//! Consumer friendly representation of Zpool's properties.

use std::{ffi::OsString, path::PathBuf};

use super::{ZpoolError, ZpoolResult};
use crate::utils::parse_float;

/// Implement this for your custom properties.
pub trait PropPair {
    /// Convert `&self` to `{key}={value}` string.
    fn to_pair(&self, key: &str) -> String;
}

impl PropPair for FailMode {
    fn to_pair(&self, key: &str) -> String {
        format!("{}={}", key, self.as_str())
    }
}

impl PropPair for bool {
    fn to_pair(&self, key: &str) -> String {
        let val = if *self { "on" } else { "off" };
        format!("{}={}", key, val)
    }
}

impl PropPair for CacheType {
    fn to_pair(&self, key: &str) -> String {
        format!("{}={}", key, self.as_str())
    }
}

impl PropPair for String {
    fn to_pair(&self, key: &str) -> String {
        format!("{}={}", key, &self)
    }
}

/// Represent state of zpool or vdev. Read
/// [more](https://docs.oracle.com/cd/E19253-01/819-5461/gamno/index.html).
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum Health {
    /// Healthy and operational.
    Online,
    /// Unhealthy, but operational.
    Degraded,
    /// Not operational.
    Faulted,
    /// Taken offline by admin.
    Offline,
    /// Spare is ready to take over failed device.
    Available,
    /// Can't open device.
    Unavailable,
    /// Physically removed while the system was running.
    Removed,
    /// Spare has taken over for failed device.
    Inuse,
}

impl Health {
    /// parse str to Health.
    #[doc(hidden)]
    pub fn try_from_str(val: Option<&str>) -> ZpoolResult<Health> {
        let val_str = val.ok_or(ZpoolError::ParseError)?;
        match val_str {
            "ONLINE" => Ok(Health::Online),
            "DEGRADED" => Ok(Health::Degraded),
            "FAULTED" => Ok(Health::Faulted),
            "OFFLINE" => Ok(Health::Offline),
            "AVAIL" => Ok(Health::Available),
            "UNAVAIL" => Ok(Health::Unavailable),
            "REMOVED" => Ok(Health::Removed),
            "INUSE" => Ok(Health::Inuse),
            _ => Err(ZpoolError::ParseError),
        }
    }
}

/// Controls the system behavior in the event of catastrophic pool failure.
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum FailMode {
    /// Blocks all I/O access until the device connectivity is recovered and
    /// the errors are
    /// cleared.  This is the default behavior.
    Wait,
    /// Returns EIO to any new write I/O requests but allows reads to any of
    /// the remaining healthy
    /// devices. Any write requests that have yet to be committed to disk would
    /// be blocked.
    Continue,
    /// Prints out a message to the console and generates a system
    /// crash dump.
    Panic,
}
impl FailMode {
    /// parse str to FailMode.
    #[doc(hidden)]
    pub fn try_from_str(val: Option<&str>) -> ZpoolResult<FailMode> {
        let val_str = val.ok_or(ZpoolError::ParseError)?;
        match val_str {
            "wait" => Ok(FailMode::Wait),
            "continue" => Ok(FailMode::Continue),
            "panic" => Ok(FailMode::Panic),
            _ => Err(ZpoolError::ParseError),
        }
    }

    #[doc(hidden)]
    pub fn as_str(&self) -> &str {
        match *self {
            FailMode::Wait => "wait",
            FailMode::Continue => "continue",
            FailMode::Panic => "panic",
        }
    }
}

/// Where to store cache for zpool.
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum CacheType {
    /// Default location.
    Default,
    /// No cache.
    None,
    /// Custom location.
    Custom(String),
}

impl CacheType {
    /// parse str to CacheType.
    pub fn try_from_str(val: Option<&str>) -> ZpoolResult<CacheType> {
        let val_str = val.ok_or(ZpoolError::ParseError)?;
        match val_str {
            "-" | "" => Ok(CacheType::Default),
            "none" => Ok(CacheType::None),
            n => Ok(CacheType::Custom(String::from(n))),
        }
    }

