#![deny(
    missing_docs,
    missing_debug_implementations,
    missing_copy_implementations,
    trivial_casts,
    trivial_numeric_casts,
    unsafe_code,
    unstable_features,
    unused_import_braces,
    unused_qualifications
)]

//! Functionality for creating, reading and manipulating a brevdash repository.

use anyhow::{bail, Context, Result};
use chrono::naive::NaiveDate;
use glob::glob;
use indexmap::IndexMap;
use log::warn;
use serde::{Deserialize, Serialize};
use std::collections::BTreeMap;
use std::path::{Path, PathBuf};
use std::str::FromStr;

/// Definition of a brevdash data repository.
#[derive(Debug)]
pub struct Repository {
    path: PathBuf,
    /// The root description string.
    pub description: RootDescription,
}

impl Repository {
    /// Open a repository from a directory path.
    pub fn open<P: AsRef<Path>>(path: P) -> Result<Self> {
        Ok(Repository {
            path: path.as_ref().to_path_buf(),
            description: RootDescription::load_from_file(
                Self::initial_brevdash_toml_path(path),
            )?,
        })
    }

    /// Create a repository at a directory path.
    ///
    /// The directory must already exist and be writable.
    pub fn create<P: AsRef<Path>>(
        path: P,
        description: RootDescription,
    ) -> Result<Self> {
        let r = Repository {
            path: path.as_ref().to_path_buf(),
            description,
        };
        r.store_description()?;
        Ok(r)
    }

    /// Store the description file inside the repository.
    pub fn store_description(&self) -> Result<()> {
        self.description.store_to_file(self.brevdash_toml_path())
    }

    fn initial_brevdash_toml_path<P: AsRef<Path>>(p: P) -> PathBuf {
        p.as_ref().join("brevdash.toml")
    }

    fn project_dir_path(&self, project_id: &str) -> PathBuf {
        self.path.join(project_id)
    }

    fn project_toml_file_path(&self, project_id: &str) -> PathBuf {
        self.project_dir_path(project_id).join("project.toml")
    }

    fn project_datapoint_directory_path(
        &self,
        project_id: &str,
        date: NaiveDate,
    ) -> PathBuf {
        self.project_dir_path(project_id)
            .join(date.format("%Y-%m-%d").to_string())
    }

    fn project_datapoint_toml_file_path(
        &self,
        project_id: &str,
        date: NaiveDate,
    ) -> PathBuf {
        self.project_datapoint_directory_path(project_id, date)
            .join("datapoint.toml")
    }

    fn project_datapoint_artifacts_directory_path(
        &self,
        project_id: &str,
        date: NaiveDate,
    ) -> PathBuf {
        self.project_datapoint_directory_path(project_id, date)
            .join("artifacts")
    }

    /// Get the path for the artifacts of a characteristic at a specific date.
    pub fn project_datapoint_characteristic_artifacts_directory_path(
        &self,
        project_id: &str,
        date: NaiveDate,
        characteristic_id: &str,
    ) -> PathBuf {
        self.project_datapoint_artifacts_directory_path(project_id, date)
            .join(characteristic_id)
    }

    /// Get the path for an artifact.
    pub fn project_datapoint_characteristic_artifact_path(
        &self,
        project_id: &str,
        date: NaiveDate,
        characteristic_id: &str,
        artifact_relative_path: &Path,
    ) -> PathBuf {
        self.project_datapoint_characteristic_artifacts_directory_path(
            project_id,
            date,
            characteristic_id,
        )
        .join(artifact_relative_path)
    }

    fn brevdash_toml_path(&self) -> PathBuf {
        self.path.join("brevdash.toml")
    }

    fn extract_project_id(
        project_toml_file_path: &Path,
    ) -> Result<String> {
        let project_path =
            project_toml_file_path.parent().with_context(|| {
                format!(
                    "Couldn't extract parent directory of {:?}",
                    project_toml_file_path
                )
            })?;
        let project_path_name_raw =
            project_path.file_name().with_context(|| {
                format!(
                    "Couldn't extract directory name of {:?}",
                    project_path
                )
            })?;
        Ok(project_path_name_raw
            .to_str()
            .with_context(|| {
                format!(
                    "Couldn't get project directory name, \
                    possibly invalid UTF-8: {:?}",
                    project_path_name_raw
                )
            })?
            .to_string())
    }

    /// Load the list of project ids inside the repository.
    pub fn load_project_ids(&self) -> Result<Vec<String>> {
        let pattern = format!("{}/*/project.toml", self.path.as_str()?);
        let mut ids = Vec::new();
        for entry in glob(&pattern).with_context(|| {
            format!("Failed to read glob pattern {:?}", pattern)
        })? {
            match entry {
                Ok(path) => match Self::extract_project_id(&path) {
                    Ok(id) => ids.push(id),
                    Err(e) => warn!("{:?}", e),
                },
                Err(e) => warn!("{:?}", e),
            }
        }
        Ok(ids)
    }

