//! The Stroke panel: weight, cap, join, alignment, dashes, arrowheads, width profiles and brushes.
//! With type selected it edits the characters' stroke (weight, cap, join, miter limit, dashes).

use serde_json::{Value, json};
use vectorcraft_color::{Color, Paint};
use vectorcraft_doc::{ArrowAlign, Arrowhead, CharStyle, Dash, LineCap, LineJoin, Node, NodeKind, SavedProfile, StrokeLayer, Unit, WidthProfile};

use super::appearance::{ItemTarget, edit_items, item_target};
use super::paint::painted;
use super::*;
use crate::DocState;
use crate::inspect::{ALIGNS, CAPS, JOINS, StrokeMixed, node_stroke};

pub fn specs() -> Vec<CommandSpec> {
    vec![
        cmd!(
            "stroke.set",
            "Stroke Options",
            ["Window", "Stroke"],
            None,
            "{weight?: pt, cap?: butt|round|square, join?: miter|round|bevel, miterLimit?, align?: center|inside|outside, dash?: [d,g,…]|null (a 0 dash with a round or projecting cap draws dots or squares; a new pattern keeps the current offset and alignment), dashOffset? (exact dashes only), alignDashes?: bool (true: dashes fitted to corners and path ends, every run between them holding whole periods with a dash centred on each corner and end; false, the default for a new pattern: exact lengths), startArrow?, endArrow?: Arrow|ArrowOpen|Barbed|Concave|DoubleArrow|HalfArrowLeft|HalfArrowRight|Chevron|Feather|Swallowtail|Triangle|TriangleOpen|TriangleReverse|TriangleBar|Kite|Leaf|Drop|Circle|CircleOpen|HalfCircle|Oval|Target|Square|SquareOpen|Tag|TagOpen|Diamond|DiamondOpen|Hexagon|HexagonOpen|Star|Cross|Plus|Bar|DoubleBar|DotOnBar|Slash|DoubleSlash|Bracket|Fork|null (HalfArrowLeft/Right: one barb, left or right of the direction the head points), arrowAlign?: \"extend\" (tip past the end point, default)|\"tip\" (tip on the end point; the stroke is shortened), profile?: \"uniform\"|\"lens\"|\"taperStart\"|\"taperEnd\"|\"pinch\"|\"teardrop\"|\"wave\"|a saved profile's name (stroke.widthProfile.list), item?: stroke item index|null (omitted: the Appearance panel's active item if it is a stroke, else the top stroke, created when missing), ids?} Without a stroke item, type takes weight, cap, join, miterLimit and the dash options as its characters' stroke (every run; text.setRangeStyle `strokeOptions` styles a range), and images and symbol instances (also in groups) are left alone",
            has_doc,
            stroke_set
        ),
        cmd!(
            "stroke.setAdvanced",
            "Stroke Options",
            [],
            None,
            "{arrowScale?: [start %, end %], swapArrows?: bool, flipProfile?: \"along\"|\"across\", brush?: name|null, item?: stroke item index|null, ids?} Stroke panel extras",
            has_doc,
            stroke_advanced
        ),
        cmd!(
            "stroke.widthProfile.add",
            "Add to Profiles",
            [],
            None,
            "{name?} save the selected stroke's variable width to the Profile list (kept with the preferences) under `name` (default \"Width Profile N\"; unique, not a built-in's) → {name}",
            can_add_profile,
            profile_add
        ),
        cmd!(
            "stroke.widthProfile.delete",
            "Delete Profile",
            [],
            None,
            "{name?} remove a saved profile from the Profile list (default: the selected stroke's); built-in profiles can't be deleted, and strokes keep their widths → {deleted}",
            has_saved_profiles,
            profile_delete
        ),
        cmd!(
            "stroke.widthProfile.reset",
            "Reset Profiles",
            [],
            None,
            "{} remove every saved profile, leaving the built-ins → {removed: count}",
            has_saved_profiles,
            profile_reset
        ),
        cmd!(
            query "stroke.widthProfile.list",
            "Width Profiles",
            [],
            None,
            "{} → {profiles: [{id (stroke.set `profile`), label, builtIn, points: [[t, left, right]…]}], current: the selected stroke's profile id or name, \"custom\" when it isn't listed, null without a stroke}",
            always,
            profile_list
        ),
    ]
}

