// status.rs

//

// Copyright 2020, Georges Racinet <georges.racinets@octobus.net>

//

// This software may be used and distributed according to the terms of the

// GNU General Public License version 2 or any later version.

use crate::error::CommandError;

use crate::ui::Ui;

use clap::{Arg, SubCommand};

use hg;

use hg::errors::IoResultExt;

use hg::matchers::AlwaysMatcher;

use hg::operations::cat;

use hg::repo::Repo;

use hg::revlog::node::Node;

use hg::utils::hg_path::{hg_path_to_os_string, HgPath};

use hg::{DirstateMap, StatusError};

use hg::{HgPathCow, StatusOptions};

use log::{info, warn};

use std::convert::TryInto;

use std::fs;

use std::io::BufReader;

use std::io::Read;

pub const HELP_TEXT: &str = "

Show changed files in the working directory

This is a pure Rust version of `hg status`.

Some options might be missing, check the list below.

";

pub fn args() -> clap::App<'static, 'static> {

    SubCommand::with_name("status")

        .alias("st")

        .about(HELP_TEXT)

        .arg(

            Arg::with_name("all")

                .help("show status of all files")

                .short("-A")

                .long("--all"),

        )

        .arg(

            Arg::with_name("modified")

                .help("show only modified files")

                .short("-m")

                .long("--modified"),

        )

        .arg(

            Arg::with_name("added")

                .help("show only added files")

                .short("-a")

                .long("--added"),

        )

        .arg(

            Arg::with_name("removed")

                .help("show only removed files")

                .short("-r")

                .long("--removed"),

        )

        .arg(

            Arg::with_name("clean")

                .help("show only clean files")

                .short("-c")

                .long("--clean"),

        )

        .arg(

            Arg::with_name("deleted")

                .help("show only deleted files")

                .short("-d")

                .long("--deleted"),

        )

        .arg(

            Arg::with_name("unknown")

                .help("show only unknown (not tracked) files")

                .short("-u")

                .long("--unknown"),

        )

        .arg(

            Arg::with_name("ignored")

                .help("show only ignored files")

                .short("-i")

                .long("--ignored"),

        )

}

/// Pure data type allowing the caller to specify file states to display

#[derive(Copy, Clone, Debug)]

pub struct DisplayStates {

    pub modified: bool,

    pub added: bool,

    pub removed: bool,

    pub clean: bool,

    pub deleted: bool,

    pub unknown: bool,

    pub ignored: bool,

}

pub const DEFAULT_DISPLAY_STATES: DisplayStates = DisplayStates {

    modified: true,

    added: true,

    removed: true,

    clean: false,

    deleted: true,

    unknown: true,

    ignored: false,

};

pub const ALL_DISPLAY_STATES: DisplayStates = DisplayStates {

    modified: true,

    added: true,

    removed: true,

    clean: true,

    deleted: true,

    unknown: true,

    ignored: true,

};

impl DisplayStates {

    pub fn is_empty(&self) -> bool {

        !(self.modified

            || self.added

            || self.removed

            || self.clean

            || self.deleted

            || self.unknown

            || self.ignored)

    }

}

pub fn run(invocation: &crate::CliInvocation) -> Result<(), CommandError> {

    let status_enabled_default = false;

    let status_enabled = invocation.config.get_option(b"rhg", b"status")?;

    if !status_enabled.unwrap_or(status_enabled_default) {

        return Err(CommandError::unsupported(

            "status is experimental in rhg (enable it with 'rhg.status = true' \

            or enable fallback with 'rhg.on-unsupported = fallback')"

        ));

    }

    let ui = invocation.ui;

    let args = invocation.subcommand_args;

    let display_states = if args.is_present("all") {

        // TODO when implementing `--quiet`: it excludes clean files

        // from `--all`

        ALL_DISPLAY_STATES

    } else {

        let requested = DisplayStates {

            modified: args.is_present("modified"),

            added: args.is_present("added"),

            removed: args.is_present("removed"),

            clean: args.is_present("clean"),

            deleted: args.is_present("deleted"),

            unknown: args.is_present("unknown"),

            ignored: args.is_present("ignored"),

        };

        if requested.is_empty() {

            DEFAULT_DISPLAY_STATES

        } else {

            requested

        }

    };

    let repo = invocation.repo?;

    let mut dmap = DirstateMap::new();

    let dirstate_data = repo.hg_vfs().mmap_open("dirstate")?;

    let parents = dmap.read(&dirstate_data)?;

    let options = StatusOptions {

        // TODO should be provided by the dirstate parsing and

        // hence be stored on dmap. Using a value that assumes we aren't

        // below the time resolution granularity of the FS and the

        // dirstate.

