use std::io::BufRead;

pub const DEFAULT_OUTPUT_FILE: &str = "numbers.json";
const LETTERS: &str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

#[derive(Clone, Debug, Default)]
pub struct NumberParser {
    pub filepath: String,
}

impl NumberParser {
    pub async fn file_dump(
        &self,
    ) -> Result<Vec<schedtxt_models::contact::Contact>, std::io::Error> {
        println!("Dumping files");
        let mut objs: Vec<schedtxt_models::contact::Contact> = Vec::new();

        match self.read_lines(&self.filepath).await {
            Ok(lines) => {
                for line in lines {
                    let contains_letters = line.chars().any(|c| LETTERS.contains(c));
                    if contains_letters {
                        continue;
                    } else {
                        let my_obj = schedtxt_models::contact::Contact {
                            phone_number: line.clone(),
                            ..Default::default()
                        };
                        if !my_obj.phone_number.is_empty() {
                            objs.push(my_obj);
                        }
                    }
                }

                let updated_contacts = self.update_contacts(&objs).await;
                let removed_duplicates = self.remove_dups(&updated_contacts).await;

                Ok(removed_duplicates)
            }
            Err(err) => Err(err),
        }
    }

    pub async fn save_file(&self, numbers: Vec<schedtxt_models::contact::Contact>, filename: &str) {
        match serde_json::to_string(&numbers) {
            Ok(json_string) => match std::fs::write(filename, json_string) {
                Ok(_) => {
                    println!("Saved to: {filename:?}");
                }
                Err(err) => {
                    eprintln!("Error: {err:?}");
                }
            },
            Err(err) => {
                eprintln!("Error: {err:?}");
            }
        };
    }

    pub fn print_phone_numbers(&self, contacts: &Vec<schedtxt_models::contact::Contact>) {
        println!("Printing phone numbers");

        for contact in contacts {
            println!("Phone Number: {:?}", contact.phone_number);
        }

        println!("Total phone numbers: {:?}", contacts.len());
    }

    async fn read_lines(&self, filename: &String) -> Result<Vec<String>, std::io::Error> {
        match std::fs::File::open(filename) {
            Ok(file) => {
                let reader = std::io::BufReader::new(file);
                reader.lines().collect()
            }
            Err(err) => Err(err),
        }
    }

    async fn remove_dups(
        &self,
        contacts: &Vec<schedtxt_models::contact::Contact>,
    ) -> Vec<schedtxt_models::contact::Contact> {
        let mut unique_contacts: Vec<schedtxt_models::contact::Contact> = Vec::new();
        let mut unique_items = std::collections::HashSet::new();

        for val in contacts {
            unique_items.insert(val.phone_number.clone());
        }

        for unique_item in unique_items {
            let contact = schedtxt_models::contact::Contact {
                phone_number: unique_item,
                ..Default::default()
            };
            unique_contacts.push(contact);
        }

        unique_contacts
    }

    async fn update_contacts(
        &self,
        contacts: &Vec<schedtxt_models::contact::Contact>,
    ) -> Vec<schedtxt_models::contact::Contact> {
        let mut updated: Vec<schedtxt_models::contact::Contact> = Vec::new();

        for ct in contacts {
            let phone_number = ct.phone_number.clone();
            if phone_number.len() < 2 {
                println!("Invalid number: {phone_number:?}");
                continue;
            }

            let pars = self.remove_some_data(&phone_number).await;

            match self.add_prefix(&pars) {
                Ok(updated_parsed) => {
                    let contact = schedtxt_models::contact::Contact {
                        phone_number: updated_parsed,
                        ..Default::default()
                    };
                    updated.push(contact);
                }
                Err(err) => {
                    eprintln!("Error: {err:?}");
                    std::process::exit(-2);
                }
            };
        }

        updated
    }

    fn add_prefix(&self, raw: &String) -> Result<String, std::io::Error> {
        if raw.is_empty() {
            Err(std::io::Error::other("Empty"))
        } else {
            let mut parsed: String = String::new();
            let first_char = raw.chars().nth(0).unwrap();

            if first_char == '1' {
                parsed = format!("+{raw}");
            } else if first_char != '+' {
                parsed = format!("+1{raw}");
            }

            Ok(parsed)
        }
    }

    async fn remove_some_data(&self, unparsed: &str) -> String {
        let mut parsed: String = String::new();

        for ch in unparsed.chars() {
            if ch == ' ' {
                continue;
            } else {
                if ch.is_numeric() {
                    parsed.push(ch);
                }
            }
        }

        parsed
    }
}

#[cfg(test)]
mod tests {
    use schedtxt_models::contact::Contact;

    const TEST_NUMBERS_0: &str = "tests/numbers-0.txt";

    #[test]
    fn test_file_dump() {
        let file_exists = {
            let path = std::path::Path::new(TEST_NUMBERS_0);
            path.exists()
        };

        assert_eq!(true, file_exists, "File does not exists {TEST_NUMBERS_0:?}");

        let filename = String::from(TEST_NUMBERS_0);
        let prsr = super::NumberParser { filepath: filename };
        let original: Vec<Contact> = vec![
            Contact {
                phone_number: String::from("+13055550112"),
                ..Default::default()
            },
            Contact {
                phone_number: String::from("+13175550123"),
                ..Default::default()
            },
            Contact {
                phone_number: String::from("+14155550135"),
                ..Default::default()
            },
            Contact {
                phone_number: String::from("+16085550190"),
                ..Default::default()
            },
            Contact {
                phone_number: String::from("+17135550167"),
                ..Default::default()
            },
            Contact {
                phone_number: String::from("+16025550177"),
                ..Default::default()
            },
            Contact {
                phone_number: String::from("+13605550158"),
                ..Default::default()
            },
            Contact {
                phone_number: String::from("+12175550194"),
                ..Default::default()
            },
        ];

        match async_std::task::block_on(prsr.file_dump()) {
            Ok(contacts) => {
                assert!((contacts.len() > 0), "No contacts has been parsed");

                let phone_numbers_1: std::collections::HashSet<_> =
                    contacts.iter().map(|p| p.phone_number.clone()).collect();
                let phone_numbers_2: std::collections::HashSet<_> =
                    original.iter().map(|p| p.phone_number.clone()).collect();
                assert_eq!(phone_numbers_1, phone_numbers_2, "No match");
            }
            Err(err) => {
                assert!(false, "Error: {err:?}");
            }
        };
    }

    #[test]
    fn test_save_file() {
        let prsr = super::NumberParser {
            filepath: String::from(TEST_NUMBERS_0),
        };
        let results = async_std::task::block_on(prsr.file_dump());
        assert!(results.is_ok(), "File dump not successful");
        let test_output_file: &str = "test-numbers.json";

        let contacts = results.unwrap();
        async_std::task::block_on(prsr.save_file(contacts, test_output_file));
        let file_exists = {
            let path = std::path::Path::new(test_output_file);
            path.exists()
        };

        assert!(file_exists, "Contacts were not saved");
        match std::fs::remove_file(test_output_file) {
            Ok(_) => {
                println!("File removed");
            }
            Err(err) => {
                assert!(false, "Error: {err:?}");
            }
        }
    }
}