    /// Query whether the repository contains a project with a specific id.
    pub fn has_project(&self, project_id: &str) -> bool {
        self.project_toml_file_path(project_id).exists()
    }

    /// Store the description of a project.
    pub fn store_project_description(
        &self,
        project_id: &str,
        description: &ProjectDescription,
    ) -> Result<()> {
        let project_dir_path = self.project_dir_path(&project_id);
        std::fs::create_dir_all(&project_dir_path).with_context(|| {
            format!(
                "Couldn't create project directory {:?}",
                project_dir_path
            )
        })?;
        description.store_to_file(self.project_toml_file_path(project_id))
    }

    /// Load the description of a project by id.
    pub fn load_project_description(
        &self,
        project_id: &str,
    ) -> Result<ProjectDescription> {
        ProjectDescription::load_from_file(
            &self.project_toml_file_path(project_id),
        )
    }

    /// Load the descriptions for all projects.
    pub fn load_project_descriptions(
        &self,
    ) -> Result<BTreeMap<String, ProjectDescription>> {
        let mut descriptions = BTreeMap::new();
        for project_id in self.load_project_ids()?.into_iter() {
            let description =
                self.load_project_description(&project_id)?;
            descriptions.insert(project_id, description);
        }
        Ok(descriptions)
    }

    /// Query whether the repository contains a datapoint at a specific date.
    pub fn project_has_datapoint_date(
        &self,
        project_id: &str,
        date: NaiveDate,
    ) -> bool {
        self.project_datapoint_toml_file_path(project_id, date)
            .exists()
    }

    /// Load a list of all datapoint dates for a specific project id.
    pub fn load_project_datapoint_dates(
        &self,
        project_id: &str,
    ) -> Result<Vec<NaiveDate>> {
        let pattern = format!(
            "{}/[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]/datapoint.toml",
            self.project_dir_path(project_id).as_str()?
        );

        let mut dates = Vec::new();

        for entry in glob(&pattern).with_context(|| {
            format!("Failed to read glob pattern {:?}", pattern)
        })? {
            match entry {
                Ok(path) => {
                    let full_date_path =
                        path.parent().with_context(|| {
                            format!(
                                "Couldn't get parent of file {:?}",
                                path
                            )
                        })?;
                    let date_raw =
                        full_date_path.file_name().with_context(|| {
                            format!(
                                "Couldn't get file name of {:?}",
                                full_date_path
                            )
                        })?;

                    let date_str = date_raw
                        .to_str()
                        .with_context(|| {
                            format!(
                                "Couldn't get file path string, \
                                 possibly invalid UTF-8: {:?}",
                                path
                            )
                        })?
                        .to_string();
                    let date =
                        NaiveDate::parse_from_str(&date_str, "%Y-%m-%d")?;
                    dates.push(date);
                }
                Err(e) => {
                    warn!("{:?}", e);
                }
            }
        }
        Ok(dates)
    }

    /// Store a datapoint at a specific date.
    pub fn store_project_datapoint(
        &self,
        project_id: &str,
        date: NaiveDate,
        datapoint: &DataPoint,
    ) -> Result<()> {
        let project_toml_file_path =
            self.project_toml_file_path(project_id);
        if !project_toml_file_path.exists() {
            bail!(
                "Attempting to store datapoint for project \
                {:?}, but no project.toml file is present",
                project_id
            );
        }
        let project_datapoint_directory_path =
            self.project_datapoint_directory_path(project_id, date);
        std::fs::create_dir_all(&project_datapoint_directory_path)
            .with_context(|| {
                format!(
                    "Couldn't create datapoint directory {:?}",
                    project_datapoint_directory_path
                )
            })?;
        datapoint.store_to_file(
            self.project_datapoint_toml_file_path(project_id, date),
        )
    }

    /// Load a datapoint at a specific date.
    pub fn load_project_datapoint(
        &self,
        project_id: &str,
        date: NaiveDate,
    ) -> Result<DataPoint> {
        DataPoint::load_from_file(
            &self.project_datapoint_toml_file_path(project_id, date),
        )
    }

    /// Load all datapoints for a project id.
    pub fn load_project_datapoints(
        &self,
        project_id: &str,
    ) -> Result<BTreeMap<NaiveDate, DataPoint>> {
        let mut datapoints = BTreeMap::new();
        for date in
            self.load_project_datapoint_dates(project_id)?.into_iter()
        {
            let datapoint =
                self.load_project_datapoint(project_id, date)?;
            datapoints.insert(date, datapoint);
        }
        Ok(datapoints)
    }
}

trait LoadFromFile: Sized {
    fn load_from_file<P: AsRef<Path>>(path: P) -> Result<Self>;
}

impl<T: serde::de::DeserializeOwned> LoadFromFile for T {
    fn load_from_file<P: AsRef<Path>>(path: P) -> Result<Self> {
        let path = path.as_ref();
        let s = std::fs::read_to_string(path).with_context(|| {
            format!("Couldn't open file {:?}", path.to_path_buf())
        })?;