/// The stroke attributes object and character strokes share, parsed from `stroke.set` params
/// (also the `strokeOptions` of `text.setRangeStyle`).
#[derive(Debug, Default)]
pub(crate) struct StrokeChange {
    pub(crate) weight: Option<f64>,
    cap: Option<LineCap>,
    join: Option<LineJoin>,
    miter_limit: Option<f64>,
    /// `Some(None)`: solid.
    dash: Option<Option<Vec<f64>>>,
    dash_offset: Option<f64>,
    align_dashes: Option<bool>,
}

/// The value param `key` names in `table` (see [`crate::inspect::CAPS`]); `None` when absent.
fn named<T: Copy>(table: &[(T, &str)], p: &Value, key: &str, cmd: &str) -> Result<Option<T>> {
    let Some(s) = str_param(p, key) else { return Ok(None) };
    let s = if key == "cap" && s == "projecting" { "square" } else { s };
    match table.iter().find(|(_, n)| *n == s) {
        Some((v, _)) => Ok(Some(*v)),
        None => Err(bad(cmd, format!("{key} must be {}, got {s}", table.iter().map(|(_, n)| *n).collect::<Vec<_>>().join("|")))),
    }
}

impl StrokeChange {
    pub(crate) fn parse(p: &Value, cmd: &str) -> Result<Self> {
        let num = |k: &str| p.get(k).and_then(Value::as_f64);
        let dash = match p.get("dash") {
            None => None,
            Some(Value::Null) => Some(None),
            Some(Value::Array(a)) => Some(Some(a.iter().filter_map(Value::as_f64).collect::<Vec<_>>()).filter(|d| !d.is_empty())),
            Some(v) => return Err(bad(cmd, format!("dash must be a list of lengths or null, got {v}"))),
        };
        Ok(Self {
            weight: num("weight").map(|w| w.clamp(0.0, 1000.0)),
            cap: named(&CAPS, p, "cap", cmd)?,
            join: named(&JOINS, p, "join", cmd)?,
            miter_limit: num("miterLimit").map(|m| m.clamp(1.0, 500.0)),
            dash,
            dash_offset: num("dashOffset"),
            align_dashes: p.get("alignDashes").and_then(Value::as_bool),
        })
    }

    pub(crate) fn is_empty(&self) -> bool {
        self.weight.is_none()
            && self.cap.is_none()
            && self.join.is_none()
            && self.miter_limit.is_none()
            && self.dash.is_none()
            && self.dash_offset.is_none()
            && self.align_dashes.is_none()
    }

    pub(crate) fn apply(&self, st: &mut StrokeLayer) {
        if let Some(w) = self.weight {
            st.width = w;
        }
        if let Some(c) = self.cap {
            st.cap = c;
        }
        if let Some(j) = self.join {
            st.join = j;
        }
        if let Some(m) = self.miter_limit {
            st.miter_limit = m;
        }
        if let Some(pattern) = &self.dash {
            // A new pattern keeps the offset and alignment of the one it replaces.
            st.dash = pattern.clone().map(|pattern| Dash { pattern, ..st.dash.take().unwrap_or_default() });
        }
        if let Some(d) = st.dash.as_mut() {
            if let Some(o) = self.dash_offset {
                d.offset = o;
            }
            if let Some(a) = self.align_dashes {
                d.align_corners = a;
            }
        }
    }

    /// [`Self::apply`] to a character stroke.
    pub(crate) fn apply_char(&self, style: &mut CharStyle) {
        let mut st = style.stroke_layer();
        self.apply(&mut st);
        style.set_stroke_layer(&st);
    }
}

