/* TA-LIB Copyright (c) 1999-2025, Mario Fortier
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 *
 * - Neither name of author nor the names of its contributors
 *   may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* Important:
 *  This file is automatically generated by the utility ta_codegen.
 *  Any modifications will be lost on next execution of ta_codegen.
 *
 *  Modifications should instead be done with the "C" source file
 *  in ta-lib\src\ta_func
 */

/* List of contributors:
 *
 *  Initial  Name/description
 *  -------------------------------------------------------------------
 *  MF       Mario Fortier
 *  JV       Jesus Viver <324122@cienz.unizar.es>
 *
 * Change history:
 *
 *  MMDDYY BY   Description
 *  -------------------------------------------------------------------
 *  112400 MF   Template creation.
 *  100502 JV   Speed optimization of the algorithm
 *  052603 MF   Adapt code to compile with .NET Managed C++
 */

// Import types from parent module
use super::*;

// Allow non-snake-case names to maintain TA-Lib API compatibility
#[allow(non_snake_case)]
#[allow(unused_variables)]
#[allow(dead_code)]
#[allow(unused_mut)]
#[allow(unused_assignments)]
impl Core {
    /// Lookback period for [`Core::var`]: the number of leading input values consumed before the
    /// first output value can be produced.
    ///
    /// # Arguments
    ///
    /// * `optInTimePeriod` — Window length for the variance (default 5, range 1..=100000)
    /// * `optInNbDev` — Deviation count accepted by the API but never used in the computation
    ///   (default 1)
    ///
    /// Returns `usize::MAX` when a parameter is out of range. Integer parameters accept `i32::MIN`
    /// to select their default value.
    #[inline]
    pub fn var_lookback(&self, mut optInTimePeriod: i32, mut optInNbDev: f64) -> usize {
        if ((optInTimePeriod) as i32) == (i32::MIN) {
            optInTimePeriod = 5;
        } else if (((optInTimePeriod) as i32) < 1) || (((optInTimePeriod) as i32) > 100000) {
            return usize::MAX;
        }
        return (optInTimePeriod - 1) as usize;
    }
    /// Rolling population variance of a real series over a given period. Measures dispersion of
    /// values around their mean. Higher values indicate greater dispersion; 0 means constant input.
    ///
    /// # Formula
    ///
    /// ```text
    /// $\mathrm{VAR} = \frac{1}{n}\sum x_i^2 - \left(\frac{1}{n}\sum x_i\right)^2$, over the last $n$ = optInTimePeriod values (population, divides by $n$).
    /// ```
    ///
    /// # Notes
    ///
    /// * Computes population variance (divides by the period), not the sample variance (n-1) used
    ///   by some definitions.
    /// * The deviation-count parameter is accepted but has no effect on the result.
    ///
    /// # Arguments
    ///
    /// * `startIdx` — Start index of the requested calculation range.
    /// * `endIdx` — End index of the requested calculation range (inclusive).
    /// * `inReal` — Source series.
    /// * `optInTimePeriod` — Window length for the variance (default 5, range 1..=100000)
    /// * `optInNbDev` — Deviation count accepted by the API but never used in the computation
    ///   (default 1)
    /// * `outBegIdx` — Set to the input index of the first output value.
    /// * `outNBElement` — Set to the number of output values written.
    /// * `outReal` — Rolling population variance.
    ///
    /// Integer parameters accept `i32::MIN` to select their default value.
    ///
    /// # Errors
    ///
    /// Returns [`RetCode::OutOfRangeStartIndex`] when `endIdx < startIdx`, and
    /// [`RetCode::BadParam`] when an optional parameter is outside its documented range.
    ///
    /// # Panics
    ///
    /// Input slices must cover `startIdx..=endIdx` and output slices must hold the number of values
    /// produced for that range: undersized slices panic or, for functions that forward to unchecked
    /// internals, cause undefined behavior. Sizing every output slice to the input length is always
    /// sufficient.
    ///
    /// # Examples
    ///
    /// ```
    /// use ta_lib::{Core, RetCode};
    ///
    /// let data: Vec<f64> = (0..252).map(|i| 100.0 + 10.0 * (0.1 * i as f64).sin()).collect();
    ///
    /// let core = Core::new();
    /// let mut out_beg = 0;
    /// let mut out_nb = 0;
    /// let mut out = vec![0.0; 252];
    ///
    /// let ret = core.var(0, data.len() - 1, &data, 5, 1.0, &mut out_beg, &mut out_nb, &mut out);
    /// assert_eq!(ret, RetCode::Success);
    /// assert!(out_nb > 0);
    /// ```
    ///
    /// # See also
    ///
    /// [`Core::stddev`]
    ///
    /// Further reading: [ta-lib.org/functions/var](https://ta-lib.org/functions/var/)
    #[doc(alias = "Variance")]
    pub fn var(
        &self,
        startIdx: usize,
        endIdx: usize,
        inReal: &[f64],
        mut optInTimePeriod: i32,
        mut optInNbDev: f64,
        outBegIdx: &mut usize,
        outNBElement: &mut usize,
        outReal: &mut [f64],
    ) -> RetCode {
        if endIdx < startIdx {
            return RetCode::OutOfRangeStartIndex;
        }
        if ((optInTimePeriod) as i32) == (i32::MIN) {
            optInTimePeriod = 5;
        } else if (((optInTimePeriod) as i32) < 1) || (((optInTimePeriod) as i32) > 100000) {
            return RetCode::BadParam;
        }
        let mut startIdx = startIdx;
        let mut tempReal: f64 = 0.0_f64;
        let mut periodTotal1: f64 = 0.0_f64;
        let mut periodTotal2: f64 = 0.0_f64;
        let mut meanValue1: f64 = 0.0_f64;
        let mut meanValue2: f64 = 0.0_f64;
