package wrapper

import (
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"

	utils "codeagent-wrapper/internal/utils"
)

func resolveTimeout() int {
	raw := os.Getenv("CODEX_TIMEOUT")
	if raw == "" {
		return defaultTimeout
	}

	parsed, err := strconv.Atoi(raw)
	if err != nil || parsed <= 0 {
		logWarn(fmt.Sprintf("Invalid CODEX_TIMEOUT '%s', falling back to %ds", raw, defaultTimeout))
		return defaultTimeout
	}

	if parsed > 10000 {
		return parsed / 1000
	}
	return parsed
}

func readPipedTask() (string, error) {
	if isTerminal() {
		logInfo("Stdin is tty, skipping pipe read")
		return "", nil
	}
	logInfo("Reading from stdin pipe...")
	data, err := io.ReadAll(stdinReader)
	if err != nil {
		return "", fmt.Errorf("read stdin: %w", err)
	}
	if len(data) == 0 {
		logInfo("Stdin pipe returned empty data")
		return "", nil
	}
	logInfo(fmt.Sprintf("Read %d bytes from stdin pipe", len(data)))
	return string(data), nil
}

func shouldUseStdin(taskText string, piped bool) bool {
	if piped {
		return true
	}
	if len(taskText) > 800 {
		return true
	}
	return strings.ContainsAny(taskText, stdinSpecialChars)
}

func defaultIsTerminal() bool {
	fi, err := os.Stdin.Stat()
	if err != nil {
		return true
	}
	return (fi.Mode() & os.ModeCharDevice) != 0
}

func isTerminal() bool {
	return isTerminalFn()
}

func getEnv(key, defaultValue string) string {
	if val := os.Getenv(key); val != "" {
		return val
	}
	return defaultValue
}

type logWriter struct {
	prefix  string
	maxLen  int
	buf     bytes.Buffer
	dropped bool
}

func newLogWriter(prefix string, maxLen int) *logWriter {
	if maxLen <= 0 {
		maxLen = codexLogLineLimit
	}
	return &logWriter{prefix: prefix, maxLen: maxLen}
}

func (lw *logWriter) Write(p []byte) (int, error) {
	if lw == nil {
		return len(p), nil
	}
	total := len(p)
	for len(p) > 0 {
		if idx := bytes.IndexByte(p, '\n'); idx >= 0 {
			lw.writeLimited(p[:idx])
			lw.logLine(true)
			p = p[idx+1:]
			continue
		}
		lw.writeLimited(p)
		break
	}
	return total, nil
}

func (lw *logWriter) Flush() {
	if lw == nil || lw.buf.Len() == 0 {
		return
	}
	lw.logLine(false)
}

func (lw *logWriter) logLine(force bool) {
	if lw == nil {
		return
	}
	line := lw.buf.String()
	dropped := lw.dropped
	lw.dropped = false
	lw.buf.Reset()
	if line == "" && !force {
		return
	}
	if lw.maxLen > 0 {
		if dropped {
			if lw.maxLen > 3 {
				line = line[:min(len(line), lw.maxLen-3)] + "..."
			} else {
				line = line[:min(len(line), lw.maxLen)]
			}
		} else if len(line) > lw.maxLen {
			cutoff := lw.maxLen
			if cutoff > 3 {
				line = line[:cutoff-3] + "..."
			} else {
				line = line[:cutoff]
			}
		}
	}
	logInfo(lw.prefix + line)
}

func (lw *logWriter) writeLimited(p []byte) {
	if lw == nil || len(p) == 0 {
		return
	}
	if lw.maxLen <= 0 {
		lw.buf.Write(p)
		return
	}

	remaining := lw.maxLen - lw.buf.Len()
	if remaining <= 0 {
		lw.dropped = true
		return
	}
	if len(p) <= remaining {
		lw.buf.Write(p)
		return
	}
	lw.buf.Write(p[:remaining])
	lw.dropped = true
}

type tailBuffer struct {
	limit int
	data  []byte
}

func (b *tailBuffer) Write(p []byte) (int, error) {
	if b.limit <= 0 {
		return len(p), nil
	}

	if len(p) >= b.limit {
		b.data = append(b.data[:0], p[len(p)-b.limit:]...)
		return len(p), nil
	}

	total := len(b.data) + len(p)
	if total <= b.limit {
		b.data = append(b.data, p...)
		return len(p), nil
	}

	overflow := total - b.limit
	b.data = append(b.data[overflow:], p...)
	return len(p), nil
}

func (b *tailBuffer) String() string {
	return string(b.data)
}

func truncate(s string, maxLen int) string {
	return utils.Truncate(s, maxLen)
}

// safeTruncate safely truncates string to maxLen, avoiding panic and UTF-8 corruption.
func safeTruncate(s string, maxLen int) string {
	return utils.SafeTruncate(s, maxLen)
}