fn stroke_set(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "stroke.set";
    let change = StrokeChange::parse(p, C)?;
    if let Some(w) = change.weight {
        s.paint.stroke_width = w;
    }
    let item = item_target(s, p, C)?.of_kind(s, false);
    let mut ids = item.targets(s, p)?;
    if item == ItemTarget::Top {
        // Images and symbol instances take no stroke from the panel.
        let d = &s.doc()?.doc;
        ids.retain(|id| !matches!(d.node(*id).map(|n| &n.kind), Some(NodeKind::Image(_) | NodeKind::SymbolInstance { .. })));
    }
    let arrow = |k: &str| -> Result<Option<Option<Arrowhead>>> {
        match p.get(k) {
            None => Ok(None),
            Some(Value::Null) => Ok(Some(None)),
            Some(Value::String(n)) if n == "none" => Ok(Some(None)),
            Some(v) => serde_json::from_value::<Arrowhead>(v.clone()).map(|a| Some(Some(a))).map_err(|_| bad(C, format!("unknown arrowhead {v}"))),
        }
    };
    let (sa, ea) = (arrow("startArrow")?, arrow("endArrow")?);
    let align = named(&ALIGNS, p, "align", C)?;
    let arrow_align = match str_param(p, "arrowAlign") {
        None => None,
        Some("extend") => Some(ArrowAlign::Extend),
        Some("tip") => Some(ArrowAlign::Tip),
        Some(o) => return Err(bad(C, format!("arrowAlign must be extend|tip, got {o}"))),
    };
    let profile = match str_param(p, "profile") {
        None => None,
        Some(id) => Some(s.resolve_profile(id).ok_or_else(|| bad(C, format!("unknown profile {id} (see stroke.widthProfile.list)")))?),
    };
    edit_items(s, &ids, item, C, "Stroke", false, |n, index| {
        if index.is_none()
            && let NodeKind::Text(t) = &mut n.kind
        {
            t.runs.iter_mut().for_each(|r| change.apply_char(&mut r.style));
            return Ok(());
        }
        if index.is_none() && n.appearance.stroke().is_none() {
            n.appearance.set_stroke(Paint::solid(Color::BLACK));
        }
        let Some(st) = n.appearance.stroke_at_mut(index) else { return Ok(()) };
        change.apply(st);
        if let Some(a) = align {
            st.align = a;
        }
        if let Some(a) = sa {
            st.start_arrow = a;
        }
        if let Some(a) = ea {
            st.end_arrow = a;
        }
        if let Some(a) = arrow_align {
            st.arrow_align = a;
        }
        if let Some(pr) = &profile {
            st.profile = pr.clone();
        }
        Ok(())
    })?;
    ok()
}

impl Session {
    /// Units > Stroke (Preferences): the unit stroke weights and dash lengths show in.
    pub fn stroke_unit(&self) -> Unit {
        super::edit::parse_unit(&self.prefs.units_stroke).unwrap_or_default()
    }

    /// The stroke the Stroke panel, the Control bar and the Properties panel show, picked as the
    /// Stroke proxy picks its paint: the Appearance panel's active item when it is a stroke, else
    /// the first selected object's (a group's first painted object's) top stroke, type's first
    /// run's character stroke. None without a selection or a stroke.
    pub fn shown_stroke(&self) -> Option<StrokeLayer> {
        let st = self.active()?;
        let first = st.doc.node(*st.selection.objects.first()?)?;
        if let Some(i) = first.appearance.item_of_kind(self.appearance_item(), false) {
            return first.appearance.stroke_at(Some(i)).cloned();
        }
        let mut nodes = vec![];
        painted(first, true, &mut nodes);
        node_stroke(nodes.first()?)
    }
}

impl DocState {
    /// Which Stroke panel values the selected objects' strokes (type: every run's) don't share,
    /// and whether Align Stroke applies to them. One walk of the selection, so callers that ask
    /// every frame cache it by revision.
    pub fn stroke_mixed(&self) -> StrokeMixed {
        let mut nodes = vec![];
        for id in &self.selection.objects {
            if let Some(n) = self.doc.node(*id) {
                painted(n, true, &mut nodes);
            }
        }
        let mut strokes = vec![];
        let mut can_align = true;
        for n in &nodes {
            match &n.kind {
                NodeKind::Text(t) => {
                    can_align = false;
                    strokes.extend(t.runs.iter().map(|r| r.style.stroke_layer()));
                }
                _ => {
                    can_align &= encloses(n);
                    strokes.extend(n.appearance.stroke().cloned());
                }
            }
        }
        let Some((first, rest)) = strokes.split_first() else { return StrokeMixed { can_align, ..Default::default() } };
        let differs = |same: fn(&StrokeLayer, &StrokeLayer) -> bool| rest.iter().any(|s| !same(first, s));
        StrokeMixed {
            weight: differs(|a, b| a.width == b.width),
            cap: differs(|a, b| a.cap == b.cap),
            join: differs(|a, b| a.join == b.join),
            miter_limit: differs(|a, b| a.miter_limit == b.miter_limit),
            align: differs(|a, b| a.align == b.align),
            dash: differs(|a, b| a.dash == b.dash),
            can_align,
        }
    }
}

