use std::cmp::max;
use std::ops::Deref;
#[cfg(unix)]
use std::sync::{Mutex, MutexGuard};

use chrono::prelude::*;

use log::*;
use once_cell::sync::Lazy;
#[cfg(unix)]
use uzers::UsersCache;

use crate::fs::feature::git::GitCache;
use crate::fs::{fields as f, File};
use crate::options::vars::EZA_WINDOWS_ATTRIBUTES;
use crate::options::Vars;
use crate::output::cell::TextCell;
use crate::output::color_scale::ColorScaleInformation;
#[cfg(unix)]
use crate::output::render::{GroupRender, OctalPermissionsRender, UserRender};
use crate::output::render::{PermissionsPlusRender, TimeRender};
use crate::output::time::TimeFormat;
use crate::theme::Theme;

use super::color_scale::ColorScaleMode;

/// Options for displaying a table.
#[derive(PartialEq, Eq, Debug)]
pub struct Options {
    pub size_format: SizeFormat,
    pub time_format: TimeFormat,
    pub user_format: UserFormat,
    pub group_format: GroupFormat,
    pub flags_format: FlagsFormat,
    pub columns: Columns,
}

/// Extra columns to display in the table.
#[allow(clippy::struct_excessive_bools)]
#[derive(PartialEq, Eq, Debug, Copy, Clone)]
pub struct Columns {
    /// At least one of these timestamps will be shown.
    pub time_types: TimeTypes,

    // The rest are just on/off
    pub inode: bool,
    pub links: bool,
    pub blocksize: bool,
    pub group: bool,
    pub git: bool,
    pub subdir_git_repos: bool,
    pub subdir_git_repos_no_stat: bool,
    pub octal: bool,
    pub security_context: bool,
    pub file_flags: bool,

    // Defaults to true:
    pub permissions: bool,
    pub filesize: bool,
    pub user: bool,
}

impl Columns {
    pub fn collect(&self, actually_enable_git: bool, git_repos: bool) -> Vec<Column> {
        let mut columns = Vec::with_capacity(4);

        if self.inode {
            #[cfg(unix)]
            columns.push(Column::Inode);
        }

        if self.octal {
            #[cfg(unix)]
            columns.push(Column::Octal);
        }

        if self.permissions {
            columns.push(Column::Permissions);
        }

        if self.links {
            #[cfg(unix)]
            columns.push(Column::HardLinks);
        }

        if self.filesize {
            columns.push(Column::FileSize);
        }

        if self.blocksize {
            #[cfg(unix)]
            columns.push(Column::Blocksize);
        }

        if self.user {
            #[cfg(unix)]
            columns.push(Column::User);
        }

        if self.group {
            #[cfg(unix)]
            columns.push(Column::Group);
        }

        if self.file_flags {
            columns.push(Column::FileFlags);
        }

        #[cfg(target_os = "linux")]
        if self.security_context {
            columns.push(Column::SecurityContext);
        }

        if self.time_types.modified {
            columns.push(Column::Timestamp(TimeType::Modified));
        }

        if self.time_types.changed {
            columns.push(Column::Timestamp(TimeType::Changed));
        }

        if self.time_types.created {
            columns.push(Column::Timestamp(TimeType::Created));
        }

        if self.time_types.accessed {
            columns.push(Column::Timestamp(TimeType::Accessed));
        }

        if self.git && actually_enable_git {
            columns.push(Column::GitStatus);
        }

        if self.subdir_git_repos && git_repos {
            columns.push(Column::SubdirGitRepo(true));
        }

        if self.subdir_git_repos_no_stat && git_repos {
            columns.push(Column::SubdirGitRepo(false));
        }

        columns
    }
}

/// A table contains these.
#[derive(Debug, Copy, Clone)]
pub enum Column {
    Permissions,
    FileSize,
    Timestamp(TimeType),
    #[cfg(unix)]
    Blocksize,
    #[cfg(unix)]
    User,
    #[cfg(unix)]
    Group,
    #[cfg(unix)]
    HardLinks,
    #[cfg(unix)]
    Inode,
    GitStatus,
    SubdirGitRepo(bool),
    #[cfg(unix)]
    Octal,
    #[cfg(unix)]
    SecurityContext,
    FileFlags,
}

