import { INDENT, MIN_SIZE, toUpperSnakeCase, formatType, STRUCTURE_FILES } from './common';
import { isCppAllowed } from './map';
import { Method } from './method';
import { Property, StaticProperty } from './property';
import { VTable } from './vtable';

export class Struct {
    readonly #name: string;
    #vtable: VTable | null;
    readonly #methods: Method[];
    readonly #properties: Property[];
    #size: number | null;
    readonly #dependencies: string[];
    readonly #staticProperties: StaticProperty[];

    // Constructor
    constructor(name: string) {
        this.#name = name;
        this.#methods = [];
        this.#properties = [];
        this.#vtable = null;
        this.#size = null;
        this.#dependencies = [];
        this.#staticProperties = [];
    }

    // Dependencies
    #addDependency(dependency: string) {
        this.#dependencies.push(dependency);
    }
    getDependencies() {
        return this.#dependencies;
    }

    // Ensure VTable Exists
    #ensureVTable() {
        if (this.#vtable === null) {
            this.#vtable = new VTable(this.#name);
            this.addProperty(this.#vtable);
        }
    }

    // Setters
    setSize(size: number) {
        this.#size = size;
    }
    // Getters
    #roundSize(size: number) {
        const alignment = this.getAlignment();
        return Math.ceil(size / alignment) * alignment;
    }
    getSize() {
        let size;
        if (this.#size !== null) {
            size = this.#size;
        } else {
            size = MIN_SIZE;
            for (const property of this.#properties) {
                const newSize = property.propertyOffset() + property.propertySize();
                if (newSize > size) {
                    size = newSize;
                }
            }
        }
        size = this.#roundSize(size);
        return size;
    }
    getName() {
        return this.#name;
    }
    getAlignment() {
        let alignment = 1;
        for (const property of this.#properties) {
            const x = property.propertyAlignment();
            if (x > alignment) {
                alignment = x;
            }
        }
        return alignment;
    }

    // Add Method
    addMethod(method: Method, isVirtual: boolean) {
        if (method.self !== this.#name) {
            throw new Error();
        }
        if (isVirtual) {
            this.#ensureVTable();
            this.#vtable!.add(method);
        } else {
            this.#methods.push(method);
        }
    }
    // Add Property
    addProperty(property: Property) {
        this.#properties.push(property);
        // Add Dependency If Needed
        const type = property.propertyType();
        if (type in STRUCTURE_FILES) {
            this.#addDependency(type);
        }
    }
    // Add Static Property
    addStaticProperty(property: StaticProperty) {
        this.#staticProperties.push(property);
    }

    // Configure VTable
    setVTableSize(size: number) {
        this.#ensureVTable();
        this.#vtable!.setSize(size);
    }
    setVTableAddress(address: number) {
        this.#ensureVTable();
        this.#vtable!.setAddress(address);
    }

    // Check
    #check() {
        // Sort Properties
        this.#properties.sort((a, b) => a.propertyOffset() - b.propertyOffset());

        // Check Size
        const size = this.getSize();
        if (this.#size !== null) {
            // Check Alignment
            if (size !== this.#size) {
                throw new Error('Size Misaligned');
            }
            // Check If Size Is Too Small
            const lastProperty = this.#properties[this.#properties.length - 1];
            if (lastProperty) {
                let realSize = lastProperty.propertyOffset() + lastProperty.propertySize();
                realSize = this.#roundSize(realSize);
                if (realSize > this.#size) {
                    throw new Error(`Structure Size Too Small: ${this.#size}`);
                }
            }
        }
    }

    // Generate Header
    generate() {
        let out = '';

        // Check
        this.#check();

        // Static Properties
        for (const property of this.#staticProperties) {
            out += `extern ${property.generateDefinition()}`;
        }

        // Methods
        for (const method of this.#methods) {
            out += method.generateTypedef();
            out += `extern ${method.generateDefinition()}`;
        }

