//! Quick dimension creation from a selected set of drawing entities.

use codec::entities::{
    Dimension, DimensionDiameter, DimensionLinear, DimensionOrdinate, DimensionRadius,
};
use codec::types::Vector3;
use codec::{EntityType, Handle};
use glam::DVec3;
use kernel::geom2d::{characteristic_points, intersect, Curve, SnapKind, Tolerance};

use crate::command::{
    CadCommand, CmdOption, CmdResult, DimensionAssociationInput, DimensionAssociationSource,
    DimensionPreview, EntityTransform, SelectionEntity, WorkingPlane,
};
use crate::modules::{IconKind, ModuleEvent, ToolDef};
use crate::scene::model::wire_model::WireModel;
use crate::t;

pub const ICON: IconKind = IconKind::Svg(include_bytes!("../../../assets/icons/qdim.svg"));

pub fn tool() -> ToolDef {
    ToolDef {
        id: "QDIM",
        label: "Quick Dim",
        icon: ICON,
        event: ModuleEvent::Command("QDIM".to_string()),
    }
}

#[derive(Clone, Copy, PartialEq, Eq)]
enum Step {
    Gathering,
    Place,
    Datum,
    Edit,
    Settings,
}

#[derive(Clone, Copy, PartialEq, Eq)]
enum Mode {
    Continuous,
    Staggered,
    Baseline,
    Ordinate,
    Radius,
    Diameter,
}

#[derive(Clone, Copy, PartialEq, Eq)]
enum SnapPriority {
    Endpoints,
    Intersections,
}

#[derive(Clone)]
struct SourceCurve {
    handle: Handle,
    curve: Curve,
}

#[derive(Clone)]
struct Candidate {
    point: DVec3,
    sources: Vec<DimensionAssociationSource>,
}

pub struct QdimCommand {
    step: Step,
    mode: Mode,
    snap_priority: SnapPriority,
    plane: WorkingPlane,
    selection: Vec<SelectionEntity>,
    datum: Option<DVec3>,
    excluded: Vec<DVec3>,
    dim_spacing: f64,
}

impl QdimCommand {
    pub fn new(selection: Vec<SelectionEntity>, dim_spacing: f64, snap_priority: u8) -> Self {
        let step = if selection.is_empty() {
            Step::Gathering
        } else {
            Step::Place
        };
        Self {
            step,
            mode: Mode::Continuous,
            snap_priority: if snap_priority == 1 {
                SnapPriority::Intersections
            } else {
                SnapPriority::Endpoints
            },
            plane: WorkingPlane::default(),
            selection,
            datum: None,
            excluded: Vec::new(),
            dim_spacing: dim_spacing.abs().max(1e-9),
        }
    }

    fn local_sources(&self) -> Vec<SourceCurve> {
        let transform = EntityTransform::Affine(self.plane.to_local_transform());
        self.selection
            .iter()
            .filter_map(|selected| {
                let mut entity = selected.entity.clone();
                crate::scene::view::dispatch::apply_transform(&mut entity, &transform);
                crate::entities::curve::entity_curve_xy(&entity).map(|curve| SourceCurve {
                    handle: selected.handle,
                    curve,
                })
            })
            .collect()
    }

    fn candidates(&self) -> Vec<Candidate> {
        let curves = self.local_sources();
        let mut candidates = if self.snap_priority == SnapPriority::Intersections {
            let mut hits = Vec::new();
            for first in 0..curves.len() {
                for second in first + 1..curves.len() {
                    for crossing in intersect(
                        &curves[first].curve,
                        &curves[second].curve,
                        Tolerance::default(),
                    ) {
                        hits.push(Candidate {
                            point: DVec3::new(crossing.point[0], crossing.point[1], 0.0),
                            // Intersections depend on two curves, but each
                            // extension origin stores one source.
                            sources: Vec::new(),
                        });
                    }
                }
            }
            hits
        } else {
            Vec::new()
        };