        let mut i: usize = 0_usize;
        let mut outIdx: usize = 0_usize;
        let mut trailingIdx: usize = 0_usize;
        let mut nbInitialElementNeeded: usize = 0_usize;
        // Validate the calculation method type and
        // identify the minimum number of price bar needed
        // to calculate at least one output.
        nbInitialElementNeeded = (optInTimePeriod - 1) as usize;
        // Move up the start index if there is not
        // enough initial data.
        if startIdx < nbInitialElementNeeded {
            startIdx = nbInitialElementNeeded;
        }
        // Make sure there is still something to evaluate.
        if startIdx > endIdx {
            (*outBegIdx) = 0;
            (*outNBElement) = 0;
            return RetCode::Success;
        }
        // Do the MA calculation using tight loops.
        // Add-up the initial periods, except for the last value.
        periodTotal1 = 0.0;
        periodTotal2 = 0.0;
        trailingIdx = startIdx - nbInitialElementNeeded;
        i = trailingIdx;
        if optInTimePeriod > 1 {
            while i < startIdx {
                tempReal = inReal[{ let _v = i; i += 1; _v }];
                periodTotal1 += tempReal;
                tempReal *= tempReal;
                periodTotal2 += tempReal;
            }
        }
        // Proceed with the calculation for the requested range.
        // Note that this algorithm allows the inReal and
        // outReal to be the same buffer.
        outIdx = 0;
        loop {
            tempReal = inReal[{ let _v = i; i += 1; _v }];
            // Square and add all the deviation over
            // the same periods.
            periodTotal1 += tempReal;
            tempReal *= tempReal;
            periodTotal2 += tempReal;
            // Square and add all the deviation over
            // the same period.
            meanValue1 = periodTotal1 / ((optInTimePeriod) as f64);
            meanValue2 = periodTotal2 / ((optInTimePeriod) as f64);
            tempReal = inReal[{ let _v = trailingIdx; trailingIdx += 1; _v }];
            periodTotal1 -= tempReal;
            tempReal *= tempReal;
            periodTotal2 -= tempReal;
            outReal[outIdx] = meanValue2 - meanValue1 * meanValue1;
            outIdx += 1;
            if !(i <= endIdx) { break; }
        }
        // All done. Indicate the output limits and return.
        (*outNBElement) = outIdx;
        (*outBegIdx) = startIdx;
        return RetCode::Success;
    }
    /// Unchecked variant of [`Core::var`], used for internal cross-indicator calls.
    ///
    /// Skips parameter validation and uses unchecked indexing internally. Every argument must
    /// satisfy the constraints documented on [`Core::var`]; an out-of-range parameter, an input
    /// slice not covering `startIdx..=endIdx`, or an undersized output slice may panic or cause
    /// undefined behavior. Prefer [`Core::var`].
    #[inline]
    pub fn var_unguarded(
        &self,
        mut startIdx: usize,
        endIdx: usize,
        inReal: &[f64],
        mut optInTimePeriod: i32,
        mut optInNbDev: f64,
        outBegIdx: &mut usize,
        outNBElement: &mut usize,
        outReal: &mut [f64],
    ) -> RetCode {
        let mut tempReal: f64 = 0.0_f64;
        let mut periodTotal1: f64 = 0.0_f64;
        let mut periodTotal2: f64 = 0.0_f64;
        let mut meanValue1: f64 = 0.0_f64;
        let mut meanValue2: f64 = 0.0_f64;
        let mut i: usize = 0_usize;
        let mut outIdx: usize = 0_usize;
        let mut trailingIdx: usize = 0_usize;
        let mut nbInitialElementNeeded: usize = 0_usize;
        unsafe {
        assert!(endIdx < inReal.len());
        let _assertLb = self.var_lookback(optInTimePeriod, optInNbDev);
        let _assertStart = if startIdx > _assertLb { startIdx } else { _assertLb };
        assert!(_assertStart > endIdx || endIdx - _assertStart < outReal.len());
        nbInitialElementNeeded = (optInTimePeriod - 1) as usize;
        if startIdx < nbInitialElementNeeded {
            startIdx = nbInitialElementNeeded;
        }
        if startIdx > endIdx {
            (*outBegIdx) = 0;
            (*outNBElement) = 0;
            return RetCode::Success;
        }
        periodTotal1 = 0.0;
        periodTotal2 = 0.0;
        trailingIdx = startIdx - nbInitialElementNeeded;
        i = trailingIdx;
        if optInTimePeriod > 1 {
            while i < startIdx {
                tempReal = *inReal.as_ptr().add({ let _v = i; i += 1; _v });
                periodTotal1 += tempReal;
                tempReal *= tempReal;
                periodTotal2 += tempReal;
            }
        }
        outIdx = 0;
        loop {
            tempReal = *inReal.as_ptr().add({ let _v = i; i += 1; _v });
            periodTotal1 += tempReal;
            tempReal *= tempReal;
            periodTotal2 += tempReal;
            meanValue1 = periodTotal1 / ((optInTimePeriod) as f64);
            meanValue2 = periodTotal2 / ((optInTimePeriod) as f64);
            tempReal = *inReal.as_ptr().add({ let _v = trailingIdx; trailingIdx += 1; _v });
            periodTotal1 -= tempReal;
            tempReal *= tempReal;
            periodTotal2 -= tempReal;
            *outReal.as_mut_ptr().add(outIdx) = meanValue2 - meanValue1 * meanValue1;
            outIdx += 1;
            if !(i <= endIdx) { break; }
        }
        (*outNBElement) = outIdx;
        (*outBegIdx) = startIdx;
        return RetCode::Success;
        } // unsafe
    }
}
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/* End of File */
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