package main

import (
	"go/ast"
	"go/parser"
	"go/token"
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

type anyUsageWarning struct {
	file    string
	line    int
	lang    string
	snippet string
}

// lineKeeper decides whether an `any` at absPath:line should be reported. A nil
// keeper keeps everything (the --all-any full scan); the diff-scoped default
// keeps only lines present in the unstaged working-tree diff.
type lineKeeper func(absPath string, line int) bool

func (k lineKeeper) keep(absPath string, line int) bool {
	return k == nil || k(absPath, line)
}

var (
	reTypeScriptAny      = regexp.MustCompile(`\bany\b`)
	reTypeScriptAsAny    = regexp.MustCompile(`\bas\s+any\b`)
	reTypeScriptColonAny = regexp.MustCompile(`:\s*any(?:\b|[\s,\]\)>|=])`)
	reTypeScriptCastAny  = regexp.MustCompile(`<\s*any\s*>`)
	reTypeScriptArrayAny = regexp.MustCompile(`\bany\s*\[\]`)
	reTypeScriptEqAny    = regexp.MustCompile(`=\s*any(?:\b|[\s;])`)
)

func checkGoAnyUsage(root string, keep lineKeeper) []anyUsageWarning {
	var warnings []anyUsageWarning

	_ = filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() || !strings.HasSuffix(path, ".go") {
			return nil
		}
		if strings.Contains(path, "/vendor/") || strings.HasSuffix(path, "_test.go") {
			return nil
		}
		if strings.HasSuffix(path, ".pb.go") || strings.HasSuffix(path, ".connect.go") || strings.HasSuffix(path, ".gen.go") || strings.HasSuffix(path, "_templ.go") {
			return nil
		}

		lines, readErr := readSourceLines(path)
		if readErr != nil {
			return nil
		}

		fset := token.NewFileSet()
		file, parseErr := parser.ParseFile(fset, path, nil, 0)
		if parseErr != nil {
			return nil
		}

		relPath, _ := filepath.Rel(root, path)
		relPath = filepath.ToSlash(relPath)
		seen := make(map[int]bool)
		recordAnyExpr := func(expr ast.Expr) {
			for _, pos := range findAnyTypePositions(expr) {
				position := fset.Position(pos)
				if seen[position.Line] {
					continue
				}
				seen[position.Line] = true
				if !keep.keep(path, position.Line) {
					continue
				}
				snippet := ""
				if position.Line-1 >= 0 && position.Line-1 < len(lines) {
					snippet = strings.TrimSpace(lines[position.Line-1])
				}
				warnings = append(warnings, anyUsageWarning{
					file:    relPath,
					line:    position.Line,
					lang:    "go",
					snippet: snippet,
				})
			}
		}

		ast.Inspect(file, func(n ast.Node) bool {
			switch node := n.(type) {
			case *ast.Field:
				recordAnyExpr(node.Type)
			case *ast.TypeSpec:
				recordAnyExpr(node.Type)
			case *ast.ValueSpec:
				recordAnyExpr(node.Type)
			case *ast.FuncDecl:
				if node.Type != nil {
					recordAnyExpr(node.Type)
				}
			case *ast.FuncLit:
				if node.Type != nil {
					recordAnyExpr(node.Type)
				}
			case *ast.TypeAssertExpr:
				recordAnyExpr(node.Type)
			case *ast.CompositeLit:
				recordAnyExpr(node.Type)
			}
			return true
		})

		return nil
	})

	return warnings
}

func findAnyTypePositions(expr ast.Expr) []token.Pos {
	if expr == nil {
		return nil
	}

	var positions []token.Pos
	switch node := expr.(type) {
	case *ast.Ident:
		if node.Name == "any" {
			positions = append(positions, node.Pos())
		}
	case *ast.ArrayType:
		positions = append(positions, findAnyTypePositions(node.Elt)...)
	case *ast.MapType:
		positions = append(positions, findAnyTypePositions(node.Key)...)
		positions = append(positions, findAnyTypePositions(node.Value)...)
	case *ast.ChanType:
		positions = append(positions, findAnyTypePositions(node.Value)...)
	case *ast.Ellipsis:
		positions = append(positions, findAnyTypePositions(node.Elt)...)
	case *ast.ParenExpr:
		positions = append(positions, findAnyTypePositions(node.X)...)
	case *ast.StarExpr:
		positions = append(positions, findAnyTypePositions(node.X)...)
	case *ast.IndexExpr:
		positions = append(positions, findAnyTypePositions(node.X)...)
		positions = append(positions, findAnyTypePositions(node.Index)...)
	case *ast.IndexListExpr:
		positions = append(positions, findAnyTypePositions(node.X)...)
		for _, index := range node.Indices {
			positions = append(positions, findAnyTypePositions(index)...)
		}
	case *ast.SelectorExpr:
		positions = append(positions, findAnyTypePositions(node.X)...)
	case *ast.StructType:
		if node.Fields != nil {
			for _, field := range node.Fields.List {
				positions = append(positions, findAnyTypePositions(field.Type)...)
			}
		}
	case *ast.InterfaceType:
		if node.Methods != nil {
			for _, field := range node.Methods.List {
				positions = append(positions, findAnyTypePositions(field.Type)...)
			}
		}
	case *ast.FuncType:
		if node.Params != nil {
			for _, field := range node.Params.List {
				positions = append(positions, findAnyTypePositions(field.Type)...)
			}
		}
		if node.Results != nil {
			for _, field := range node.Results.List {
				positions = append(positions, findAnyTypePositions(field.Type)...)
			}
		}
	}

	return positions
}

func checkTypeScriptAnyUsage(root string, keep lineKeeper) []anyUsageWarning {
	var warnings []anyUsageWarning

	_ = filepath.Walk(root, 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/") || strings.Contains(path, "/generated/") {
			return nil
		}
		if strings.HasSuffix(path, ".d.ts") || strings.HasSuffix(path, ".gen.ts") || strings.HasSuffix(path, ".gen.tsx") {
			return nil
		}

		lines, readErr := readSourceLines(path)
		if readErr != nil {
			return nil
		}

		relPath, _ := filepath.Rel(root, path)
		relPath = filepath.ToSlash(relPath)
		for idx, line := range lines {
			trimmed := strings.TrimSpace(line)
			if trimmed == "" || strings.HasPrefix(trimmed, "//") || strings.HasPrefix(trimmed, "/*") || strings.HasPrefix(trimmed, "*") {
				continue
			}
			if strings.Contains(line, "'any'") || strings.Contains(line, `"any"`) || strings.Contains(line, "`any") || strings.Contains(line, "any`") {
				continue
			}
			if !reTypeScriptAny.MatchString(line) {
				continue
			}
			if !reTypeScriptAsAny.MatchString(line) && !reTypeScriptColonAny.MatchString(line) && !reTypeScriptCastAny.MatchString(line) && !reTypeScriptArrayAny.MatchString(line) && !reTypeScriptEqAny.MatchString(line) {
				continue
			}

			warnings = append(warnings, anyUsageWarning{
				file:    relPath,
				line:    idx + 1,
				lang:    "ts",
				snippet: trimmed,
			})
		}

		return nil
	})

	return warnings
}