        if candidates.is_empty() {
            for source in &curves {
                for point in characteristic_points(&source.curve)
                    .into_iter()
                    .filter(|point| point.kind == SnapKind::Endpoint)
                {
                    candidates.push(Candidate {
                        point: DVec3::new(point.point[0], point.point[1], 0.0),
                        sources: vec![DimensionAssociationSource::inferred(source.handle)],
                    });
                }
            }
        }

        for selected in &self.selection {
            if let EntityType::Dimension(dimension) = &selected.entity {
                for point in dimension_reference_points(dimension) {
                    candidates.push(Candidate {
                        point: self.plane.to_local(point),
                        sources: vec![DimensionAssociationSource::inferred(selected.handle)],
                    });
                }
            }
        }

        let tolerance = candidate_tolerance(candidates.iter().map(|candidate| candidate.point));
        let mut unique: Vec<Candidate> = Vec::new();
        for candidate in candidates {
            if let Some(existing) = unique
                .iter_mut()
                .find(|existing| existing.point.distance(candidate.point) <= tolerance)
            {
                for source in candidate.sources {
                    if !existing
                        .sources
                        .iter()
                        .any(|current| current.handle == source.handle)
                    {
                        existing.sources.push(source);
                    }
                }
            } else {
                unique.push(candidate);
            }
        }
        unique.retain(|candidate| {
            !self
                .excluded
                .iter()
                .any(|point| point.distance(candidate.point) <= tolerance)
        });
        unique
    }

    fn radial_sources(&self) -> Vec<(Handle, Curve)> {
        self.local_sources()
            .into_iter()
            .filter(|source| matches!(source.curve, Curve::Circle(_) | Curve::Arc(_)))
            .map(|source| (source.handle, source.curve))
            .collect()
    }

    fn orientation(&self, points: &[Candidate], place: DVec3) -> bool {
        let min_x = points
            .iter()
            .map(|point| point.point.x)
            .fold(f64::INFINITY, f64::min);
        let max_x = points
            .iter()
            .map(|point| point.point.x)
            .fold(f64::NEG_INFINITY, f64::max);
        let min_y = points
            .iter()
            .map(|point| point.point.y)
            .fold(f64::INFINITY, f64::min);
        let max_y = points
            .iter()
            .map(|point| point.point.y)
            .fold(f64::NEG_INFINITY, f64::max);
        let outside_y = (place.y - max_y).max(min_y - place.y).max(0.0);
        let outside_x = (place.x - max_x).max(min_x - place.x).max(0.0);
        if (outside_x - outside_y).abs() > 1e-9 {
            outside_y >= outside_x
        } else {
            max_x - min_x >= max_y - min_y
        }
    }

    fn build_dimensions(&self, place_world: DVec3) -> Vec<(EntityType, DimensionAssociationInput)> {
        let place = self.plane.to_local(place_world);
        if matches!(self.mode, Mode::Radius | Mode::Diameter) {
            return self.build_radial_dimensions(place);
        }
        let mut points = self.candidates();
        if points.is_empty() {
            return Vec::new();
        }
        let horizontal = self.orientation(&points, place);
        points.sort_by(|first, second| {
            if horizontal {
                first.point.x.total_cmp(&second.point.x)
            } else {
                first.point.y.total_cmp(&second.point.y)
            }
        });
        let tolerance = candidate_tolerance(points.iter().map(|point| point.point));
        points.dedup_by(|first, second| {
            let delta = if horizontal {
                first.point.x - second.point.x
            } else {
                first.point.y - second.point.y
            };
            delta.abs() <= tolerance
        });

