package main

import (
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

type frontendViolation struct {
	file    string
	line    int
	rule    string
	snippet string
}

// Future enhancement (FUTURE-WO-012-ENFORCE): Add a lint rule that requires
// every string literal in a JSX text node to be wrapped in t(). This was
// intentionally omitted from WO-012 to avoid breaking all in-flight WOs that
// have untranslated strings. The scaffolding (i18next init, en.json catalog,
// t() + useTranslation exports) was shipped in WO-012; strict enforcement is
// deferred to a follow-up work order.

// Files/dirs where fetch() and manual clients are allowed.
// Each entry has a documented reason — add new entries only with justification.
var allowedFrontendFiles = map[string]bool{
	"lib/transport.ts":                               true, // Global transport setup
	"lib/api/transport.ts":                           true, // Orchestrator global transport setup
	"lib/token-refresh.ts":                           true, // Auth bootstrap client (avoids interceptor loop)
	"lib/sync/sync-engine.ts":                        true, // Jotai sync — lives outside React, can't use hooks
	"components/media-library/media-upload-area.tsx": true, // Multipart file upload via FormData
	"components/html-editor/preview-iframe.tsx":      true, // Block HTML preview (returns HTML, not proto)
	"lib/editor-bridge/iframe-script.ts":             true, // Editor iframe preview
	"player/human-proof/index.ts":                    true, // Standalone player bundle — no React, fetches public REST endpoint

	// createClient exceptions — each has a technical reason why useQuery/useMutation can't be used:
	// use-entity-search fans one debounced query out to 10 RPCs across 8 services
	// via useQueries (single combined loading state + result blending for the
	// command palette); generated per-RPC hooks can't express this without 10
	// independent hook instances and manual aggregation.
	"hooks/use-entity-search.ts":                          true,
	"routes/admin/plugins.tsx":                            true, // Server-streaming (for await...of) — useMutation doesn't support streaming
	"hooks/use-restart-operation.ts":                      true, // Server-streaming + raw Connect envelope for cross-origin orchestrator stream
	"routes/admin/menus.tsx":                              true, // Imperative async callback in useCallback
	"components/data-platform/tables/creation-wizard.tsx": true, // useMutation has serialization bug with oneof fields
}

// Plugin web files that are allowed to call plugin-owned REST handlers because
// there is no ConnectRPC surface for them yet. Keep this list narrow.
var allowedPluginRESTFiles = map[string]bool{
	"backend/internal/plugins/calcomblock/web/settings.tsx": true, // Plugin settings/test endpoints are mounted via HTTPHandler; no generated hooks exist yet
	"backend/internal/plugins/calcomblock/web/editor.tsx":   true, // Block editor reads plugin /settings + /event-types via HTTPHandler routes
}

// Specific fetch paths that are non-proto REST endpoints (no ConnectRPC equivalent)
// These get a WARN, not a FAIL
var knownNonProtoFetches = map[string]bool{
	"/api/plugins/":        true, // Plugin REST APIs
	"/api/mcp/":            true, // MCP device auth flow
	"/api/lists/subscribe": true, // Public subscribe endpoint
	"/preview/":            true, // Preview HTML endpoints
	"/api/ai/chat/stream":  true, // AI chat SSE streaming (EventSource/fetch — ConnectRPC doesn't support SSE)
	"/api/support/":        true, // CMS helpdesk widget: multipart attachment upload to the Chi proxy — connect-query can't send FormData
	"/api/helpdesk/upload": true, // Orchestrator helpdesk: multipart attachment upload — same FormData limitation
}

var (
	// Anti-pattern: importing axios
	reAxios = regexp.MustCompile(`(?:import|require).*['"]axios['"]`)

	// Anti-pattern: useQueryClient (should use refetch() instead)
	reUseQueryClient = regexp.MustCompile(`useQueryClient\s*\(`)

	// Anti-pattern in plugins: QueryClientProvider is already mounted by core
	reQueryClientProvider = regexp.MustCompile(`\bQueryClientProvider\b`)

	// Anti-pattern: createClient from connectrpc (should use generated hooks)
	reCreateClient = regexp.MustCompile(`createClient\s*\(`)

	// Anti-pattern: fetch() to /api/ or proto paths (should use ConnectRPC)
	reFetchAPI = regexp.MustCompile(`fetch\s*\(\s*['\x60"/]`)

	// Anti-pattern: createConnectTransport (only allowed in transport.ts)
	reCreateTransport = regexp.MustCompile(`createConnectTransport\s*\(`)

