import { NodeMaterialBlockConnectionPointTypes } from './nodeMaterialBlockConnectionPointTypes';
import { NodeMaterialBuildState } from './nodeMaterialBuildState';
import { Nullable } from '../../types';
import { NodeMaterialConnectionPoint } from './nodeMaterialBlockConnectionPoint';
import { NodeMaterialBlockTargets } from './nodeMaterialBlockTargets';
import { Effect, EffectFallbacks } from '../effect';
import { AbstractMesh } from '../../Meshes/abstractMesh';
import { Mesh } from '../../Meshes/mesh';
import { NodeMaterial, NodeMaterialDefines } from './nodeMaterial';

/**
 * Defines a block that can be used inside a node based material
 */
export class NodeMaterialBlock {
    private _buildId: number;
    private _target: NodeMaterialBlockTargets;
    private _isFinalMerger = false;
    private _isInput = false;

    /** @hidden */
    public _inputs = new Array<NodeMaterialConnectionPoint>();
    /** @hidden */
    public _outputs = new Array<NodeMaterialConnectionPoint>();

    /**
     * Gets or sets the name of the block
     */
    public name: string;

    /**
     * Gets a boolean indicating that this block is an end block (e.g. it is generating a system value)
     */
    public get isFinalMerger(): boolean {
        return this._isFinalMerger;
    }

    /**
     * Gets a boolean indicating that this block is an input (e.g. it sends data to the shader)
     */
    public get isInput(): boolean {
        return this._isInput;
    }

    /**
     * Gets or sets the build Id
     */
    public get buildId(): number {
        return this._buildId;
    }

    public set buildId(value: number) {
        this._buildId = value;
    }

    /**
     * Gets or sets the target of the block
     */
    public get target() {
        return this._target;
    }

    public set target(value: NodeMaterialBlockTargets) {
        if ((this._target & value) !== 0) {
            return;
        }
        this._target = value;
    }

    /**
     * Gets the list of input points
     */
    public get inputs(): NodeMaterialConnectionPoint[] {
        return this._inputs;
    }

    /** Gets the list of output points */
    public get outputs(): NodeMaterialConnectionPoint[] {
        return this._outputs;
    }

    /**
     * Find an input by its name
     * @param name defines the name of the input to look for
     * @returns the input or null if not found
     */
    public getInputByName(name: string) {
        let filter = this._inputs.filter((e) => e.name === name);

        if (filter.length) {
            return filter[0];
        }

        return null;
    }

    /**
     * Find an output by its name
     * @param name defines the name of the outputto look for
     * @returns the output or null if not found
     */
    public getOutputByName(name: string) {
        let filter = this._outputs.filter((e) => e.name === name);

        if (filter.length) {
            return filter[0];
        }

        return null;
    }

    /**
     * Creates a new NodeMaterialBlock
     * @param name defines the block name
     * @param target defines the target of that block (Vertex by default)
     * @param isFinalMerger defines a boolean indicating that this block is an end block (e.g. it is generating a system value). Default is false
     * @param isInput defines a boolean indicating that this block is an input (e.g. it sends data to the shader). Default is false
     */
    public constructor(name: string, target = NodeMaterialBlockTargets.Vertex, isFinalMerger = false, isInput = false) {
        this.name = name;

        this._target = target;

        this._isFinalMerger = isFinalMerger;
        this._isInput = isInput;
    }

    /**
     * Initialize the block and prepare the context for build
     * @param state defines the state that will be used for the build
     */
    public initialize(state: NodeMaterialBuildState) {
        // Do nothing
    }

    /**
     * Bind data to effect. Will only be called for blocks with isBindable === true
     * @param effect defines the effect to bind data to
     * @param nodeMaterial defines the hosting NodeMaterial
     * @param mesh defines the mesh that will be rendered
     */
    public bind(effect: Effect, nodeMaterial: NodeMaterial, mesh?: Mesh) {
        // Do nothing
    }

    protected _declareOutput(output: NodeMaterialConnectionPoint, state: NodeMaterialBuildState): string {
        // if (output.isVarying) {
        //     return `${output.associatedVariableName}`;
        // }

        return `${state._getGLType(output.type)} ${output.associatedVariableName}`;
    }

    protected _writeVariable(currentPoint: NodeMaterialConnectionPoint): string {
        let connectionPoint = currentPoint.connectedPoint!;
        return `${currentPoint.associatedVariableName}${connectionPoint.swizzle ? "." + connectionPoint.swizzle : ""}`;
    }

    protected _writeFloat(value: number) {
        let stringVersion = value.toString();

        if (stringVersion.indexOf(".") === -1) {
            stringVersion += ".0";
        }
        return `${stringVersion}`;
    }