        last_normal_time: 0,

        // we're currently supporting file systems with exec flags only

        // anyway

        check_exec: true,

        list_clean: display_states.clean,

        list_unknown: display_states.unknown,

        list_ignored: display_states.ignored,

        collect_traversed_dirs: false,

    };

    let ignore_file = repo.working_directory_vfs().join(".hgignore"); // TODO hardcoded

    let ((lookup, ds_status), pattern_warnings) = hg::status(

        &dmap,

        &AlwaysMatcher,

        repo.working_directory_path().to_owned(),

        vec![ignore_file],

        options,

    )?;

    if !pattern_warnings.is_empty() {

        warn!("Pattern warnings: {:?}", &pattern_warnings);

    }

    if !ds_status.bad.is_empty() {

        warn!("Bad matches {:?}", &(ds_status.bad))

    }

    if !lookup.is_empty() {

        info!(

            "Files to be rechecked by retrieval from filelog: {:?}",

            &lookup

        );

    }

    // TODO check ordering to match `hg status` output.

    // (this is as in `hg help status`)

    if display_states.modified {

        display_status_paths(ui, &(ds_status.modified), b"M")?;

    }

    if !lookup.is_empty() {

        let p1: Node = parents

            .expect(

                "Dirstate with no parents should not list any file to

                 be rechecked for modifications",

            )

            .p1

            .into();

        let p1_hex = format!("{:x}", p1);

        let mut rechecked_modified: Vec<HgPathCow> = Vec::new();

        let mut rechecked_clean: Vec<HgPathCow> = Vec::new();

        for to_check in lookup {

            if cat_file_is_modified(repo, &to_check, &p1_hex)? {

                rechecked_modified.push(to_check);

            } else {

                rechecked_clean.push(to_check);

            }

        }

        if display_states.modified {

            display_status_paths(ui, &rechecked_modified, b"M")?;

        }

        if display_states.clean {

            display_status_paths(ui, &rechecked_clean, b"C")?;

        }

    }

    if display_states.added {

        display_status_paths(ui, &(ds_status.added), b"A")?;

    }

    if display_states.clean {

        display_status_paths(ui, &(ds_status.clean), b"C")?;

    }

    if display_states.removed {

        display_status_paths(ui, &(ds_status.removed), b"R")?;

    }

    if display_states.deleted {

        display_status_paths(ui, &(ds_status.deleted), b"!")?;

    }

    if display_states.unknown {

        display_status_paths(ui, &(ds_status.unknown), b"?")?;

    }

    if display_states.ignored {

        display_status_paths(ui, &(ds_status.ignored), b"I")?;

    }

    Ok(())

}

// Probably more elegant to use a Deref or Borrow trait rather than

// harcode HgPathBuf, but probably not really useful at this point

fn display_status_paths(

    ui: &Ui,

    paths: &[HgPathCow],

    status_prefix: &[u8],

) -> Result<(), CommandError> {

    for path in paths {

        // Same TODO as in commands::root

        let bytes: &[u8] = path.as_bytes();

        // TODO optim, probably lots of unneeded copies here, especially

        // if out stream is buffered

        ui.write_stdout(&[status_prefix, b" ", bytes, b"\n"].concat())?;

    }

    Ok(())

}

/// Check if a file is modified by comparing actual repo store and file system.

///

/// This meant to be used for those that the dirstate cannot resolve, due

/// to time resolution limits.

///

/// TODO: detect permission bits and similar metadata modifications

fn cat_file_is_modified(

    repo: &Repo,

    hg_path: &HgPath,

    rev: &str,

) -> Result<bool, CommandError> {

    // TODO CatRev expects &[HgPathBuf], something like

    // &[impl Deref<HgPath>] would be nicer and should avoid the copy

    let path_bufs = [hg_path.into()];

    // TODO IIUC CatRev returns a simple Vec<u8> for all files

    //      being able to tell them apart as (path, bytes) would be nicer

    //      and OPTIM would allow manifest resolution just once.

    let output = cat(repo, rev, &path_bufs).map_err(|e| (e, rev))?;

    let fs_path = repo

        .working_directory_vfs()

        .join(hg_path_to_os_string(hg_path).expect("HgPath conversion"));

    let hg_data_len: u64 = match output.concatenated.len().try_into() {

        Ok(v) => v,

        Err(_) => {

            // conversion of data length to u64 failed,

            // good luck for any file to have this content

            return Ok(true);

        }

    };

    let fobj = fs::File::open(&fs_path).when_reading_file(&fs_path)?;

    if fobj.metadata().map_err(|e| StatusError::from(e))?.len() != hg_data_len

    {

        return Ok(true);

    }

    for (fs_byte, hg_byte) in

        BufReader::new(fobj).bytes().zip(output.concatenated)

    {

        if fs_byte.map_err(|e| StatusError::from(e))? != hg_byte {

            return Ok(true);

        }

    }

    Ok(false)

}