// Std
use std::fmt::{Display, Formatter, Result};
use std::rc::Rc;
use std::result::Result as StdResult;
use std::ffi::{OsStr, OsString};
use std::mem;

// Internal
use args::{AnyArg, Arg, ArgSettings, Base, DispOrder, Switched, Valued};
use map::{self, VecMap};
use INTERNAL_ERROR_MSG;

#[allow(missing_debug_implementations)]
#[doc(hidden)]
#[derive(Default, Clone)]
pub struct OptBuilder<'n, 'e>
where
    'n: 'e,
{
    pub b: Base<'n, 'e>,
    pub s: Switched<'e>,
    pub v: Valued<'n, 'e>,
}

impl<'n, 'e> OptBuilder<'n, 'e> {
    pub fn new(name: &'n str) -> Self {
        OptBuilder {
            b: Base::new(name),
            ..Default::default()
        }
    }
}

impl<'n, 'e, 'z> From<&'z Arg<'n, 'e>> for OptBuilder<'n, 'e> {
    fn from(a: &'z Arg<'n, 'e>) -> Self {
        OptBuilder {
            b: Base::from(a),
            s: Switched::from(a),
            v: Valued::from(a),
        }
    }
}

impl<'n, 'e> From<Arg<'n, 'e>> for OptBuilder<'n, 'e> {
    fn from(mut a: Arg<'n, 'e>) -> Self {
        a.v.fill_in();
        OptBuilder {
            b: mem::replace(&mut a.b, Base::default()),
            s: mem::replace(&mut a.s, Switched::default()),
            v: mem::replace(&mut a.v, Valued::default()),
        }
    }
}

impl<'n, 'e> Display for OptBuilder<'n, 'e> {
    fn fmt(&self, f: &mut Formatter) -> Result {
        debugln!("OptBuilder::fmt:{}", self.b.name);
        let sep = if self.b.is_set(ArgSettings::RequireEquals) {
            "="
        } else {
            " "
        };
        // Write the name such --long or -l
        if let Some(l) = self.s.long {
            write!(f, "--{}{}", l, sep)?;
        } else {
            write!(f, "-{}{}", self.s.short.unwrap(), sep)?;
        }
        let delim = if self.is_set(ArgSettings::RequireDelimiter) {
            self.v.val_delim.expect(INTERNAL_ERROR_MSG)
        } else {
            ' '
        };

        // Write the values such as <name1> <name2>
        if let Some(ref vec) = self.v.val_names {
            let mut it = vec.iter().peekable();
            while let Some((_, val)) = it.next() {
                write!(f, "<{}>", val)?;
                if it.peek().is_some() {
                    write!(f, "{}", delim)?;
                }
            }
            let num = vec.len();
            if self.is_set(ArgSettings::Multiple) && num == 1 {
                write!(f, "...")?;
            }
        } else if let Some(num) = self.v.num_vals {
            let mut it = (0..num).peekable();
            while let Some(_) = it.next() {
                write!(f, "<{}>", self.b.name)?;
                if it.peek().is_some() {
                    write!(f, "{}", delim)?;
                }
            }
            if self.is_set(ArgSettings::Multiple) && num == 1 {
                write!(f, "...")?;
            }
        } else {
            write!(
                f,
                "<{}>{}",
                self.b.name,
                if self.is_set(ArgSettings::Multiple) {
                    "..."
                } else {
                    ""
                }
            )?;
        }

