package python

import (
	"context"
	"regexp"
	"strings"

	contractevents "bit.admedia.com/scm/ad/adpilot-indexing-code-parser.com/internal/contracts/events"
	"bit.admedia.com/scm/ad/adpilot-indexing-code-parser.com/internal/contracts/graph"
	"bit.admedia.com/scm/ad/adpilot-indexing-code-parser.com/internal/service/parser/analyzers/common"
	"bit.admedia.com/scm/ad/adpilot-indexing-code-parser.com/internal/service/parser/analyzers/detectors"
)

type Analyzer struct {
	detectors *detectors.Registry
}

func NewAnalyzer(det *detectors.Registry) *Analyzer {
	if det == nil {
		det = detectors.DefaultRegistry()
	}
	return &Analyzer{detectors: det}
}

func (a *Analyzer) SupportedLanguages() []string {
	return []string{"python"}
}

func (a *Analyzer) ParseFile(ctx context.Context, source []byte, filePath, language string) (*graph.Artifact, []contractevents.CodeChunk, error) {
	_ = ctx
	b := common.NewBuilder(filePath, "python")
	lines := common.Lines(source)

	importPattern := regexp.MustCompile(`^(?:from\s+([\w.]+)\s+import|import\s+([\w.]+))`)
	classPattern := regexp.MustCompile(`^class\s+([A-Za-z_][A-Za-z0-9_]*)`)
	funcPattern := regexp.MustCompile(`^(?:async\s+)?def\s+([A-Za-z_][A-Za-z0-9_]*)`)

	for i, line := range lines {
		trimmed := strings.TrimSpace(line)
		if m := importPattern.FindStringSubmatch(trimmed); len(m) > 0 {
			imp := m[1]
			if imp == "" {
				imp = m[2]
			}
			if imp != "" {
				b.AddImport(imp, i+1)
			}
		}
		if m := classPattern.FindStringSubmatch(trimmed); len(m) > 1 {
			end := findPythonBlockEnd(lines, i)
			b.AddSymbol(m[1], contractevents.SymbolTypeType, i+1, end, map[string]string{"type_kind": "class"})
		}
		if m := funcPattern.FindStringSubmatch(trimmed); len(m) > 1 {
			end := findPythonBlockEnd(lines, i)
			symbolType := contractevents.SymbolTypeFunction
			if strings.HasPrefix(trimmed, " ") || strings.HasPrefix(trimmed, "\t") {
				symbolType = contractevents.SymbolTypeMethod
			}
			b.AddSymbol(m[1], symbolType, i+1, end, nil)
		}
	}

	a.detectors.ApplyAll(detectors.Context{
		Source:   source,
		FilePath: filePath,
		Language: "python",
		Builder:  b,
	})

	b.EnsureLineWindowChunks(source)

	return b.Artifact(), b.Chunks(), nil
}

func findPythonBlockEnd(lines []string, start int) int {
	indent := leadingIndent(lines[start])
	for i := start + 1; i < len(lines); i++ {
		line := lines[i]
		if strings.TrimSpace(line) == "" {
			continue
		}
		if leadingIndent(line) <= indent {
			return i
		}
	}
	return len(lines)
}

func leadingIndent(line string) int {
	n := 0
	for _, ch := range line {
		if ch == ' ' {
			n++
		} else if ch == '\t' {
			n += 4
		} else {
			break
		}
	}
	return n
}