    #[doc(hidden)]
    pub fn as_str(&self) -> &str {
        match *self {
            CacheType::Default => "",
            CacheType::None => "none",
            CacheType::Custom(ref e) => e,
        }
    }
}

/// Available properties for write at run time. This doesn't include properties
/// that are writable
/// only during creation/import of zpool. See `zpool(8)` for more information.
///
/// ```rust
/// use libzetta::zpool::{CacheType, ZpoolPropertiesWriteBuilder};
///
/// let props = ZpoolPropertiesWriteBuilder::default().build().unwrap();
///
/// assert!(!props.auto_expand());
/// assert!(props.boot_fs().is_none());
/// assert_eq!(props.cache_file(), &CacheType::Default);
///
/// let props = ZpoolPropertiesWriteBuilder::default().build();
/// assert!(props.is_ok());
/// ```
#[derive(Getters, Builder, Debug, Clone, PartialEq, Eq)]
#[get = "pub"]
pub struct ZpoolPropertiesWrite {
    /// Make zpool readonly. This can only be changed during import.
    #[builder(default = "false")]
    read_only: bool,
    /// Controls automatic pool expansion when the underlying LUN is grown.
    #[builder(default = "false")]
    auto_expand: bool,

    /// Controls automatic device replacement. If set to "on", any new device,
    /// found in the
    /// same physical location as a device that previously belonged to the
    /// pool, is automatically
    /// formatted and replaced. The default behavior is "off".
    #[builder(default = "false")]
    auto_replace: bool,

    ///  Identifies the default bootable dataset for the root pool.
    #[builder(default)]
    boot_fs: Option<String>,

    /// Controls the location of where the pool configuration is cached.
    #[builder(default = "CacheType::Default")]
    cache_file: CacheType,

    /// An administrator can provide additional information about a pool using
    /// this property.
    #[builder(default)]
    #[builder(setter(into))]
    comment: String,
    /// Controls whether a non-privileged user is granted access based on the
    /// dataset permissions defined on the dataset. See zfs(8) for more
    /// information on ZFS delegated administration.
    #[builder(default = "false")]
    delegation: bool,
    /// Controls the system behavior in the event of catastrophic pool
    /// failure. This condition is typically a result of a loss of
    /// connectivity to the underlying storage device(s) or a failure of all
    /// devices within the pool.
    #[builder(default = "FailMode::Wait")]
    fail_mode: FailMode,
}

impl ZpoolPropertiesWrite {
    /// A preferred way to create this structure.
    pub fn builder() -> ZpoolPropertiesWriteBuilder {
        ZpoolPropertiesWriteBuilder::default()
    }

    #[doc(hidden)]
    pub fn into_args(self) -> Vec<OsString> {
        let mut ret = Vec::with_capacity(7);
        ret.push(PropPair::to_pair(&self.auto_expand, "autoexpand"));
        ret.push(PropPair::to_pair(&self.auto_replace, "autoreplace"));
        ret.push(PropPair::to_pair(&self.cache_file, "cachefile"));
        ret.push(PropPair::to_pair(&self.comment, "comment"));
        ret.push(PropPair::to_pair(&self.delegation, "delegation"));
        ret.push(PropPair::to_pair(&self.fail_mode, "failmode"));
        if let Some(ref btfs) = self.boot_fs {
            ret.push(PropPair::to_pair(btfs, "bootfs"));
        }
        ret.iter().map(OsString::from).collect()
    }
}

impl ZpoolPropertiesWriteBuilder {
    /// Construct new builder given existing properties. Useful for updates.
    pub fn from_props(props: &ZpoolProperties) -> ZpoolPropertiesWriteBuilder {
        let mut b = ZpoolPropertiesWriteBuilder::default();
        b.read_only(props.read_only);
        b.auto_expand(props.auto_expand);
        b.auto_replace(props.auto_replace);
        b.boot_fs(props.boot_fs.clone());
        b.cache_file(props.cache_file.clone());
        b.delegation(props.delegation);
        b.fail_mode(props.fail_mode.clone());
        if let Some(ref comment) = props.comment {
            b.comment(comment.clone());
        }
        b
    }
}

