//! Docked at a station, or landed somewhere no one lives: what the place
//! is like, and at a station, a market for the ore in your hold and the
//! salvage you've brought back from wrecks. Worlds
//! where people live have whole cities instead (`scenes::town`), which you
//! walk out to through your ship; here there's no city, so landing brings
//! you straight here, and leaving takes off again.

use ratatui::Frame;
use ratatui::crossterm::event::{KeyCode, KeyEvent};
use ratatui::layout::{Constraint, Flex, Layout};
use ratatui::style::{Color, Style, Stylize};
use ratatui::text::{Line, Span};
use ratatui::widgets::{Block, Padding, Paragraph, Wrap};

use super::character::Sheet;
use super::keys::{self, ACCENT, DIM};
use super::pause::{Choice, Pause};
use super::sky;
use super::{Scene, Transition};
use crate::app::{Ctx, Hold};
use crate::items;
use crate::names;
use crate::space::locale::Ore;
use crate::space::system::{PlaceKind, System};
use crate::trade;

/// The colour fuel is shown in, everywhere.
pub const FUEL: Color = Color::Rgb(120, 210, 255);

pub struct Port {
    title: String,
    /// "a desert world, home of the Qaari".
    subtitle: String,
    description: Vec<String>,
    colour: Color,
    /// What each ore sells for here, if anyone's buying.
    prices: Option<Vec<(&'static Ore, u32)>>,
    /// What a jump's worth of fuel costs, at a station.
    fuel_price: Option<u32>,
    /// What happened at the market.
    report: Option<String>,
    place: usize,
    /// Whether this is a dock, which you undock from, or ground you take
    /// off from.
    docked: bool,
    /// The menu `esc` opens.
    pause: Option<Pause>,
}

impl Port {
    pub fn new(ctx: &Ctx, place: usize) -> Port {
        let s = &ctx.system;
        let (title, subtitle, description, colour, people) = match s.places[place].kind {
            PlaceKind::Planet(p) => {
                let planet = &s.planets[p];
                let home = if s.is_homeworld(p) { ", homeworld of " } else { ", settled by " };
                let people = planet
                    .people
                    .map_or(", uninhabited".to_string(), |c| format!("{home}{}", c.name()));
                (
                    planet.name.clone(),
                    format!("{}{people}", names::a(planet.kind.name)),
                    planet.description.clone(),
                    planet.kind.rgb,
                    planet.people,
                )
            }
            PlaceKind::Moon(p, m) => {
                let moon = &s.planets[p].moons[m];
                let people = moon
                    .people
                    .map_or(", uninhabited".to_string(), |c| format!(", settled by {}", c.name()));
                let kind = moon.kind.name.trim_end_matches(" world");
                let what = format!("{} moon of {}{people}", names::a(kind), s.planets[p].name);
                (moon.name.clone(), what, moon.description.clone(), moon.kind.rgb, moon.people)
            }
            PlaceKind::Station(i) => {
                let station = &s.stations[i];
                let (_, colour) = sky::station_art(station.culture);
                let what = format!("a {} station", station.culture.adjective());
                (
                    station.name.clone(),
                    what,
                    station.description.clone(),
                    colour,
                    Some(station.culture),
                )
            }
            PlaceKind::Belt => (
                s.belt.name.clone(),
                "an asteroid belt".to_string(),
                Vec::new(),
                (150, 138, 124),
                None,
            ),
        };
        Port {
            title,
            subtitle,
            description,
            colour: sky::rgb(colour),
            prices: people.map(|_| trade::ore_prices(s, place)),
            fuel_price: s.sells_fuel_at(place).then(|| trade::fuel_price(s, place)),
            report: None,
            place,
            docked: matches!(s.places[place].kind, PlaceKind::Station(_)),
            pause: None,
        }
    }

    fn refuel(&mut self, hold: &mut Hold) {
        let Some(price) = self.fuel_price else {
            self.report = Some("No one here sells fuel.".to_string());
            return;
        };
        self.report = Some(match trade::buy_fuel(hold, price) {
            (0, _) if hold.fuel >= hold.fuel_capacity => "Your tank's already full.".to_string(),
            (0, _) => "You can't afford any fuel.".to_string(),
            (jumps, cost) => format!(
                "Bought {jumps} jump{} of fuel for {cost} ¤. Tank: {}/{}.",
                if jumps == 1 { "" } else { "s" },
                hold.fuel,
                hold.fuel_capacity
            ),
        });
    }