        match self.mode {
            Mode::Continuous | Mode::Staggered => points
                .windows(2)
                .enumerate()
                .map(|(index, pair)| {
                    let offset = if self.mode == Mode::Staggered {
                        index as f64 * self.dim_spacing
                    } else {
                        0.0
                    };
                    let direction = if horizontal {
                        if place.y >= (pair[0].point.y + pair[1].point.y) * 0.5 {
                            1.0
                        } else {
                            -1.0
                        }
                    } else if place.x >= (pair[0].point.x + pair[1].point.x) * 0.5 {
                        1.0
                    } else {
                        -1.0
                    };
                    let shifted = if horizontal {
                        DVec3::new(place.x, place.y + direction * offset, 0.0)
                    } else {
                        DVec3::new(place.x + direction * offset, place.y, 0.0)
                    };
                    self.linear_dimension(&pair[0], &pair[1], shifted, horizontal)
                })
                .collect(),
            Mode::Baseline => {
                let datum = self.datum.unwrap_or(points[0].point);
                let datum_candidate = Candidate {
                    point: datum,
                    sources: points
                        .iter()
                        .find(|point| point.point.distance(datum) <= tolerance)
                        .map(|point| point.sources.clone())
                        .unwrap_or_default(),
                };
                points
                    .iter()
                    .filter(|point| point.point.distance(datum) > tolerance)
                    .map(|point| self.linear_dimension(&datum_candidate, point, place, horizontal))
                    .collect()
            }
            Mode::Ordinate => points
                .iter()
                .map(|point| self.ordinate_dimension(point, place, horizontal))
                .collect(),
            Mode::Radius | Mode::Diameter => Vec::new(),
        }
    }

    fn linear_dimension(
        &self,
        first: &Candidate,
        second: &Candidate,
        place: DVec3,
        horizontal: bool,
    ) -> (EntityType, DimensionAssociationInput) {
        let mut dimension = DimensionLinear::new(v3(first.point), v3(second.point));
        dimension.rotation = if horizontal {
            0.0
        } else {
            std::f64::consts::FRAC_PI_2
        };
        let definition = if horizontal {
            DVec3::new(second.point.x, place.y, 0.0)
        } else {
            DVec3::new(place.x, second.point.y, 0.0)
        };
        let text = if horizontal {
            DVec3::new((first.point.x + second.point.x) * 0.5, place.y, 0.0)
        } else {
            DVec3::new(place.x, (first.point.y + second.point.y) * 0.5, 0.0)
        };
        dimension.definition_point = v3(definition);
        dimension.base.definition_point = v3(definition);
        dimension.base.text_middle_point = v3(text);
        dimension.base.insertion_point = v3(text);
        crate::entities::dimension::reset_automatic_text_position(&mut dimension.base);
        dimension.base.actual_measurement = dimension.measurement();
        let association = DimensionAssociationInput::Explicit(vec![
            first.sources.first().copied(),
            second.sources.first().copied(),
        ]);
        (
            self.plane
                .place_entity(EntityType::Dimension(Box::new(Dimension::Linear(dimension)))),
            association,
        )
    }

    fn ordinate_dimension(
        &self,
        point: &Candidate,
        place: DVec3,
        horizontal: bool,
    ) -> (EntityType, DimensionAssociationInput) {
        let datum = self.datum.unwrap_or(DVec3::ZERO);
        let leader = if horizontal {
            DVec3::new(point.point.x, place.y, 0.0)
        } else {
            DVec3::new(place.x, point.point.y, 0.0)
        };
        let mut dimension = DimensionOrdinate::new(v3(point.point), v3(leader), horizontal);
        dimension.definition_point = v3(datum);
        dimension.base.definition_point = v3(datum);
        dimension.base.text_middle_point = v3(leader);
        dimension.base.insertion_point = v3(leader);
        dimension.refresh_measurement();
        (
            self.plane
                .place_entity(EntityType::Dimension(Box::new(Dimension::Ordinate(dimension)))),
            DimensionAssociationInput::Explicit(vec![point.sources.first().copied()]),
        )
    }