        Ok(())
    }
}

impl<'n, 'e> AnyArg<'n, 'e> for OptBuilder<'n, 'e> {
    fn name(&self) -> &'n str { self.b.name }
    fn overrides(&self) -> Option<&[&'e str]> { self.b.overrides.as_ref().map(|o| &o[..]) }
    fn requires(&self) -> Option<&[(Option<&'e str>, &'n str)]> {
        self.b.requires.as_ref().map(|o| &o[..])
    }
    fn blacklist(&self) -> Option<&[&'e str]> { self.b.blacklist.as_ref().map(|o| &o[..]) }
    fn required_unless(&self) -> Option<&[&'e str]> { self.b.r_unless.as_ref().map(|o| &o[..]) }
    fn val_names(&self) -> Option<&VecMap<&'e str>> { self.v.val_names.as_ref() }
    fn is_set(&self, s: ArgSettings) -> bool { self.b.settings.is_set(s) }
    fn has_switch(&self) -> bool { true }
    fn set(&mut self, s: ArgSettings) { self.b.settings.set(s) }
    fn max_vals(&self) -> Option<u64> { self.v.max_vals }
    fn val_terminator(&self) -> Option<&'e str> { self.v.terminator }
    fn num_vals(&self) -> Option<u64> { self.v.num_vals }
    fn possible_vals(&self) -> Option<&[&'e str]> { self.v.possible_vals.as_ref().map(|o| &o[..]) }
    fn validator(&self) -> Option<&Rc<Fn(String) -> StdResult<(), String>>> {
        self.v.validator.as_ref()
    }
    fn validator_os(&self) -> Option<&Rc<Fn(&OsStr) -> StdResult<(), OsString>>> {
        self.v.validator_os.as_ref()
    }
    fn min_vals(&self) -> Option<u64> { self.v.min_vals }
    fn short(&self) -> Option<char> { self.s.short }
    fn long(&self) -> Option<&'e str> { self.s.long }
    fn val_delim(&self) -> Option<char> { self.v.val_delim }
    fn takes_value(&self) -> bool { true }
    fn help(&self) -> Option<&'e str> { self.b.help }
    fn long_help(&self) -> Option<&'e str> { self.b.long_help }
    fn default_val(&self) -> Option<&'e OsStr> { self.v.default_val }
    fn default_vals_ifs(&self) -> Option<map::Values<(&'n str, Option<&'e OsStr>, &'e OsStr)>> {
        self.v.default_vals_ifs.as_ref().map(|vm| vm.values())
    }
    fn env<'s>(&'s self) -> Option<(&'n OsStr, Option<&'s OsString>)> {
        self.v
            .env
            .as_ref()
            .map(|&(key, ref value)| (key, value.as_ref()))
    }
    fn longest_filter(&self) -> bool { true }
    fn aliases(&self) -> Option<Vec<&'e str>> {
        if let Some(ref aliases) = self.s.aliases {
            let vis_aliases: Vec<_> = aliases
                .iter()
                .filter_map(|&(n, v)| if v { Some(n) } else { None })
                .collect();
            if vis_aliases.is_empty() {
                None
            } else {
                Some(vis_aliases)
            }
        } else {
            None
        }
    }
}

impl<'n, 'e> DispOrder for OptBuilder<'n, 'e> {
    fn disp_ord(&self) -> usize { self.s.disp_ord }
}

impl<'n, 'e> PartialEq for OptBuilder<'n, 'e> {
    fn eq(&self, other: &OptBuilder<'n, 'e>) -> bool { self.b == other.b }
}

#[cfg(test)]
mod test {
    use args::settings::ArgSettings;
    use super::OptBuilder;
    use map::VecMap;

    #[test]
    fn optbuilder_display1() {
        let mut o = OptBuilder::new("opt");
        o.s.long = Some("option");
        o.b.settings.set(ArgSettings::Multiple);

        assert_eq!(&*format!("{}", o), "--option <opt>...");
    }

    #[test]
    fn optbuilder_display2() {
        let mut v_names = VecMap::new();
        v_names.insert(0, "file");
        v_names.insert(1, "name");

        let mut o2 = OptBuilder::new("opt");
        o2.s.short = Some('o');
        o2.v.val_names = Some(v_names);

        assert_eq!(&*format!("{}", o2), "-o <file> <name>");
    }

    #[test]
    fn optbuilder_display3() {
        let mut v_names = VecMap::new();
        v_names.insert(0, "file");
        v_names.insert(1, "name");

        let mut o2 = OptBuilder::new("opt");
        o2.s.short = Some('o');
        o2.v.val_names = Some(v_names);
        o2.b.settings.set(ArgSettings::Multiple);

        assert_eq!(&*format!("{}", o2), "-o <file> <name>");
    }

    #[test]
    fn optbuilder_display_single_alias() {
        let mut o = OptBuilder::new("opt");
        o.s.long = Some("option");
        o.s.aliases = Some(vec![("als", true)]);

        assert_eq!(&*format!("{}", o), "--option <opt>");
    }

    #[test]
    fn optbuilder_display_multiple_aliases() {
        let mut o = OptBuilder::new("opt");
        o.s.long = Some("option");
        o.s.aliases = Some(vec![
            ("als_not_visible", false),
            ("als2", true),
            ("als3", true),
            ("als4", true),
        ]);
        assert_eq!(&*format!("{}", o), "--option <opt>");
    }
}