    /// Sells all your ore, and all your salvage, on you and aboard.
    fn sell(&mut self, hold: &mut Hold, system: &System) {
        let Some(prices) = &self.prices else {
            self.report = Some("No one lives here to buy anything.".to_string());
            return;
        };
        let debt = hold.debt;
        let ore = trade::sell_ore(hold, prices);
        let salvage = trade::sell_all_salvage(hold, system, self.place);
        let mut sold = Vec::new();
        if let Some((tons, earned)) = ore {
            sold.push(format!("{tons} t of ore for {earned} ¤"));
        }
        if let Some((pieces, earned)) = salvage {
            let s = if pieces == 1 { "" } else { "s" };
            sold.push(format!("{pieces} piece{s} of salvage for {earned} ¤"));
        }
        self.report = Some(if sold.is_empty() {
            "You've no ore or salvage to sell.".to_string()
        } else {
            format!("Sold {}.{}", sold.join(" and "), trade::debt_note(debt - hold.debt, hold))
        });
    }
}

impl Scene for Port {
    fn key(&mut self, key: KeyEvent, ctx: &mut Ctx) -> Transition {
        if let Some(pause) = &mut self.pause {
            let Some(choice) = pause.key(key) else { return Transition::None };
            self.pause = None;
            return match choice {
                Choice::Quit => Transition::Title,
                Choice::Here => Transition::Pop,
                Choice::Resume => Transition::None,
            };
        }
        match key.code {
            KeyCode::Esc => {
                let (here, note) = if self.docked {
                    ("Undock", format!("Docked at {}.", self.title))
                } else {
                    ("Take off", format!("Landed on {}.", self.title))
                };
                self.pause = Some(Pause::new(Some(here), Some(note)));
                Transition::None
            }
            KeyCode::Char('s' | 'S') => {
                self.sell(&mut ctx.hold, &ctx.system);
                Transition::None
            }
            KeyCode::Char('f' | 'F') => {
                self.refuel(&mut ctx.hold);
                Transition::None
            }
            KeyCode::Char('c' | 'C') => Transition::Push(Box::new(Sheet::new())),
            // Only `l`, as it landed you: enter or space mashed through a
            // message shouldn't take off.
            KeyCode::Char('l' | 'L') => Transition::Pop,
            _ => Transition::None,
        }
    }

    fn render(&self, frame: &mut Frame, ctx: &Ctx) {
        let area = frame.area();
        let [area] = Layout::horizontal([Constraint::Max(68)]).flex(Flex::Center).areas(area);

        let mut lines = vec![Line::from(self.subtitle.clone()).fg(DIM), Line::default()];
        for sentence in &self.description {
            lines.push(Line::from(sentence.clone()));
            lines.push(Line::default());
        }

        let hold = &ctx.hold;
        match &self.prices {
            Some(prices) => {
                lines.push(Line::from("THE MARKET").fg(ACCENT).bold());
                for (ore, price) in prices {
                    let have = hold.ore.get(ore.name).copied().unwrap_or(0);
                    let have = if have > 0 { format!("you have {have} t") } else { String::new() };
                    lines.push(Line::from(vec![
                        Span::raw("  * ").fg(sky::rgb(ore.rgb)),
                        Span::raw(format!("{:<16}{:>4} ¤ a ton   ", ore.name, price)),
                        Span::raw(have).fg(DIM),
                    ]));
                }
            }
            None => lines.push(Line::from("No one lives here to trade with.").fg(DIM)),
        }
        if let Some(price) = self.fuel_price {
            lines.push(Line::from(vec![
                Span::raw("  ◆ ").fg(FUEL),
                Span::raw(format!("{:<16}{:>4} ¤ a jump    ", "fuel", price)),
                Span::raw(format!("tank {}/{}", hold.fuel, hold.fuel_capacity)).fg(DIM),
            ]));
        }
        lines.push(Line::default());
        let salvage = if self.prices.is_some() {
            trade::salvage_kept(hold, &ctx.system, self.place)
        } else {
            Vec::new()
        };
        if !salvage.is_empty() {
            let worth: u32 = salvage.iter().map(|(_, w)| w).sum();
            lines.push(Line::from(vec![
                Span::raw("  ( ").fg(Color::Rgb(150, 200, 222)),
                Span::raw(format!("{:<16}{:>4} ¤ the lot", "your salvage", worth)),
            ]));
        }
        lines.push(Line::from(format!(
            "Your hold: {} t of ore, {} artifacts, {} ¤. You carry {} of {} kg.",
            hold.ore_tons(),
            hold.artifacts(),
            hold.scrip,
            items::kg(hold.gear.carried()),
            items::kg(hold.gear.capacity)
        )));
        if hold.debt > 0 {
            lines.push(Line::from(format!("You owe {} ¤ for a tow.", hold.debt)).fg(DIM));
        }
        if let Some(report) = &self.report {
            lines.push(Line::from(report.clone()).fg(ACCENT));
        }
        lines.push(Line::default());
        let mut hints = vec![];
        if self.prices.is_some() {
            hints.push(("s", "sell ore and salvage"));
        }
        if self.fuel_price.is_some() {
            hints.push(("f", "fill the tank"));
        }
        hints.push(("l", if self.docked { "undock" } else { "take off" }));
        hints.extend([("c", "character"), ("esc", "menu")]);
        lines.extend(keys::packed(&hints, area.width.saturating_sub(4)));

