package template

import (
	"encoding/json"
	"fmt"
	"strings"

	"gopkg.in/yaml.v3"
)

// ToJSON converts a value to JSON string
// Usage: {{ .Database | toJSON }}
func ToJSON(v interface{}) string {
	data, err := json.Marshal(v)
	if err != nil {
		return fmt.Sprintf("{\"error\": \"failed to marshal: %v\"}", err)
	}
	return string(data)
}

// ToJSONPretty converts a value to pretty-printed JSON string
// Usage: {{ .Database | toJSONPretty "  " }}
func ToJSONPretty(v interface{}, indent string) string {
	data, err := json.MarshalIndent(v, "", indent)
	if err != nil {
		return fmt.Sprintf("{\"error\": \"failed to marshal: %v\"}", err)
	}
	return string(data)
}

// ToYAML converts a value to YAML string
// Usage: {{ .Database | toYAML }}
func ToYAML(v interface{}) string {
	data, err := yaml.Marshal(v)
	if err != nil {
		return fmt.Sprintf("error: failed to marshal: %v", err)
	}
	return string(data)
}

// Indent indents each line of a string by the specified number of spaces
// Usage: {{ .Column.Description | indent 4 }}
func Indent(s string, spaces int) string {
	if s == "" {
		return ""
	}

	prefix := strings.Repeat(" ", spaces)
	lines := strings.Split(s, "\n")
	for i, line := range lines {
		if line != "" {
			lines[i] = prefix + line
		}
	}
	return strings.Join(lines, "\n")
}

// IndentWith indents each line of a string with a custom prefix
// Usage: {{ .Column.Description | indentWith "    " }}
func IndentWith(s string, prefix string) string {
	if s == "" {
		return ""
	}

	lines := strings.Split(s, "\n")
	for i, line := range lines {
		if line != "" {
			lines[i] = prefix + line
		}
	}
	return strings.Join(lines, "\n")
}

// Escape escapes special characters in a string for use in code
// Usage: {{ .Column.Default | escape }}
func Escape(s string) string {
	s = strings.ReplaceAll(s, "\\", "\\\\")
	s = strings.ReplaceAll(s, "\"", "\\\"")
	s = strings.ReplaceAll(s, "\n", "\\n")
	s = strings.ReplaceAll(s, "\r", "\\r")
	s = strings.ReplaceAll(s, "\t", "\\t")
	return s
}

// EscapeQuotes escapes only quote characters
// Usage: {{ .Column.Comment | escapeQuotes }}
func EscapeQuotes(s string) string {
	s = strings.ReplaceAll(s, "\"", "\\\"")
	s = strings.ReplaceAll(s, "'", "\\'")
	return s
}

// Comment adds comment prefix to a string
// Supports: "//" (Go, C++, etc.), "#" (Python, shell), "--" (SQL), "/* */" (block)
// Usage: {{ .Table.Description | comment "//" }}
func Comment(s string, style string) string {
	if s == "" {
		return ""
	}

	lines := strings.Split(s, "\n")

	switch style {
	case "//":
		for i, line := range lines {
			lines[i] = "// " + line
		}
		return strings.Join(lines, "\n")

	case "#":
		for i, line := range lines {
			lines[i] = "# " + line
		}
		return strings.Join(lines, "\n")

	case "--":
		for i, line := range lines {
			lines[i] = "-- " + line
		}
		return strings.Join(lines, "\n")

	case "/* */", "/**/":
		if len(lines) == 1 {
			return "/* " + lines[0] + " */"
		}
		result := "/*\n"
		for _, line := range lines {
			result += " * " + line + "\n"
		}
		result += " */"
		return result

	default:
		// Default to // style
		for i, line := range lines {
			lines[i] = "// " + line
		}
		return strings.Join(lines, "\n")
	}
}

// QuoteString adds quotes around a string
// Usage: {{ .Column.Default | quoteString }}
func QuoteString(s string) string {
	return "\"" + s + "\""
}

// UnquoteString removes quotes from a string
// Usage: {{ .Value | unquoteString }}
func UnquoteString(s string) string {
	if len(s) >= 2 {
		if (s[0] == '"' && s[len(s)-1] == '"') || (s[0] == '\'' && s[len(s)-1] == '\'') {
			return s[1 : len(s)-1]
		}
	}
	return s
}