//! Composition menu, part two: crop to region of interest / layer bounds, Save Frame As ▸ File,
//! Responsive Design — Time.

use effectcraft_keyframe::Value as KV;
use effectcraft_project::Marker;
use effectcraft_time::Tick;
use serde_json::{Value, json};

use super::{CommandSpec, bad, comp_id, f_p, has_comp, has_layers, layers_p, str_p};
use crate::{EngineError, Result, Session, cmd};

fn has_roi(s: &Session) -> std::result::Result<(), String> {
    has_comp(s)?;
    if s.state.region_of_interest.is_some() { Ok(()) } else { Err("draw a region of interest in the viewer first".into()) }
}

/// Crop the comp to `[x, y, w, h]`: the comp shrinks and every unparented layer moves by -x, -y
/// (all position keys too) so nothing moves on screen.
fn crop(s: &mut Session, cid: effectcraft_project::ItemId, r: [f64; 4], label: &str) -> Result<Value> {
    let (x, y) = (r[0].round(), r[1].round());
    let (w, h) = (r[2].round().max(1.0) as u32, r[3].round().max(1.0) as u32);
    s.edit(label, None, |proj, st| {
        let c = proj.comp_mut(cid).ok_or(EngineError::NoComp)?;
        c.width = w;
        c.height = h;
        for l in c.layers.iter_mut().filter(|l| l.parent.is_none()) {
            let Some(pos) = l.transform_mut().and_then(|tr| tr.get_mut("position")) else { continue };
            let mv = |v: &KV| {
                let a = v.as_vec3();
                KV::Vec3([a[0] - x, a[1] - y, a[2]])
            };
            pos.value = mv(&pos.value);
            for k in &mut pos.keys {
                k.value = mv(&k.value);
            }
        }
        for g in &mut c.guides {
            g.position -= if g.vertical { x } else { y };
        }
        st.region_of_interest = None;
        Ok(())
    })?;
    Ok(json!({"width": w, "height": h, "offset": [x, y]}))
}

fn crop_to_roi(s: &mut Session, p: &Value) -> Result<Value> {
    let cid = comp_id(s, p)?;
    let r = s.state.region_of_interest.ok_or_else(|| bad("comp.cropToRegionOfInterest", "no region of interest"))?;
    crop(s, cid, r, "Crop Comp to Region of Interest")
}

fn crop_to_layers(s: &mut Session, p: &Value) -> Result<Value> {
    let (cid, ids) = layers_p(s, p)?;
    let t = s.time();
    let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
    let ctx = effectcraft_render::EvalCtx::new(&s.project, cid, comp, t);
    let mut b = [f64::MAX, f64::MAX, f64::MIN, f64::MIN];
    for l in comp.layers.iter().filter(|l| ids.contains(&l.id)) {
        let Some([x0, y0, x1, y1]) = effectcraft_render::content_bounds(&ctx, l) else { continue };
        let (m, _) = ctx.layer_to_comp(l);
        for (px, py) in [(x0, y0), (x1, y0), (x1, y1), (x0, y1)] {
            let v = m.0;
            let wz = v[2][0] * px + v[2][1] * py + v[2][2];
            let wz = if wz.abs() < 1e-9 { 1.0 } else { wz };
            let cx = (v[0][0] * px + v[0][1] * py + v[0][2]) / wz;
            let cy = (v[1][0] * px + v[1][1] * py + v[1][2]) / wz;
            b = [b[0].min(cx), b[1].min(cy), b[2].max(cx), b[3].max(cy)];
        }
    }
    if b[0] > b[2] {
        return Err(bad("comp.cropToLayerBounds", "the selected layers have no visible bounds"));
    }
    let (x0, y0) = (b[0].floor(), b[1].floor());
    crop(s, cid, [x0, y0, b[2].ceil() - x0, b[3].ceil() - y0], "Crop Comp to Selected Layer(s) Bounds")
}

/// Encode straight 8-bit RGBA as PNG.
pub(crate) fn encode_png(rgba: &[u8], w: u32, h: u32) -> std::result::Result<Vec<u8>, String> {
    use image::ImageEncoder;
    let mut out = vec![];
    image::codecs::png::PngEncoder::new(&mut out).write_image(rgba, w, h, image::ExtendedColorType::Rgba8).map_err(|e| e.to_string())?;
    Ok(out)
}

