// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

use crate::raw::*;
use crate::*;

/// Entry returned by [`Lister`] or [`BlockingLister`] to represent a path and it's relative metadata.
///
/// # Notes
///
/// Entry returned by [`Lister`] or [`BlockingLister`] may carry some already known metadata.
/// Lister by default only make sure that `Mode` is fetched. To make sure the entry contains
/// metadata you want, please use `list_with` or `lister_with` and `metakey`.
///
/// For example:
///
/// ```no_run
/// # use anyhow::Result;
/// use opendal::EntryMode;
/// use opendal::Metakey;
/// use opendal::Operator;
/// # async fn test(op: Operator) -> Result<()> {
/// let mut entries = op
///     .list_with("dir/")
///     .metakey(Metakey::ContentLength | Metakey::LastModified)
///     .await?;
/// for entry in entries {
///     let meta = entry.metadata();
///     match meta.mode() {
///         EntryMode::FILE => {
///             println!(
///                 "Handling file {} with size {}",
///                 entry.path(),
///                 meta.content_length()
///             )
///         }
///         EntryMode::DIR => {
///             println!("Handling dir {}", entry.path())
///         }
///         EntryMode::Unknown => continue,
///     }
/// }
/// # Ok(())
/// # }
/// ```
#[derive(Clone, Debug)]
pub struct Entry {
    /// Path of this entry.
    path: String,

    /// Metadata of this entry.
    metadata: Metadata,
}

impl Entry {
    /// Create an entry with metadata.
    ///
    /// # Notes
    ///
    /// The only way to get an entry with associated cached metadata
    /// is `Operator::list`.
    pub(crate) fn new(path: String, metadata: Metadata) -> Self {
        Self { path, metadata }
    }

    /// Path of entry. Path is relative to operator's root.
    ///
    /// Only valid in current operator.
    ///
    /// If this entry is a dir, `path` MUST end with `/`
    /// Otherwise, `path` MUST NOT end with `/`.
    pub fn path(&self) -> &str {
        &self.path
    }

    /// Name of entry. Name is the last segment of path.
    ///
    /// If this entry is a dir, `name` MUST end with `/`
    /// Otherwise, `name` MUST NOT end with `/`.
    pub fn name(&self) -> &str {
        get_basename(&self.path)
    }

    /// Fetch metadata of this entry.
    ///
    /// # Notes
    ///
    /// Metadata only guaranteed to have results of `metakey` (which default to `Metakey::Mode`).
    ///
    /// - `Some(T)` means the metadata is valid.
    /// - `None` means the metadata is not provided by services.
    ///
    /// Visiting a metadata that not covered by `metakey` could result in panic.
    ///
    /// # Examples
    ///
    /// Please use `metakey` to specify the metadata you want, for example:
    ///
    /// ```no_run
    /// # use anyhow::Result;
    /// use opendal::EntryMode;
    /// use opendal::Metakey;
    /// use opendal::Operator;
    /// # async fn test(op: Operator) -> Result<()> {
    /// let mut entries = op
    ///     .list_with("dir/")
    ///     .metakey(Metakey::ContentLength | Metakey::LastModified)
    ///     .await?;
    /// for entry in entries {
    ///     let meta = entry.metadata();
    ///     match meta.mode() {
    ///         EntryMode::FILE => {
    ///             println!(
    ///                 "Handling file {} with size {}",
    ///                 entry.path(),
    ///                 meta.content_length()
    ///             )
    ///         }
    ///         EntryMode::DIR => {
    ///             println!("Handling dir {}", entry.path())
    ///         }
    ///         EntryMode::Unknown => continue,
    ///     }
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub fn metadata(&self) -> &Metadata {
        &self.metadata
    }

    /// Consume this entry to get it's path and metadata.
    ///
    /// # Notes
    ///
    /// Metadata only guaranteed to have results of `metakey` (which default to `Metakey::Mode`).
    ///
    /// - `Some(T)` means the metadata is valid.
    /// - `None` means the metadata is not provided by services.
    ///
    /// Visiting a metadata that not covered by `metakey` could result in panic.
    ///
    /// # Examples
    ///
    /// Please use `metakey` to specify the metadata you want, for example:
    ///
    /// ```no_run
    /// # use anyhow::Result;
    /// use opendal::EntryMode;
    /// use opendal::Metakey;
    /// use opendal::Operator;
    /// # async fn test(op: Operator) -> Result<()> {
    /// let mut entries = op
    ///     .list_with("dir/")
    ///     .metakey(Metakey::ContentLength | Metakey::LastModified)
    ///     .await?;
    /// for entry in entries {
    ///     let (path, meta) = entry.into_parts();
    ///     match meta.mode() {
    ///         EntryMode::FILE => {
    ///             println!("Handling file {} with size {}", path, meta.content_length())
    ///         }
    ///         EntryMode::DIR => {
    ///             println!("Handling dir {}", path)
    ///         }
    ///         EntryMode::Unknown => continue,
    ///     }
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub fn into_parts(self) -> (String, Metadata) {
        (self.path, self.metadata)
    }
}