    fn build_radial_dimensions(
        &self,
        place: DVec3,
    ) -> Vec<(EntityType, DimensionAssociationInput)> {
        self.radial_sources()
            .into_iter()
            .enumerate()
            .map(|(index, (handle, curve))| {
                let (center, radius) = match curve {
                    Curve::Circle(circle) => (circle.centre, circle.radius),
                    Curve::Arc(arc) => (arc.centre, arc.radius),
                    _ => unreachable!(),
                };
                let center = DVec3::new(center[0], center[1], 0.0);
                let mut direction = place - center;
                direction.z = 0.0;
                direction = if direction.length_squared() <= f64::EPSILON {
                    DVec3::X
                } else {
                    direction.normalize()
                };
                let chord = center + direction * radius;
                let text = place + DVec3::new(0.0, index as f64 * self.dim_spacing, 0.0);
                let association = DimensionAssociationInput::Explicit(vec![Some(
                    DimensionAssociationSource::inferred(handle),
                )]);
                let entity = if self.mode == Mode::Radius {
                    let mut dimension = DimensionRadius::new(v3(center), v3(chord));
                    dimension.base.definition_point = v3(chord);
                    dimension.base.text_middle_point = v3(text);
                    dimension.base.insertion_point = v3(text);
                    dimension.base.text_user_positioned = true;
                    dimension.leader_length = chord.distance(text);
                    dimension.base.actual_measurement = dimension.measurement();
                    EntityType::Dimension(Box::new(Dimension::Radius(dimension)))
                } else {
                    let opposite = center - direction * radius;
                    let mut dimension = DimensionDiameter::new(v3(chord), v3(opposite));
                    dimension.base.definition_point = v3(opposite);
                    dimension.base.text_middle_point = v3(text);
                    dimension.base.insertion_point = v3(text);
                    dimension.base.text_user_positioned = true;
                    dimension.leader_length = chord.distance(text);
                    dimension.base.actual_measurement = dimension.measurement();
                    EntityType::Dimension(Box::new(Dimension::Diameter(dimension)))
                };
                (self.plane.place_entity(entity), association)
            })
            .collect()
    }

    fn remove_candidate(&mut self, point_world: DVec3) {
        let point = self.plane.to_local(point_world);
        let all = self.candidates();
        let Some(nearest) = all.iter().min_by(|first, second| {
            first
                .point
                .distance(point)
                .total_cmp(&second.point.distance(point))
        }) else {
            return;
        };
        self.excluded.push(nearest.point);
    }

    fn preview_dimensions(&self, point: DVec3) -> Vec<WireModel> {
        self.build_dimensions(point)
            .into_iter()
            .enumerate()
            .flat_map(|(index, (entity, _))| preview_entity(index, &entity))
            .collect()
    }
}

impl CadCommand for QdimCommand {
    fn set_working_plane(&mut self, plane: WorkingPlane) {
        self.plane = plane;
    }
    fn name(&self) -> &'static str {
        "QDIM"
    }

    fn prompt(&self) -> String {
        match self.step {
            Step::Gathering => {
                t!("QDIM  Select geometry to dimension (Enter when done):").into_owned()
            }
            Step::Place => {
                t!("QDIM  Specify dimension line position or choose an option:").into_owned()
            }
            Step::Datum => t!("QDIM  Specify datum point:").into_owned(),
            Step::Edit => t!("QDIM  Select a point to remove (Enter when done):").into_owned(),
            Step::Settings => {
                t!("QDIM  Choose extension origin priority [Endpoints/Intersections]:").into_owned()
            }
        }
    }

    fn options(&self) -> Vec<CmdOption> {
        match self.step {
            Step::Place => vec![
                CmdOption::new("Continuous", "CONTINUOUS"),
                CmdOption::new("Staggered", "STAGGERED"),
                CmdOption::new("Baseline", "BASELINE"),
                CmdOption::new("Ordinate", "ORDINATE"),
                CmdOption::new("Radius", "RADIUS"),
                CmdOption::new("Diameter", "DIAMETER"),
                CmdOption::new("Datum point", "DATUM"),
                CmdOption::new("Edit", "EDIT"),
                CmdOption::new("Settings", "SETTINGS"),
            ],
            Step::Settings => vec![
                CmdOption::new("Endpoints", "ENDPOINTS"),
                CmdOption::new("Intersections", "INTERSECTIONS"),
            ],
            _ => Vec::new(),
        }
    }

    fn is_selection_gathering(&self) -> bool {
        self.step == Step::Gathering
    }
    fn selection_forces_add(&self) -> bool {
        self.step == Step::Gathering
    }
    fn on_selection_complete(&mut self, _handles: Vec<Handle>) -> CmdResult {
        CmdResult::NeedPoint
    }
    fn inject_selection_entities(&mut self, entities: Vec<SelectionEntity>) {
        self.selection = entities;
    }
    fn wants_text_input(&self) -> bool {
        matches!(self.step, Step::Place | Step::Settings)
    }
    fn point_step_accepts_keywords(&self) -> bool {
        self.step == Step::Place
    }