/// Save Frame As ▸ File with `queue`: a Render Queue item for the current frame, from the Frame
/// Default templates (Edit ▸ Templates).
fn queue_frame(s: &mut Session, p: &Value) -> Result<Value> {
    use effectcraft_project::render_queue::{RenderQueueItem, TimeSpan};
    use effectcraft_project::render_templates::TemplateSlot;
    let cid = comp_id(s, p)?;
    let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
    let t = f_p(p, "time").map(Tick::from_seconds_f64).unwrap_or(s.time());
    let mut it = RenderQueueItem::new(0, cid);
    it.settings = s.project.render_templates.default_render_settings(TemplateSlot::Still);
    it.settings.time_span = TimeSpan::Custom { start: t, end: t + comp.frame_duration() };
    it.output = s.project.render_templates.default_output_module(TemplateSlot::Still);
    if let Some(path) = str_p(p, "path") {
        it.output.output = path.to_string();
    } else if !it.output.format.is_sequence() {
        it.output.output = "[compName]_frame.[fileExtension]".into();
    }
    let id = s.edit("Save Frame As", None, |proj, _| {
        it.id = proj.render_queue.iter().map(|i| i.id).max().unwrap_or(0) + 1;
        let id = it.id;
        proj.render_queue.push(it);
        Ok(id)
    })?;
    let path = s.project.render_queue.last().and_then(|i| s.resolve_output(i));
    Ok(json!({"item": id, "queued": true, "output": path, "time": t.seconds()}))
}

fn save_frame(s: &mut Session, p: &Value) -> Result<Value> {
    if p.get("queue").and_then(Value::as_bool) == Some(true) {
        return queue_frame(s, p);
    }
    let path = str_p(p, "path").ok_or_else(|| bad("comp.saveFrameAs", "missing `path` (.png)"))?.to_string();
    let cid = comp_id(s, p)?;
    let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
    let t = f_p(p, "time").map(Tick::from_seconds_f64).unwrap_or(s.time());
    let scale = f_p(p, "scale").unwrap_or(1.0).clamp(0.01, 4.0);
    let bg = comp.background;
    let img = s.render(cid, t, effectcraft_render::RenderOpts { scale, backend: effectcraft_render::Backend::Auto, ..Default::default() });
    let rgba = img.to_rgba8_over(bg);
    let png = encode_png(&rgba, img.width, img.height).map_err(|e| EngineError::Other(format!("PNG encoding failed: {e}")))?;
    s.services.write_file(&path, &png).map_err(|e| EngineError::Other(format!("cannot write {path}: {e}")))?;
    s.toast(format!("Saved frame to {path}"));
    Ok(json!({"path": path, "width": img.width, "height": img.height, "time": t.seconds()}))
}

/// Responsive Design — Time: protected comp markers for an intro, an outro or the work area.
fn responsive_time(s: &mut Session, p: &Value) -> Result<Value> {
    let cid = comp_id(s, p)?;
    let comp = s.project.comp(cid).ok_or(EngineError::NoComp)?;
    let t = s.time();
    let (start, end, comment) = match str_p(p, "op").unwrap_or("workArea") {
        "intro" => (Tick::ZERO, t, "Intro"),
        "outro" => (t, comp.duration, "Outro"),
        "workArea" => (comp.work_area.0, comp.work_area.1, "Protected Region"),
        o => return Err(bad("comp.responsiveTime", format!("op: intro|outro|workArea, not `{o}`"))),
    };
    if end <= start {
        return Err(bad("comp.responsiveTime", "move the current time first (the region would be empty)"));
    }
    s.edit("Create Protected Region", None, |proj, _| {
        let c = proj.comp_mut(cid).ok_or(EngineError::NoComp)?;
        c.markers.push(Marker { time: start, duration: end - start, comment: comment.into(), protected: true, ..Default::default() });
        c.markers.sort_by_key(|m| m.time);
        Ok(())
    })?;
    Ok(json!({"start": start.seconds(), "end": end.seconds()}))
}

pub fn specs() -> Vec<CommandSpec> {
    vec![
        cmd!("comp.cropToRegionOfInterest", "Crop Comp to Region of Interest", ["Composition"], None, "{comp?}", has_roi, crop_to_roi),
        cmd!("comp.cropToLayerBounds", "Crop Comp to Selected Layer(s) Bounds", ["Composition"], None, "{layers?}", has_layers, crop_to_layers),
        cmd!(
            "comp.saveFrameAs",
            "File...",
            ["Composition", "Save Frame As"],
            Some("Cmd+Alt+S"),
            "{path (.png; with queue: an output path or template), time?, scale?, queue?: bool (add a Render Queue item from the Frame Default templates instead of writing now)}",
            has_comp,
            save_frame
        ),
        cmd!("comp.responsiveTime", "Responsive Design — Time", [], None, "{op: intro|outro|workArea}", has_comp, responsive_time),
    ]
}