use crate::gene::Gene;
use crate::utils;
use rand::prelude::*;

pub struct DNA {
    // The pool size, number of genes
    pub pool_size: u16,
    // The amount of marker each gene has, each marker is f32
    pub gene_size: u16,
    // The genes for this DNA sequence
    pub genes: Vec<Gene>,
}

impl DNA {
    /// Constructs a new `DNA`.
    ///
    /// # Examples
    ///
    /// ```
    /// use genome::DNA;
    ///
    /// let dna = DNA::new(2, 2);
    /// ```
    pub fn new(pool_size: u16, gene_size: u16) -> DNA {
        DNA {
            pool_size: pool_size,
            gene_size: gene_size,
            genes: (0..pool_size).map(|_| Gene::new(gene_size)).collect(),
        }
    }
    /// Check if current DNA string is valid.
    ///
    /// # Examples
    ///
    /// ```
    /// use genome::DNA;
    /// let dna = DNA::new(2, 2);
    ///
    /// let is_valid = DNA::is_valid(dna.to_string());
    /// ```
    pub fn is_valid(dna_str: String) -> bool {
        let pool_size_hex = &dna_str[0..8];
        let dna = DNA::from(dna_str.clone());
        if dna.get_sum() == utils::f32_from_str(pool_size_hex) {
            return true;
        }
        return false;
    }
    /// Merge two `DNA` into one
    ///
    /// # Examples
    ///
    /// ```
    /// use genome::DNA;
    ///
    /// let dna1 = DNA::new(2, 2);
    /// let dna2 = DNA::new(2, 2);
    ///
    /// let merged = DNA::merge(dna1, dna2, false);
    /// ```
    pub fn merge(left_dna: DNA, right_dna: DNA, mutate: bool) -> Option<DNA> {
        let mut ration_rng = thread_rng();
        let mut mutate_rng = thread_rng();
        match (left_dna.pool_size == right_dna.pool_size)
            && (left_dna.gene_size == right_dna.gene_size)
        {
            true => Some(DNA {
                pool_size: left_dna.pool_size,
                gene_size: left_dna.gene_size,
                genes: (0..left_dna.pool_size)
                    .map(|i| {
                        if ration_rng.gen::<f32>() >= 0.5 {
                            left_dna.genes[i as usize].to_string()
                        } else {
                            right_dna.genes[i as usize].to_string()
                        }
                    })
                    .map(|g| {
                        let mut gene = Gene::from(g);
                        if mutate && mutate_rng.gen::<f32>() >= 0.9 {
                            gene.mutate();
                        }
                        gene
                    })
                    .collect(),
            }),
            false => None,
        }
    }
    /// Compare two `DNA` similarity, return the percentage of same genes
    ///
    /// # Examples
    ///
    /// ```
    /// use genome::DNA;
    ///
    /// let dna1 = DNA::new(256, 2);
    /// let dna_str = dna1.to_string();
    /// let dna2 = DNA::new(256, 2);
    ///
    /// let merged = DNA::merge(dna1, dna2, false).unwrap();
    ///
    /// let is_parent = DNA::compare(DNA::from(dna_str), merged) > 0.3;
    /// ```
    pub fn compare(left_dna: DNA, right_dna: DNA) -> f64 {
        let mut same_markers = 0;
        if left_dna.pool_size != right_dna.pool_size {
            return 0 as f64;
        }
        (0..left_dna.pool_size).for_each(|i| {
            if left_dna.genes[i as usize].to_string() == right_dna.genes[i as usize].to_string() {
                same_markers = same_markers + 1;
            }
        });
        same_markers as f64 / left_dna.pool_size as f64
    }
    /// Convert DNA to GAN latent vector
    ///
    /// # Examples
    ///
    /// ```
    /// use genome::DNA;
    ///
    /// let dna1 = DNA::new(2, 2);
    ///
    /// let latent = dna1.to_latent_vec();
    /// ```
    pub fn to_latent_vec(&self) -> Vec<f32> {
        self.genes
            .iter()
            .map(|g| g.markers.iter().map(|m| m.value).collect::<Vec<f32>>())
            .collect::<Vec<Vec<f32>>>()
            .concat()
    }
    /// Convert DNA to string
    ///
    /// # Examples
    ///
    /// ```
    /// use genome::DNA;
    ///
    /// let dna1 = DNA::new(2, 2);
    ///
    /// let dna1_str = dna1.to_string();
    /// ```
    pub fn to_string(&self) -> String {
        let pool_size_hex: String = utils::u16_to_string(self.pool_size);
        let gene_size_hex: String = utils::u16_to_string(self.gene_size);
        let check_sum: String = utils::f32_to_string(self.get_sum());

