import os from 'node:os'
import url from 'node:url'
import path from 'node:path'
import fs from 'node:fs/promises'

import logger from '@wdio/logger'
import { parse, print, visit, types } from 'recast'
import typescriptParser from 'recast/parsers/typescript.js'
import type { Plugin } from 'vite'

import type { MockHandler } from '../mock.js'

const log = logger('@wdio/browser-runner:mockHoisting')
const INTERNALS_TO_IGNORE = [
    '@vite/client', 'vite/dist/client', '/webdriverio/build/', '/@wdio/', '/webdriverio/node_modules/',
    'virtual:wdio', '?html-proxy', '/__fixtures__/', '/__mocks__/', '/.vite/deps/@testing-library_vue.js'
]

const b = types.builders
const MOCK_PREFIX = '/@mock'
export function mockHoisting(mockHandler: MockHandler): Plugin[] {
    let spec: string | null = null
    let isTestDependency = false
    const sessionMocks = new Set<string>()
    const importMap = new Map<string, string>()

    return [{
        name: 'wdio:mockHoisting:pre',
        enforce: 'pre',
        resolveId: mockHandler.resolveId.bind(mockHandler),
        load: async function (id) {
            if (id.startsWith(MOCK_PREFIX)) {
                try {
                    const orig = await fs.readFile(id.slice(MOCK_PREFIX.length + (os.platform() === 'win32' ? 1 : 0)))
                    return orig.toString()
                } catch (err) {
                    log.error(`Failed to read file (${id}) for mocking: ${(err as Error).message}`)
                    return ''
                }
            }
        }
    }, {
        name: 'wdio:mockHoisting',
        enforce: 'post',
        transform(code, id) {
            const isSpecFile = id === spec
            if (isSpecFile) {
                isTestDependency = true
            }

            /**
             * only transform files:
             */
            if (
                // where loading was inititated through the test file
                (!isTestDependency && (
                    // however when files are inlined they will be loaded when parsing file under test
                    // in this case we want to transform them, but make sure we exclude these paths
                    id.includes('/node_modules/') || id.includes('/?cid=') || id.startsWith('virtual:'))
                ) ||
                // are not Vite or WebdriverIO internals
                INTERNALS_TO_IGNORE.find((f) => id.includes(f)) ||
                // when the spec file is actually mocking any dependencies
                (!isSpecFile && sessionMocks.size === 0)
            ) {
                return { code }
            }

            let ast: types.namedTypes.File
            const start = Date.now()
            try {
                ast = parse(code, {
                    parser: typescriptParser,
                    sourceFileName: id,
                    sourceRoot: path.dirname(id)
                })
                log.trace(`Parsed file for mocking: ${id} in ${Date.now() - start}ms`)
            } catch {
                return { code }
            }

            let importIndex = 0
            let mockFunctionName: string
            let unmockFunctionName: string
            const mockCalls: (types.namedTypes.ExpressionStatement | types.namedTypes.ImportDeclaration)[] = []

            visit(ast, {
                /**
                 * find function name for mock and unmock calls
                 */
                visitImportDeclaration: function (path) {
                    const dec = path.value as types.namedTypes.ImportDeclaration
                    const source = dec.source.value!

                    if (!dec.specifiers || dec.specifiers.length === 0 || source !== '@wdio/browser-runner') {
                        return this.traverse(path)
                    }

                    /**
                     * get name of mock function variable
                     */
                    const mockSpecifier = (dec.specifiers as types.namedTypes.ImportSpecifier[])
                        .filter((s) => s.type === types.namedTypes.ImportSpecifier.toString())
                        .find((s) => s.imported.name === 'mock')
                    if (mockSpecifier && mockSpecifier.local) {
                        mockFunctionName = mockSpecifier.local.name as string
                    }

                    const unmockSpecifier = (dec.specifiers as types.namedTypes.ImportSpecifier[])
                        .filter((s) => s.type === types.namedTypes.ImportSpecifier.toString())
                        .find((s) => s.imported.name === 'unmock')
                    if (unmockSpecifier && unmockSpecifier.local) {
                        unmockFunctionName = unmockSpecifier.local.name as string
                    }
                    mockCalls.push(dec)
                    path.prune()
                    return this.traverse(path)
                },
                /**
                 * detect which modules are supposed to be mocked
                 */
                ...(isSpecFile ? {
                    visitExpressionStatement: function (path) {
                        const exp = path.value as types.namedTypes.ExpressionStatement
                        if (exp.expression.type !== types.namedTypes.CallExpression.toString()) {
                            return this.traverse(path)
                        }

