// The snapshot's input is the COMMITTED binding default in config/security.yml, not src/.env.
//
// It used to read rootProject.file('.env'). /.gitignore:7 excludes `src/.env*` (allowing only the
// two *.example files), so `git ls-files src/.env` is empty and the file does not exist in a CI
// checkout — a gate whose expected value comes from an untracked file is not reproducible, and the
// first line of this closure turned that into a hard failure on any clean machine. Locally it was
// worse than a failure: it passed against one developer's file. The committed snapshot recorded
// `/api/healthcheck`, taken from that local .env, while the shipped default in
// app-bootstrap/src/main/resources/config/security.yml binds
//   public-paths: ${SECURITY_PUBLIC_PATHS:${PRESENTATION_API_BASE_PATH:/v1}/healthcheck}
// = /v1/healthcheck. The reviewed snapshot therefore described a surface no deployment had.
//
// What the snapshot now pins is the permitAll surface a deployment gets when no operator override
// is set — the thing a reviewer must see change. An operator's own SECURITY_PUBLIC_PATHS at run
// time is outside the repository and outside any build gate; the default is the part this
// repository is accountable for.
Closure<String> renderPublicPathSnapshot = { File securityConfigFile ->
    if (!securityConfigFile.isFile()) {
        throw new GradleException(
                "missing public-path security configuration ${securityConfigFile}")
    }

    def bindingPattern = ~/^\s*public-paths:\s*(\S.*?)\s*$/
    List<String> bindings = securityConfigFile.readLines('UTF-8').findResults { String line ->
        def matcher = bindingPattern.matcher(line)
        matcher.matches() ? matcher.group(1) : null
    }
    if (bindings.size() != 1) {
        throw new GradleException(
                "expected exactly one 'public-paths:' binding in ${securityConfigFile}, " +
                        "found ${bindings.size()} — the snapshot cannot say which surface it pins")
    }

    // Resolve Spring placeholders to their defaults, innermost first:
    // ${A:${B:/v1}/healthcheck} -> ${A:/v1/healthcheck} -> /v1/healthcheck.
    // `[^{}]*` only ever matches the innermost placeholder, so one substitution per pass unwinds
    // the nesting from the inside out without any replacement-string escaping.
    def defaultedPlaceholder = ~/\$\{[A-Za-z0-9_.]+:([^{}]*)\}/
    String raw = bindings.first()
    for (int guard = 0; guard < 16; guard++) {
        def matcher = defaultedPlaceholder.matcher(raw)
        if (!matcher.find()) {
            break
        }
        raw = raw.substring(0, matcher.start()) + matcher.group(1) + raw.substring(matcher.end())
    }
    if (raw.contains('${')) {
        throw new GradleException(
                "'public-paths' in ${securityConfigFile} resolves to '${raw}', which still holds a " +
                        'placeholder with no default — the deployed public path surface is not ' +
                        'determined by the repository and cannot be snapshotted')
    }
    List<String> publicPaths = raw.split(',')
            .collect { String value -> value.trim() }
            .findAll { String value -> !value.isEmpty() }
            .toSorted()

    String header =
            "# feature-security-operational-baseline D5 — deny-by-default public path snapshot.\n" +
                    "# SSOT: ca-skeleton.security.public-paths default in " +
                    "app-bootstrap/src/main/resources/config/security.yml\n" +
                    "# -> SecurityConfig permitAll(); anyRequest authenticated. An operator's own " +
                    "SECURITY_PUBLIC_PATHS\n" +
                    "# overrides it at run time and is outside this snapshot.\n" +
                    "# Update only after review with: ./gradlew updatePublicPathSnapshot " +
                    "-PapprovePublicPathChange\n"
    header + (publicPaths.isEmpty() ? '' : publicPaths.join('\n') + '\n')
}

File publicPathSourceFile =
        rootProject.file('app-bootstrap/src/main/resources/config/security.yml')
File publicPathSnapshotFile =
        rootProject.file('../docs/security/public-paths-snapshot.txt')
boolean publicPathUpdateApproved = project.hasProperty('approvePublicPathChange')
def existingPublicPathSource = providers.provider {
    publicPathSourceFile.isFile() ? publicPathSourceFile : null
}
def existingPublicPathSnapshot = providers.provider {
    publicPathSnapshotFile.isFile() ? publicPathSnapshotFile : null
}

tasks.register('verifyPublicPathSnapshot') {
    group = 'verification'
    description = 'Fails without mutation when the committed deny-by-default public path baseline drifts.'
    inputs.file(existingPublicPathSource).optional()
    inputs.file(existingPublicPathSnapshot).optional()
    inputs.property('updateApprovalRequested', publicPathUpdateApproved)

    doLast {
        if (publicPathUpdateApproved) {
            throw new GradleException(
                    'verifyPublicPathSnapshot is read-only; use updatePublicPathSnapshot ' +
                            '-PapprovePublicPathChange for an intentional update.')
        }
        String canonical
        try {
            canonical = renderPublicPathSnapshot(publicPathSourceFile)
        } catch (GradleException exception) {
            throw new GradleException(
                    "verifyPublicPathSnapshot: ${exception.message}", exception)
        }
        if (!publicPathSnapshotFile.isFile()) {
            throw new GradleException(
                    "verifyPublicPathSnapshot: missing committed baseline ${publicPathSnapshotFile}")
        }

        String existing = publicPathSnapshotFile.getText('UTF-8')
        if (existing != canonical) {
            throw new GradleException(
                    "verifyPublicPathSnapshot: the deny-by-default public path surface changed.\n" +
                            "  expected (snapshot):\n${existing}\n" +
                            "  actual (security.yml public-paths default):\n${canonical}\n" +
                            'A protected endpoint may now be public. Review the change, then run:\n' +
                            '  ./gradlew updatePublicPathSnapshot -PapprovePublicPathChange')
        }
        logger.lifecycle(
                'verifyPublicPathSnapshot: OK — committed public paths are unchanged.')
    }
}

tasks.register('updatePublicPathSnapshot') {
    group = 'build setup'
    description = 'Explicitly updates the committed public path baseline after security review.'
    inputs.file(existingPublicPathSource).optional()
    inputs.property('approved', publicPathUpdateApproved)
    outputs.file(publicPathSnapshotFile)
    outputs.upToDateWhen { false }

    doLast {
        if (!publicPathUpdateApproved) {
            throw new GradleException(
                    'updatePublicPathSnapshot requires -PapprovePublicPathChange')
        }
        String canonical
        try {
            canonical = renderPublicPathSnapshot(publicPathSourceFile)
        } catch (GradleException exception) {
            throw new GradleException(
                    "updatePublicPathSnapshot: ${exception.message}", exception)
        }
        if (!publicPathSnapshotFile.parentFile.isDirectory()
                && !publicPathSnapshotFile.parentFile.mkdirs()) {
            throw new GradleException(
                    "updatePublicPathSnapshot: failed to create ${publicPathSnapshotFile.parentFile}")
        }
        publicPathSnapshotFile.setText(canonical, 'UTF-8')
        logger.lifecycle(
                "updatePublicPathSnapshot: wrote reviewed baseline ${publicPathSnapshotFile}")
    }
}