        // Early Exit For Undefined Structures
        if (this.#properties.length === 0 && this.#size === null) {
            return out;
        }

        // VTable
        if (this.#vtable !== null) {
            out += this.#vtable.generate();
        }

        // Structure
        out += `struct ${this.#name} {\n`;
        for (let i = 0; i <= this.#properties.length; i++) {
            const property = this.#properties[i];

            // Padding
            const lastProperty = this.#properties[i - 1];
            let neededPadding = 0;
            if (i === 0) {
                // Start Of Structure Padding
                if (property) {
                    neededPadding = property.propertyOffset();
                } else if (this.#properties.length === 0) {
                    if (this.#size !== null) {
                        neededPadding = this.#size;
                    } else {
                        neededPadding = MIN_SIZE;
                    }
                }
            } else if (i === this.#properties.length) {
                // End Of Structure Padding
                if (this.#size !== null && lastProperty) {
                    const realSize = lastProperty.propertyOffset() + lastProperty.propertySize();
                    neededPadding = this.#size - realSize;
                }
            } else {
                // Inner Structure Padding
                if (property && lastProperty) {
                    const realSize = lastProperty.propertyOffset() + lastProperty.propertySize();
                    neededPadding = property.propertyOffset() - realSize;
                }
            }
            if (neededPadding > 0) {
                out += `${INDENT}uchar padding${i}[${neededPadding}];\n`;
            } else if (neededPadding < 0) {
                throw new Error('Overlapping properties detected!');
            }

            // Property
            if (property) {
                // Check Offset
                const offset = property.propertyOffset();
                const alignment = property.propertyAlignment();
                if ((offset % alignment) !== 0) {
                    throw new Error('Misaligned Property Offset');
                }
                // Add
                const type = formatType(property.propertyType());
                out += `${INDENT}${type}${property.propertyName()};\n`;
            }
        }
        out += `};\n`;

        // Sanity Check Offsets
        const assertFunction = isCppAllowed() ? 'static_assert' : '_Static_assert';
        for (let i = 0; i < this.#properties.length; i++) {
            const property = this.#properties[i]!;
            const name = property.propertyName();
            const offset = property.propertyOffset();
            out += `${assertFunction}(offsetof(${this.#name}, ${name}) == ${offset}, "Invalid Offset");\n`;
        }

        // Sanity Check Size
        const size = this.getSize();
        out += `#define ${toUpperSnakeCase(this.#name)}_SIZE ${size}\n`;
        out += `${assertFunction}(sizeof (${this.#name}) == ${toUpperSnakeCase(this.#name)}_SIZE, "Invalid Structure Size");\n`;
        if (this.#size === null) {
            // Hide Structure Size As The Real Size Is Unknown
            out += `#undef ${toUpperSnakeCase(this.#name)}_SIZE\n`;
        }

        // Allocation Function
        if (this.#size !== null) {
            out += `${this.#name} *alloc_${this.#name}();\n`;
        }

        // Return
        return out;
    }

    // Generate Compiled Code
    generateCode() {
        let declarations = '';
        let init = '';

        // Check
        this.#check();

        // Static Properties
        for (const property of this.#staticProperties) {
            init += `${INDENT}${property.getName()} = (${property.getType()}) ${property.address};\n`;
            declarations += property.generateDefinition();
        }

        // Methods
        for (const method of this.#methods) {
            init += `${INDENT}${method.getName()} = (${method.getType()}) ${method.address};\n`;
            declarations += method.generateDefinition();
        }

        // VTable
        if (this.#vtable !== null) {
            const vtable = this.#vtable.generateCode();
            declarations += vtable.declarations;
            init += vtable.init;
        }

        // Allocation Function
        if (this.#size !== null) {
            declarations += `${this.#name} *alloc_${this.#name}() {\n`;
            declarations += `${INDENT}return (${this.#name} *) ::operator new(${this.#size});\n`;
            declarations += '}\n';
        }

        // Return
        return {functions: declarations, init};
    }
}