	// Anti-pattern: new XMLHttpRequest
	reXHR = regexp.MustCompile(`new\s+XMLHttpRequest`)

	// Anti-pattern: importing from @connectrpc/connect-web directly to create clients
	reConnectWebImport = regexp.MustCompile(`from\s+['"]@connectrpc/connect-web['"]`)

	// Anti-pattern: browser confirm() instead of the shared confirm dialog
	reWindowConfirm = regexp.MustCompile(`\bwindow\.confirm\s*\(`)
	reBareConfirm   = regexp.MustCompile(`(?:^|[^\w.])confirm\s*\(`)
)

func checkFrontend(webSrcDir string) (violations []frontendViolation, warnings []frontendViolation) {
	if err := filepath.Walk(webSrcDir, func(path string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() {
			return nil
		}

		ext := filepath.Ext(path)
		if ext != ".ts" && ext != ".tsx" && ext != ".js" && ext != ".jsx" {
			return nil
		}

		// Skip node_modules and build output.
		if strings.Contains(path, "node_modules") || strings.Contains(path, "/dist/") {
			return nil
		}
		// Skip test/spec files — they legitimately use createClient/transport and
		// fetch mocks to exercise the transport layer and are never shipped UI.
		// (Matches the convention the coming-soon and TODO checks already follow.)
		if strings.HasSuffix(path, ".test.ts") || strings.HasSuffix(path, ".test.tsx") ||
			strings.HasSuffix(path, ".spec.ts") || strings.HasSuffix(path, ".spec.tsx") {
			return nil
		}

		relPath, _ := filepath.Rel(webSrcDir, path)
		if relPath == "" {
			relPath = path
		}

		// Check if this file is in the allow list
		isAllowed := false
		for allowed := range allowedFrontendFiles {
			if strings.HasSuffix(relPath, allowed) || relPath == allowed {
				isAllowed = true
				break
			}
		}

		lines, err := readSourceLines(path)
		if err != nil {
			return nil
		}
		for idx, line := range lines {
			lineNum := idx + 1
			trimmed := strings.TrimSpace(line)

			if isCommentLine(trimmed) {
				continue
			}

			// Check axios
			if reAxios.MatchString(line) {
				violations = append(violations, frontendViolation{
					file: relPath, line: lineNum, rule: "no-axios",
					snippet: strings.TrimSpace(line),
				})
			}

			// Check useQueryClient
			if reUseQueryClient.MatchString(line) {
				violations = append(violations, frontendViolation{
					file: relPath, line: lineNum, rule: "no-useQueryClient",
					snippet: strings.TrimSpace(line),
				})
			}

			// Check XMLHttpRequest
			if reXHR.MatchString(line) {
				violations = append(violations, frontendViolation{
					file: relPath, line: lineNum, rule: "no-xhr",
					snippet: strings.TrimSpace(line),
				})
			}

			if isBrowserConfirmCall(lines, idx) {
				violations = append(violations, frontendViolation{
					file: relPath, line: lineNum, rule: "no-browser-confirm",
					snippet: strings.TrimSpace(line),
				})
			}

			// For allowed files, skip the remaining checks
			if isAllowed {
				continue
			}

			// Check createClient (only outside allowed files)
			if reCreateClient.MatchString(line) {
				// Check if it's a documented exception (streaming, oneof bug, etc.)
				violations = append(violations, frontendViolation{
					file: relPath, line: lineNum, rule: "no-createClient",
					snippet: strings.TrimSpace(line),
				})
			}

			// Check createConnectTransport
			if reCreateTransport.MatchString(line) {
				violations = append(violations, frontendViolation{
					file: relPath, line: lineNum, rule: "no-createConnectTransport",
					snippet: strings.TrimSpace(line),
				})
			}

			// Check @connectrpc/connect-web imports (manual client creation)
			if reConnectWebImport.MatchString(line) {
				violations = append(violations, frontendViolation{
					file: relPath, line: lineNum, rule: "no-connect-web-import",
					snippet: strings.TrimSpace(line),
				})
			}

