use crate::addressing::Address;
use crate::database::{Entry, EntryValue, InnerEntry, InsertEntry, QueryEntries};
use crate::hash::{ComputeHash, Hash, HasherWorker};
use crate::models;
use anyhow::{anyhow, Result};
use log::{info, warn};
use serde::export::Formatter;
use serde_json::Value;
use std::fs;
use std::path::{Path, PathBuf};
use walkdir::WalkDir;

use actix::prelude::*;
use chrono::prelude::*;
use uuid::Uuid;

const DIR_KEY: &str = "DIR";
const DIR_HAS_KEY: &str = "DIR_HAS";

#[derive(Debug, PartialEq)]
pub struct UDirectory {
    name: String,
}

#[derive(Debug, PartialEq)]
pub struct UPath(Vec<UDirectory>);

const TOP_SEPARATOR: &str = "//";

impl std::str::FromStr for UPath {
    type Err = anyhow::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if s.len() == 0 {
            Ok(UPath(vec![]))
        } else {
            match s.find(TOP_SEPARATOR) {
                Some(head_idx) => {
                    let (head, rest) = s.split_at(head_idx);
                    let mut result: Vec<UDirectory> = Vec::new();
                    result.push(UDirectory {
                        name: String::from(head),
                    });
                    result.append(
                        rest[TOP_SEPARATOR.len()..rest.len()]
                            .split("/")
                            .map(|part| UDirectory {
                                name: String::from(part),
                            })
                            .collect::<Vec<UDirectory>>()
                            .as_mut(),
                    );
                    Ok(UPath(result))
                }
                None => Ok(UPath(
                    s.split("/")
                        .map(|part| UDirectory {
                            name: String::from(part),
                        })
                        .collect(),
                )),
            }
        }
    }
}

impl std::fmt::Display for UDirectory {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.name)
    }
}

impl std::fmt::Display for UPath {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        match self.0.len() {
            0 => write!(f, ""),
            1 => write!(f, "{}", self.0.first().unwrap().name),
            _ => {
                let (head, tail) = self.0.split_first().unwrap();
                write!(
                    f,
                    "{}//{}",
                    head.name,
                    tail.iter()
                        .map(|udir| udir.name.clone())
                        .collect::<Vec<String>>()
                        .join("/")
                )
            }
        }
    }
}

pub async fn fetch_or_create_dir(
    db_executor: &Addr<crate::database::DbExecutor>,
    parent: Option<Address>,
    directory: UDirectory,
) -> Result<Address> {
    let dir_value = EntryValue::Value(Value::String(directory.name));
    let directories: Vec<Address> = db_executor
        .send(QueryEntries {
            target: None,
            key: Some(String::from(DIR_KEY)),
            value: Some(dir_value.clone()),
        })
        .await??
        .into_iter()
        .map(|e: Entry| e.target)
        .collect();

    let valid_directories: Vec<Address> = match parent.clone() {
        Some(address) => {
            let parent_has: Vec<Address> = db_executor
                .send(QueryEntries {
                    target: Some(address),
                    key: Some(String::from(DIR_HAS_KEY)),
                    value: None,
                })
                .await??
                .into_iter()
                .map(|e: Entry| e.target)
                .collect();

            directories
                .into_iter()
                .filter(|a| parent_has.contains(a))
                .collect()
        }
        None => directories,
    };

    match valid_directories.len() {
        0 => {
            let new_directory_address = Address::UUID(Uuid::new_v4());
            let directory_entry = InnerEntry {
                target: new_directory_address.clone(),
                key: String::from(DIR_KEY),
                value: dir_value,
            };
            let _ = db_executor
                .send(InsertEntry {
                    entry: directory_entry,
                })
                .await??;

            if parent.is_some() {
                let has_entry = InnerEntry {
                    target: parent.unwrap(),
                    key: String::from(DIR_HAS_KEY),
                    value: EntryValue::Address(new_directory_address.clone()),
                };
                let _ = db_executor.send(InsertEntry { entry: has_entry }).await??;
            }

            Ok(new_directory_address)
        }
        1 => Ok(valid_directories[0].clone()),
        _ => Err(anyhow!(
            "Invalid database state - more than one directory matches the query!"
        )),
    }
}

pub fn fetch_path(path: &UPath) -> Vec<Entry> {
    unimplemented!();
}

async fn _reimport_directory<T: AsRef<Path>>(
    directory: T,
    db_executor: &Addr<crate::database::DbExecutor>,
    hasher_worker: &Addr<HasherWorker>,
) -> Result<()> {
    for entry in WalkDir::new(&directory)
        .into_iter()
        .filter_map(|e| e.ok())
        .filter(|e| e.path().is_file())
    {
        info!("Processing: {}", entry.path().display());

        let metadata = fs::metadata(entry.path())?;
        let size = metadata.len() as i64;
        if size < 0 {
            panic!("File {} too large?!", entry.path().display());
        }

        let msg = ComputeHash {
            path: entry.path().to_path_buf(),
        };

        let digest: Result<Result<Hash>, MailboxError> = hasher_worker.send(msg).await;

        let new_file = models::NewFile {
            path: entry
                .path()
                .to_str()
                .expect("path not valid unicode?!")
                .to_string(),
            hash: digest??.0,
            size,
            created: NaiveDateTime::from_timestamp(Utc::now().timestamp(), 0),
        };

        let _insert_result = db_executor
            .send(crate::database::InsertFile { file: new_file })
            .await?;
    }
    info!("Finished updating {}.", directory.as_ref().display());

    Ok(())
}

pub async fn reimport_directory(
    directory: PathBuf,
    db_executor: Addr<crate::database::DbExecutor>,
    hasher_worker: Addr<HasherWorker>,
) {
    let result = _reimport_directory(directory, &db_executor, &hasher_worker).await;
    if result.is_err() {
        warn!("Update did not succeed!");
    }
}

#[cfg(test)]
mod tests {
    use crate::filesystem::{UDirectory, UPath};
    use anyhow::Result;

    #[test]
    fn test_path_codec() {
        let path = UPath(vec![
            UDirectory {
                name: "top".to_string(),
            },
            UDirectory {
                name: "foo".to_string(),
            },
            UDirectory {
                name: "bar".to_string(),
            },
            UDirectory {
                name: "baz".to_string(),
            },
        ]);

        let str_path = path.to_string();
        assert!(str_path.len() > 0);

        let decoded_path: Result<UPath> = str_path.parse();
        assert!(decoded_path.is_ok());

        assert_eq!(path, decoded_path.unwrap());
    }
}