package languages

import (
	"regexp"
	"strings"

	"github.com/zzet/gortex/internal/graph"
	"github.com/zzet/gortex/internal/parser"
)

// Mojo is Python-flavored with Rust-like `fn` and `struct`. Bodies
// are indent-delimited. We capture `fn`/`def` functions, `struct`
// and `trait` types, plus `from ... import ...` and `import ...`.
var (
	mojoFuncRe   = regexp.MustCompile(`(?m)^\s*(?:async\s+)?(?:fn|def)\s+(\w+)\s*\(`)
	mojoTypeRe   = regexp.MustCompile(`(?m)^\s*(?:struct|trait)\s+(\w+)`)
	mojoFromRe   = regexp.MustCompile(`(?m)^\s*from\s+([\w.]+)\s+import\s+`)
	mojoImportRe = regexp.MustCompile(`(?m)^\s*import\s+([\w.]+)`)
	mojoCallRe   = regexp.MustCompile(`\b([a-zA-Z_]\w*)\s*\(`)
)

// MojoExtractor extracts Mojo source using regex.
type MojoExtractor struct{}

func NewMojoExtractor() *MojoExtractor { return &MojoExtractor{} }

func (e *MojoExtractor) Language() string     { return "mojo" }
func (e *MojoExtractor) Extensions() []string { return []string{".mojo", ".🔥"} }

func (e *MojoExtractor) Extract(filePath string, src []byte) (*parser.ExtractionResult, error) {
	lines := strings.Split(string(src), "\n")
	result := &parser.ExtractionResult{}

	fileNode := &graph.Node{
		ID: filePath, Kind: graph.KindFile, Name: filePath,
		FilePath: filePath, StartLine: 1, EndLine: len(lines),
		Language: "mojo",
	}
	result.Nodes = append(result.Nodes, fileNode)

	seen := make(map[string]bool)
	add := func(name string, kind graph.NodeKind, start, end int) {
		if name == "" || isMojoKeyword(name) {
			return
		}
		id := filePath + "::" + name
		if seen[id] {
			return
		}
		seen[id] = true
		result.Nodes = append(result.Nodes, &graph.Node{
			ID: id, Kind: kind, Name: name,
			FilePath: filePath, StartLine: start, EndLine: end,
			Language: "mojo",
		})
		result.Edges = append(result.Edges, &graph.Edge{
			From: fileNode.ID, To: id, Kind: graph.EdgeDefines,
			FilePath: filePath, Line: start,
		})
	}

	for _, m := range mojoFuncRe.FindAllSubmatchIndex(src, -1) {
		name := string(src[m[2]:m[3]])
		line := lineAt(src, m[0])
		add(name, graph.KindFunction, line, findIndentedBlockEnd(lines, line))
	}
	for _, m := range mojoTypeRe.FindAllSubmatchIndex(src, -1) {
		name := string(src[m[2]:m[3]])
		line := lineAt(src, m[0])
		add(name, graph.KindType, line, findIndentedBlockEnd(lines, line))
	}

	for _, m := range mojoFromRe.FindAllSubmatchIndex(src, -1) {
		mod := string(src[m[2]:m[3]])
		line := lineAt(src, m[0])
		result.Edges = append(result.Edges, &graph.Edge{
			From: fileNode.ID, To: "unresolved::import::" + mod,
			Kind: graph.EdgeImports, FilePath: filePath, Line: line,
		})
	}
	for _, m := range mojoImportRe.FindAllSubmatchIndex(src, -1) {
		mod := string(src[m[2]:m[3]])
		line := lineAt(src, m[0])
		result.Edges = append(result.Edges, &graph.Edge{
			From: fileNode.ID, To: "unresolved::import::" + mod,
			Kind: graph.EdgeImports, FilePath: filePath, Line: line,
		})
	}

	funcRanges := buildFuncRanges(result)
	for _, m := range mojoCallRe.FindAllSubmatchIndex(src, -1) {
		name := string(src[m[2]:m[3]])
		if isMojoKeyword(name) {
			continue
		}
		line := lineAt(src, m[0])
		callerID := findEnclosingFunc(funcRanges, line)
		if callerID == "" || strings.HasSuffix(callerID, "::"+name) {
			continue
		}
		result.Edges = append(result.Edges, &graph.Edge{
			From: callerID, To: "unresolved::" + name,
			Kind: graph.EdgeCalls, FilePath: filePath, Line: line,
		})
	}

	return result, nil
}

func isMojoKeyword(s string) bool {
	switch s {
	case "if", "elif", "else", "while", "for", "in", "not", "and", "or",
		"fn", "def", "struct", "trait", "alias", "var", "let",
		"return", "yield", "raise", "try", "except", "finally",
		"import", "from", "as", "with", "pass", "break", "continue",
		"True", "False", "None", "self", "async", "await", "owned",
		"borrowed", "inout", "mut", "ref":
		return true
	}
	return false
}

var _ parser.Extractor = (*MojoExtractor)(nil)