import { z, ZodTypeAny } from 'zod'
import * as path from 'path'
import { accessSync, constants, lstatSync, existsSync } from 'fs'

import { isString } from '@polymech/'

import { logger } from '../logger'

import { sync as exists } from '@polymech/fs/exists'
import { sync as read } from '@polymech/fs/read'

import { DEFAULT_VARS, resolve, resolveVariables } from '../variables'

import { getDescription } from '../'
import { isFile } from '../lib/fs'


type TResult = { resolved: string, source: string, value: unknown }
type TRefine = (src: string, ctx: any, variables: Record<string, string>) => string | z.ZodNever
type TTransform = (src: string, variables?: Record<string, string>) => string | TResult
type TExtend = { refine: Array<TRefine>, transform: Array<TTransform> }

const DefaultPathSchemaBase = z.string().describe('Path to a file or directory')

const PathErrorMessages = {
    INVALID_INPUT: 'INVALID_INPUT: ${inputPath}',
    PATH_DOES_NOT_EXIST: 'Path does not exist ${inputPath} = ${resolvedPath}',
    DIRECTORY_NOT_WRITABLE: 'Directory is not writable ${inputPath} = ${resolvedPath}',
    NOT_A_DIRECTORY: 'Path is not a directory or does not exist ${inputPath} = ${resolvedPath}',
    NOT_A_JSON_FILE: 'File is not a JSON file or does not exist ${inputPath} = ${resolvedPath}',
    PATH_NOT_ABSOLUTE: 'Path is not absolute ${inputPath} = ${resolvedPath}',
    PATH_NOT_RELATIVE: 'Path is not relative ${inputPath} = ${resolvedPath}',
} as const

export enum E_PATH {
    ENSURE_PATH_EXISTS = 1,
    INVALID_INPUT,
    ENSURE_DIRECTORY_WRITABLE,
    ENSURE_FILE_IS_JSON,
    ENSURE_PATH_IS_ABSOLUTE,
    ENSURE_PATH_IS_RELATIVE,
    GET_PATH_INFO
}
export const Transformers = {
    resolve: (val: string, variables: Record<string, string> = {}) => {
        if (!val) {
            return null
        }
        return {
            resolved: path.resolve(resolve(val, false, variables)),
            source: val
        }
    },
    json: (val: string | { resolved: string, source: string }, variables: Record<string, string> = {}) => {
        if (!val) {
            return null
        }
        const resolved = path.resolve(resolve(isString(val) ? val : val.source, false, variables))
        return {
            resolved,
            source: val,
            value: read(resolved, 'json')
        }
    },
    string: (val: string | { resolved: string, source: string }, variables: Record<string, string> = {}) => {
        if (!val) {
            return null
        }
        let src = isString(val) ? val : val.source
        src = resolve(src, false, variables)
        const resolved = path.resolve(src)
        if (!exists(resolved) || !isFile(resolved)) {
            return {
                resolved,
                source: val,
                value: null
            }
        }
        else {
            let value = null
            try {
                value = read(resolved, 'string')
            } catch (e) {
                logger.error('Failed to read file', { resolved, source: val, error: e.message })
            }
            return {
                resolved,
                source: val,
                value
            }
        }
    }
}

export const TransformersDescription = [
    {
        description: 'RESOLVE_PATH',
        fn: Transformers.resolve
    },
    {
        description: 'READ_JSON',
        fn: Transformers.json
    },
    {
        description: 'READ_STRING',
        fn: Transformers.string
    }
]
const extendType = (type: ZodTypeAny, extend: TExtend, variables: Record<string, string> = {}) => {
    if (Array.isArray(extend.refine)) {
        for (const refine of extend.refine) {
            type = type.refine(refine as any)
        }
    } else {
        type = type.refine(extend.refine)
    }
    if (Array.isArray(extend.transform)) {
        for (const transform of extend.transform) {
            type = type.transform((val) => transform(val, variables))
        }
    } else {
        type = type.transform(extend.transform)
    }
    return type
}

const extendTypeDescription = (type: ZodTypeAny, extension: TExtend, variables: Record<string, string> = {}) => {
    const description = getDescription(type) || ''
    let transformerDescriptions = 'Transformers:\n'
    if (Array.isArray(extension.transform)) {
        for (const transform of extension.transform) {
            transformerDescriptions += transformerDescription(transform) + '\n'
        }
    } else {
        transformerDescriptions += transformerDescription(extension.transform) + '\n'
    }
    type = type.describe(description + '\n' + transformerDescriptions)
    return type
}