    /**
     * Gets the current class name e.g. "NodeMaterialBlock"
     * @returns the class name
     */
    public getClassName() {
        return "NodeMaterialBlock";
    }

    /**
     * Register a new input. Must be called inside a block constructor
     * @param name defines the connection point name
     * @param type defines the connection point type
     * @param isOptional defines a boolean indicating that this input can be omitted
     * @param target defines the target to use to limit the connection point (will be VetexAndFragment by default)
     * @returns the current block
     */
    public registerInput(name: string, type: NodeMaterialBlockConnectionPointTypes, isOptional: boolean = false, target?: NodeMaterialBlockTargets) {
        let point = new NodeMaterialConnectionPoint(name, this);
        point.type = type;
        point.isOptional = isOptional;
        if (target) {
            point.target = target;
        }

        this._inputs.push(point);

        return this;
    }

    /**
     * Register a new output. Must be called inside a block constructor
     * @param name defines the connection point name
     * @param type defines the connection point type
     * @param target defines the target to use to limit the connection point (will be VetexAndFragment by default)
     * @returns the current block
     */
    public registerOutput(name: string, type: NodeMaterialBlockConnectionPointTypes, target?: NodeMaterialBlockTargets) {
        let point = new NodeMaterialConnectionPoint(name, this);
        point.type = type;
        if (target) {
            point.target = target;
        }

        this._outputs.push(point);

        return this;
    }

    /**
     * Will return the first available input e.g. the first one which is not an uniform or an attribute
     * @param forOutput defines an optional connection point to check compatibility with
     * @returns the first available input or null
     */
    public getFirstAvailableInput(forOutput: Nullable<NodeMaterialConnectionPoint> = null) {
        for (var input of this._inputs) {
            if (!input.connectedPoint) {
                if (!forOutput || (forOutput.type & input.type) !== 0 || input.type === NodeMaterialBlockConnectionPointTypes.AutoDetect) {
                    return input;
                }
            }
        }

        return null;
    }

    /**
     * Will return the first available output e.g. the first one which is not yet connected and not a varying
     * @param forBlock defines an optional block to check compatibility with
     * @returns the first available input or null
     */
    public getFirstAvailableOutput(forBlock: Nullable<NodeMaterialBlock> = null) {
        for (var output of this._outputs) {
            if (!forBlock || !forBlock.target || (forBlock.target & output.target) !== 0) {
                return output;
            }
        }

        return null;
    }

    /**
     * Connect current block with another block
     * @param other defines the block to connect with
     * @param options define the various options to help pick the right connections
     * @returns the current block
     */
    public connectTo(other: NodeMaterialBlock, options?: {
        input?: string,
        output?: string,
        outputSwizzle?: string
    }) {
        if (this._outputs.length === 0) {
            return;
        }

        let output = options && options.output ? this.getOutputByName(options.output) : this.getFirstAvailableOutput(other);
        let input = options && options.input ? other.getInputByName(options.input) : other.getFirstAvailableInput(output);

        if (output && input) {
            output.swizzle = options ? options.outputSwizzle || "" : "";
            output.connectTo(input);
        } else {
            throw "Unable to find a compatible match";
        }

        return this;
    }

    protected _buildBlock(state: NodeMaterialBuildState) {
        // Empty. Must be defined by child nodes
    }

    protected _emit(state: NodeMaterialBuildState, define?: string) {
        // Empty. Must be defined by child nodes
    }

    /**
     * Add uniforms, samplers and uniform buffers at compilation time
     * @param state defines the state to update
     * @param nodeMaterial defines the node material requesting the update
     * @param defines defines the material defines to update
     */
    public updateUniformsAndSamples(state: NodeMaterialBuildState, nodeMaterial: NodeMaterial, defines: NodeMaterialDefines) {
        // Do nothing
    }

