use std::path::PathBuf;

use crate::dirstate::parsers::Timestamp;
use crate::dirstate::CopyMapIter;
use crate::dirstate::StateMapIter;
use crate::dirstate_tree::on_disk::DirstateV2ParseError;
use crate::matchers::Matcher;
use crate::utils::hg_path::{HgPath, HgPathBuf};
use crate::DirstateEntry;
use crate::DirstateError;
use crate::DirstateParents;
use crate::DirstateStatus;
use crate::PatternFileWarning;
use crate::StatusError;
use crate::StatusOptions;

/// `rust/hg-cpython/src/dirstate/dirstate_map.rs` implements in Rust a
/// `DirstateMap` Python class that wraps `Box<dyn DirstateMapMethods + Send>`,
/// a trait object of this trait. Except for constructors, this trait defines
/// all APIs that the class needs to interact with its inner dirstate map.
///
/// A trait object is used to support two different concrete types:
///
/// * `rust/hg-core/src/dirstate/dirstate_map.rs` defines the "flat dirstate
///   map" which is based on a few large `HgPath`-keyed `HashMap` and `HashSet`
///   fields.
/// * `rust/hg-core/src/dirstate_tree/dirstate_map.rs` defines the "tree
///   dirstate map" based on a tree data struture with nodes for directories
///   containing child nodes for their files and sub-directories. This tree
///   enables a more efficient algorithm for `hg status`, but its details are
///   abstracted in this trait.
///
/// The dirstate map associates paths of files in the working directory to
/// various information about the state of those files.
pub trait DirstateMapMethods {
    /// Remove information about all files in this map
    fn clear(&mut self);

    /// Add the given filename to the map if it is not already there, and
    /// associate the given entry with it.
    fn set_entry(
        &mut self,
        filename: &HgPath,
        entry: DirstateEntry,
    ) -> Result<(), DirstateV2ParseError>;

    /// Add or change the information associated to a given file.
    fn add_file(
        &mut self,
        filename: &HgPath,
        entry: DirstateEntry,
    ) -> Result<(), DirstateError>;

    /// Mark a file as "removed" (as in `hg rm`).
    fn remove_file(
        &mut self,
        filename: &HgPath,
        in_merge: bool,
    ) -> Result<(), DirstateError>;

    /// Drop information about this file from the map if any.
    ///
    /// `get` will now return `None` for this filename.
    fn drop_entry_and_copy_source(
        &mut self,
        filename: &HgPath,
    ) -> Result<(), DirstateError>;

    /// Returns whether the sub-tree rooted at the given directory contains any
    /// tracked file.
    ///
    /// A file is tracked if it has a `state` other than `EntryState::Removed`.
    fn has_tracked_dir(
        &mut self,
        directory: &HgPath,
    ) -> Result<bool, DirstateError>;

    /// Returns whether the sub-tree rooted at the given directory contains any
    /// file with a dirstate entry.
    fn has_dir(&mut self, directory: &HgPath) -> Result<bool, DirstateError>;

    /// Clear mtimes equal to `now` in entries with `state ==
    /// EntryState::Normal`, and serialize bytes to write the `.hg/dirstate`
    /// file to disk in dirstate-v1 format.
    fn pack_v1(
        &mut self,
        parents: DirstateParents,
        now: Timestamp,
    ) -> Result<Vec<u8>, DirstateError>;

    /// Clear mtimes equal to `now` in entries with `state ==
    /// EntryState::Normal`, and serialize  bytes to write a dirstate data file
    /// to disk in dirstate-v2 format.
    ///
    /// Returns new data and metadata together with whether that data should be
    /// appended to the existing data file whose content is at
    /// `self.on_disk` (true), instead of written to a new data file
    /// (false).
    ///
    /// Note: this is only supported by the tree dirstate map.
    fn pack_v2(
        &mut self,
        now: Timestamp,
        can_append: bool,
    ) -> Result<(Vec<u8>, Vec<u8>, bool), DirstateError>;

    /// Run the status algorithm.
    ///
    /// This is not sematically a method of the dirstate map, but a different
    /// algorithm is used for the flat v.s. tree dirstate map so having it in
    /// this trait enables the same dynamic dispatch as with other methods.
    fn status<'a>(
        &'a mut self,
        matcher: &'a (dyn Matcher + Sync),
        root_dir: PathBuf,
        ignore_files: Vec<PathBuf>,
        options: StatusOptions,
    ) -> Result<(DirstateStatus<'a>, Vec<PatternFileWarning>), StatusError>;

    /// Returns how many files in the dirstate map have a recorded copy source.
    fn copy_map_len(&self) -> usize;

    /// Returns an iterator of `(path, copy_source)` for all files that have a
    /// copy source.
    fn copy_map_iter(&self) -> CopyMapIter<'_>;

    /// Returns whether the givef file has a copy source.
    fn copy_map_contains_key(
        &self,
        key: &HgPath,
    ) -> Result<bool, DirstateV2ParseError>;

    /// Returns the copy source for the given file.
    fn copy_map_get(
        &self,
        key: &HgPath,
    ) -> Result<Option<&HgPath>, DirstateV2ParseError>;

    /// Removes the recorded copy source if any for the given file, and returns
    /// it.
    fn copy_map_remove(
        &mut self,
        key: &HgPath,
    ) -> Result<Option<HgPathBuf>, DirstateV2ParseError>;

    /// Set the given `value` copy source for the given `key` file.
    fn copy_map_insert(
        &mut self,
        key: HgPathBuf,
        value: HgPathBuf,
    ) -> Result<Option<HgPathBuf>, DirstateV2ParseError>;

    /// Returns the number of files that have an entry.
    fn len(&self) -> usize;

    /// Returns whether the given file has an entry.
    fn contains_key(&self, key: &HgPath)
        -> Result<bool, DirstateV2ParseError>;

    /// Returns the entry, if any, for the given file.
    fn get(
        &self,
        key: &HgPath,
    ) -> Result<Option<DirstateEntry>, DirstateV2ParseError>;

    /// Returns a `(path, entry)` iterator of files that have an entry.
    ///
    /// Because parse errors can happen during iteration, the iterated items
    /// are `Result`s.
    fn iter(&self) -> StateMapIter<'_>;

    /// Returns an iterator of tracked directories.
    ///
    /// This is the paths for which `has_tracked_dir` would return true.
    /// Or, in other words, the union of ancestor paths of all paths that have
    /// an associated entry in a "tracked" state in this dirstate map.
    ///
    /// Because parse errors can happen during iteration, the iterated items
    /// are `Result`s.
    fn iter_tracked_dirs(
        &mut self,
    ) -> Result<
        Box<
            dyn Iterator<Item = Result<&HgPath, DirstateV2ParseError>>
                + Send
                + '_,
        >,
        DirstateError,
    >;

    /// Return an iterator of `(path, (state, mode, size, mtime))` for every
    /// node stored in this dirstate map, for the purpose of the `hg
    /// debugdirstate` command.
    ///
    /// If `all` is true, include  nodes that don’t have an entry.
    /// For such nodes `state` is the ASCII space.
    /// An `mtime` may still be present. It is used to optimize `status`.
    ///
    /// Because parse errors can happen during iteration, the iterated items
    /// are `Result`s.
    fn debug_iter(
        &self,
        all: bool,
    ) -> Box<
        dyn Iterator<
                Item = Result<
                    (&HgPath, (u8, i32, i32, i32)),
                    DirstateV2ParseError,
                >,
            > + Send
            + '_,
    >;
}