {
    if formatter.is_empty() {
        return None;
    }
    // 1. parse usize
    if let Ok(precision) = formatter.parse::<usize>() {
        return Some(precision);
    }

    // 2. if formatter is "{:.N}", parse N
    if let Some(inner) = formatter
        .strip_prefix("{:.")
        .and_then(|s| s.strip_suffix("}"))
    {
        if let Ok(precision) = inner.parse::<usize>() {
            return Some(precision);
        }
    }

    None
}

pub(crate) fn format_series_value(value: f32, formatter: &str) -> String {
    if formatter == THOUSANDS_FORMAT_LABEL {
        return thousands_format_float(value);
    }
    let mut str = if let Some(precision) = parse_precision(formatter) {
        format!("{:.precision$}", value, precision = precision)
    } else if value < 1.1 {
        format!("{:.2}", value)
    } else {
        format!("{:.1}", value)
    };
    if str.contains('.') {
        while str.ends_with('0') {
            str.pop();
        }

        if str.ends_with('.') {
            str.pop();
        }
    }

    str
}

pub(crate) fn thousands_format_float(value: f32) -> String {
    if value < 1000.0 {
        return format_float(value);
    }
    let str = format!("{:.0}", value);
    let unit = 3;
    let mut index = str.len() % unit;
    let mut arr = vec![];
    if index != 0 {
        arr.push(str.substring(0, index))
    }

    loop {
        if index >= str.len() {
            break;
        }
        arr.push(str.substring(index, index + unit));
        index += unit;
    }
    arr.join(",")
}

pub(crate) fn format_float(value: f32) -> String {
    let str = format!("{:.1}", value);
    if str.ends_with(".0") {
        return str.substring(0, str.len() - 2).to_string();
    }
    str
}

#[derive(Clone, Debug, Default)]
pub(crate) struct AxisValueParams {
    pub data_list: Vec<f32>,
    pub min: Option<f32>,
    pub max: Option<f32>,
    pub split_number: usize,
    pub reverse: Option<bool>,
    pub thousands_format: bool,
    pub scale: AxisScale,
}
#[derive(Clone, Debug, Default)]
pub struct AxisValues {
    pub data: Vec<String>,
    pub min: f32,
    pub max: f32,
    pub scale: AxisScale,
}

impl AxisValues {
    pub(crate) fn get_offset(&self) -> f32 {
        self.max - self.min
    }
    pub(crate) fn get_offset_height(&self, value: f32, max_height: f32) -> f32 {
        match &self.scale {
            AxisScale::Linear => {
                let offset = self.get_offset();
                if offset == 0.0 {
                    return max_height;
                }
                let percent = (value - self.min) / offset;
                max_height - percent * max_height
            }
            AxisScale::Log(base) => {
                let safe = value.max(f32::MIN_POSITIVE);
                let log_val = safe.log(*base);
                let log_min = self.min.max(f32::MIN_POSITIVE).log(*base);
                let log_max = self.max.max(f32::MIN_POSITIVE).log(*base);
                let log_range = log_max - log_min;
                if log_range == 0.0 {
                    return max_height;
                }
                let percent = (log_val - log_min) / log_range;
                max_height - percent * max_height
            }
        }
    }
}

const K_VALUE: f32 = 1000.00_f32;
const M_VALUE: f32 = K_VALUE * K_VALUE;
const G_VALUE: f32 = M_VALUE * K_VALUE;
const T_VALUE: f32 = G_VALUE * K_VALUE;

fn format_axis_value(value: f32) -> String {
    let mut v = value;
    let mut unit = "";
    v = if v >= T_VALUE {
        unit = "T";
        v / T_VALUE
    } else if v >= G_VALUE {
        unit = "G";
        v / G_VALUE
    } else if v >= M_VALUE {
        unit = "M";
        v / M_VALUE
    } else if v >= K_VALUE {
        unit = "k";
        v / K_VALUE
    } else {
        v
    };
    format_float(v) + unit
}

fn get_log_axis_values(params: AxisValueParams, base: f32) -> AxisValues {
    let split_number = if params.split_number == 0 {
        6
    } else {
        params.split_number
    };

    let mut min_val = f32::MAX;
    let mut max_val = f32::MIN_POSITIVE;
    for &v in &params.data_list {
        if v != NIL_VALUE && v > 0.0 {
            if v < min_val {
                min_val = v;
            }
            if v > max_val {
                max_val = v;
            }
        }
    }
    if let Some(m) = params.min {
        if m > 0.0 && m < min_val {
            min_val = m;
        }
    }
    if let Some(m) = params.max {
        if m > 0.0 && m > max_val {
            max_val = m;
        }
    }

    if min_val == f32::MAX || max_val <= 0.0 {
        return AxisValues::default();
    }

    let exp_min = min_val.log(base).floor() as i32;
    let exp_max = max_val.log(base).ceil() as i32;