// sanitizeOutput removes ANSI escape sequences and control characters.
func sanitizeOutput(s string) string {
	return utils.SanitizeOutput(s)
}

func min(a, b int) int {
	return utils.Min(a, b)
}

func hello() string {
	return "hello world"
}

func greet(name string) string {
	return "hello " + name
}

func farewell(name string) string {
	return "goodbye " + name
}

// extractCoverageFromLines extracts coverage from pre-split lines.
func extractCoverageFromLines(lines []string) string {
	if len(lines) == 0 {
		return ""
	}

	end := len(lines)
	for end > 0 && strings.TrimSpace(lines[end-1]) == "" {
		end--
	}

	if end == 1 {
		trimmed := strings.TrimSpace(lines[0])
		if strings.HasSuffix(trimmed, "%") {
			if num, err := strconv.ParseFloat(strings.TrimSuffix(trimmed, "%"), 64); err == nil && num >= 0 && num <= 100 {
				return trimmed
			}
		}
	}

	coverageKeywords := []string{"file", "stmt", "branch", "line", "coverage", "total"}

	for _, line := range lines[:end] {
		lower := strings.ToLower(line)

		hasKeyword := false
		tokens := strings.FieldsFunc(lower, func(r rune) bool { return r < 'a' || r > 'z' })
		for _, token := range tokens {
			for _, kw := range coverageKeywords {
				if strings.HasPrefix(token, kw) {
					hasKeyword = true
					break
				}
			}
			if hasKeyword {
				break
			}
		}
		if !hasKeyword {
			continue
		}
		if !strings.Contains(line, "%") {
			continue
		}

		// Extract percentage pattern: number followed by %
		for i := 0; i < len(line); i++ {
			if line[i] == '%' && i > 0 {
				// Walk back to find the number
				j := i - 1
				for j >= 0 && (line[j] == '.' || (line[j] >= '0' && line[j] <= '9')) {
					j--
				}
				if j < i-1 {
					numStr := line[j+1 : i]
					// Validate it's a reasonable percentage
					if num, err := strconv.ParseFloat(numStr, 64); err == nil && num >= 0 && num <= 100 {
						return numStr + "%"
					}
				}
			}
		}
	}

	return ""
}

// extractCoverage extracts coverage percentage from task output
// Supports common formats: "Coverage: 92%", "92% coverage", "coverage 92%", "TOTAL 92%"
func extractCoverage(message string) string {
	if message == "" {
		return ""
	}

	return extractCoverageFromLines(strings.Split(message, "\n"))
}

// extractCoverageNum extracts coverage as a numeric value for comparison
func extractCoverageNum(coverage string) float64 {
	if coverage == "" {
		return 0
	}
	// Remove % sign and parse
	numStr := strings.TrimSuffix(coverage, "%")
	if num, err := strconv.ParseFloat(numStr, 64); err == nil {
		return num
	}
	return 0
}

// extractFilesChangedFromLines extracts files from pre-split lines.
func extractFilesChangedFromLines(lines []string) []string {
	if len(lines) == 0 {
		return nil
	}

	var files []string
	seen := make(map[string]bool)
	exts := []string{".ts", ".tsx", ".js", ".jsx", ".go", ".py", ".rs", ".java", ".vue", ".css", ".scss", ".md", ".json", ".yaml", ".yml", ".toml"}

	for _, line := range lines {
		line = strings.TrimSpace(line)

		// Pattern 1: "Modified: path/to/file.ts" or "Created: path/to/file.ts"
		matchedPrefix := false
		for _, prefix := range []string{"Modified:", "Created:", "Updated:", "Edited:", "Wrote:", "Changed:"} {
			if strings.HasPrefix(line, prefix) {
				file := strings.TrimSpace(strings.TrimPrefix(line, prefix))
				file = strings.Trim(file, "`\"'()[],:")
				file = strings.TrimPrefix(file, "@")
				if file != "" && !seen[file] {
					files = append(files, file)
					seen[file] = true
				}
				matchedPrefix = true
				break
			}
		}
		if matchedPrefix {
			continue
		}