/// Does `n` enclose an area a stroke can be aligned inside or outside of (no open path)?
fn encloses(n: &Node) -> bool {
    match &n.kind {
        NodeKind::Path { path, .. } => path.is_closed(),
        NodeKind::Compound { children, .. } => children.iter().all(|c| encloses(c)),
        _ => true,
    }
}

/// Mirror a width profile along the path (t → 1 − t) or across it (swap left/right widths).
pub(crate) fn flip_profile(p: &WidthProfile, along: bool) -> WidthProfile {
    let mut pts: Vec<(f64, f64, f64)> =
        if along { p.points.iter().map(|&(t, l, r)| (1.0 - t, l, r)).collect() } else { p.points.iter().map(|&(t, l, r)| (t, r, l)).collect() };
    pts.sort_by(|a, b| a.0.total_cmp(&b.0));
    WidthProfile { points: pts }
}

fn stroke_advanced(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "stroke.setAdvanced";
    let scale = match p.get("arrowScale") {
        None => None,
        Some(v) => {
            let a = v.as_array().filter(|a| a.len() == 2).ok_or_else(|| bad(C, "arrowScale must be [start, end]"))?;
            let f = |i: usize| a[i].as_f64().map(|x| x.clamp(1.0, 1000.0));
            Some((f(0).ok_or_else(|| bad(C, "bad arrowScale"))?, f(1).ok_or_else(|| bad(C, "bad arrowScale"))?))
        }
    };
    let flip = match str_param(p, "flipProfile") {
        None => None,
        Some("along") => Some(true),
        Some("across") => Some(false),
        Some(o) => return Err(bad(C, format!("flipProfile must be along|across, got {o}"))),
    };
    let swap = bool_or(p, "swapArrows", false);
    let brush = match p.get("brush") {
        None => None,
        Some(Value::Null) => Some(None),
        Some(Value::String(b)) => Some(Some(b.clone())),
        Some(_) => return Err(bad(C, "brush must be a name or null")),
    };
    if scale.is_none() && flip.is_none() && !swap && brush.is_none() {
        return Err(bad(C, "nothing to change"));
    }
    let item = item_target(s, p, C)?.of_kind(s, false);
    let ids = item.targets(s, p)?;
    edit_items(s, &ids, item, C, "Stroke", false, |n, index| {
        let Some(st) = n.appearance.stroke_at_mut(index) else { return Ok(()) };
        if let Some(sc) = scale {
            st.arrow_scale = sc;
        }
        if swap {
            std::mem::swap(&mut st.start_arrow, &mut st.end_arrow);
            st.arrow_scale = (st.arrow_scale.1, st.arrow_scale.0);
        }
        if let (Some(along), Some(pr)) = (flip, &st.profile) {
            st.profile = Some(flip_profile(pr, along));
        }
        if let Some(b) = &brush {
            st.brush = b.clone();
        }
        Ok(())
    })?;
    ok()
}

/// One row of the Profile list: a built-in profile or a saved one.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct ProfileEntry<'a> {
    /// What `stroke.set {profile}` takes: a built-in's id, a saved profile's name.
    pub id: &'a str,
    pub label: &'a str,
    pub points: &'a [(f64, f64, f64)],
    pub built_in: bool,
}

impl ProfileEntry<'_> {
    /// Does this row describe `p` (`None`: the plain stroke, the Uniform row)?
    pub fn matches(&self, p: Option<&WidthProfile>) -> bool {
        match p {
            None => self.built_in && self.id == "uniform",
            Some(p) => p.points == self.points,
        }
    }
}

impl Session {
    /// The Profile list: the built-in profiles, then the saved ones.
    pub fn profile_entries(&self) -> impl Iterator<Item = ProfileEntry<'_>> {
        let built_in = WidthProfile::PRESETS.iter().map(|p| ProfileEntry { id: p.id, label: p.label, points: p.points, built_in: true });
        let saved =
            self.prefs.width_profiles.iter().map(|p| ProfileEntry { id: &p.name, label: &p.name, points: &p.profile.points, built_in: false });
        built_in.chain(saved)
    }

