package typst

import (
	"os"
	"strconv"
	"time"
)

type OutputFormat string

const (
	OutputFormatAuto OutputFormat = ""

	OutputFormatPDF OutputFormat = "pdf"
	OutputFormatPNG OutputFormat = "png"
	OutputFormatSVG OutputFormat = "svg"
)

type CLIOptions struct {
	Root              string            // Configures the project root (for absolute paths).
	Input             map[string]string // String key-value pairs visible through `sys.inputs`.
	FontPaths         []string          // Adds additional directories that are recursively searched for fonts.
	IgnoreSystemFonts bool              // Ensures system fonts won't be searched, unless explicitly included via FontPaths.
	CreationTime      time.Time         // The document's creation date. For more information, see https://reproducible-builds.org/specs/source-date-epoch/.
	PackagePath       string            // Custom path to local packages, defaults to system-dependent location.
	PackageCachePath  string            // Custom path to package cache, defaults to system-dependent location.
	Jobs              int               // Number of parallel jobs spawned during compilation, defaults to number of CPUs. Setting it to 1 disables parallelism.

	// Which pages to export. When unspecified, all document pages are exported.
	//
	// Pages to export are separated by commas, and can be either simple page numbers (e.g. '2,5' to export only pages 2 and 5) or page ranges (e.g. '2,3-6,8-' to export page 2, pages 3 to 6 (inclusive), page 8 and any pages after it).
	//
	// Page numbers are one-indexed and correspond to real page numbers in the document (therefore not being affected by the document's page counter).
	Pages string

	Format OutputFormat // The format of the output file, inferred from the extension by default.
	PPI    int          // The PPI (pixels per inch) to use for PNG export. Defaults to 144.

	// One (or multiple comma-separated) PDF standards that Typst will enforce conformance with.
	//
	// Possible values:
	//
	//	- 1.7: PDF 1.7
	//	- a-2b: PDF/A-2b
	PDFStandard string

	Custom []string // Custom command line options go here.
}

// Args returns a list of CLI arguments that should be passed to the executable.
func (c *CLIOptions) Args() (result []string) {
	if c.Root != "" {
		result = append(result, "--root", c.Root)
	}

	for key, value := range c.Input {
		result = append(result, "--input", key+"="+value)
	}

	if len(c.FontPaths) > 0 {
		var paths string
		for i, path := range c.FontPaths {
			if i > 0 {
				paths += string(os.PathListSeparator)
			}
			paths += path
		}
	}

	if c.IgnoreSystemFonts {
		result = append(result, "--ignore-system-fonts")
	}

	if !c.CreationTime.IsZero() {
		result = append(result, "--creation-timestamp", strconv.FormatInt(c.CreationTime.Unix(), 10))
	}

	if c.PackagePath != "" {
		result = append(result, "--package-path", c.PackagePath)
	}

	if c.PackageCachePath != "" {
		result = append(result, "--package-cache-path", c.PackageCachePath)
	}

	if c.Jobs > 0 {
		result = append(result, "-j", strconv.FormatInt(int64(c.Jobs), 10))
	}

	if c.Pages != "" {
		result = append(result, "--pages", c.Pages)
	}

	if c.Format != OutputFormatAuto {
		result = append(result, "-f", string(c.Format))
	}

	if c.PPI > 0 {
		result = append(result, "--ppi", strconv.FormatInt(int64(c.PPI), 10))
	}

	if c.PDFStandard != "" {
		result = append(result, "--pdf-standard", c.PDFStandard)
	}

	return
}