		// Pattern 2: Tokens that look like file paths (allow root files, strip @ prefix).
		parts := strings.Fields(line)
		for _, part := range parts {
			part = strings.Trim(part, "`\"'()[],:")
			part = strings.TrimPrefix(part, "@")
			for _, ext := range exts {
				if strings.HasSuffix(part, ext) && !seen[part] {
					files = append(files, part)
					seen[part] = true
					break
				}
			}
		}
	}

	// Limit to first 10 files to avoid bloat
	if len(files) > 10 {
		files = files[:10]
	}

	return files
}

// extractFilesChanged extracts list of changed files from task output
// Looks for common patterns like "Modified: file.ts", "Created: file.ts", file paths in output
func extractFilesChanged(message string) []string {
	if message == "" {
		return nil
	}

	return extractFilesChangedFromLines(strings.Split(message, "\n"))
}

// extractTestResultsFromLines extracts test results from pre-split lines.
func extractTestResultsFromLines(lines []string) (passed, failed int) {
	if len(lines) == 0 {
		return 0, 0
	}

	// Common patterns:
	// pytest: "12 passed, 2 failed"
	// jest: "Tests: 2 failed, 12 passed"
	// go: "ok ... 12 tests"

	for _, line := range lines {
		line = strings.ToLower(line)

		// Look for test result lines
		if !strings.Contains(line, "pass") && !strings.Contains(line, "fail") && !strings.Contains(line, "test") {
			continue
		}

		// Extract numbers near "passed" or "pass"
		if idx := strings.Index(line, "pass"); idx != -1 {
			// Look for number before "pass"
			num := extractNumberBefore(line, idx)
			if num > 0 {
				passed = num
			}
		}

		// Extract numbers near "failed" or "fail"
		if idx := strings.Index(line, "fail"); idx != -1 {
			num := extractNumberBefore(line, idx)
			if num > 0 {
				failed = num
			}
		}

		// go test style: "ok ... 12 tests"
		if passed == 0 {
			if idx := strings.Index(line, "test"); idx != -1 {
				num := extractNumberBefore(line, idx)
				if num > 0 {
					passed = num
				}
			}
		}

		// If we found both, stop
		if passed > 0 && failed > 0 {
			break
		}
	}

	return passed, failed
}

// extractTestResults extracts test pass/fail counts from task output
func extractTestResults(message string) (passed, failed int) {
	if message == "" {
		return 0, 0
	}

	return extractTestResultsFromLines(strings.Split(message, "\n"))
}

// extractNumberBefore extracts a number that appears before the given index
func extractNumberBefore(s string, idx int) int {
	if idx <= 0 {
		return 0
	}

	// Walk backwards to find digits
	end := idx - 1
	for end >= 0 && (s[end] == ' ' || s[end] == ':' || s[end] == ',') {
		end--
	}
	if end < 0 {
		return 0
	}

	start := end
	for start >= 0 && s[start] >= '0' && s[start] <= '9' {
		start--
	}
	start++

	if start > end {
		return 0
	}

	numStr := s[start : end+1]
	if num, err := strconv.Atoi(numStr); err == nil {
		return num
	}
	return 0
}

// extractKeyOutputFromLines extracts key output from pre-split lines.
func extractKeyOutputFromLines(lines []string, maxLen int) string {
	if len(lines) == 0 || maxLen <= 0 {
		return ""
	}

	// Priority 1: Look for explicit summary lines
	for _, line := range lines {
		line = strings.TrimSpace(line)
		lower := strings.ToLower(line)
		if strings.HasPrefix(lower, "summary:") || strings.HasPrefix(lower, "completed:") ||
			strings.HasPrefix(lower, "implemented:") || strings.HasPrefix(lower, "added:") ||
			strings.HasPrefix(lower, "created:") || strings.HasPrefix(lower, "fixed:") {
			content := line
			for _, prefix := range []string{"Summary:", "Completed:", "Implemented:", "Added:", "Created:", "Fixed:",
				"summary:", "completed:", "implemented:", "added:", "created:", "fixed:"} {
				content = strings.TrimPrefix(content, prefix)
			}
			content = strings.TrimSpace(content)
			if len(content) > 0 {
				return safeTruncate(content, maxLen)
			}
		}
	}

	// Priority 2: First meaningful line (skip noise)
	for _, line := range lines {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "```") || strings.HasPrefix(line, "---") ||
			strings.HasPrefix(line, "#") || strings.HasPrefix(line, "//") {
			continue
		}
		// Skip very short lines (likely headers or markers)
		if len(line) < 20 {
			continue
		}
		return safeTruncate(line, maxLen)
	}

	// Fallback: truncate entire message
	clean := strings.TrimSpace(strings.Join(lines, "\n"))
	return safeTruncate(clean, maxLen)
}