/// Each column can pick its own **Alignment**. Usually, numbers are
/// right-aligned, and text is left-aligned.
#[derive(Copy, Clone)]
pub enum Alignment {
    Left,
    Right,
}

impl Column {
    /// Get the alignment this column should use.
    #[cfg(unix)]
    pub fn alignment(self) -> Alignment {
        #[allow(clippy::wildcard_in_or_patterns)]
        match self {
            Self::FileSize | Self::HardLinks | Self::Inode | Self::Blocksize | Self::GitStatus => {
                Alignment::Right
            }
            Self::Timestamp(_) | _ => Alignment::Left,
        }
    }

    #[cfg(windows)]
    pub fn alignment(self) -> Alignment {
        match self {
            Self::FileSize | Self::GitStatus => Alignment::Right,
            _ => Alignment::Left,
        }
    }

    /// Get the text that should be printed at the top, when the user elects
    /// to have a header row printed.
    pub fn header(self) -> &'static str {
        match self {
            #[cfg(unix)]
            Self::Permissions => "Permissions",
            #[cfg(windows)]
            Self::Permissions => "Mode",
            Self::FileSize => "Size",
            Self::Timestamp(t) => t.header(),
            #[cfg(unix)]
            Self::Blocksize => "Blocksize",
            #[cfg(unix)]
            Self::User => "User",
            #[cfg(unix)]
            Self::Group => "Group",
            #[cfg(unix)]
            Self::HardLinks => "Links",
            #[cfg(unix)]
            Self::Inode => "inode",
            Self::GitStatus => "Git",
            Self::SubdirGitRepo(_) => "Repo",
            #[cfg(unix)]
            Self::Octal => "Octal",
            #[cfg(unix)]
            Self::SecurityContext => "Security Context",
            Self::FileFlags => "Flags",
        }
    }
}

/// Formatting options for file sizes.
#[allow(clippy::enum_variant_names)]
#[derive(PartialEq, Eq, Debug, Default, Copy, Clone)]
pub enum SizeFormat {
    /// Format the file size using **decimal** prefixes, such as “kilo”,
    /// “mega”, or “giga”.
    #[default]
    DecimalBytes,

    /// Format the file size using **binary** prefixes, such as “kibi”,
    /// “mebi”, or “gibi”.
    BinaryBytes,

    /// Do no formatting and just display the size as a number of bytes.
    JustBytes,
}

/// Formatting options for user and group.
#[derive(PartialEq, Eq, Debug, Copy, Clone)]
pub enum UserFormat {
    /// The UID / GID
    Numeric,
    /// Show the name
    Name,
}

/// Formatting options for group only.
#[derive(PartialEq, Eq, Debug, Copy, Clone)]
pub enum GroupFormat {
    /// Numeric or text value
    Regular,
    /// Show ":" if user-group value is the same
    Smart,
}

/// The types of a file’s time fields. These three fields are standard
/// across most (all?) operating systems.
#[derive(PartialEq, Eq, Debug, Copy, Clone)]
pub enum TimeType {
    /// The file’s modified time (`st_mtime`).
    Modified,

    /// The file’s changed time (`st_ctime`)
    Changed,

    /// The file’s accessed time (`st_atime`).
    Accessed,

    /// The file’s creation time (`btime` or `birthtime`).
    Created,
}

impl TimeType {
    /// Returns the text to use for a column’s heading in the columns output.
    pub fn header(self) -> &'static str {
        match self {
            Self::Modified => "Date Modified",
            Self::Changed => "Date Changed",
            Self::Accessed => "Date Accessed",
            Self::Created => "Date Created",
        }
    }

    /// Returns the corresponding time from [File]
    pub fn get_corresponding_time(self, file: &File<'_>) -> Option<NaiveDateTime> {
        match self {
            TimeType::Modified => file.modified_time(),
            TimeType::Changed => file.changed_time(),
            TimeType::Accessed => file.accessed_time(),
            TimeType::Created => file.created_time(),
        }
    }
}

/// How display file flags.
#[derive(PartialEq, Eq, Debug, Default, Copy, Clone)]
pub enum FlagsFormat {
    /// Display flags as comma seperated descriptions
    #[default]
    Long,
    /// Display flags as single character abbreviations (Windows only)
    Short,
}

impl FlagsFormat {
    pub(crate) fn deduce<V: Vars>(vars: &V) -> FlagsFormat {
        vars.get(EZA_WINDOWS_ATTRIBUTES)
            .and_then(|v| match v.to_ascii_lowercase().to_str() {
                Some("short") => Some(FlagsFormat::Short),
                Some("long") => Some(FlagsFormat::Long),
                _ => None,
            })
            .unwrap_or_default()
    }
}