/// All pre-defined properties of Zpool - both immutable and mutable. Majority of this documentation
/// lifted from manual page.
#[derive(Debug, Clone, PartialEq, Getters)]
#[get = "pub"]
pub struct ZpoolProperties {
    /// Amount of storage space within the pool that has been physically
    /// allocated.
    alloc: usize,
    /// Percentage of pool space used. Percentage.
    capacity: u8,
    /// A text string consisting of printable ASCII characters that will be
    /// stored such that it is
    /// available even if the pool becomes faulted. An administrator can
    /// provide additional information about a pool using this property.
    comment: Option<String>,
    /// The deduplication ratio specified for a pool, expressed as a
    /// multiplier.  For example,
    /// a dedupratio value of 1.76 indicates that 1.76 units of data were
    /// stored but only 1 unit
    /// of disk space was actually consumed. See `zfs(8)` for a description of
    /// the deduplication feature.
    dedup_ratio: f64,
    /// Amount of uninitialized space within the pool or device that
    /// can be used to increase the total capacity of the pool.
    /// Uninitialized space consists of any space on an EFI labeled
    /// vdev, which has not been brought online (i.e. zpool online
    /// -e).  This space occurs when a LUN is dynamically expanded.
    expand_size: Option<usize>,
    /// The amount of fragmentation in the pool. In percents.
    fragmentation: i8,
    /// Number of blocks within the pool that are not allocated.
    free: i64,
    ///  After a file system or snapshot is destroyed, the space it
    ///  was using is returned to the pool asynchronously.  freeing is
    /// the amount of space remaining to be reclaimed.  Over time
    /// freeing will decrease while free increases.
    freeing: i64,
    /// A unique identifier for the pool.
    guid: u64,
    /// The current health of the pool.
    health: Health,
    /// Total size of the storage pool.
    size: usize,
    /// Leaked space?
    leaked: usize,
    // writable
    /// Alternate root directory, can only be set during creation or import.
    alt_root: Option<PathBuf>,
    /// Pool is read only
    read_only: bool,
    /// Controls automatic pool expansion when the underlying LUN is grown.
    auto_expand: bool,
    /// Controls automatic device replacement. If set to "on", any new device,
    /// found in the
    /// same physical location as a device that previously belonged to the
    /// pool, is automatically
    /// formatted and replaced. The default behavior is "off".
    auto_replace: bool,
    ///  Identifies the default bootable dataset for the root pool.
    boot_fs: Option<String>,
    /// Controls the location of where the pool configuration is cached.
    cache_file: CacheType,
    /// Threshold for the number of block ditto copies. If the reference
    /// count for a deduplicated block increases above this number, a new
    /// ditto copy of this block is automatically stored. Default setting is
    /// 0 which causes no ditto copies to be created for deduplicated blocks.
    /// The minimum legal nonzero setting is 100.
    dedup_ditto: usize,
    /// Controls whether a non-privileged user is granted access based on the
    /// dataset permissions defined on the dataset. See `zfs(8)` for more
    /// information on ZFS delegated administration.
    delegation: bool,
    /// Controls the system behavior in the event of catastrophic pool
    /// failure. This condition is typically a result of a loss of
    /// connectivity to the underlying storage device(s) or a failure of all
    /// devices within the pool.
    fail_mode: FailMode,
}