                        const callExp = exp.expression as types.namedTypes.CallExpression
                        const isUnmockCall = unmockFunctionName && (callExp.callee as types.namedTypes.Identifier).name === unmockFunctionName
                        const isMockCall = mockFunctionName && (callExp.callee as types.namedTypes.Identifier).name === mockFunctionName

                        if (!isMockCall && !isUnmockCall) {
                            return this.traverse(path)
                        }

                        /**
                         * hoist unmock calls
                         */
                        if (isUnmockCall && callExp.arguments[0] && typeof (callExp.arguments[0] as types.namedTypes.Literal).value === 'string') {
                            mockHandler.unmock((callExp.arguments[0] as types.namedTypes.Literal).value as string)
                        } else if (isMockCall) {
                            /**
                             * if only one mock argument is set, we take the fixture from the automock directory
                             */
                            const mockCall = exp.expression as types.namedTypes.CallExpression
                            if (mockCall.arguments.length === 1) {
                                /**
                                 * enable manual mock
                                 */
                                mockHandler.manualMocks.push((mockCall.arguments[0] as types.namedTypes.StringLiteral).value)
                            } else {
                                if ((exp.expression as types.namedTypes.CallExpression).arguments.length) {
                                    sessionMocks.add(((exp.expression as types.namedTypes.CallExpression).arguments[0] as types.namedTypes.Literal).value as string)
                                }

                                /**
                                 * hoist mock calls
                                 */
                                mockCalls.push(exp)
                            }
                        }

                        path.prune()
                        this.traverse(path)
                    }
                } : {})
            })
            visit(ast, {
                /**
                 * rewrite import statements
                 */
                visitImportDeclaration: function (nodePath) {
                    const dec = nodePath.value as types.namedTypes.ImportDeclaration
                    const source = dec.source.value as string

                    if (!dec.specifiers || dec.specifiers.length === 0) {
                        return this.traverse(nodePath)
                    }

                    const newImportIdentifier = `__wdio_import${importIndex++}`
                    const isMockedModule = Boolean(
                        // matches if a dependency is mocked
                        sessionMocks.has(source) ||
                        // matches if a relative file is mocked
                        (
                            source.startsWith('.') &&
                            [...sessionMocks.values()].find((m) => {
                                const fileImportPath = path.resolve(path.dirname(id), source)
                                const fileImportPathSliced = fileImportPath.slice(0, path.extname(fileImportPath).length * -1)
                                const testMockPath = path.resolve(path.dirname(spec || '/'), m)
                                const testMockPathSliced = testMockPath.slice(0, path.extname(testMockPath).length * -1)
                                return fileImportPathSliced === testMockPathSliced && fileImportPathSliced.length > 0
                            })
                        )
                    )

                    /**
                     * add to import map if module is mocked and imported in the test file
                     */
                    if (isMockedModule && isSpecFile) {
                        importMap.set(source, newImportIdentifier)
                    }

                    /**
                     * Assign imports outside of spec files or when module gets mocked
                     * into custom import identifier, e.g.
                     *
                     *   from:
                     *      import { foo } from 'bar'
                     *
                     *   to:
                     *      import * as __wdio_import0 from 'bar'
                     */
                    if (!isSpecFile || isMockedModule) {
                        const newNode = b.importDeclaration(
                            [b.importNamespaceSpecifier(b.identifier(newImportIdentifier))],
                            b.literal(source)
                        )
                        mockCalls.unshift(newNode)
                    }