    /**
     * Add potential fallbacks if shader compilation fails
     * @param mesh defines the mesh to be rendered
     * @param fallbacks defines the current prioritized list of fallbacks
     */
    public provideFallbacks(mesh: AbstractMesh, fallbacks: EffectFallbacks) {
        // Do nothing
    }

    /**
     * Update defines for shader compilation
     * @param mesh defines the mesh to be rendered
     * @param nodeMaterial defines the node material requesting the update
     * @param defines defines the material defines to update
     * @param useInstances specifies that instances should be used
     */
    public prepareDefines(mesh: AbstractMesh, nodeMaterial: NodeMaterial, defines: NodeMaterialDefines, useInstances: boolean = false) {
        // Do nothing
    }

    /**
     * Lets the block try to connect some inputs automatically
     */
    public autoConfigure() {
        // Do nothing
    }

    /**
     * Function called when a block is declared as repeatable content generator
     * @param vertexShaderState defines the current compilation state for the vertex shader
     * @param fragmentShaderState defines the current compilation state for the fragment shader
     * @param mesh defines the mesh to be rendered
     * @param defines defines the material defines to update
     */
    public replaceRepeatableContent(vertexShaderState: NodeMaterialBuildState, fragmentShaderState: NodeMaterialBuildState, mesh: AbstractMesh, defines: NodeMaterialDefines) {
        // Do nothing
    }

    /**
     * Checks if the block is ready
     * @param mesh defines the mesh to be rendered
     * @param nodeMaterial defines the node material requesting the update
     * @param defines defines the material defines to update
     * @param useInstances specifies that instances should be used
     * @returns true if the block is ready
     */
    public isReady(mesh: AbstractMesh, nodeMaterial: NodeMaterial, defines: NodeMaterialDefines, useInstances: boolean = false) {
        return true;
    }

    /**
     * Compile the current node and generate the shader code
     * @param state defines the current compilation state (uniforms, samplers, current string)
     * @returns the current block
     */
    public build(state: NodeMaterialBuildState) {
        if (this._buildId === state.sharedData.buildId) {
            return;
        }

        // Check if "parent" blocks are compiled
        for (var input of this._inputs) {
            if (!input.connectedPoint) {
                if (!input.isOptional) { // Emit a warning
                    state.sharedData.checks.notConnectedNonOptionalInputs.push(input);
                }
                continue;
            }

            if ((input.target & this.target!) === 0) {
                continue;
            }

            if ((input.target & state.target!) === 0) {
                continue;
            }

            let block = input.connectedPoint.ownerBlock;
            if (block && block !== this && block.buildId !== state.sharedData.buildId) {
                block.build(state);
            }
        }

        if (this._buildId === state.sharedData.buildId) {
            return; // Need to check again as inputs can be connected multiple time to this endpoint
        }

        // Logs
        if (state.sharedData.verbose) {
            console.log(`${state.target === NodeMaterialBlockTargets.Vertex ? "Vertex shader" : "Fragment shader"}: Building ${this.name} [${this.getClassName()}]`);
        }


        /** Emit input blocks */
        this._emit(state);

        /** Prepare outputs */
        for (var output of this._outputs) {
            if ((output.target & this.target!) === 0) {
                continue;
            }
            if ((output.target & state.target!) === 0) {
                continue;
            }

            if (!output.associatedVariableName) {
                output.associatedVariableName = state._getFreeVariableName(output.name);
            }
        }

        // Checks final outputs
        if (this.isFinalMerger) {
            switch (state.target) {
                case NodeMaterialBlockTargets.Vertex:
                    state.sharedData.checks.emitVertex = true;
                    break;
                case NodeMaterialBlockTargets.Fragment:
                    state.sharedData.checks.emitFragment = true;
                    break;
            }
        }

        if (!this.isInput && state.sharedData.emitComments) {
            state.compilationString += `\r\n//${this.name}\r\n`;
        }

        this._buildBlock(state);

        this._buildId = state.sharedData.buildId;

        // Compile connected blocks
        for (var output of this._outputs) {
            if ((output.target & state.target) === 0) {
                continue;
            }

            for (var block of output.connectedBlocks) {
                if (block && (block.target & state.target) !== 0) {
                    block.build(state);
                }
            }
        }
        return this;
    }
}