fn parse_bool(val: Option<&str>) -> ZpoolResult<bool> {
    let val_str = val.ok_or(ZpoolError::ParseError)?;
    match val_str {
        "off" => Ok(false),
        "on" => Ok(true),
        _ => Err(ZpoolError::ParseError),
    }
}
fn parse_usize(val: Option<&str>) -> ZpoolResult<usize> {
    let val_str = val.ok_or(ZpoolError::ParseError)?;
    Ok(val_str.parse()?)
}
fn parse_i64(val: Option<&str>) -> ZpoolResult<i64> {
    let val_str = val.ok_or(ZpoolError::ParseError)?;
    Ok(val_str.parse()?)
}
fn parse_u64(val: Option<&str>) -> ZpoolResult<u64> {
    let val_str = val.ok_or(ZpoolError::ParseError)?;
    Ok(val_str.parse()?)
}
impl ZpoolProperties {
    pub(crate) fn try_from_stdout(out: &[u8]) -> ZpoolResult<ZpoolProperties> {
        let mut stdout: String = String::from_utf8_lossy(out).into();
        // remove new line at the end.
        stdout.pop();
        let mut cols = stdout.split('\t');

        let alloc = parse_usize(cols.next())?;

        let cap_str = cols.next().ok_or(ZpoolError::ParseError)?;
        let cap: u8 = cap_str.parse()?;

        let comment_str = cols.next().ok_or(ZpoolError::ParseError)?;
        let comment = match comment_str {
            "-" | "" => None,
            c => Some(String::from(c)),
        };

        let mut dedup_ratio_string = cols
            .next()
            .ok_or(ZpoolError::ParseError)
            .map(String::from)?;
        let dedup_ratio: f64 = parse_float(&mut dedup_ratio_string)?;

        let expand_size_str = cols.next().ok_or(ZpoolError::ParseError)?;
        let expand_size: Option<usize> = match expand_size_str {
            "-" => None,
            c => Some(c.parse()?),
        };

        // remove '%'
        let mut frag_string = cols
            .next()
            .ok_or(ZpoolError::ParseError)
            .map(String::from)?;
        let last_char = {
            let chars = frag_string.chars();
            chars.last()
        };
        if last_char == Some('%') {
            frag_string.pop();
        }
        let fragmentation: i8 = frag_string.parse()?;

        let free = parse_i64(cols.next())?;
        let freeing = parse_i64(cols.next())?;
        let guid = parse_u64(cols.next())?;
        let health = Health::try_from_str(cols.next())?;
        let size = parse_usize(cols.next())?;
        let leaked = parse_usize(cols.next())?;

        let alt_root_str = cols.next().ok_or(ZpoolError::ParseError)?;
        let alt_root = match alt_root_str {
            "-" => None,
            r => Some(PathBuf::from(r)),
        };

        let read_only = parse_bool(cols.next())?;
        let auto_expand = parse_bool(cols.next())?;
        let auto_replace = parse_bool(cols.next())?;

        let boot_fs_str = cols.next().ok_or(ZpoolError::ParseError)?;
        let boot_fs = match boot_fs_str {
            "-" => None,
            r => Some(String::from(r)),
        };
        let cache_file = CacheType::try_from_str(cols.next())?;
        let dedup_ditto = parse_usize(cols.next())?;
        let delegation = parse_bool(cols.next())?;
        let fail_mode = FailMode::try_from_str(cols.next())?;

        Ok(ZpoolProperties {
            alloc,
            capacity: cap,
            comment,
            dedup_ratio,
            expand_size,
            fragmentation,
            free,
            freeing,
            guid,
            health,
            size,
            leaked,
            alt_root,
            read_only,
            auto_expand,
            auto_replace,
            boot_fs,
            cache_file,
            dedup_ditto,
            delegation,
            fail_mode,
        })
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_defaults() {
        let built = ZpoolPropertiesWriteBuilder::default().build().unwrap();
        let handmade = ZpoolPropertiesWrite {
            read_only: false,
            auto_expand: false,
            auto_replace: false,
            boot_fs: None,
            cache_file: CacheType::Default,
            comment: String::new(),
            delegation: false,
            fail_mode: FailMode::Wait,
        };

        assert_eq!(handmade, built);
    }

    #[test]
    fn test_create_props() {
        let built = ZpoolPropertiesWriteBuilder::default()
            .boot_fs(Some("bootpool".into()))
            .build()
            .unwrap();
        let args = built.into_args();
        assert_eq!(7, args.len());
    }