        format!(
            "{}{}{}{}",
            check_sum,
            pool_size_hex,
            gene_size_hex,
            self.genes.iter().map(|m| m.to_string()).collect::<String>()
        )
    }
    /// Get checksum for the dna, return back f32 sum of all genes.
    ///
    /// # Examples
    ///
    /// ```
    /// use genome::DNA;
    ///
    /// let dna1 = DNA::new(2, 2);
    ///
    /// let dna1_str = dna1.get_sum();
    /// ```
    pub fn get_sum(&self) -> f32 {
        self.genes.iter().map(|g| g.get_sum()).sum()
    }
}

/// Convert DNA to string
///
/// # Examples
///
/// ```
/// use genome::DNA;
///
/// let dna1 = DNA::new(2, 2);
///
/// let dna1_str = String::from(dna1);
/// ```
impl std::convert::From<DNA> for String {
    fn from(dna: DNA) -> String {
        let pool_size_hex: String = utils::u16_to_string(dna.pool_size);
        let gene_size_hex: String = utils::u16_to_string(dna.gene_size);
        let check_sum: String = utils::f32_to_string(dna.get_sum());

        format!(
            "{}{}{}{}",
            check_sum,
            pool_size_hex,
            gene_size_hex,
            dna.genes.iter().map(|m| m.to_string()).collect::<String>()
        )
    }
}

/// Convert DNA to string
///
/// # Examples
///
/// ```
/// use genome::DNA;
///
/// let dna1 = DNA::new(2, 2);
/// let dna1_str = dna1.to_string();
///
/// let dna_copy = DNA::from(dna1_str);
/// ```
impl std::convert::From<String> for DNA {
    fn from(dna: String) -> DNA {
        // Ignore the first 8 char for checksum
        let pool_size_hex = &dna[8..12];
        let gene_size_hex = &dna[12..16];
        let genes_hex = &dna[16..];

        let gene_size = utils::u16_from_str(gene_size_hex);

        let genes = utils::partition_str(genes_hex, 8 * (gene_size + 1) as usize)
            .iter()
            .map(|s| String::from(*s))
            .collect::<Vec<String>>();

        DNA {
            pool_size: utils::u16_from_str(pool_size_hex),
            gene_size,
            genes: genes.iter().map(|g| Gene::from(g.clone())).collect(),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn can_be_converted_and_back() {
        let dna = DNA::new(4, 2);
        let dna2 = DNA::from(dna.to_string());
        assert_eq!(dna.gene_size, dna2.gene_size);
        assert_eq!(dna.pool_size, dna2.pool_size);
        assert_eq!(dna.genes.len(), dna2.genes.len());
        assert_eq!(dna.to_string(), dna2.to_string());
    }
    #[test]
    fn can_be_merged() {
        let dna1 = DNA::new(2, 2);
        let dna2 = DNA::new(2, 2);
        match DNA::merge(dna1, dna2, false) {
            Some(_) => assert!(true),
            None => assert!(false),
        };
    }
    #[test]
    fn cannot_be_merged() {
        let dna1 = DNA::new(2, 2);
        let dna2 = DNA::new(3, 2);
        match DNA::merge(dna1, dna2, false) {
            Some(_) => assert!(false),
            None => assert!(true),
        };
    }
    #[test]
    fn check_merged_gene_ratio() {
        let dna1 = DNA::new(512, 4);
        let dna2 = DNA::new(512, 4);
        let dna1str = dna1.to_string();
        let dna2str = dna2.to_string();
        let child = DNA::merge(dna1, dna2, false).unwrap();
        let child_str = child.to_string();
        let parent1_ratio = DNA::compare(DNA::from(child_str.clone()), DNA::from(dna1str));
        let parent2_ratio = DNA::compare(DNA::from(child_str), DNA::from(dna2str));
        assert!(parent1_ratio != 0 as f64);
        assert!(parent2_ratio != 0 as f64);
        assert!(parent1_ratio + parent2_ratio == 1 as f64);
    }
}