                    // determine file extension length so we can cut it out, fall back to infinity if no extension is set
                    const mockExtensionLengh = (path.extname(source).length * -1) || Infinity
                    const wdioImportModuleIdentifier = source.startsWith('.') || source.startsWith('/')
                        ? url.pathToFileURL(path.resolve(path.dirname(id), source).slice(0, mockExtensionLengh)).pathname
                        : source
                    const isNamespaceImport = dec.specifiers.length === 1 && dec.specifiers[0].type === types.namedTypes.ImportNamespaceSpecifier.toString()
                    const mockImport = isSpecFile && !isMockedModule
                        /**
                         * within spec files we transform import declarations into import expresssions, e.g.
                         *     from: import { foo } from 'bar'
                         *     to:   const { foo } = await wdioImport('bar', await import('bar'))
                         *
                         * in order to hoist `mock(...)` calls and have them run first
                         */
                        ? b.variableDeclaration('const', [
                            b.variableDeclarator(
                                isNamespaceImport
                                    /**
                                     * we deal with a ImportNamespaceSpecifier, e.g.:
                                     * import * as foo from 'bar'
                                     */
                                    ? dec.specifiers[0].local as types.namedTypes.Identifier
                                    /**
                                     * we deal with default or named import, e.g.
                                     * import foo from 'bar'
                                     * or
                                     * import { foo } from 'bar'
                                     */
                                    : b.objectPattern(dec.specifiers.map((s: types.namedTypes.ImportSpecifier) => {
                                        if (s.type === types.namedTypes.ImportDefaultSpecifier.toString()) {
                                            return b.property('init', b.identifier('default'), b.identifier(s.local!.name as string))
                                        }
                                        return b.property('init', b.identifier(s.imported.name as string), b.identifier(s.local!.name as string))
                                    })),
                                b.awaitExpression(b.importExpression(b.literal(source)))
                            )
                        ])
                        /**
                         * outside of spec files we transform import declarations so that the imported module gets
                         * wrapped within `wdioImport`, e.g.:
                         *
                         *   from:
                         *      import { foo } from 'bar'
                         *
                         *   to:
                         *      import { foo as __wdio_import0 } from 'bar'
                         *      const { foo } = await wdioImport('bar', __wdio_import0)
                         */
                        : b.variableDeclaration('const', [
                            b.variableDeclarator(
                                dec.specifiers.length === 1 && dec.specifiers[0].type === types.namedTypes.ImportNamespaceSpecifier.toString()
                                    ? b.identifier(dec.specifiers[0].local!.name as string)
                                    : b.objectPattern(dec.specifiers.map((s: types.namedTypes.ImportSpecifier) => {
                                        if (s.type === types.namedTypes.ImportDefaultSpecifier.toString()) {
                                            return b.property('init', b.identifier('default'), b.identifier(s.local!.name as string))
                                        }
                                        return b.property('init', b.identifier(s.imported.name as string), b.identifier(s.local!.name as string))
                                    })),
                                b.callExpression(
                                    b.identifier('wdioImport'),
                                    [
                                        b.literal(wdioImportModuleIdentifier),
                                        b.identifier(newImportIdentifier)
                                    ]
                                )
                            )
                        ])
                    nodePath.replace(mockImport)
                    this.traverse(nodePath)
                }
            })

            ast.program.body.unshift(...mockCalls.map((mc) => {
                const exp = mc as types.namedTypes.ExpressionStatement
                if (exp.expression && exp.expression.type === types.namedTypes.CallExpression.toString()) {
                    const mockCallExpression = exp.expression as types.namedTypes.CallExpression
                    const mockedModule = (mockCallExpression.arguments[0] as types.namedTypes.Literal).value as string
                    const mockFactory = (mockCallExpression.arguments[1] as types.namedTypes.FunctionExpression)

                    /**
                     * add actual module as 3rd parameter to the mock call if imported in the same test file
                     */
                    if (importMap.has(mockedModule)) {
                        mockCallExpression.arguments.push(b.identifier(importMap.get(mockedModule)!))
                    } else if (mockFactory.params.length > 0) {
                        /**
                         * `importMap` only has an entry if the module is imported in the same test file.
                         * However if the user mocks a dependency of a different dependency we need to add
                         * the import manually if the users wants to access the original module.
                         */
                        const newImportIdentifier = `__wdio_import${importIndex++}`
                        ast.program.body.unshift(b.importDeclaration(
                            [b.importNamespaceSpecifier(b.identifier(newImportIdentifier))],
                            b.literal(mockedModule)
                        ))
                        mockCallExpression.arguments.push(b.identifier(newImportIdentifier))
                    }
                    return b.expressionStatement(b.awaitExpression(mockCallExpression))
                }

                return mc
            }))

            try {
                const newCode = print(ast, { sourceMapName: id })
                log.trace(`Transformed file for mocking: ${id} in ${Date.now() - start}ms`)
                return newCode
            } catch (err) {
                log.trace(`Failed to transformed file (${id}) for mocking: ${(err as Error).stack}`)
                return { code }
            }
        },
        configureServer(server) {
            return () => {
                server.middlewares.use('/', async (req, res, next) => {
                    if (!req.originalUrl) {
                        return next()
                    }

                    const urlParsed = url.parse(req.originalUrl)
                    const urlParamString = new URLSearchParams(urlParsed.query || '')
                    const specParam = urlParamString.get('spec')

                    if (specParam) {
                        mockHandler.resetMocks()
                        isTestDependency = false
                        spec = os.platform() === 'win32' ? specParam.slice(1) : specParam
                    }

                    return next()
                })
            }
        }
    }]
}