use crate::asset::GlyphAssetSlotIndex;
use crate::frame_composer::FrameComposer;
use crate::gfx::Gfx;
use crate::memory_banks::{GlyphBankPoolAccess, MemoryBanks, SceneBankPoolAccess};
use prometeu_hal::app_mode::AppMode;
use prometeu_hal::{
    OwnedRgba8888Frame, RenderSubmission, RenderSubmissionPacket, RenderWorkerBackend,
    RenderWorkerError,
};
use std::sync::{Arc, Mutex};

pub struct LocalFramebufferRenderBackend {
    gfx: Mutex<Gfx>,
    frame_composer: Mutex<FrameComposer>,
}

impl LocalFramebufferRenderBackend {
    pub fn new(width: usize, height: usize, glyph_banks: Arc<dyn GlyphBankPoolAccess>) -> Self {
        Self::new_with_parts(
            width,
            height,
            glyph_banks,
            Arc::new(MemoryBanks::new()),
            GlyphAssetSlotIndex::new(),
        )
    }

    pub fn new_with_memory_banks(
        width: usize,
        height: usize,
        memory_banks: Arc<MemoryBanks>,
        glyph_slot_index: GlyphAssetSlotIndex,
    ) -> Self {
        Self::new_with_parts(
            width,
            height,
            Arc::clone(&memory_banks) as Arc<dyn GlyphBankPoolAccess>,
            memory_banks,
            glyph_slot_index,
        )
    }

    fn new_with_parts(
        width: usize,
        height: usize,
        glyph_banks: Arc<dyn GlyphBankPoolAccess>,
        scene_banks: Arc<dyn SceneBankPoolAccess>,
        glyph_slot_index: GlyphAssetSlotIndex,
    ) -> Self {
        Self {
            gfx: Mutex::new(Gfx::new(width, height, glyph_banks)),
            frame_composer: Mutex::new(FrameComposer::new(
                width,
                height,
                scene_banks,
                glyph_slot_index,
            )),
        }
    }

    pub fn render_submission(
        &self,
        submission: &RenderSubmission,
    ) -> Result<OwnedRgba8888Frame, RenderWorkerError> {
        let mut gfx = self.gfx.lock().map_err(|_| RenderWorkerError::InternalFailure)?;
        match &submission.packet {
            RenderSubmissionPacket::Game2D(packet) if submission.app_mode == AppMode::Game => {
                if packet.composer.bound_scene.is_none() {
                    gfx.render_game2d_frame_packet(packet);
                } else {
                    let mut frame_composer = self
                        .frame_composer
                        .lock()
                        .map_err(|_| RenderWorkerError::InternalFailure)?;
                    frame_composer.render_game2d_frame_packet(packet, &mut *gfx);
                    gfx.apply_gfx2d_commands(&packet.gfx2d);
                }
            }
            RenderSubmissionPacket::ShellUi(packet) if submission.app_mode == AppMode::Shell => {
                gfx.render_shell_ui_frame_packet(packet);
            }
            _ => return Err(RenderWorkerError::RenderFailed),
        }

        gfx.present();
        let (width, height) = gfx.size();
        OwnedRgba8888Frame::packed(
            submission.frame_id,
            submission.ownership,
            width,
            height,
            gfx.front_buffer().to_vec(),
        )
        .map_err(|_| RenderWorkerError::InternalFailure)
    }
}

impl RenderWorkerBackend for LocalFramebufferRenderBackend {
    fn render(
        &self,
        submission: &RenderSubmission,
    ) -> Result<OwnedRgba8888Frame, RenderWorkerError> {
        self.render_submission(submission)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::memory_banks::MemoryBanks;
    use prometeu_hal::app_mode::AppMode;
    use prometeu_hal::color::Color;
    use prometeu_hal::primitives::Rect;
    use prometeu_hal::{
        FrameId, Game2DFramePacket, Gfx2dCommand, GfxUiCommand, RenderOwnership, ShellUiFramePacket,
    };

    fn backend() -> LocalFramebufferRenderBackend {
        let banks = Arc::new(MemoryBanks::new());
        LocalFramebufferRenderBackend::new(4, 4, banks)
    }

    #[test]
    fn local_backend_renders_game2d_submission_to_owned_frame() {
        let backend = backend();
        let mut packet = Game2DFramePacket::default();
        packet.gfx2d = vec![Gfx2dCommand::FillRect {
            rect: Rect { x: 1, y: 1, w: 2, h: 2 },
            color: Color::RED,
        }];
        let ownership = RenderOwnership::new(3, AppMode::Game, 9);
        let submission =
            RenderSubmission::game2d(FrameId::new(5), packet).with_ownership(ownership);

        let frame = backend.render(&submission).expect("game frame should render");

        assert_eq!(frame.frame_id, FrameId::new(5));
        assert_eq!(frame.ownership, ownership);
        assert_eq!(frame.width, 4);
        assert_eq!(frame.height, 4);
        assert_eq!(frame.pixels[1 + 4], Color::RED.raw());
        assert_eq!(frame.pixels[2 + 2 * 4], Color::RED.raw());
    }

    #[test]
    fn local_backend_renders_shell_ui_submission_to_owned_frame() {
        let backend = backend();
        let packet = ShellUiFramePacket::new(vec![GfxUiCommand::FillRect {
            rect: Rect { x: 0, y: 0, w: 1, h: 1 },
            color: Color::GREEN,
        }]);
        let ownership = RenderOwnership::new(4, AppMode::Shell, 10);
        let submission =
            RenderSubmission::shell_ui(FrameId::new(6), packet).with_ownership(ownership);

        let frame = backend.render(&submission).expect("shell frame should render");

        assert_eq!(frame.frame_id, FrameId::new(6));
        assert_eq!(frame.ownership, ownership);
        assert_eq!(frame.pixels[0], Color::GREEN.raw());
    }
}