    #[test]
    fn parsing_health() {
        let online = Some("ONLINE");
        let degraded = Some("DEGRADED");
        let faulted = Some("FAULTED");
        let offline = Some("OFFLINE");
        let unavailable = Some("UNAVAIL");
        let removed = Some("REMOVED");
        let bad = Some("wat");

        assert_eq!(Health::Online, Health::try_from_str(online).unwrap());
        assert_eq!(Health::Degraded, Health::try_from_str(degraded).unwrap());
        assert_eq!(Health::Faulted, Health::try_from_str(faulted).unwrap());
        assert_eq!(Health::Offline, Health::try_from_str(offline).unwrap());
        assert_eq!(
            Health::Unavailable,
            Health::try_from_str(unavailable).unwrap()
        );
        assert_eq!(Health::Removed, Health::try_from_str(removed).unwrap());

        let err = Health::try_from_str(bad);
        assert!(err.is_err());

        let err = Health::try_from_str(None);

        assert!(err.is_err());
    }

    #[test]
    fn parsing_fail_mode() {
        let wait = Some("wait");
        let cont = Some("continue");
        let panic = Some("panic");
        let bad = Some("wat");

        assert_eq!(FailMode::Wait, FailMode::try_from_str(wait).unwrap());
        assert_eq!(FailMode::Continue, FailMode::try_from_str(cont).unwrap());
        assert_eq!(FailMode::Panic, FailMode::try_from_str(panic).unwrap());

        let err = FailMode::try_from_str(bad);
        assert!(err.is_err());

        let err = FailMode::try_from_str(None);
        assert!(err.is_err());
    }

    #[test]
    fn parsing_cache_file() {
        assert_eq!(
            CacheType::Default,
            CacheType::try_from_str(Some("-")).unwrap()
        );
        assert_eq!(
            CacheType::Default,
            CacheType::try_from_str(Some("")).unwrap()
        );
        assert_eq!(
            CacheType::None,
            CacheType::try_from_str(Some("none")).unwrap()
        );
        assert_eq!(
            CacheType::Custom("/wat".into()),
            CacheType::try_from_str(Some("/wat")).unwrap()
        );

        let err = CacheType::try_from_str(None);
        assert!(err.is_err());
    }

    #[test]
    fn parsing_props_u64_guid() {
        let line = b"69120\t0\t-\t1.00x\t-\t1%\t67039744\t0\t15867762423891129245\tONLINE\t67108864\t0\t-\toff\toff\toff\t-\t-\t0\ton\twait\n";
        let props = ZpoolProperties::try_from_stdout(line);
        assert!(props.is_ok());
    }

    #[test]
    fn parsing_on_zol() {
        let line = b"99840\t0\t-\t1.00\t-\t1\t67009024\t0\t5667188105885376774\tONLINE\t67108864\t0\t-\toff\toff\toff\t-\t-\t0\ton\twait\n";
        let props = ZpoolProperties::try_from_stdout(line);
        assert!(props.is_ok());
    }

