/* tslint:disable */

import * as Lint from 'tslint'
import { findImports, ImportKind } from 'tsutils'
import * as ts from 'typescript'

export class Rule extends Lint.Rules.AbstractRule {
    /* tslint:disable object-literal-sort-keys */
    public static metadata: Lint.IRuleMetadata = {
        ruleName: 'no-reaching-imports',
        description: Lint.Utils.dedent`
            Disallows importing any submodule.`,
        rationale: Lint.Utils.dedent`
            I hope this will help prevent circular dependencies.`,
        optionsDescription: 'None.',
        options: {},
        optionExamples: [ true ],
        type: 'functionality',
        typescriptOnly: false,
        hasFix: true,
    }

    public static FAILURE_STRING = 'Do not reach into a module to import its submodules; maybe this module needs to expose this submodule?'

    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
        return this.applyWithFunction(sourceFile, walk, this.ruleArguments)
    }
}

function walk(ctx: Lint.WalkContext<string[]>) {
    for (const name of findImports(ctx.sourceFile, ImportKind.All)) {
        if (isSubmodulePath(name.text)) {

            const fix = new Lint.Replacement(name.getStart(), name.getWidth(), fixedSubmodulePath(name.text))

            ctx.addFailureAtNode(name, Rule.FAILURE_STRING, fix)
        }
    }
}

function isSubmodulePath(path: string): boolean {
    const steps = path.split('/')
    if (steps[ 0 ][ 0 ] === '@') {
        return false
    }
    let badSteps = 0
    steps.forEach(step => {
        if (step !== '..' && step !== '.') {
            badSteps += 1
        }
    })
    return badSteps > 1
}

function fixedSubmodulePath(path: string): string {
    const steps = path.split('/')
    let output = '\''
    let finished = false
    steps.forEach((step, index) => {
        if (finished) {
            return
        }
        if (index > 0) {
            output += '/'
        }
        output += step
        if (step !== '..' && step !== '.') {
            finished = true
        }
    })
    return output + '\''
}