import { path as pathModule, Plugin, type ProjectFile, Shape, StringShape, ts } from '@servicenow/sdk-build-core'
import { applyPathMappings } from './utils'

const HTML_IMPORT_PREFIX = `<!-- @fluent-import-html`
const HTML_IMPORT_WARNING = `WARNING: This file was imported from the output of a static build. Modifications of any kind are likely to result in unintended behavior. In most cases, you should edit the source file of the HTML imported below. If you are absolutely certain you want to take control of this HTML, you can remove this comment to prevent the SDK from regenerating it. However, you will then be responsible for the management of this HTML in your Fluent file. -->`

const getDeclarationAndModuleSpecifierIfHtml = (node: ts.Node): [ts.ImportDeclaration, string] | null => {
    const [importClause] = node.getSymbol()?.getDeclarations() ?? []
    if (!importClause) {
        return null
    }

    const importDeclaration = importClause.getParent()?.asKind(ts.SyntaxKind.ImportDeclaration)
    if (!importDeclaration) {
        return null
    }

    const moduleSpecifier = importDeclaration.getModuleSpecifierValue()
    if (!moduleSpecifier.endsWith('.html')) {
        return null
    }

    return [importDeclaration, moduleSpecifier]
}

export const HtmlImportPlugin = Plugin.create({
    name: 'HtmlImportPlugin',
    noTelemetry: true,
    shapes: [
        {
            shape: StringShape,
            commit(shape, target) {
                const results = getDeclarationAndModuleSpecifierIfHtml(target)
                if (!results) {
                    return { success: false }
                }
                const shapeContent = shape.getValue().trim()
                // skip committing if the content has the import directive comment
                return { success: shapeContent.startsWith(HTML_IMPORT_PREFIX) }
            },
        },
    ],
    nodes: [
        {
            node: 'Identifier',
            fileTypes: ['fluent'],
            toShape(node, context) {
                const { project, diagnostics, config } = context
                const results = getDeclarationAndModuleSpecifierIfHtml(node)
                if (!results) {
                    return { success: false }
                }
                const [importDeclaration, moduleSpecifier] = results

                if (!/^\.\.?\/.*$/.test(moduleSpecifier.trim())) {
                    diagnostics.error(importDeclaration, 'import must be a relative path')
                    return { success: false }
                }

                const currentDir = pathModule.dirname(node.getSourceFile().getFilePath())
                const resolvedPath = project.resolvePath(currentDir, moduleSpecifier)
                const projectRelativePath = pathModule.relative(project.getRootDir(), resolvedPath)

                if (projectRelativePath.startsWith('..')) {
                    diagnostics.error(importDeclaration, `import not within project: ${moduleSpecifier}`)
                    return { success: false }
                }

                const mappedPath = applyPathMappings(projectRelativePath, config.staticContent.paths)

                let htmlFile: ProjectFile
                try {
                    htmlFile = project.addFile(mappedPath, { resolveDependencies: false, excludeFromCompiler: true })
                } catch (e) {
                    diagnostics.error(
                        importDeclaration,
                        `failed to add HTML file: ${e instanceof Error ? e.message : String(e)}`
                    )
                    return { success: false }
                }

                return {
                    success: true,
                    // add a directive comment to the imported HTML content to warn users against modifing it
                    value: Shape.from(node, `${HTML_IMPORT_PREFIX} ${HTML_IMPORT_WARNING}\n${htmlFile.getContent()}`),
                }
            },
        },
    ],
})