    #[test]
    fn parsing_props() {
        let line = b"69120\t0\t-\t1.50x\t-\t22%\t67039744\t0\t4957928072935098740\tONLINE\t67108864\t0\t-\toff\toff\toff\t-\t-\t0\ton\twait\n";
        let props = ZpoolProperties::try_from_stdout(line);
        assert!(props.is_ok());

        let line = b"69120\t0\ttouch it\t1.50x\t-\t22%\t67039744\t0\t4957928072935098740\tONLINE\t67108864\t0\t-\toff\toff\toff\t-\t-\t0\ton\tpanic\n";
        let props = ZpoolProperties::try_from_stdout(line).unwrap();
        assert_eq!(Some(String::from("touch it")), props.comment);
        assert_eq!(FailMode::Panic, props.fail_mode);

        let line = b"69120\t0\ttouch it\t1.50x\t-\t22%\t67039744\t0\t4957928072935098740\tOFFLINE\t67108864\t0\t/mnt/\toff\toff\toff\t-\t-\t0\ton\twait\n";
        let props = ZpoolProperties::try_from_stdout(line).unwrap();
        assert_eq!(Health::Offline, props.health);
        assert_eq!(Some(PathBuf::from("/mnt")), props.alt_root);

        let line = b"waf\tasd";
        let props = ZpoolProperties::try_from_stdout(line);
        assert!(props.is_err());

        let line = b"69120\t0\ttouch it\t1.50x\t1\t22%\t67039744\t0\t4957928072935098740\tOFFLINE\t67108864\t0\t/mnt/\toff\toff\toff\tz/ROOT/default\t-\t0\ton\twait\n";
        let props = ZpoolProperties::try_from_stdout(line).unwrap();
        assert_eq!(Some(String::from("z/ROOT/default")), props.boot_fs);
        assert_eq!(Some(1), props.expand_size);

        let line = b"69120\t0\t-\t1.50x\t-\t22%\t67039744\t0\t4957928072935098740\tONLINE\t67108864\t0\t-\toff\toff\toff\t-\t-\t0\tomn\twait\n";
        let props = ZpoolProperties::try_from_stdout(line);
        assert!(props.is_err());
    }

    #[test]
    fn to_arg() {
        let props = ZpoolPropertiesWriteBuilder::default().build().unwrap();
        let expected: Vec<OsString> = vec![
            "autoexpand=off",
            "autoreplace=off",
            "cachefile=",
            "comment=",
            "delegation=off",
            "failmode=wait",
        ]
        .into_iter()
        .map(OsString::from)
        .collect();
        let result = props.into_args();
        assert_eq!(expected, result);

        let props = ZpoolPropertiesWriteBuilder::default()
            .auto_expand(true)
            .cache_file(CacheType::None)
            .fail_mode(FailMode::Panic)
            .build()
            .unwrap();
        let expected: Vec<OsString> = vec![
            "autoexpand=on",
            "autoreplace=off",
            "cachefile=none",
            "comment=",
            "delegation=off",
            "failmode=panic",
        ]
        .into_iter()
        .map(OsString::from)
        .collect();
        let result = props.into_args();
        assert_eq!(expected, result);

        let props = ZpoolPropertiesWriteBuilder::default()
            .fail_mode(FailMode::Continue)
            .cache_file(CacheType::Custom("wat".into()))
            .build()
            .unwrap();
        let expected: Vec<OsString> = vec![
            "autoexpand=off",
            "autoreplace=off",
            "cachefile=wat",
            "comment=",
            "delegation=off",
            "failmode=continue",
        ]
        .into_iter()
        .map(OsString::from)
        .collect();
        let result = props.into_args();
        assert_eq!(expected, result);

        let props = ZpoolPropertiesWriteBuilder::default()
            .auto_replace(true)
            .comment("a test")
            .build()
            .unwrap();
        let expected: Vec<OsString> = vec![
            "autoexpand=off",
            "autoreplace=on",
            "cachefile=",
            "comment=a test",
            "delegation=off",
            "failmode=wait",
        ]
        .into_iter()
        .map(OsString::from)
        .collect();
        let result = props.into_args();
        assert_eq!(expected, result);
    }

    #[test]
    fn write_builder() {
        let _right: ZpoolPropertiesWriteBuilder = ZpoolPropertiesWrite::builder();
    }
}