/// Fields for which of a file’s time fields should be displayed in the
/// columns output.
///
/// There should always be at least one of these — there’s no way to disable
/// the time columns entirely (yet).
#[derive(PartialEq, Eq, Debug, Copy, Clone)]
#[rustfmt::skip]
#[allow(clippy::struct_excessive_bools)]
pub struct TimeTypes {
    pub modified: bool,
    pub changed:  bool,
    pub accessed: bool,
    pub created:  bool,
}

impl Default for TimeTypes {
    /// By default, display just the ‘modified’ time. This is the most
    /// common option, which is why it has this shorthand.
    fn default() -> Self {
        Self {
            modified: true,
            changed: false,
            accessed: false,
            created: false,
        }
    }
}

/// The **environment** struct contains any data that could change between
/// running instances of exa, depending on the user’s computer’s configuration.
///
/// Any environment field should be able to be mocked up for test runs.
pub struct Environment {
    /// The computer’s current time offset, determined from time zone.
    time_offset: FixedOffset,

    /// Localisation rules for formatting numbers.
    numeric: locale::Numeric,

    /// Mapping cache of user IDs to usernames.
    #[cfg(unix)]
    users: Mutex<UsersCache>,
}

impl Environment {
    #[cfg(unix)]
    pub fn lock_users(&self) -> MutexGuard<'_, UsersCache> {
        self.users.lock().unwrap()
    }

    fn load_all() -> Self {
        let time_offset = *Local::now().offset();

        let numeric =
            locale::Numeric::load_user_locale().unwrap_or_else(|_| locale::Numeric::english());

        #[cfg(unix)]
        let users = Mutex::new(UsersCache::new());

        Self {
            time_offset,
            numeric,
            #[cfg(unix)]
            users,
        }
    }
}

static ENVIRONMENT: Lazy<Environment> = Lazy::new(Environment::load_all);

pub struct Table<'a> {
    columns: Vec<Column>,
    theme: &'a Theme,
    env: &'a Environment,
    widths: TableWidths,
    time_format: TimeFormat,
    size_format: SizeFormat,
    #[cfg(unix)]
    user_format: UserFormat,
    #[cfg(unix)]
    group_format: GroupFormat,
    flags_format: FlagsFormat,
    git: Option<&'a GitCache>,
}

#[derive(Clone)]
pub struct Row {
    cells: Vec<TextCell>,
}

impl<'a> Table<'a> {
    pub fn new(
        options: &'a Options,
        git: Option<&'a GitCache>,
        theme: &'a Theme,
        git_repos: bool,
    ) -> Table<'a> {
        let columns = options.columns.collect(git.is_some(), git_repos);
        let widths = TableWidths::zero(columns.len());
        let env = &*ENVIRONMENT;

        debug!("Creating table with columns: {:?}", columns);

        Table {
            theme,
            widths,
            columns,
            git,
            env,
            time_format: options.time_format.clone(),
            size_format: options.size_format,
            #[cfg(unix)]
            user_format: options.user_format,
            #[cfg(unix)]
            group_format: options.group_format,
            flags_format: options.flags_format,
        }
    }

    pub fn widths(&self) -> &TableWidths {
        &self.widths
    }

    pub fn header_row(&self) -> Row {
        let cells = self
            .columns
            .iter()
            .map(|c| TextCell::paint_str(self.theme.ui.header.unwrap_or_default(), c.header()))
            .collect();

        Row { cells }
    }

    pub fn row_for_file(
        &self,
        file: &File<'_>,
        xattrs: bool,
        color_scale_info: Option<ColorScaleInformation>,
    ) -> Row {
        let cells = self
            .columns
            .iter()
            .map(|c| self.display(file, *c, xattrs, color_scale_info))
            .collect();

        Row { cells }
    }

    pub fn add_widths(&mut self, row: &Row) {
        self.widths.add_widths(row);
    }

    #[cfg(unix)]
    fn permissions_plus(&self, file: &File<'_>, xattrs: bool) -> Option<f::PermissionsPlus> {
        file.permissions().map(|p| f::PermissionsPlus {
            file_type: file.type_char(),
            permissions: p,
            xattrs,
        })
    }