    // Choose a step so we generate at most split_number+1 ticks.
    let num_powers = (exp_max - exp_min).max(1) as usize;
    let step = ((num_powers as f32 / split_number as f32).ceil() as i32).max(1);

    let mut data = vec![];
    let mut exp = exp_min;
    loop {
        data.push(format_axis_value(base.powi(exp)));
        if exp >= exp_max {
            break;
        }
        exp = (exp + step).min(exp_max);
    }

    if params.reverse.unwrap_or_default() {
        data.reverse();
    }

    AxisValues {
        data,
        min: base.powi(exp_min),
        max: base.powi(exp_max),
        scale: AxisScale::Log(base),
    }
}

pub(crate) fn get_axis_values(params: AxisValueParams) -> AxisValues {
    if let AxisScale::Log(base) = params.scale {
        return get_log_axis_values(params, base);
    }

    let mut min = f32::MAX;
    let mut max = f32::MIN;

    let mut split_number = params.split_number;
    if split_number == 0 {
        split_number = 6;
    }
    for item in params.data_list.iter() {
        let value = item.to_owned();
        if value == NIL_VALUE {
            continue;
        }
        if value > max {
            max = value;
        }
        if value < min {
            min = value;
        }
    }
    let mut is_custom_min = false;

    if let Some(value) = params.min {
        if value < min {
            min = value;
            is_custom_min = true;
        }
    }
    // it should use 0, if min gt 0 and not custom value
    if !is_custom_min && min > 0.0 {
        min = 0.0;
    }
    let mut is_custom_max = false;
    if let Some(value) = params.max {
        if value > max {
            max = value;
            is_custom_max = true
        }
    }
    let mut unit = (max - min) / split_number as f32;
    if !is_custom_max {
        let ceil_value = (unit * 10.0).ceil();
        if ceil_value < 12.0 {
            unit = ceil_value / 10.0;
        } else {
            let mut new_unit = unit as i32;
            let adjust_unit = |current: i32, small_unit: i32| -> i32 {
                if current % small_unit == 0 {
                    return current + small_unit;
                }
                ((current / small_unit) + 1) * small_unit
            };
            if new_unit < 10 {
                new_unit = adjust_unit(new_unit, 2);
            } else if new_unit < 100 {
                new_unit = adjust_unit(new_unit, 5);
            } else if new_unit < 500 {
                new_unit = adjust_unit(new_unit, 10);
            } else if new_unit < 1000 {
                new_unit = adjust_unit(new_unit, 20);
            } else if new_unit < 5000 {
                new_unit = adjust_unit(new_unit, 50);
            } else if new_unit < 10000 {
                new_unit = adjust_unit(new_unit, 100);
            } else {
                let small_unit = ((max - min) / 20.0) as i32;
                new_unit = adjust_unit(new_unit, small_unit / 100 * 100);
            }
            unit = new_unit as f32;
        }
    }
    let split_unit = unit;

    let mut data = vec![];
    for i in 0..=split_number {
        let value = min + (i as f32) * split_unit;
        if params.thousands_format {
            data.push(thousands_format_float(value));
        } else {
            data.push(format_axis_value(value));
        }
    }
    if params.reverse.unwrap_or_default() {
        data.reverse();
    }

    AxisValues {
        data,
        min,
        max: min + split_unit * split_number as f32,
        scale: AxisScale::Linear,
    }
}
pub fn convert_to_points(values: &[(f32, f32)]) -> Vec<Point> {
    values.iter().map(|item| item.to_owned().into()).collect()
}

pub fn get_quadrant(cx: f32, cy: f32, point: &Point) -> u8 {
    if point.x > cx {
        if point.y > cy {
            4
        } else {
            1
        }
    } else if point.y > cy {
        3
    } else {
        2
    }
}

#[derive(Clone, Debug, Default)]
pub(crate) struct LabelOption {
    pub series_name: String,
    pub category_name: String,
    pub value: f32,
    pub percentage: f32,
    pub formatter: String,
}
impl LabelOption {
    pub fn format(&self) -> String {
        // {a} for series name, {b} for category name, {c} for data value, {d} for percentage
        let value = format_float(self.value);
        let percentage = format_float(self.percentage * 100.0) + "%";
        if self.formatter.is_empty() {
            return value;
        }
        self.formatter
            .replace(SERIES_NAME_FORMAT_LABEL, &self.series_name)
            .replace(CATEGORY_NAME_FORMAT_LABEL, &self.category_name)
            .replace(VALUE_FORMAT_LABEL, &value)
            .replace(PERCENTAGE_FORMAT_LABEL, &percentage)
            .replace(THOUSANDS_FORMAT_LABEL, &thousands_format_float(self.value))
    }
}

pub fn format_string(value: &str, formatter: &str) -> String {
    if formatter.is_empty() {
        value.to_string()
    } else {
        formatter
            .replace(VALUE_FORMAT_LABEL, value)
            .replace(THOUSANDS_FORMAT_LABEL, value)
    }
}

pub(crate) fn get_pie_point(cx: f32, cy: f32, r: f32, angle: f32) -> Point {
    let value = angle / 180.0 * std::f32::consts::PI;
    let x = cx + r * value.sin();
    let y = cy - r * value.cos();
    Point { x, y }
}
pub(crate) fn get_box_of_points(points: &[Point]) -> Box {
    let mut b = Box {
        left: f32::MAX,
        top: f32::MAX,
        ..Default::default()
    };
    for p in points.iter() {
        if p.x < b.left {
            b.left = p.x;
        }
        if p.x > b.right {
            b.right = p.x;
        }
        if p.y < b.top {
            b.top = p.y;
        }
        if p.y > b.bottom {
            b.bottom = p.y;
        }
    }
    b
}