    /// The Profile list row showing `p` (`None`: the plain stroke), if it is listed.
    pub fn profile_entry(&self, p: Option<&WidthProfile>) -> Option<ProfileEntry<'_>> {
        self.profile_entries().find(|e| e.matches(p))
    }

    /// The profile `stroke.set {profile: key}` applies: `Some(None)` for "uniform" (the plain
    /// stroke), else a built-in's id or a saved profile's name; `None` when nothing is called `key`.
    pub fn resolve_profile(&self, key: &str) -> Option<Option<WidthProfile>> {
        let e = self.profile_entries().find(|e| e.id == key)?;
        Some((!e.matches(None)).then(|| WidthProfile { points: e.points.to_vec() }))
    }

    /// The name Add to Profiles suggests: the first free "Width Profile N".
    pub fn next_profile_name(&self) -> String {
        (1..).map(|n| format!("Width Profile {n}")).find(|n| !self.profile_name_taken(n)).unwrap_or_default()
    }

    /// Does a listed profile have `name` as its id or label (ignoring case)?
    fn profile_name_taken(&self, name: &str) -> bool {
        self.profile_entries().any(|e| e.id.eq_ignore_ascii_case(name) || e.label.eq_ignore_ascii_case(name))
    }

    /// The variable width Add to Profiles saves: the shown stroke's profile, when it isn't listed.
    fn profile_to_add(&self) -> std::result::Result<WidthProfile, String> {
        let p = self.shown_stroke().and_then(|s| s.profile).ok_or("select a stroke with a variable width")?;
        match self.profile_entry(Some(&p)) {
            Some(e) => Err(format!("the selected stroke's profile is already listed as {}", e.label)),
            None => Ok(p),
        }
    }
}

fn can_add_profile(s: &Session) -> std::result::Result<(), String> {
    has_doc(s)?;
    s.profile_to_add().map(|_| ())
}

fn has_saved_profiles(s: &Session) -> std::result::Result<(), String> {
    if s.prefs.width_profiles.is_empty() { Err("no saved profiles".into()) } else { Ok(()) }
}

fn profile_add(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "stroke.widthProfile.add";
    let profile = s.profile_to_add().map_err(|e| bad(C, e))?;
    let name = match str_param(p, "name").map(str::trim) {
        None => s.next_profile_name(),
        Some("") => return Err(bad(C, "the name is empty")),
        Some(n) if s.profile_name_taken(n) => return Err(bad(C, format!("a profile is already called {n}"))),
        Some(n) => n.to_string(),
    };
    s.prefs.width_profiles.push(SavedProfile { name: name.clone(), profile });
    Ok(json!({ "name": name }))
}

fn profile_delete(s: &mut Session, p: &Value) -> Result<Value> {
    const C: &str = "stroke.widthProfile.delete";
    let name = match str_param(p, "name") {
        Some(n) => n.to_string(),
        None => {
            let shown = s.shown_stroke().and_then(|st| st.profile);
            let entry = shown.as_ref().and_then(|p| s.profile_entry(Some(p)));
            entry.map(|e| e.id.to_string()).ok_or_else(|| bad(C, "give a name, or select a stroke with a saved profile"))?
        }
    };
    if WidthProfile::PRESETS.iter().any(|b| b.id == name || b.label == name) {
        return Err(bad(C, format!("{name} is built in and can't be deleted")));
    }
    let i = s.prefs.width_profiles.iter().position(|sp| sp.name == name).ok_or_else(|| bad(C, format!("no saved profile called {name}")))?;
    s.prefs.width_profiles.remove(i);
    Ok(json!({ "deleted": name }))
}

fn profile_reset(s: &mut Session, _: &Value) -> Result<Value> {
    let removed = std::mem::take(&mut s.prefs.width_profiles).len();
    Ok(json!({ "removed": removed }))
}

fn profile_list(s: &mut Session, _: &Value) -> Result<Value> {
    let profiles: Vec<Value> = s
        .profile_entries()
        .map(|e| json!({"id": e.id, "label": e.label, "builtIn": e.built_in, "points": e.points.iter().map(|&(t, l, r)| [t, l, r]).collect::<Vec<_>>()}))
        .collect();
    let current = s.shown_stroke().map(|st| s.profile_entry(st.profile.as_ref()).map_or("custom", |e| e.id).to_string());
    Ok(json!({ "profiles": profiles, "current": current }))
}