const transformerDescription = (fn: TTransform) => {
    const description = TransformersDescription.find((t) => t.fn === fn)
    return description ? description.description : 'Unknown'
}

export const extendSchema = (baseSchema: z.ZodObject<any>, extend: Record<string, any>) => {
    const baseShape = baseSchema.shape
    const extendedShape: Record<string, ZodTypeAny> = { ...baseShape }
    for (const [key, refines] of Object.entries(extend)) {
        if (!baseShape[key])
            continue

        let fieldSchema = baseShape[key]
        if (Array.isArray(refines.refine)) {
            for (const refine of refines.refine) {
                fieldSchema = fieldSchema.superRefine(refine)
            }
        } else {
            fieldSchema = fieldSchema.superRefine(refines)
        }
        if (Array.isArray(refines.transform)) {
            for (const transform of refines.transform) {
                fieldSchema = fieldSchema.transform((val) => transform(val))
            }
        } else {
            fieldSchema = fieldSchema.transform(refines.transform)
        }
        extendedShape[key] = fieldSchema

    }
    return z.object(extendedShape)
}

export const ENSURE_DIRECTORY_WRITABLE = (inputPath: string, ctx: any, variables: Record<string, string>) => {
    const resolvedPath = path.resolve(resolve(inputPath, false, variables))
    const parts = path.parse(resolvedPath)
    if (resolvedPath && existsSync(parts.dir) && lstatSync(parts.dir).isDirectory()) {
        try {
            accessSync(resolvedPath, constants.W_OK)
            return resolvedPath
        } catch (e) {
            ctx.addIssue({
                code: E_PATH.ENSURE_DIRECTORY_WRITABLE,
                message: resolveVariables(PathErrorMessages.DIRECTORY_NOT_WRITABLE, false, { inputPath, resolvedPath })
            })
            return z.NEVER
        }
    } else {
        ctx.addIssue({
            code: E_PATH.ENSURE_DIRECTORY_WRITABLE,
            message: resolveVariables(PathErrorMessages.NOT_A_DIRECTORY, false, { inputPath, resolvedPath })
        })
        return z.NEVER
    }

}
export const IS_VALID_STRING = (inputPath: string) => {
    return isString(inputPath)
}
export const ENSURE_PATH_EXISTS = (inputPath: string, ctx: any, variables: Record<string, string>) => {
    if (!inputPath || !ctx) {
        return z.NEVER
    }
    if (!isString(inputPath)) {
        ctx.addIssue({
            code: E_PATH.INVALID_INPUT,
            message: resolveVariables(PathErrorMessages.INVALID_INPUT, false, {})
        })
        return z.NEVER
    }
    const resolvedPath = path.resolve(resolve(inputPath, false, variables))
    if (!exists(resolvedPath)) {
        ctx.addIssue({
            code: E_PATH.ENSURE_PATH_EXISTS,
            message: resolveVariables(PathErrorMessages.PATH_DOES_NOT_EXIST, false, { inputPath, resolvedPath })
        })

        return z.NEVER
    }
    return resolvedPath
}

export const test = () => {
    const BaseCompilerOptions = () => z.object({
        root: DefaultPathSchemaBase.default(`${process.cwd()}`)
    })
    const ret = extendSchema(BaseCompilerOptions(), {
        root: {
            refine: [
                (val, ctx) => ENSURE_DIRECTORY_WRITABLE(val, ctx, DEFAULT_VARS({ exampleVar: 'exampleValue' })),
                (val, ctx) => ENSURE_PATH_EXISTS(val, ctx, DEFAULT_VARS({ exampleVar: 'exampleValue' }))
            ],
            transform: [
                (val) => path.resolve(resolve(val, false, DEFAULT_VARS({ exampleVar: 'exampleValue' })))
            ]
        }
    })
    return ret
}

export const Templates =
{
    json: {
        refine: [IS_VALID_STRING, ENSURE_PATH_EXISTS],
        transform: [Transformers.resolve, Transformers.json]
    },
    string: {
        refine: [ENSURE_PATH_EXISTS],
        transform: [Transformers.resolve, Transformers.string]
    }
}

export const extend = (baseSchema: ZodTypeAny, template: any, variables: Record<string, string> = {}) => {
    const type = extendType(baseSchema, template, variables)
    return extendTypeDescription(type, template, variables)
}