#[cfg(test)]
mod tests {
    use crate::{thousands_format_float, AxisScale};

    use super::{
        convert_to_points, format_float, get_axis_values, get_box_of_points, AxisValueParams, Box,
        Point,
    };
    use pretty_assertions::assert_eq;

    #[test]
    fn point() {
        let p: Point = (1.2, 1.3).into();

        assert_eq!(1.2, p.x);
        assert_eq!(1.3, p.y);
    }

    #[test]
    fn box_width_height() {
        let b: Box = (10.0).into();

        assert_eq!(10.0, b.left);
        assert_eq!(10.0, b.top);
        assert_eq!(10.0, b.right);
        assert_eq!(10.0, b.bottom);
        assert_eq!(0.0, b.width());
        assert_eq!(10.0, b.outer_width());
        assert_eq!(0.0, b.height());
        assert_eq!(10.0, b.outer_height());

        let b: Box = (5.0, 10.0, 30.0, 50.0).into();
        assert_eq!(5.0, b.left);
        assert_eq!(10.0, b.top);
        assert_eq!(30.0, b.right);
        assert_eq!(50.0, b.bottom);
        assert_eq!(25.0, b.width());
        assert_eq!(30.0, b.outer_width());
        assert_eq!(40.0, b.height());
        assert_eq!(50.0, b.outer_height());
    }

    #[test]
    fn format() {
        assert_eq!("1", format_float(1.0));
        assert_eq!("1.1", format_float(1.12));
        assert_eq!("100.1", format_float(100.14));
        assert_eq!("100", format_float(100.04));
        assert_eq!("1000.1", format_float(1000.14));
    }
    #[test]
    fn thousands_format() {
        assert_eq!("1", thousands_format_float(1.0));
        assert_eq!("1.1", thousands_format_float(1.12));
        assert_eq!("100.1", thousands_format_float(100.14));
        assert_eq!("100", thousands_format_float(100.04));
        assert_eq!("1,000", thousands_format_float(1000.14));
        assert_eq!("100,000", thousands_format_float(100000.14));
        assert_eq!("1,000,000", thousands_format_float(1_000_000.1));
    }

    #[test]
    fn axis_values() {
        let values = get_axis_values(AxisValueParams {
            data_list: vec![1.0, 10.0, 13.5, 18.9],
            ..Default::default()
        });

        assert_eq!(vec!["0", "4", "8", "12", "16", "20", "24"], values.data);
        assert_eq!(0.0, values.min);
        assert_eq!(24.0, values.max);
        assert_eq!(24.0, values.get_offset());
        assert_eq!(50.0, values.get_offset_height(12.0, 100.0));
    }

    #[test]
    fn axis_values_log() {
        // Base-10 log scale over [1, 1000]: ticks at 1, 10, 100, 1000
        let values = get_axis_values(AxisValueParams {
            data_list: vec![1.0, 5.0, 100.0, 800.0],
            scale: AxisScale::Log(10.0),
            ..Default::default()
        });
        // exp_min = floor(log10(1)) = 0  → 10^0 = 1
        // exp_max = ceil(log10(800)) = 3 → 10^3 = 1000
        assert_eq!(1.0, values.min);
        assert_eq!(1000.0, values.max);
        // Ticks: 1, 10, 100, 1000  (step=1, 4 ticks ≤ split_number=6+1)
        assert_eq!(vec!["1", "10", "100", "1k"], values.data);
        // 10 is at 1/3 of the log range → pixel = 100 - 33.3.. = 66.6..
        let h = values.get_offset_height(10.0, 100.0);
        assert!((h - 66.67).abs() < 0.1, "expected ~66.67, got {h}");
        // 100 is at 2/3 → pixel = 100 - 66.6.. = 33.3..
        let h = values.get_offset_height(100.0, 100.0);
        assert!((h - 33.33).abs() < 0.1, "expected ~33.33, got {h}");
        // min maps to max_height, max maps to 0
        assert!((values.get_offset_height(1.0, 100.0) - 100.0).abs() < 0.01);
        assert!((values.get_offset_height(1000.0, 100.0)).abs() < 0.01);
    }

    #[test]
    fn get_box() {
        let points: Vec<Point> = convert_to_points(&[
            (2.0, 10.0),
            (50.0, 10.0),
            (50.0, 30.0),
            (150.0, 30.0),
            (150.0, 80.0),
            (210.0, 60.0),
            (250.0, 90.0),
        ]);
        let b = get_box_of_points(&points);
        assert_eq!(2.0, b.left);
        assert_eq!(10.0, b.top);
        assert_eq!(250.0, b.right);
        assert_eq!(90.0, b.bottom);
    }
}