    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
        let keyword = text.trim().to_ascii_uppercase();
        if self.step == Step::Settings {
            match keyword.as_str() {
                "E" | "ENDPOINT" | "ENDPOINTS" => {
                    self.snap_priority = SnapPriority::Endpoints;
                    self.step = Step::Place;
                    return Some(CmdResult::SetQuickDimensionSnapPriority(0));
                }
                "I" | "INTERSECTION" | "INTERSECTIONS" => {
                    self.snap_priority = SnapPriority::Intersections;
                    self.step = Step::Place;
                    return Some(CmdResult::SetQuickDimensionSnapPriority(1));
                }
                _ => return Some(CmdResult::NeedPoint),
            }
        }
        match keyword.as_str() {
            "C" | "CONTINUOUS" => self.mode = Mode::Continuous,
            "S" | "STAGGERED" => self.mode = Mode::Staggered,
            "B" | "BASELINE" => self.mode = Mode::Baseline,
            "O" | "ORDINATE" => self.mode = Mode::Ordinate,
            "R" | "RADIUS" => self.mode = Mode::Radius,
            "DI" | "DIAMETER" => self.mode = Mode::Diameter,
            "DA" | "DATUM" | "DATUMPOINT" => {
                self.step = Step::Datum;
                return Some(CmdResult::NeedPoint);
            }
            "E" | "EDIT" => {
                self.step = Step::Edit;
                return Some(CmdResult::NeedPoint);
            }
            "SE" | "SETTINGS" => {
                self.step = Step::Settings;
                return Some(CmdResult::NeedPoint);
            }
            _ => return Some(CmdResult::NeedPoint),
        }
        Some(CmdResult::NeedPoint)
    }

    fn on_point(&mut self, point: DVec3) -> CmdResult {
        match self.step {
            Step::Gathering | Step::Settings => CmdResult::NeedPoint,
            Step::Datum => {
                self.datum = Some(self.plane.to_local(point));
                self.step = Step::Place;
                CmdResult::NeedPoint
            }
            Step::Edit => {
                self.remove_candidate(point);
                CmdResult::NeedPoint
            }
            Step::Place => {
                let dimensions = self.build_dimensions(point);
                if dimensions.is_empty() {
                    CmdResult::NeedPoint
                } else {
                    CmdResult::CommitDimensionsAndExit(dimensions)
                }
            }
        }
    }

    fn on_enter(&mut self) -> CmdResult {
        match self.step {
            Step::Gathering if !self.selection.is_empty() => {
                self.step = Step::Place;
                CmdResult::NeedPoint
            }
            Step::Edit | Step::Datum | Step::Settings => {
                self.step = Step::Place;
                CmdResult::NeedPoint
            }
            _ => CmdResult::Cancel,
        }
    }

    fn on_preview_wires(&mut self, point: DVec3) -> Vec<WireModel> {
        if self.step == Step::Place {
            return self.preview_dimensions(point);
        }
        if self.step == Step::Edit {
            let size = self.dim_spacing * 0.12;
            return self
                .candidates()
                .into_iter()
                .enumerate()
                .flat_map(|(index, candidate)| {
                    let x_start = self.plane.to_world(candidate.point - DVec3::X * size);
                    let x_end = self.plane.to_world(candidate.point + DVec3::X * size);
                    let y_start = self.plane.to_world(candidate.point - DVec3::Y * size);
                    let y_end = self.plane.to_world(candidate.point + DVec3::Y * size);
                    [
                        WireModel::solid_f64(
                            format!("qdim_edit_{index}_x"),
                            vec![x_start.to_array(), x_end.to_array()],
                            WireModel::CYAN,
                            false,
                        ),
                        WireModel::solid_f64(
                            format!("qdim_edit_{index}_y"),
                            vec![y_start.to_array(), y_end.to_array()],
                            WireModel::CYAN,
                            false,
                        ),
                    ]
                })
                .collect();
        }
        Vec::new()
    }