        let block = Block::bordered()
            .title(format!(" {} ", self.title))
            .title_style(Style::new().fg(self.colour).bold())
            .border_style(Style::new().fg(self.colour))
            .padding(Padding::horizontal(1));
        // As tall as the text, wrapped, and no taller.
        let width = usize::from(area.width.saturating_sub(4)).max(1);
        let rows: usize = lines.iter().map(|l| l.width().div_ceil(width).max(1)).sum();
        let height = u16::try_from(rows + 3).unwrap_or(u16::MAX);
        let [area] = Layout::vertical([Constraint::Length(height)]).flex(Flex::Center).areas(area);
        frame.render_widget(Paragraph::new(lines).wrap(Wrap { trim: true }).block(block), area);
        if let Some(pause) = &self.pause {
            pause.render(frame, frame.area());
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::scenes::tests::test_ctx;

    #[test]
    fn only_l_takes_off() {
        use ratatui::crossterm::event::KeyModifiers;
        let mut ctx = test_ctx();
        let mut port = Port::new(&ctx, 0);
        let mut press = |code| port.key(KeyEvent::new(code, KeyModifiers::NONE), &mut ctx);
        assert!(matches!(press(KeyCode::Enter), Transition::None));
        assert!(matches!(press(KeyCode::Char(' ')), Transition::None));
        assert!(matches!(press(KeyCode::Char('c')), Transition::Push(_)));
        assert!(matches!(press(KeyCode::Char('l')), Transition::Pop));
    }

    #[test]
    fn stations_buy_ore() {
        let mut ctx = test_ctx();
        let station =
            ctx.system.places.iter().position(|p| matches!(p.kind, PlaceKind::Station(_))).unwrap();
        let mut port = Port::new(&ctx, station);
        let prices = port.prices.clone().expect("stations trade");
        ctx.hold.ore.insert("iron ore", 3);
        ctx.hold.ore.insert("iridium", 2);
        let salvage = crate::items::Salvage { title: "hull plate".into(), value: 20, mass: 9000 };
        ctx.hold
            .lockers
            .push(crate::items::Stack::one(crate::items::Item::Salvage(salvage.clone())));
        port.sell(&mut ctx.hold, &ctx.system);
        let scrap = trade::salvage_offer(&ctx.system, station, &salvage);
        assert!(ctx.hold.lockers.is_empty(), "the salvage goes too");
        let price = |name: &str| prices.iter().find(|(o, _)| o.name == name).unwrap().1;
        assert_eq!(ctx.hold.scrip, 3 * price("iron ore") + 2 * price("iridium") + scrap);
        assert_eq!(ctx.hold.ore_tons(), 0);
    }

    #[test]
    fn stations_sell_fuel() {
        let mut ctx = test_ctx();
        let station =
            ctx.system.places.iter().position(|p| matches!(p.kind, PlaceKind::Station(_))).unwrap();
        let mut port = Port::new(&ctx, station);
        let price = port.fuel_price.expect("stations sell fuel");
        ctx.hold.fuel = 1;
        ctx.hold.scrip = 10 * price;
        port.key(KeyEvent::from(KeyCode::Char('f')), &mut ctx);
        assert_eq!(ctx.hold.fuel, ctx.hold.fuel_capacity);
        assert_eq!(ctx.hold.scrip, 7 * price);
    }
}