    #[allow(clippy::unnecessary_wraps)] // Needs to match Unix function
    #[cfg(windows)]
    fn permissions_plus(&self, file: &File<'_>, xattrs: bool) -> Option<f::PermissionsPlus> {
        Some(f::PermissionsPlus {
            file_type: file.type_char(),
            #[cfg(windows)]
            attributes: file.attributes(),
            xattrs,
        })
    }

    #[cfg(unix)]
    fn octal_permissions(&self, file: &File<'_>) -> Option<f::OctalPermissions> {
        file.permissions()
            .map(|p| f::OctalPermissions { permissions: p })
    }

    fn display(
        &self,
        file: &File<'_>,
        column: Column,
        xattrs: bool,
        color_scale_info: Option<ColorScaleInformation>,
    ) -> TextCell {
        match column {
            Column::Permissions => self.permissions_plus(file, xattrs).render(self.theme),
            Column::FileSize => file.size().render(
                self.theme,
                self.size_format,
                &self.env.numeric,
                color_scale_info,
            ),
            #[cfg(unix)]
            Column::HardLinks => file.links().render(self.theme, &self.env.numeric),
            #[cfg(unix)]
            Column::Inode => file.inode().render(self.theme.ui.inode.unwrap_or_default()),
            #[cfg(unix)]
            Column::Blocksize => {
                file.blocksize()
                    .render(self.theme, self.size_format, &self.env.numeric)
            }
            #[cfg(unix)]
            Column::User => {
                file.user()
                    .render(self.theme, &*self.env.lock_users(), self.user_format)
            }
            #[cfg(unix)]
            Column::Group => file.group().render(
                self.theme,
                &*self.env.lock_users(),
                self.user_format,
                self.group_format,
                file.user(),
            ),
            #[cfg(unix)]
            Column::SecurityContext => file.security_context().render(self.theme),
            Column::FileFlags => file
                .flags()
                .render(self.theme.ui.flags.unwrap_or_default(), self.flags_format),
            Column::GitStatus => self.git_status(file).render(self.theme),
            Column::SubdirGitRepo(status) => self.subdir_git_repo(file, status).render(self.theme),
            #[cfg(unix)]
            Column::Octal => self
                .octal_permissions(file)
                .render(self.theme.ui.octal.unwrap_or_default()),

            Column::Timestamp(time_type) => time_type.get_corresponding_time(file).render(
                if color_scale_info.is_some_and(|csi| csi.options.mode == ColorScaleMode::Gradient)
                {
                    color_scale_info.unwrap().apply_time_gradient(
                        self.theme.ui.date.unwrap_or_default(),
                        file,
                        time_type,
                    )
                } else {
                    self.theme.ui.date.unwrap_or_default()
                },
                self.env.time_offset,
                self.time_format.clone(),
            ),
        }
    }

    fn git_status(&self, file: &File<'_>) -> f::Git {
        debug!("Getting Git status for file {:?}", file.path);

        self.git
            .map(|g| g.get(&file.path, file.is_directory()))
            .unwrap_or_default()
    }

    fn subdir_git_repo(&self, file: &File<'_>, status: bool) -> f::SubdirGitRepo {
        debug!("Getting subdir repo status for path {:?}", file.path);

        if file.is_directory() {
            return f::SubdirGitRepo::from_path(&file.path, status);
        }
        f::SubdirGitRepo::default()
    }

    pub fn render(&self, row: Row) -> TextCell {
        let mut cell = TextCell::default();

        let iter = row.cells.into_iter().zip(self.widths.iter()).enumerate();

        for (n, (this_cell, width)) in iter {
            let padding = width - *this_cell.width;

            match self.columns[n].alignment() {
                Alignment::Left => {
                    cell.append(this_cell);
                    cell.add_spaces(padding);
                }
                Alignment::Right => {
                    cell.add_spaces(padding);
                    cell.append(this_cell);
                }
            }

            cell.add_spaces(1);
        }

        cell
    }
}

pub struct TableWidths(Vec<usize>);

impl Deref for TableWidths {
    type Target = [usize];

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl TableWidths {
    pub fn zero(count: usize) -> Self {
        Self(vec![0; count])
    }

    pub fn add_widths(&mut self, row: &Row) {
        for (old_width, cell) in self.0.iter_mut().zip(row.cells.iter()) {
            *old_width = max(*old_width, *cell.width);
        }
    }

    pub fn total(&self) -> usize {
        self.0.len() + self.0.iter().sum::<usize>()
    }
}