			// Check fetch() calls to /api/ or proto RPC paths
			if reFetchAPI.MatchString(line) {
				isProtoFetch := strings.Contains(line, "/blockninja.v1.")
				isAPIFetch := strings.Contains(line, "/api/")

				if isProtoFetch {
					// fetch() to a proto RPC endpoint — should always use ConnectRPC client
					violations = append(violations, frontendViolation{
						file: relPath, line: lineNum, rule: "no-fetch-proto",
						snippet: strings.TrimSpace(line),
					})
				} else if isAPIFetch {
					// Check if this is a known non-proto endpoint (warn, not fail)
					isKnownNonProto := false
					for prefix := range knownNonProtoFetches {
						if strings.Contains(line, prefix) {
							isKnownNonProto = true
							break
						}
					}
					if isKnownNonProto {
						warnings = append(warnings, frontendViolation{
							file: relPath, line: lineNum, rule: "fetch-non-proto-api",
							snippet: strings.TrimSpace(line),
						})
					} else {
						violations = append(violations, frontendViolation{
							file: relPath, line: lineNum, rule: "no-fetch-api",
							snippet: strings.TrimSpace(line),
						})
					}
				}
			}
		}

		return nil
	}); err != nil {
		warnings = append(warnings, frontendViolation{
			file:    filepath.ToSlash(webSrcDir),
			line:    0,
			rule:    "walk-error",
			snippet: err.Error(),
		})
	}

	return violations, warnings
}

// checkPluginPages scans plugin web page directories for plugin-specific frontend
// anti-patterns. Plugins must use useQuery/useMutation with { transport } options
// (AGENT-GUIDE §7.2c) — createClient+useMemo is forbidden. Plugins must also
// never use raw fetch() and must not mount their own QueryClientProvider because
// core already provides it.
func checkPluginPages(dirs []string) []frontendViolation {
	var violations []frontendViolation

	for _, dir := range dirs {
		if err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
			if err != nil || info.IsDir() {
				return nil
			}

			ext := filepath.Ext(path)
			if ext != ".ts" && ext != ".tsx" {
				return nil
			}

			if strings.Contains(path, "node_modules") || strings.Contains(path, "/dist/") {
				return nil
			}

			relPath, _ := filepath.Rel(dir, path)
			if relPath == "" {
				relPath = path
			}
			pluginRESTAllowed := pluginRESTFileAllowed(path)

			lines, openErr := readSourceLines(path)
			if openErr != nil {
				return nil
			}
			for idx, line := range lines {
				lineNum := idx + 1
				trimmed := strings.TrimSpace(line)

				if isCommentLine(trimmed) {
					continue
				}

				if reFetchAPI.MatchString(line) && !pluginRESTAllowed {
					violations = append(violations, frontendViolation{
						file: relPath, line: lineNum, rule: "no-fetch-in-plugin",
						snippet: strings.TrimSpace(line),
					})
				}

				if reQueryClientProvider.MatchString(line) {
					violations = append(violations, frontendViolation{
						file: relPath, line: lineNum, rule: "no-queryclientprovider-in-plugin",
						snippet: "remove QueryClientProvider; BlockNinja core provides it.",
					})
				}

				if reCreateClient.MatchString(line) {
					violations = append(violations, frontendViolation{
						file: relPath, line: lineNum, rule: "no-createClient-in-plugin",
						snippet: strings.TrimSpace(line),
					})
				}

				if isBrowserConfirmCall(lines, idx) {
					violations = append(violations, frontendViolation{
						file: relPath, line: lineNum, rule: "no-browser-confirm-in-plugin",
						snippet: strings.TrimSpace(line),
					})
				}
			}

			return nil
		}); err != nil {
			violations = append(violations, frontendViolation{
				file:    filepath.ToSlash(dir),
				line:    0,
				rule:    "walk-error",
				snippet: err.Error(),
			})
		}
	}

	return violations
}

func pluginRESTFileAllowed(path string) bool {
	slashPath := filepath.ToSlash(path)
	for allowed := range allowedPluginRESTFiles {
		if strings.HasSuffix(slashPath, allowed) {
			return true
		}
	}
	return false
}

func readSourceLines(path string) ([]string, error) {
	content, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	return strings.Split(string(content), "\n"), nil
}

func isCommentLine(trimmed string) bool {
	return strings.HasPrefix(trimmed, "//") || strings.HasPrefix(trimmed, "*") || strings.HasPrefix(trimmed, "/*")
}

func isBrowserConfirmCall(lines []string, idx int) bool {
	line := lines[idx]
	if reWindowConfirm.MatchString(line) {
		return true
	}

	if !reBareConfirm.MatchString(line) {
		return false
	}

	start := max(idx-1, 0)
	end := min(idx+8, len(lines)-1)
	window := strings.Join(lines[start:end+1], " ")
	window = strings.Join(strings.Fields(window), " ")

	if strings.Contains(window, "await confirm(") {
		return false
	}
	if strings.Contains(window, "confirm(") && strings.Contains(window, ").then(") {
		return false
	}

	return true
}