        let t: T = toml::from_str(&s).with_context(|| {
            format!("Couldn't read file: {:?}", path.to_path_buf())
        })?;
        Ok(t)
    }
}

trait StoreToFile {
    fn store_to_file<P: AsRef<Path>>(&self, path: P) -> Result<()>;
}

impl<T: Serialize> StoreToFile for T {
    fn store_to_file<P: AsRef<Path>>(&self, path: P) -> Result<()> {
        let path = path.as_ref();
        let s = toml::to_string(&self).with_context(|| {
            format!(
                "Couldn't serialize data for file {:?}",
                path.to_path_buf()
            )
        })?;
        std::fs::write(&path, s).with_context(|| {
            format!("Couldn't write file {:?}", path.to_path_buf())
        })?;
        Ok(())
    }
}

trait PathAsStr {
    fn as_str(&self) -> Result<&str>;
}

impl<P: AsRef<Path>> PathAsStr for P {
    fn as_str(&self) -> Result<&str> {
        let p = self.as_ref();
        p.to_str().with_context(|| {
            format!("Couldn't get path, possibly invalid UTF-8: {:?}", p)
        })
    }
}

/// A single datapoint containing multiple entries.
pub type DataPoint = BTreeMap<String, DataEntry>;

/// A data entry.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct DataEntry {
    /// The value of the entry.
    pub value: DataValue,

    /// The list of artifacts available for the data entry.
    #[serde(
        default = "Default::default",
        skip_serializing_if = "Vec::is_empty"
    )]
    pub artifacts: Vec<PathBuf>,
}

/// The value of a data entry.
#[derive(Copy, Clone, Debug, Serialize, Deserialize)]
#[serde(untagged)]
pub enum DataValue {
    /// A boolean value.
    Boolean(bool),
    /// An integer value.
    Integer(i64),
}

impl FromStr for DataValue {
    type Err = anyhow::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if let Ok(v) = s.parse::<bool>() {
            Ok(DataValue::Boolean(v))
        } else if let Ok(v) = s.parse::<i64>() {
            Ok(DataValue::Integer(v))
        } else {
            bail!("Couldn't parse argument {:?}", s);
        }
    }
}

impl DataValue {
    /// Unwrap the contained value if it is a DataValue::Boolean.
    /// If the value is not a DataValue::Boolean, this method panics.
    pub fn unwrap_boolean(&self) -> bool {
        self.boolean().unwrap()
    }

    /// Unwrap the contained value if it is a DataValue::Integer.
    /// If the value is not a DataValue::Integer, this method panics.
    pub fn unwrap_integer(&self) -> i64 {
        self.integer().unwrap()
    }

    /// Get the contained value if it is a DataValue::Boolean.
    /// If the value is not a DataValue::Boolean, None is returned.
    pub fn boolean(&self) -> Option<bool> {
        if let DataValue::Boolean(v) = *self {
            Some(v)
        } else {
            None
        }
    }

    /// Get the contained value if it is a DataValue::Integer.
    /// If the value is not a DataValue::Integer, None is returned.
    pub fn integer(&self) -> Option<i64> {
        if let DataValue::Integer(v) = *self {
            Some(v)
        } else {
            None
        }
    }

    /// Get the type of the data value.
    pub fn datatype(&self) -> DataType {
        match self {
            DataValue::Integer(_) => DataType::Integer,
            DataValue::Boolean(_) => DataType::Boolean,
        }
    }
}

/// Possible types for data entries.
#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "lowercase")]
pub enum DataType {
    /// A boolean entry type.
    Boolean,

    /// A integer entry type.
    Integer,
}

impl FromStr for DataType {
    type Err = anyhow::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "boolean" => Ok(DataType::Boolean),
            "integer" => Ok(DataType::Integer),
            s => bail!("Couldn't parse argument {:?}", s),
        }
    }
}

/// The description for a characteristic.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct CharacteristicDescription {
    /// The type of values for datapoints of this characteristic.
    pub datatype: DataType,

    /// The human-readable name for the characteristic.
    pub name: String,
}

/// The description for the root of a brevdash repository.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct RootDescription {
    /// The human-readable name of the repository.
    pub name: String,

    /// The caracteristics available in the repository.
    pub characteristics: IndexMap<String, CharacteristicDescription>,
}

/// The description of a project inside a brevdash repository.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct ProjectDescription {
    /// The human-readable name of the project.
    pub name: String,

    /// A more detailed description of the project.
    #[serde(
        default = "Default::default",
        skip_serializing_if = "String::is_empty"
    )]
    pub description: String,

    /// The website URL of the project.
    #[serde(
        default = "Default::default",
        skip_serializing_if = "String::is_empty"
    )]
    pub website: String,

    /// The VCS url of the project (e.g. a git url)
    #[serde(
        default = "Default::default",
        skip_serializing_if = "String::is_empty"
    )]
    pub vcs: String,
}