    fn dimension_preview(&self, cursor: DVec3) -> Option<Vec<DimensionPreview>> {
        (self.step == Step::Place).then(|| {
            self.build_dimensions(cursor)
                .into_iter()
                .map(|(entity, _)| DimensionPreview::current_style(entity))
                .collect()
        })
    }
}

fn v3(point: DVec3) -> Vector3 {
    Vector3::new(point.x, point.y, point.z)
}
fn d3(point: Vector3) -> DVec3 {
    DVec3::new(point.x, point.y, point.z)
}

fn candidate_tolerance(points: impl Iterator<Item = DVec3>) -> f64 {
    let magnitude = points
        .map(|point| point.x.abs().max(point.y.abs()).max(point.z.abs()))
        .fold(1.0_f64, f64::max);
    Tolerance::default()
        .linear()
        .max(magnitude * f64::EPSILON * 64.0)
}

fn dimension_reference_points(dimension: &Dimension) -> Vec<DVec3> {
    match dimension {
        Dimension::Linear(value) => vec![d3(value.first_point), d3(value.second_point)],
        Dimension::Aligned(value) => vec![d3(value.first_point), d3(value.second_point)],
        Dimension::Radius(value) => vec![d3(value.angle_vertex), d3(value.definition_point)],
        Dimension::Diameter(value) => vec![d3(value.angle_vertex), d3(value.definition_point)],
        Dimension::Ordinate(value) => vec![d3(value.feature_location)],
        Dimension::Angular2Ln(value) => vec![
            d3(value.first_point),
            d3(value.second_point),
            d3(value.angle_vertex),
            d3(value.definition_point),
        ],
        Dimension::Angular3Pt(value) => vec![
            d3(value.angle_vertex),
            d3(value.first_point),
            d3(value.second_point),
        ],
        Dimension::Arc(value) => vec![
            d3(value.center_point),
            d3(value.first_extension_point),
            d3(value.second_extension_point),
        ],
        Dimension::LargeRadial(value) => vec![d3(value.definition_point), d3(value.chord_point)],
    }
}

fn preview_entity(index: usize, entity: &EntityType) -> Vec<WireModel> {
    let EntityType::Dimension(dimension) = entity else {
        return Vec::new();
    };
    let mut lines: Vec<Vec<[f64; 3]>> = Vec::new();
    match &**dimension {
        Dimension::Linear(value) => {
            let first = d3(value.first_point);
            let second = d3(value.second_point);
            let definition = d3(value.definition_point);
            let horizontal = value.rotation.cos().abs() >= value.rotation.sin().abs();
            let first_line = if horizontal {
                DVec3::new(first.x, definition.y, definition.z)
            } else {
                DVec3::new(definition.x, first.y, definition.z)
            };
            let second_line = if horizontal {
                DVec3::new(second.x, definition.y, definition.z)
            } else {
                DVec3::new(definition.x, second.y, definition.z)
            };
            lines.push(vec![first.to_array(), first_line.to_array()]);
            lines.push(vec![second.to_array(), second_line.to_array()]);
            lines.push(vec![first_line.to_array(), second_line.to_array()]);
        }
        Dimension::Ordinate(value) => lines.push(vec![
            d3(value.feature_location).to_array(),
            d3(value.leader_endpoint).to_array(),
        ]),
        Dimension::Radius(value) => lines.push(vec![
            d3(value.angle_vertex).to_array(),
            d3(value.definition_point).to_array(),
            d3(value.base.text_middle_point).to_array(),
        ]),
        Dimension::Diameter(value) => lines.push(vec![
            d3(value.definition_point).to_array(),
            d3(value.angle_vertex).to_array(),
            d3(value.base.text_middle_point).to_array(),
        ]),
        _ => {}
    }
    lines
        .into_iter()
        .enumerate()
        .map(|(part, points)| {
            WireModel::solid_f64(
                format!("qdim_preview_{index}_{part}"),
                points,
                WireModel::CYAN,
                false,
            )
        })
        .collect()
}

inventory::submit!(crate::command::CommandRegistration { names: &["QDIM"] });